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Abstract

Although Autism Spectrum Disorders (ASD) are generally assumed to be lifelong, we review evidence that between 3% and 25% of children reportedly lose their ASD diagnosis and enter the normal range of cognitive, adaptive and social skills. Predictors of recovery include relatively high intelligence, receptive language, verbal and motor imitation, and motor development, but not overall symptom severity. Earlier age of diagnosis and treatment, and a diagnosis of Pervasive Developmental Disorder-Not Otherwise Specified are also favorable signs. The presence of seizures, mental retardation and genetic syndromes are unfavorable signs, whereas head growth does not predict outcome. Controlled studies that report the most recovery came about after the use of behavioral techniques. Residual vulnerabilities affect higher-order communication and attention. Tics, depression and phobias are frequent residual co-morbidities after recovery. Possible mechanisms of recovery include: normalizing input by forcing attention outward or enriching the environment; promoting the reinforcement value of social stimuli; preventing interfering behaviors; mass practice of weak skills; reducing stress and stabilizing arousal. Improving nutrition and sleep quality is non-specifically beneficial.
Can Children with Autism Recover? If So, How?
Molly Helt &Elizabeth Kelley &Marcel Kinsbourne &
Juhi Pandey &Hilary Boorstein &Martha Herbert &
Deborah Fein
Received: 2 September 2008 / Accepted: 11 September 2008 / Published online: 14 November 2008
#Springer Science + Business Media, LLC 2008
Abstract Although Autism Spectrum Disorders (ASD) are
generally assumed to be lifelong, we review evidence that
between 3% and 25% of children reportedly lose their ASD
diagnosis and enter the normal range of cognitive, adaptive
and social skills. Predictors of recovery include relatively
high intelligence, receptive language, verbal and motor
imitation, and motor development, but not overall symptom
severity. Earlier age of diagnosis and treatment, and a
diagnosis of Pervasive Developmental Disorder-Not Other-
wise Specified are also favorable signs. The presence of
seizures, mental retardation and genetic syndromes are
unfavorable signs, whereas head growth does not predict
outcome. Controlled studies that report the most recovery
came about after the use of behavioral techniques. Residual
vulnerabilities affect higher-order communication and at-
tention. Tics, depression and phobias are frequent residual
co-morbidities after recovery. Possible mechanisms of
recovery include: normalizing input by forcing attention
outward or enriching the environment; promoting the
reinforcement value of social stimuli; preventing interfering
behaviors; mass practice of weak skills; reducing stress and
stabilizing arousal. Improving nutrition and sleep quality is
non-specifically beneficial.
Keywords Autism spectrum disorders .
Language development .Recovery .
Stereotyped motor behavior
Introduction
Autism Spectrum Disorders (ASD) are a group of related
developmental disorders that are characterized by impair-
ments in reciprocal social interaction, language develop-
ment and intentional communication, and restricted
interests and stereotyped motor behaviors (American
Psychological Association 1994). Once considered to be a
rare disorder, ASD is now estimated to occur in as many as
one in 150 births or even more (Centers for Disease Control
and Prevention 2007). ASDs are almost universally regarded
as life-long conditions, although the severity of cognitive,
language, social and adaptive skill impairments varies widely
among children and across time within children. However, in
recent years, it has been claimed that a significant minority of
children with well-documented ASD have recovered. In this
paper, we will (1) define recovery, (2) present evidence
that supports the phenomenon of recoveryin ASD, (3)
briefly review the evidence concerning child and treatment
characteristics that can lead to recovery, and (4) suggest
mechanisms that might underlie recoveryfrom this
neurological developmental disorder.
Neuropsychol Rev (2008) 18:339366
DOI 10.1007/s11065-008-9075-9
M. Helt (*):H. Boorstein :D. Fein
Department of Psychology, University of Connecticut,
Storrs, CT 06268, USA
e-mail: molly.helt@uconn.edu
E. Kelley
Department of Psychology, Queens University,
Kingston, Ontario, Canada
M. Kinsbourne
Department of Psychology, New School,
New York, NY, USA
J. Pandey
Center for Autism Research, Childrens Hospital of Philadelphia,
Philadelphia, PA, USA
M. Herbert
Department of Neurology and TRANSCEND Research Program,
Massachusetts General Hospital,
Charlestown, MA, USA
Defining Recovery
Improvement in all aspects of ASD, including language,
adaptive skills, academics, social interaction, and decreased
repetitive behavior, among others, has been well docu-
mented in the treatment literature, and especially in the
studies that describe behavioral treatments (Filipek et al.
2000; Harris and Handleman 2000; Howard et al. 2005;
Lord and McGee 2001; Myers and Johnson 2007; Sallows
and Graupner 2005). However, except in a few behavioral
studies (reviewed below), improved behavior and skills do
not reach levels within the normal range. We present a
general, and then a more specific, definition of what is
meant here by recovery. What do the children recover
from and what do they recover to?
In order to be defined as recovered, a child must first
have a convincing history of ASD. Some of his/her
development will have been delayed in onset, slow to
progress, and/or abnormal in quality. To be considered
recovered, the child must now be learning and applying a
core set of skills at a level and with a quality that reaches
the trajectory of typical development in most or all areas. A
corollary of this is that there will probably have been a
period in the childs development in which his/her progress
was more rapid than normal; in fact, accelerated learning
has been reported by Sallows and Graupner (2005) and
Howard et al. (2005). Furthermore, the recovered individual
no longer meets criteria for any ASD.
The term recoveryor best outcomewas probably
first used by the UCLA group, headed by Lovaas, in
describing the outcomes of their program of intensive
Applied Behavior Analysis (ABA) therapy (Lovaas 1987).
They used the term to describe children whose IQ had risen
into the average range and who were functioning in regular
education classrooms. However, Mundy (1993) pointed out
that it is not easy to demonstrate recovery to full normal
functioning, and that children with high functioning autism
who still show clear autistic symptoms might also have
average (or higher) IQs and be able to function in a regular
classroom. We agree that more needs to be demonstrated to
warrant the term recovered.
In our current study of 818 year old children with a
history of ASD who are now recoveredor have reached
optimal outcomes, we use the following specific defini-
tion (the definition might need to be modified for different
age groups):
By history: (1) The child was diagnosed with an ASD
in early childhood (i.e., by age 5) by a specialist (i.e.
someone whose practice is at least 50% devoted to
autism). (2) There was early language delay (either no
words by 18 months or no word combinations by
24 months). (3) Review by one of our team, blind to
current group membership, of early reports (age 25)
and/or videotapes, with diagnostic formulations elided,
confirms early ASD.
By current functioning: (1) The participant does not
meet criteria for any Pervasive Developmental Disor-
der, including PDD-NOS (at least one symptom in
social domain plus one additional symptom), which
generally means that no social symptom of ASD is
present by best clinical judgment. (2) The participant
does not meet ASD cutoff on social or communication
domain of the Autism Diagnostic Observation Sched-
ule, (3) any special education services the participant
receives are to remediate difficulties with attention,
organization, or specific academic difficulties and not
to address features of autism, (4) the participant is
functioning without an individual assistant in a regular
education classroom, (5) VIQ, PIQ, and FSIQ are all at
78 or above (1.5 standard deviations below average),
(6) Vineland Communication and Socialization Scales
are all at 78 or above.
These are the working criteria for our current study,
although modifications may be made as we study the
individual children. Some children with clear early ASD
clinical pictures may show no convincing early language
delay; in addition, some recovered children with excellent
social skills with familiar adults and children have social
anxiety with strangers and show mildly elevated ADOS
scores as a consequence. It will also be seen that children
who no longer meet criteria for an ASD but are functioning
in the mentally-retarded range are not considered recov-
eredby these criteria. In addition, there are many possible
impairments or diagnoses that are not ruled out: For
example, the child may have clinically significant problems
with attention, learning disabilities, and psychiatric diagno-
ses such as anxiety (including social phobia and obsession-
ality) or depression. Also, the requirement of language
delay, if it is retained, precludes an initial accurate diagnosis
of Aspergers Syndrome; the purpose of this exclusion is to
eliminate children with normal early development with later
emerging eccentric personalities. Some children that we
include may have had an early Autistic Disorder or PDD-
NOS diagnosis and then later received an Aspergers
diagnosis (before their apparent recovery), or they may
have received an early diagnosis of Aspergers despite
language delay. The definition of recovery, furthermore,
applies to the behavioral level, and is neutral with regard to
neurobiological mechanisms by which this behavioral
recoveryis achieved.
Many researchers and clinicians are highly skeptical
about the possibility of recoveryin ASD, believing, for
example, that if ASD is an organic condition, recoveryis
necessarily unattainable (Schopler et al. 1989). In particu-
340 Neuropsychol Rev (2008) 18:339366
lar, Mundy (1993) raises some cogent objections. He
rightly criticizes the claim that recoveredchildren
function within the normal range emotionally and socially,
and even cognitively, without the support of extensive
documentation; a normal range Vineland and IQ score is
insufficient. Mundy points out that weak executive func-
tions can co-exist with an IQ in the normal range, and
might be expected to characterize children with high
functioning autism who have not recovered, as might
obsessive or odd thoughts, or depression. In his comment
on McEachin et al. (1993) (discussed further below),
Mundy points out that about half of the best-outcome
children had elevated scores on a personality test, and that
therefore ...it seems difficult to interpret these data as
evidence for the achievement of normal functioning in the
best-outcome group.(p. 383).
However, such residual challenges do not, in themselves,
refute the possibility of an optimal outcome. The claim of
recovery from autism does not necessarily entail the claim
of fully normal cognitive, social, and emotional function-
ing. Children who have recovered from autism are at risk
for other disorders, and thus may not be fully normal.
Research is required to identify these continuing vulner-
abilities, both for what they can tell us about autism, and for
what they can tell us about the childrens continued
treatment needs.
How can recoveryfrom a neurodevelopmental disor-
der be possible? There are at least three fundamental but not
mutually exclusive answers. The first is that these children
did not really have an ASD to begin with. We will review
below the extensive pretreatment similarities between
children who recoverand those who do not. On the
behavioral level, the two groups are very hard to distin-
guish. The second possibility is that there are forms of ASD
that are alleviated with maturation alone. Third is that
successful treatment moved children who otherwise would
have retained the full ASD picture off the spectrum. Since
most children who receive the best intervention do not
recover, the treatment alone cannot be responsible. Some
combination of child and treatment characteristics therefore
seems the most likely possibility.
Having offered our definition of recovery, we will
dispense with the quotation marks, keeping in mind that
losing the behavioral characteristics of ASD is what is
meant here by recovery. In some cases, optimal
outcomewill be used as a synonym for recovery.
Evidence for Recovery
Outcome research in the field of ASD has historically
focused on broad-based measures of functioning (intellec-
tual level, adaptive behavior, living and working situations)
primarily in adults. Only recently have studies begun to
focus on more specific outcome measures in older children
and adolescents. We will briefly discuss some of the
seminal outcome studies in adults, and then in younger
children. This is by no means a comprehensive review of
the many outcome studies; we will focus primarily on those
that document cases in which autistic behavior and
cognition disappear to the extent that an ASD diagnosis is
no longer warranted and/or cognition or adaptive living
skills are within the normal range.
In one of the first contemporary adult-outcome studies,
Gillberg and Steffenburg (1987) found a generally poor
prognosis for individuals who had been diagnosed with
autism as children. Only one out of their 23 participants
was living independently. Living independently, working
full-time, being married, and having friends have generally
been considered to be indicators of an optimal outcome in
the outcome literature, at least for adults. Similar results
were reported by Billstedt et al. (2005), who found that of
108 individuals followed from childhood, only four were
living relatively independently and only one was in a long-
term relationship; however, this study included both low-
and high-functioning individuals and therefore would be
expected to show a low proportion of good outcomes. In a
study of 58 high-functioning adolescents and young adults
with a history of autism, Ventner et al. (1992) found a wide
range of outcomes. While a few individuals were doing
quite well (which was defined as being mainstreamed in
school or, if older, living independently), generally the
individuals in this study still required extensive help in their
daily lives and were quite dependent upon their parents.
Over the years, adult outcome studies, like that of
Ventner et al. (1992), have frequently found a handful of
individuals in their samples that have achieved an optimal
outcome, including fully independent living and some
successful relationships. Perhaps the first study to hint at
the possibility of individuals with an ASD diagnosis losing
the diagnosis was by Rutter (1970). In this early longitu-
dinal outcome study, they found that 1.5% of the original
group were functioning normally on follow-up, while the
rest were divided between fair or goodadjustment (35%)
and severely handicapped (60%). Higher numbers of
recovered individuals in the more recent studies described
below perhaps result from the great improvement in early
intervention and educational services in later years.
In a review of the outcome literature, Seltzer et al.
(2004) found that the core symptoms of autism tend to
improve by adulthood, especially communication deficits.
Restricted and repetitive behaviors become subtler and
more complex. Seltzer and colleagues found that in a
number of adult outcome studies it appeared that about 10
20% of the sample no longer met criteria for a diagnosis on
the autism spectrum. They did note, however, that in the
Neuropsychol Rev (2008) 18:339366 341341
majority of outcome studies, the criteria for a good outcome
are very poorly defined. It is also unclear if these
individuals actually no longer met the criteria for a
diagnosis on the autism spectrum since standardized
diagnostic instruments were not always used.
More recently, studies that have examined only higher-
functioning individuals have tended to find a higher
proportion of individuals who are achieving good or
optimal outcomes. Howlin et al. (2004) studied a group of
68 adults who had an IQ score greater than 50 as children.
Although the majority of this sample was still living with
their parents or in residential care, one-third of the sample
was working and two of 68 had gotten married. This study
found that social and adaptive outcomes were more highly
correlated with verbal than with performance IQ. They
concluded that having an IQ over 70 is necessary but not
sufficient for an optimal outcome. Similar findings were
reported by Szatmari et al. (1989). They assessed 16 very
high-functioning individuals with a history of an ASD, and
found that four no longer met criteria for any ASD as
adults. Of these 16 individuals, one had married, one lived
with a roommate, and three lived alone. Eight of them were
able to manage their own finances. Perhaps most impres-
sively, at least eight of the 16 scored within the normal
range on all subscales of the Vineland Adaptive Behavior
Scales. This is particularly striking as studies have
generally found that adaptive behavior generally lags well
behind IQ and remains problematic throughout the lifespan
in individuals with ASD (Eaves and Ho 2004; Loveland
and Kelley 1988,1991; Ventner et al. 1992).
An early diagnosis of Aspergers Syndrome (AS) carries
a better prognosis than Autistic Disorder (AD). In a group
of individuals with an early diagnosis of AS, 19 out of 70
were either employed or in school full-time AND were
either living independently (over age 22 years) or had two
or more friends or a steady relationship (age 22 years and
under) (Cederlund et al. 2008). Using the Diagnostic
Interview for Social and Communication Disorders, they
found that 12% of their AS sample no longer met criteria
for a diagnosis on the autism spectrum. None of their AD
group had moved off the spectrum or had achieved a
relatively high level of functioning as adults; however, the
majority of this group functioned in the mentally-retarded
range as children. Similarly, PDD-NOS carries a better
prognosis for recovery than Autistic Disorder (Lord et al.
2006; Sutera et al. 2007).
Clearly, there are a handful of high-functioning individ-
uals on the autism spectrum who appear to improve to a
great extent by adolescence or adulthood. These adult
outcome studies, however, do not clearly demonstrate when
this improvement may occur. Moreover, because the
assessment is conducted so long after the original diagno-
sis, it is more difficult to assess which factors might be
predictive of this optimal outcome. Some studies that have
examined outcome in younger samples have begun to
address these questions. Beadle-Brown et al. (2000), in a
review of the child outcome literature, found that, generally,
self-care, communication, and educational achievement
tended to improve over the course of childhood and level
off in adolescence. They found that the higher the IQ of the
children, the greater the gains that were made. No reference
was made to any optimal outcome studies in their review;
however, very little research had examined optimal out-
come in children with an ASD at the time this review was
written.
Several, more recent studies have examined outcome in
middle childhood or adolescence. Sigman and Ruskin
(1999) followed children longitudinally, with some cases
dating as far back as 1979. In their sample of 51 children
who were originally diagnosed with an ASD (at a mean
age=45 months), 17% lost their diagnosis of an ASD over
time (at a mean age of 154 months). Fein et al. (1999) and
Stevens et al. (2000) studied a large group of preschool
children with ASD and 95 of them were followed to school
age (7 or 9 years old). At preschool, cluster analysis
indicated that the children could best be classified into low-
and high-functioning groups based on cognitive scores
(with a nonverbal IQ of 65 the best dividing line and the
two groups about equal in size). At school age, again, the
ASD group was divided into a lower functioning group,
whichwasnowmuchbigger(n=71) and a higher
functioning group, which was smaller (n= 24). In general,
as has been found by others, the lower-functioning
preschool group tended to lose ground relative to peers,
while the higher-functioning group tended to show im-
provement in standard scores. Although this paper did not
explicitly discuss optimal outcome or loss of diagnosis, the
smaller, high-functioning group showed mean verbal and
nonverbal scores within the normal range, and few autism
symptoms; many of them would probably have met our
current definition for recovery. Gabriels et al. (2001) also
found two clearly separable developmental trajectories in a
group of individuals with ASD who were studied from
preschool to school-age. Unlike Stevens et al. (2000),
however, Gabriels and colleagues found that in both
groups, IQ tended to increase across development. They
hypothesized that the children might become more testable
as their autistic symptoms wane over time. Although no
studies, to our knowledge, empirically assess whether the
children with autism are actually more cooperative in
testing situations over the course of development, many
clinicians do report this observation, and it is certainly a
factor to keep in mind when interpreting the results of these
outcome studies.
An additional study reports on 11 cases of children with
clear early histories of an ASD in which the clinical picture
342 Neuropsychol Rev (2008) 18:339366
evolved into cases of ADHD with no autism, about equally
divided into inattentive and combined type (Fein et al.
2005). As in other studies, more of these children had
original PDD-NOS than AD diagnoses. Interestingly, nine
of the 11 showed evidence of a regressive history, and ten
of the 11 had recurrent ear infections. Eight had received
intensive ABA therapy, while the other three had received
intensive, preschool classroom interventions that included
some ABA methods. In contrast to the later age reported by
Sigman and Ruskin (1999), average age of loss of ASD
diagnosis was at age 7 years; in some cases, the children
may have lost their ASD behaviors earlier, but the diagnosis
was not withdrawn immediately because the clinician did
not want to be premature or the child was not seen right
away. However, age seven is consistent with the UCLA
findings (McEachin et al. 1993). Some of the children in
the Fein et al. study had some mild residual features,
including social awkwardness (but more of the ADHD than
autistic type), and mild perseverative interests. The authors
suggest that attention may have been a core symptom in the
early development of these children with ASD; when the
other core symptoms resolve, the attention problems persist,
resulting in a clinical picture for which ADHDis the best
description.
A similar series of cases was reported by Zappella (1999,
2002,2005a,b). These were young children with PDD who
subsequently evolved into cases of ADHD and/or Tour-
ettes Syndrome. They were predominantly male, most
showed a regressive course, the initial autistic behaviors
resolved, and they were left with tics, many with co-morbid
ADHD. Zappella also notes extensive family histories of
tics and ADHD in this series. He also notes that none of his
cases were treated with ABA, but most did receive a
developmental therapy that is described in Zappella
(2005a).
Were the apparently recovered individuals misdiagnosed
in early childhood and did they not really have an ASD?
Two types of evidence bear on this question: First is
whether the children who show later recoveries are
behaviorally distinct in early childhood (e.g. have milder
or qualitatively different symptoms); this will be considered
below. Second is the stability of an ASD diagnosis in early
childhood. Several recent studies have documented the
accuracy of ASD diagnoses in children under the age of
3 years old (Charman and Baird 2002; Cox et al. 1999;
Eaves and Ho 2004; Gillberg and Steffenburg 1987;
Kleinman et al. 2008; Lord 1995; Moore and Goodson
2003; Stone et al. 1999; Sutera et al. 2007; Turner and
Stone 2007). In a review of the earlier literature, Kleinman
et al. (2008) report that between 75% and 95% of children
diagnosed before 3 years old retained an ASD or non-ASD
diagnosis at later evaluation. They found that 81% of
children retained an ASD diagnosis between the ages of 2
and 4 years old, and none gained an ASD diagnosis.
Stability was particularly good for clinical judgment,
Autism Diagnostic Observation Schedule (ADOS) diagno-
sis, and Childhood Autism Rating Scale (CARS) score, and
less so for the Autism Diagnostic Interview (ADI). Eaves
and Ho (2004) also assessed children at age 2 and 4 years
old; three of the 49 children moved off the autism spectrum
(one of the 34 with AD and two of the nine with PDD-
NOS); 94% retained the ASD diagnosis. As in the Klein-
man study, no children moved onto the autism spectrum
between 2 and 4 years of age. Turner and Stone (2007)
found somewhat lower stability: 68% of children diagnosed
with an ASD at age 2 years retained that diagnosis at age
4 years, while Sutera et al. (2007) (using some of the same
participants as Kleinman) reported that 82% of 2-year-olds
with ASD retained the diagnosis.
Therefore, diagnostic stability even in children as young
as two is good; although a number of children move off the
spectrum in each study, the overall percent of children who
retain their diagnosis ranges from 68% to 95%, and few if
anychildrenmoveontothespectrumfollowingan
evaluation at age 2 years. This, in addition to the
pretreatment similarity of recovered and persistent ASD
children (see below), suggests that early misdiagnosis is not
a major factor in apparent recovery.
A number of studies have investigated optimal outcome
specifically in older children, where the issue of diagnostic
error is presumably less of a factor than the impact of
treatment or the childs characteristics. Lovaas and his
colleagues (Lovaas 1987; McEachin et al. 1993) described
a group of children who had undergone intensive behav-
ioral therapy as young children and seemed to be
indistinguishable from their typically-developing peers.
These studies suggested that a significant proportion of
children with autism can benefit appreciably from this early
intervention. The benefits accrued include intellectual
functioning within the average range and being main-
streamed into regular classrooms without requiring any
extra support. Although these two studies have been
criticized for their lack of experimental rigor in the
assignment of individuals to the different treatment groups
(Gresham and MacMillan 1998; Schopler et al. 1989), they
still clearly document a group of children who had
improved to function normally or close to normally. Several
studies have failed to confirm the best outcomegroup
(Anderson et al. 1987; Birnbrauer and Leach 1993);
however, Howard et al. (2005) point out that these children
started with lower IQs and did not receive comparable
intensity of treatment as in the UCLA studies, or for as
long. Sallows and Graupner (2005) investigated the differ-
ences in outcome between clinic- and home-based behav-
ioral interventions. However, rather than finding differences
between groups they found differences within groups; that
Neuropsychol Rev (2008) 18:339366 343343
is, they found group differences between a group of rapid
and moderatelearners who were evenly distributed across
the clinic- and home-based intervention groups. The rapid
learners (11 of the 23 children) made striking gains between
intake to the study in preschool and follow-up 4 years after
completion of treatment. These gains occurred across many
areas of functioning including language, adaptive behavior,
autistic symptomatology, and intelligence; indeed their
mean full-scale IQ increased from 55 to 104. Furthermore,
eight of the 11 no longer met criteria for an ASD according
to the ADI-R. Forty-eight percent of the children reached
best outcomestatus, scoring normally on tests of IQ,
language, adaptive functioning, school placement, and
personality, with mild elevations on some personality and
diagnostic scales (two of the rapid learners were given
parent scores in the clinically-significant range on worry-
ing,and teachers rated one rapid learner as high on
aggression). Three of these best outcomechildren needed
classroom aides for attention problems, and one would
probably still meet criteria for ASD, but the remaining
seven or eight children would probably meet our criteria for
optimal outcome (OO), outlined above. Of these children,
one still had language problems on the ADI, and one had
rigid play, but no other autism features.
We have been conducting an additional longitudinal
study of a group of optimal outcome children who no
longer meet the criteria for an autism diagnosis on the ADI-
R or the ADOS, and who have been mainstreamed into
regular classrooms without the help of an aide (see above
for research criteria for optimal outcome). At the first
data collection point (Kelley et al. 2006), the 14 optimal-
outcome children with a history of autism were between the
ages of 5 and 9 years old. Although all of these children no
longer carried a diagnosis on the autism spectrum and were
mainstreamed without help, they continued to experience
some subtle difficulties in certain aspects of language.
Specifically, the optimal-outcome children performed well
within the average range on tests of receptive vocabulary,
grammar, and verbal memory (Kelley et al. 2006). They
also demonstrated intact grammatical competence on less
structured, experimental tasks and a narrative task. How-
ever, the optimal outcome group continued to experience
difficulties with the more semantic aspects of language.
They had more difficulty in understanding the certainty
differences between mental state verbs, such as think and
guess, versus know. Categorical induction was problematic;
they had difficulties extending the properties of an object to
a new object based on the semantic label alone in
comparison to their typically-developing peers. Interesting-
ly, this inability to extend properties was more problematic
with animate rather than inanimate categories. In addition
to their semantic language difficulties, the optimal outcome
group continued to experience problems with social-
cognitive and pragmatic language tasks. They scored lower
than their typically developing peers on tests of theory of
mind, or the ability to understand that others have mental
states that may be different from onesown. Although the
optimal outcome group experienced no grammatical diffi-
culties while telling a story from a wordless picture book,
they were less likely than their typically-developing peers
to discuss the goals of the main character and the causes of
various events in the story, elements that are considered key
to a well-structured narrative. Moreover, the optimal
outcome group was more likely than the control group to
misinterpret what was going on in the story.
Since some of these children were still quite young and
had only recently lost their diagnosis or been mainstreamed,
it was unclear whether they would continue to close the gap
with their typically-developing peers or whether behavioral
and cognitive problems would re-emerge as they entered
adolescence. Thus, we decided to re-evaluate them approx-
imately 3 years after the first study to further explore their
strengths and weaknesses. Moreover, in addition to com-
paring the optimal-outcome children to their typically
developing peers, we also compared them to a group of
children with ASD whose intelligence was in the average
range, but whose diagnoses clearly persisted. This high-
functioning autism (HFA) group was expected to perform at
the same level as the optimal-outcome and typically-
developing groups on standardized tests of vocabulary and
grammar, but show clear autistic symptomatology, and
semantic and pragmatic language difficulties (Tager-Flusberg
1997). All children in the study were between the ages of
8 and 13 (Kelley et al., in preparation). They were tested on
a large battery of language tests assessing grammar,
semantics, and a number of pragmatic tasks. Additionally,
we assessed their adaptive behavior as measured by the
Vineland, as well as socio-emotional functioning as assessed
by the Behavior Assessment Scales for Children. The pattern
of test results was consistent across all measures: On all
measures, the typically-developing children had the highest
average scores, followed by the optimal-outcome group,
and the HFA group showed the lowest level of functioning
on all tasks. Additionally, the optimal outcome group, as a
whole, scored within the normal range on all tasks and only
the high-functioning ASD group scored in the impaired
range on some of the standardized tests. Specifically, the
HFA group scored in the impaired range on tests of
pragmatic language, verbal memory, expressive language,
general communication and socialization, and daily-living
skills. Our typically-developing group, which was matched
on age and socioeconomic status to the OO group, was
above average in intelligence, however, and thus there were
a number of areas in which the optimal outcome group
scored significantly lower than the typically developing
group, including pragmatic language. The OO group also
344 Neuropsychol Rev (2008) 18:339366
scored lower than the typically developing group (but well
within the average range) on parent ratings of attention
problems, atypical behavior, and depression. On the
numerous other tasks that we used to assess these groups,
the children in the optimal-outcome group were statistically
indistinguishable from their typically developing peers. In
sum, we appear to have found a group that, with the
possible exception of some very subtle pragmatic deficits,
is currently functioning at the same level as their typically
developing peers, and we are continuing to follow this
group.
Predictors of Outcome: Child Characteristics
Although the mechanisms of improvement for any given
child are not known, a combination of treatment character-
istics and the childs own characteristics probably contrib-
utes to cognitive, behavioral, and diagnostic status in later
life. A few studies have examined early predictors of
development and symptomatology at an outcome point. It
should be noted, however, that the vast majority of these
studies examined predictors of relative severity of behav-
ioral and cognitive impairments at outcome, rather than
optimal-outcome status. It can be presumed that the
indicators of relative improvement would also predict
recovery, but this has not yet been proven.
The most consistent prognostic indicator is early
communication and language abilities (e.g., Mawhood et
al. 2000; Ventner et al. 1992). Luyster et al. (2007) found
communication scores at age 2 years, and especially age
3 years, to predict language and other outcomes at age
9 years. After they covaried for nonverbal IQ and age at the
final time period, age three receptive and expressive
language scores significantly predicted age nine verbal
and nonverbal IQs, receptive and expressive language, and
ADI-R/ADOS composite score. Use of symbolic and
communicative gestures at age 2 also predicted age nine
verbal IQ, expressive language, and adaptive skills. The
predictive value of expressive and receptive language, and
gesture suggests the importance of early symbolic and
imitative skills as foundational skills that may make
intervention more effective. Charman et al. (2003)also
examined potential predictors of language outcomes in
young children with ASDs (evaluated at 20 months and
42 months of age). They found that the children who met
criteria for AD in early life had significantly poorer
language outcomes than children with PDD-NOS diagno-
ses as well as more impaired initial, joint attention.
Language outcomes were also positively associated with
early, joint attention but not with play or goal detection;
however, there were significant floor effects on these
variables. In contrast to Luyster s study, initial NVIQ in
this study was not related to later expressive or receptive
language skills. Toth et al. (2006) found that early
imitation, joint attention, and toy play were good predic-
tors of later language, and that joint attention, in particular,
mediated the relationship between social engagement and
language.
Dietz et al. (2007) found a high correlation between IQ
scores as measured by the Mullen Scales of Early
Development at 24 months and 43 months of age.
However, there was significant heterogeneity in the scores;
12 of their 39 children had their scores increase by at least
one standard deviation (15 points) and three children
displayed a commensurate decrease in their scores. The
children whose scores increased had milder initial delays.
In the Sigman and Ruskin (1999) study, early, joint
attention skills predicted later expressive language and
early play skills, and nonverbal communication abilities
predicted peer engagement in later childhood. Goldstein
(2002) found that verbal imitation, IQ and age, together,
strongly predicted language outcome. Gabriels et al. (2001),
in their study of differential outcome after 3 years of
treatment, found that no early characteristics significantly
predicted outcome, although initial IQ scores tended to
predict outcome. There was a 21-point gap in initial
developmental IQ between the children who responded
best to intervention as compared to the low outcome
group; this difference was 51 points at follow-up.
None of the aforementioned studies specifically exam-
ined predictors of optimal outcome. In the Sallows and
Graupner (2005) study mentioned above, initial status was
examined to see what would predict membership in the
rapid learninggroup after 4 years of ABA-based
treatment. They found that optimal outcome at follow-up
was predicted by a combination of pretreatment verbal and
nonverbal imitation skills, language ability, and social
interest, where higher initial skills in these areas predicted
better functioning post-treatment. The most accurate re-
gression model was produced by a combination of
pretreatment verbal imitation and ADI Communication
score. Individual scores, however, were not strong predic-
tors: in examining the pretreatment scores of the rapid vs.
moderate learners, only NVIQ showed a substantial
difference (14 points); most other scores of the two groups
were very close (e.g. Vineland Communication 61 vs. 59,
receptive language 39 vs. 38). In their 4 to 6 year follow-up
of 27 children who received services at an ABA-based
preschool center, Harris and Handleman (2000) also found
that higher baseline IQ predicted higher, later cognitive
functioning. In addition, they found that age when
treatment was begun was related to classroom placement
in elementary school. Those who were younger when
treatment was initiated (mean age = 42 months) were more
likely to be in inclusive classrooms while those who were
Neuropsychol Rev (2008) 18:339366 345345
older (mean age=54 months) when they began treatment
were more likely to be in special-education classrooms.
There was no correlation between age when treatment
began and initial IQ. Autistic symptom severity, as
measured by the CARS, was not predictive of later
cognitive functioning or classroom placement.
Sutera et al. (2007) reported on 13 preschoolers who
were diagnosed with an ASD at age two but who failed to
meet criteria for an ASD diagnosis at follow-up at
approximately age four. These 13 children were drawn
from a sample of 73 children who were evaluated initially
after screening positive on the M-CHAT (Robins et al.
2001) and who were given an ASD diagnosis. There was a
significant difference in early diagnosis: of the children
who were initially diagnosed with PDD-NOS, 39%
exhibited optimal outcome while only 11% of children
with Autistic Disorder did. Aside from diagnosis, the only
significant differences between the optimal outcome and
persistent ASD groups at age two were in the motor area:
Mullen Fine Motor and Vineland Motor Skills were
significantly higher initially in the optimal outcome. This
difference in early motor skills may be due to these
measures serving as proxies for underlying cognitive and/
or neurological impairments. There were no other statisti-
cally significant differences between those children with
optimal outcome and those who remained on the spectrum
on initial nonverbal skills (as measured by the Mullen),
expressive or receptive language skills (from the Mullen
and Vineland), socialization (Vineland), or measures of
autistic symptoms (CARS and number of DSM-IV-TR
symptoms), except that receptive language and IQ scores
showed trends; a larger sample of optimal outcome children
might well show significantly higher scores in these areas.
Similar predictive value of diagnostic status was found by
Lord et al. 2006; they followed children with a diagnosis of
either PDD-NOS or Autistic Disorder from age 4 years to
age eight or nine. Only one child with Autistic Disorder lost
the diagnosis by age 9 years, whereas almost half of the
children with PDD-NOS lost the diagnosis.
Remington et al. (2007) also examined a subset of
preschool-aged children who achieved a best outcome
status in their comparison study of EIBI and a treatment-as-
usual group. The children were evaluated at baseline and
then again after 2 years of intervention. They did not look
at diagnostic change but defined best outcome as reliable
and clinically-significant changein IQ scores based on
Jacobson and Truaxs criteria (1991). They found that five
of the 23 children who received early, intensive behavior
intervention and three of the 21 comparison group children
showed such change. Exploratory analyses suggested that
the most positive responders had higher initial IQ, mental
age, Vineland Communication and Socialization scores,
more behavioral problems as reported on the Developmen-
tal Behavior Checklist Autism Algorithm, and fewer hours
of individual intervention in the second year as compared to
those children whose IQs diminished. Preliminary exam-
ination of our own M-CHAT sample also suggests that for
some measures, there may be an inverse relationship
between number of hours of intervention and outcome; we
presume that this is because the highest functioning and most
rapid responders are eventually given fewer hours of service.
In the Fein et al. (1999) and Stevens et al. (2000) studies
mentioned above, almost all the lower-functioning group at
preschool stayed in the lower-functioning school-age
group, whereas the higher-functioning preschool group
had divergent outcomes, with some going into the lower-
functioning school age group and the remainder forming
the small, high-functioning school age group. When
examining specific preschool predictors of group member-
ship at school age, cognitive and developmental variables
(receptive vocabulary standard scores, nonverbal IQ, Vine-
land Socialization and Communication) strongly differenti-
ated the groups, while degree of autistic symptomatology in
any domain failed to differentiate the groups. As with some
of the aforementioned adult studies, therefore, early
appearing higher intelligence level was a necessary, but
not sufficient, factor in predicting optimal school-age
outcomes. Turner and Stone (2007) found that the children
who were more likely to move off the spectrum were those
who were under 30 months of age when diagnosed, had
milder social impairment, and higher intelligence levels.
They did not find any differences between those who
moved off the spectrum and those who did not on the
amount of intervention received, although this may have
been an issue of restricted range. Turner and Stone
conclude that, maturation alone may lead to significant
improvement in symptoms for some children(p. 799).
One promising predictor is early response to interven-
tion. Although not strictly speaking a pretreatment charac-
teristic, a small number of studies document that rapid
responses to intervention are positive predictors for later
outcomes (Newsom and Rincover 1989; Weiss 1999). In
particular, early learning of verbal and motor imitation and
receptive language is important in predicting outcome (Weiss
1999). This is certainly a fruitful avenue for more study.
Therefore, severity of autistic symptoms is not a good
predictor of optimal outcome, but better cognitive and
motor development, and a PDD-NOS rather than AD
diagnosis are predictors of optimal outcome. It is hard to
reconcile the lack of power of symptom severity to predict
outcome, with the better outcome for PDD-NOS over AD.
Two possibilities present themselves: one is that the
presence of restricted, repetitive behaviors per se, rather
than severity of social and communication symptoms, is the
poor prognostic feature. The other is that children with AD
tend to be lower functioning intellectually than those with
346 Neuropsychol Rev (2008) 18:339366
PDD-NOS diagnoses. Both of these possibilities are
supported by the literature (Szatmari et al. 2006; Gabriels
et al. 2005; Lord et al. 2006). It is also interesting to note
that in our current sample of optimal outcome children,
their IQ is not only higher than non-recovered children, but
significantly above average in some cases. Ongoing and
future studies should investigate whether above-average IQ
is a predictor of recovery.
While the above articles describe behavioral factors
which may be related to outcome, there are physiologic
factors which, when finally identified and investigated, will
have far greater predictive value. The fact that ASD varies
across such a wide range of severity, and that behaviorally
similar children can respond very differently to the same
intervention, makes this obvious. Accelerated head growth
may be one such marker of a biological subtype, as well as
seizures. In their meta-analysis of studies involving
participants with ASD, Aimet et al. (2008) found that
seizures are associated with intellectual disability (ID), with
higher seizure rates in children with more significant
intellectual impairment. They found that the pooled
prevalence of seizures was 21.4% in individuals with ID
(n=1485) but only 8% in those participants without ID (n=
627). Early onset of seizures, especially infantile spasms or
medication-refractory seizures, are associated with a poorer
prognosis for children with ASDs (Saemundsen et al.
2007a,b; Danielsson et al. 2005)Secondary autismthat
complicates other conditions also has generally poorer
outcomes. These conditions include congenital rubella,
tuberous sclerosis complex, Fragile X syndrome, Joubert
syndrome, Down syndrome, and many other genetic
disorders (Peake et al. 2005; Asano et al. 2001). The
poorer prognosis is probably due to the underlying
neurological deficits that produce mental retardation,
limiting amount and speed of learning independent of the
autistic behaviors. In addition, children with idiopathic
ASDs who also have other disabilities, especially sensory
impairments, may have more limited potential for recovery.
Children who exhibit high levels of stereotyped behaviors
that are resistant to behavioral and pharmacological
management (especially motor and object stereotypies,
and delayed echolalia) face additional challenges because
these self-stimulatory behaviors limit the ability of the child
to attend to interventions and to engage in adaptive
behaviors. They also tend to be associated with lower
developmental or intelligence quotients (Bishop et al. 2006;
Szatmari et al. 2006).
Two studies bear on the predictive value of head
circumference development. Elder et al. (2008) conducted
a records review of 77 younger siblings of children with a
confirmed ASD diagnosis (considered at high risk for ASD)
to examine whether early differences in head circumference
predicted later ASD diagnosis for the younger siblings.
Head circumference slopes and intercepts at twelve months
of age were associated with social and communication (but
not repetitive behavior) symptoms at age 2224 months as
well as M-CHAT critical items at the same age. In addition,
the rate of z-score change in head circumference was
associated with social symptoms; the slope was steeper for
those children with more social impairment. Children with
more communication symptoms had larger head circumfer-
ence at 12 months of age, with a slope that leveled off more
quickly between 12 and 24 months of age. Mraz et al.
(2007) and Mraz (2007) also examined growth records to
see if the abnormal patterns of growth reported by Elder et
al. (2008) and a number of others (e.g., Courchesne et al.
2001) would differentiate the optimal-outcome children
from those with persisting ASD. However, the optimal-
outcome group had the same pattern of head growth as the
ASD groupnormal or slightly small at birth, and acceler-
ating until about 1 year of age, then leveling off. The optimal
outcome group, however, did show less acceleration of body
length and weight, showing values close to the CDC
averages for these variables across the first 2 years, while
the ASD group showed an acceleration of length and weight
that paralleled their head circumference. Thus, while
accelerated head circumference in the first year has been
confirmed to statistically predict the emergence of autistic
symptoms, especially in children at risk, it does not seem to
predict the possibility of an optimal outcome.
Which Characteristics Improve?
Another way of asking this question is to ask what residual
or comorbid problems the recovered children experience.
There are almost no data bearing directly on this question,
but a few observations can be made: In Howard et al.
(2005) the behavior-therapy group is described as a whole,
rather than separating out the best outcomechildren.
Some data, however, are very suggestive: As a group, the
behavior therapy group did extremely well in most areas;
the scores that were somewhat below average were in the
areas of receptive language, expressive language, and self-
help (although these data were collected after only
14 months of therapy, they suggest which areas might be
most difficult to remediate). In the Kelley et al. (2006)
study described above, which focused on language func-
tioning, there were residual problems with higher-order
language functions, including constructing a narrative,
discourse, and social cognitive problems such as under-
standing the subtleties of mental-state verbs. The Fein et al.
(2005) case series suggests that children who move off the
autism spectrum are still at risk for significant attention
problems, as well as some subtle social difficulties and
perseverative interests. Our current study should shed some
Neuropsychol Rev (2008) 18:339366 347347
light on this question; although data collection is still
ongoing, preliminary examination of the functioning of the
optimal outcome group suggests minimal difficulties with
executive functions (cognitive functioning by testing and
behavioral functioning by parent report), verbal memory, or
other standardized IQ and language tests (Rosenthal et al.
2008; Tyson et al. 2008). In addition, the optimal outcome
and HFA groups appear to have significant psychiatric co-
morbidities, whereas the typically-developing controls do
not. Specifically, the 12 optimal outcome children exam-
ined so far showed present or past history of depression (1),
phobias (8), ADHD (4), and tics (2). Zappella (2005a)
reported tics and attention problems in his series of children
who moved off the spectrum. In the Sallows and Graupner
study (2005), similarly, one or more of the best outcome
children were worriers, had still-delayed social skills,
preoccupation/inattention, or somewhat poor communica-
tion skills. Bailey (2001) examined children who met
criteria for the UCLA best outcomestatus, and found
that they obtained lower scores than typically-developing
children on most measures of social competence, especially
parent rating of inappropriate behavior (but social func-
tioning within the normal range was not required for best
outcomestatus in the UCLA definition). McEachin et al.
(1993) also followed a group of nine best outcome
UCLA patients to an average age of 13 years old. They were
administered an IQ test, a Vineland Adaptive Behavior
Scales, and a Personality Inventory for Children. Except for
one child, they were still in regular education settings. IQs
ranged from 99 to 136, confirming the tentative findings of
our current study that high IQ may facilitate recovery.
Vineland scores, including Socialization, were overall at an
average level, but several of the children had borderline
Socialization scores. Aside from one child whose scores
were of questionable validity (the same child who was no
longer in regular education), the personality scores were
mostly normal, with one child elevated for delinquency, two
borderline for social withdrawal, and one borderline for
psychosis (odd behaviors). Most important, blinded clinical
assessors did not discriminate the eight still-best outcome
children from the children with no histories of ASD.
Thus, although data are quite preliminary, the residual
vulnerabilities of the recovered children appear to include
anxiety (especially social anxiety), depression, tics, atten-
tion problems, and perhaps continuing difficulty with
higher-level, complex social and language interactions.
Predictors of Outcome: Treatment Characteristics
A comprehensive treatment of this issue is well beyond the
scope of this paper. The Journal of Autism and Develop-
mental Disordersspecial issue (volume 30 (5), 2000) is
devoted to treatments. Rogers and Vismaras(2008) recent
comprehensive review is also focused on evidence-based
treatments. It becomes apparent that no treatment has been
subjected to the same level of examination as Lovaas
behavioral approach and treatments stemming from it. In
addition to some pharmacological approaches, psychosocial
treatments such as Pivotal Response Training (PRT) and the
Denver Model have shown promise in single-subject
designs but have not been held to the same level of
empirical scrutiny. Rogers and Vismara (2008) separated
treatment protocols published between 1998 and 2006 into
three effectiveness categories: well-established,proba-
bly efficacious,andpossibly efficacious.Lovaass
treatment is the only protocol that meets criteria for being
well-establishedbecause it incorporates a treatment
manual and has clearly specified participant groups. It has
been shown to be better than placebo or alternative
treatments by two independent well-designed group studies,
and has been studied by several single-subject design
studies (Rogers and Vismara 2008). See Smith et al.
(2000), Howard et al. (2005) and Eikseth et al. (2002), in
particular, for comparisons of behavioral treatment to other
therapies, or clinic vs. parent-directed behavioral treatment.
None of the remaining treatment protocols in the Rogers
and Vismara review fell into the well-establishedcatego-
ry because they lack rigorously obtained empirical support
(Rogers and Vismara 2008).
Pivotal response training (PRT) developed by Koegel et
al. (1999) uses both developmental and applied behavior
analysis procedures to increase a childs motivation to
participate in learning skills within the domains of
communication, language, play, and imitation (Schriebman
and Koegel 1996). Although PRT does not meet the
necessary criterion of strict empirical group comparisons,
Rogers and Vismara suggest that this treatment protocol
should be considered probably efficaciousbecause of the
large numbers of independent single-subject design studies
that have demonstrated PRT to be effective compared to
other treatments.
The Denver Model integrates behavioral, developmental,
and relationship-oriented intervention to enhance function
in language and developmental domains and is described in
detail by Rogers et al. (2000). In short, this treatment
technique has a curriculum and makes use of specific
teaching techniques (trials and naturalistic behavioral
exchanges) within an interpersonal relationship to teach
necessary skills. A number of pre-post studies have been
conducted demonstrating improvements across a range of
skills for children who participate in this treatment (Rogers
et al. 2006). Like PRT however, the Denver model has
not been compared to other treatment approaches in a
controlled manner and hence, can only currently be
classified as probably efficacious.
348 Neuropsychol Rev (2008) 18:339366
Three interventions that are included in the Rogers and
Vismara (2008) review were deemed possibly efficacious
because these studies compared their interventions to other
protocols and found their interventions to be effective.
Aldred et al. (2004) implemented a combination of parent-
training pragmatic language workshops, speech and lan-
guage therapy, the North Carolina TEACCH model, and
social-skills training. A second treatment protocol included
a parent-trained group who implemented techniques to
foster joint attention and behavior management in a
naturalistic setting and the parents received in-home speech
and language consultation every 6 weeks, for 3 h (Drew et
al. 2002). The local services group received a mixture of
standard treatments (speech and language, occupational
therapy, etc), with some parents receiving direct treatment,
and three children receiving in-home 1:1 discrete trial
training for an average of 33 h/week. Third, Jocelyn et al.
(1998) implemented a 12-week protocol targeting language,
social, and play development, and decreasing unwanted
behavior, delivered by trained child care workers in a
typical day care center and at home with their trained
parents (15 h of training and additional consultation). The
control group attended community day care alone.
Most of the published treatment studies compare relative
outcome of groups receiving two different treatments, or
different intensities of the same treatment. They are
generally not designed to examine retrospectively the
treatment parameters for the best-outcome children. Exam-
ination of the studies mentioned previously in documenting
the existence of recovery is not generally informative about
treatments received by the most successful children, but
there are some clues. Gabriels et al. (2001) noted that
children in their high outcomegroup received an average
of 40.3 more hours per month of intervention. Although
this difference was not statistically significant, the authors
suggested that it may reflect differential treatment effects in
community-based settings in which children with initially
higher developmental ability may be given more hours of
intervention. Of the 11 children in the case study conducted
by Fein et al. (2005), eight received intensive ABA therapy
and three of the children were in an intensive preschool
program with interventions that included some ABA
techniques (but this was determined by record review, with
no random assignment to groups). While the combination
of treatments for children diagnosed with autism in the
Sigman and Ruskin (1999) study is largely unknown
because treatment data were collected by parent question-
naires, it is known that 93% of the children in the autism
group were enrolled in special education. Of the 93%, 83%
of the children received speech and language therapy, 25%
received play therapy, 25% received physical therapy, and
45% received therapy focused on social skills. Sallows and
Graupner (2005),whosesampleincludedsomebest-
outcome children (see above), compared a clinic-treatment
group to a parent-directed treatment group. Both groups
received Lovaas treatments, and (unintentionally) did not
differ in intensity of intervention. Children in the Zappella
(2005a) treatment study did not receive any behavioral
therapy, but all were enrolled in some form of develop-
mental therapy.
Although none of the studies found significant treatment
differences between the children who moved off the
spectrum and those who did not, measuring treatment is
generally done by measuring treatment quantity and type
rather than quality, which is much more difficult to assess.
In addition to the confounding factor that Gabriels et al.
(2001) suggested, another potential confound could work in
the opposite direction: children who make slower progress
are sometimes given more intensive treatment, making
interpretation of the relationship between progress and
treatment intensity very difficult. All of the children in the
studies that reported participants with optimal outcome
were receiving at least some level of treatment and thus it is
possible that the treatment, in combination with the
potential for normal levels of cognition, was responsible
for their improvements. While the majority of studies
reporting on recovery included some behavioral methodol-
ogy, this was not always the case.
Preliminary Conclusions About Recovery
It is very difficult to integrate results across studies because
both initial and outcome data vary so widely. Also,
although many of the studies (e.g. Stevens et al. 2000)
meet most aspects of our definition of recovery, they do not
explicitly assess whether the participants continue to meet
criteria for any ASD.
However, the following tentative conclusions seem to be
warranted: (1) A certain number of children with well-
documented ASD lose the diagnosis and function within
the generally normal range of cognitive, adaptive, and
social skills. This improvement may be attributable to
treatment techniques, the nature of the original clinical
presentation, brain maturation, or other endogenous bio-
logical changes such as diminution of neuroimflammation.
(2) The percent of children with ASD who can reach this
outcome varies widely; studies with unselected samples
show anywhere between 3% in the earliest studies to about
25%, although a few ABA studies claim higher rates of
success (up to 50%, but some of these started with higher
IQ children). (3) Factors that seem to predict the potential
for recovery are higher intelligence (when it can be reliably
measured), receptive language, verbal and motor imitation,
motor development, a diagnosis of PDD-NOS rather than
AD, and earlier age at diagnosis and initiation of treatment.
Neuropsychol Rev (2008) 18:339366 349349
Social development, play, and joint attention show more
mixed results: although joint attention in particular predicts
relative improvement, there is no evidence as yet that early
joint attention can predict recovery, although it would make
sense that it would. However, severity of autistic symptoms
per se generally fails to predict optimal outcome. (4)
Physiological factors (e.g. seizures) that are associated with
poorer outcome probably mark the presence of significant
mental retardation and possibly specific syndromes; head
circumference trajectory in the first year fails to predict
recovery. (5) Almost no controlled studies directly compare
outcome between behavioral vs. other therapies (e.g.
developmental stimulation, Denver Developmental model,
Floortime) or with biomedicaltreatments. Therefore,
no definitive statements can be made about which treat-
ments can produce recovery in the greatest number of
children. However, although it cannot be stated categori-
cally that behavioral treatment is necessary for recovery, the
majority of studies that report actual recovery used
behavioral techniques, alone or in combination with other
therapies, for some or all of the children, and therapies that
include behavioral methods are the most empirically
validated. In addition to the well-described learning
principles that govern behavior therapy, competent behav-
ioral therapy requires a highly affective, emotionally
positive set of interactions that promote the reward value
of social interactions and more or less continuous social
engagement, especially in very young children. (6) The
range of residual vulnerabilities in recovered children is not
yet known. Preliminary evidence suggests potential weak-
nesses in some children in higher order communication
functions, as well as possible vulnerability to tics, depres-
sion, phobias (including social phobias), and ADHD.
It is very difficult or impossible to predict speed or
ultimate level of progress at initial evaluation. However, if a
child is seen after a year or more of good intervention and
has made limited progress, clinical experience suggests that
it is possible to clinically identify the rate-limiting factor
for that child. For some, it seems to be a significant degree
of mental retardation, which places a limit on speed and
amount of learning. For others, it seems to be a very
significant language disorder, where nonverbal learning
may be good, but receptive and expressive language are
severely impaired, despite reasonable teaching as well as
attention and effort by the child. For yet others, the extent
of repetitive behaviors is the limiting factor. Probably both
because engaging in repetitive behaviors distracts attention
away from learning opportunities, and because these
behaviors can become increasingly reinforcing and compul-
sive with practice, severe repetitive behaviors can interfere
greatly with development and behavioral improvement.
A key component of early intervention is that it occurs
early enough in development to harness maximum plastic-
ity (Thomas and Karmiloff-Smith 2002; Kolb et al. 2001).
Harris and Handleman (2000) showed that optimal out-
come, as measured by successful full inclusion, is more
likely when intervention starts at an earlier age. Animal
models of social deficits provide myriad examples of
lesions being more or less consequential dependent upon
whether they were inflicted early or later in development.
The greater biological plasticity of the infant brain affords
more potential for healing. If the brain can be forced to
engage in exercisesthat represent normal behavior and
cognition, there is more potential for these activities to
develop neurological representation. This, however, should
not be used as an argument against therapeutic interven-
tions in older children because there is a growing literature
on plasticity throughout the lifespan (e.g., Doidge 2007).
On the other hand, if a child begins to create alternate
experiences for him/herself or to use alternate information
processing strategies, the brains plasticity will work against
him/her by wiring itself in an alternate way, thus making
the child an expert at maladaptive cognitive strategies. In
some children, maladaptive plasticity may have progressed
too far to be reversed. Similarly, just as auditory deprivation
may cause cortical elaboration of vision, early deprivation
of social stimuli may cause elaboration of other modules,
such as spatial skills, in the autistic brain. In the absence of
language input, or where a maladaptive strategy such as
chunking auditory stimuli into long segments has been
solidified, a childs mental lexicon may develop in terms of
picturesrather than words and consequently there may be
a sophistication of thought processes beyond which a child
is unable to reconstruct his/her fundamental units of
thought. An emerging structure or schema places con-
straints on the structures and schemas that can emerge next;
Lewis (2004) refers to this principle as cascading con-
straints. Beyond a certain point, the window in which the
brain teaches itself what to learn will have been missed.
Many basic cognitive skills are needed early in life to
scaffold development of more complex cognitive skills. In
short, early-onset neurological disorders such as autism may
have the potential for both excellent and devastating
outcomes, depending on whether plasticity is harnessed to
work for the child or allowed to work against the child. If
primary experiences and cognitive skills can be forced early
in development, preventing the harder to reverse secondary
consequences of the disorder, and if deficits such as severe
mental retardation are not present, recovery may be possible.
Possible Mechanisms for Recovery
Our understanding of the mechanisms of recovery will
depend on basic assumptions about whether ASDs consti-
tute a unitary disorder, or several disorders, whether they
350 Neuropsychol Rev (2008) 18:339366
are congenital, or diseases that can arise at different ages in
childhood, whether the underlying abnormalities are mod-
ular or network properties, and whether autistic deficits and
behaviors are fixed or state-dependent. Eventually, ade-
quate explanations of the mechanisms of recovery will need
to take into account the following general points:
First, any explanation of recovery that is applicable to
the majority of cases needs to encompass great diversity in
severity, pattern of impairment and age of onset. For
instance, a currently influential approach assumes highly
specific (modular) core deficits that limit learning opportu-
nities very early in development, leading to a broadening
range of secondary limitations in environment-expectant
processes. This approach would predict that the later the
autistic deficits present, the milder or less extensive the
ultimate impairments would be expected to be. This is
because an initial period of normal or near-normal develop-
ment would offer opportunities for learning that are not
available to early onset cases. Therefore, one would expect
that the 2040% of children who regress into ASD in the
second year of life or later would be less severely and less
extensively involved than the children with early onset. In
fact, if anything, the opposite seems to be the case; outcome
is generally very similar in regressive vs. non-regressive
cases (Werner et al. 2005), and to the extent that there are
differences, the regressive children as an overall group tend
to have worse outcomes (Rogers 2004), although some
studies have reported that a large number of their optimal
outcome children have experienced regressive courses (e.g.,
Fein et al. 2005; Zappella 2005a,b). That being so, we are
left wondering why the regressive phenotype is nonetheless
so similar to the early onset phenotype in its pattern of
impairments and response to therapies.
Second, if there are core deficits in key structures in
ASD, focused, mass-trial interventions such as intensive
learning sessions applied to the central deficits might be
effective. Alternatively, the core deficits might be regarded
as untreatable, and efforts could be directed at by-pass,
teaching alternative approaches to practical goals, and
perhaps engaging intact areas of the neural network. But
if, as has been vigorously advocated, there are network
impairments of a broad organizational type (Happe and
Frith 2006; Just et al. 2004; Rippon et al. 2007), then a
quite different set of constraints on functioning might be
hypothesized. A dearth of long-range cortico-cortical
connections would be expected to handicap distant associ-
ations and limit the individual to concrete and local
solutions. Such impairment in executive processes or
abstract thinking would hardly be addressable by intense
training, but would call for by-pass. A variant of the
network-impairment model is that the network impairments
may be a consequence of biological mechanisms such as
oxidative stress that are difficult but not impossible to
reverse, and that if reversed or even diminished, could have
widespread impact on functioning due to a widespread
improvement in connectivity parameters (Herbert and
Anderson 2008).
In the light of these more general considerations, we present
possible mechanisms by which early intervention might result
in loss of ASD diagnosis and normalization of surface
behavior and cognition. We begin with attempts to avert the
full autistic syndrome by attempting to treat before hypothe-
sized core deficits have had enough time to broaden into the
full syndrome. This methodology is based on assumptions
about the evolution of autism from its early beginning.
If the pre-autistic infant is subject to core limitations
which result in a cumulatively-reduced exposure to and
experience of the social environment, then secondary
detrimental effects on additional brain areas are anticipated,
which would culminate in the gradually unfolding full
panoply of autistic symptoms, behaviors and cognitive
limitations. If early intervention can ameliorate the core
limitations, further expansion of the autistic syndrome
could potentially be averted. The reader is referred to
Mundy and Crowson (1997), Dawson and Zanolli (2003)
and Dawson (2008) for additional discussions of this issue.
Dawson (2008) presents a model in which risk factors
(genetic as well as environmental factors such as viruses,
toxins and intrauterine conditions) lead to risk processes,
which are the behaviors, such as very early abnormalities in
social interaction and attention, which precede the full
syndromic picture. These risk processes prevent exposure
to the normal social and linguistic inputs that are needed to
drive development during early sensitive periods. Specifi-
cally, Dawson suggests that social engagement is necessary
for the brain regions that underwrite perception of social
stimuli to integrate with areas that mediate reward, thus
motivating the developing child to seek social engagement
for its own sake, and benefit from the experiences that it
offers. These risk processes would be the appropriate
targets of intervention, in order to forestall the development
of the full syndrome. Furthermore, restriction of early social
interaction prevents social contact from acquiring reward
value, with all the downstream consequences to the types of
learning that require an ongoing social context, and
permanent epigenetic consequences to the stress/arousal
system. In the models timeline, the initial risk processes
are most prominent at 612 months, after which these basic
events (social reward, anticipatory pleasure at being called)
form the foundation for more elaborate social and cognitive
processes, beginning at 1218 months, including joint
attention, imitation, and intentional communication. The
Dawson paper presents a very heuristic model, for which
research can focus on filling in the details and testing
specific candidates for risk factors, risk processes, and
interventions.
Neuropsychol Rev (2008) 18:339366 351351
The idea that autism develops from a set of core deficits
and gradually broadens into a full syndromeis, however,
hard to reconcile with the fact that the full syndrome arises
rather quickly in children who regress into autism, or who
become autistic due to encephalopathies. In such cases,
why do they not seem to have benefitted from their period
of early normality or near-normality?
In the not-too-distant future, it is to be hoped, biological
therapies will directly address causes of autism: Identification
of missing gene products or verification of neuroinflammatory
reactions (Vargas et al. 2005) or abnormal immune response
in children with ASD might, for example, lead to direct
medical treatments (see Herbert and Anderson 2008,for
evidence for some of these processes). The recovered
children studied by us and others, and described above,
however, have generally not received any biomedical
intervention. In this section we consider psychological or
biological mechanisms that may underlie the empirically-
demonstrated effectiveness of behavioral treatments (in this
context, behavioraltreatments include any treatment that
works at the behavioral level, including treatments, such as
the Denver model, not usually defined as behavioral). The
suggestions we make here are consistent with the general
Dawson (2008) model, and suggest some more specific
mechanisms that might be possible to test.
It is currently not known which specific cognitive or
affective mechanisms are impacted by such therapy and
how the brain may be changed by such intervention. This
question is made more difficult by the fact that autism may
be the end point of multiple pathophysiological processes.
It may very well be that the different responses of children
with ASD to intervention are a function of which cognitive
or affective mechanisms are inhibiting an individual childs
learning (which may differ from child to child) and how
much plasticity underlies each one. Alternatively, there may
be one disease process or set of cognitive mechanisms and
the variable responses to intervention may reflect the timing
or severity of these processes. Finally, there may be
multiple, relatively independent deficits in autism, and
intervention may tap multiple routes to recovery simulta-
neously. Uncertainties aside, we will lay out what we view
as the major candidates for the mechanisms of change.
These are certainly not mutually exclusive or exhaustive;
several may be operating simultaneously, and some are
similar. The first three mechanisms are all variants of
normalizing environmental input:
1. Normalizing input through forcing of attention
Experience-expectant programming may begin to di-
verge from the normal developmental trajectory because the
inborn deficits of children with ASD prevent their exposure
to experiences that allow for typical development (Dawson
2008; Johnson et al. 2002; Mundy and Crowson 1997). For
example, human infants are able to categorically perceive
phonemes from all languages, but by the age of 1 year are
only able to categorically perceive phonemes from their
own language (Kuhl et al. 1991; Werker and Tees 1984).
Similarly, human infants have been shown to be better at
discriminating monkey faces than adults are (Pascalis et al.
2002), leading some to argue that there is a perceptual
narrowing, or critical period, for both language and face
processing, and that lack of early experience with the
stimuli these systems expectto encounter will prevent
infants from developing specialized face processing or
phonetic systems (Dawson and Zanolli 2003; Dawson
2008). Intervention then, by forcing attention to those
critical stimuli, hypothetically prevents the catastrophic
cascade into an autistic endpoint, and puts in place the
necessary cognitive and affective building blocks for
typical development to take place. If providing these critical
experiences via intervention simply allows development to
resume its natural course, resulting in normalization of
neural processes, then structural and especially functional
brain studies should be similar or identical to those of
normal children with no ASD histories.
The most likely candidates for a psychological deficit
that would prevent normal environmental input would be
abnormal attention or deficient motivation. It has been
suggested over the past two decades or so that one
fundamental aspect of autism is a very early social
disinterest (Baranek 1999; Waterhouse et al. 1996; Werner
et al. 2000). That lack of observable interest could be a
selective deficiency in a specific brain mechanism, or it
could be due to negative reinforcement of social interaction
by aversive concomitants such as overwhelming arousal
(Kinsbourne 1987) or hyperstimulation from cortical noise
(Belmonte and Yurgelun-Todd 2003; Rubenstein and
Merzenich 2003). Lacking the keen interest in caregivers
and others that drives much of early behavior and learning
in normal development (e.g. Trevarthen and Aitken 1994),
the entire motivational structure that drives attention and
learning would be abnormal. Two related impairments in
the operation of attention have been posited: one is inability
to disengage attention from the current focus (Courchesne
et al. 1994; Kinsbourne 1987). This stickyor overfocused
attention (Kinsbourne 1987) could confine the acquisition
of skills and information to restricted areas, as well as cause
severe deficiency in social functions such as joint attention,
that require rapid shifting of attention (Courchesne et al.
1994). Indeed, Zwaigenbaum et al. (2005) found social
disinterest and inability to disengage visual attention to be
among the earliest signs of autism (in the first year) in
children at risk for ASD.
A second possible attentional deficit is that on the
continuum of inward vs. outward directed attention,
individuals with ASD are stuck at the extreme inward end
352 Neuropsychol Rev (2008) 18:339366
(Kinsbourne 1987). This certainly seems to be clinically
observable, in cases where it is difficult or impossible to
draw the childs attention away from inward preoccupations
to the instructional environment. It is also consistent with
research findings using neuroimaging. Recent studies have
delineated a default networkin the brain, which is
activated at rest and deactivated during task performance,
and includes medial frontal cortex, anterior and posterior
cingulate gyrus and precuneus (Gusnard et al. 2001;
Johnson et al. 2006). This network is active when people
engage in self-reflective thought. Kennedy et al. (2006)
reported that in individuals with ASD, this network fails to
deactivate when the child is given tasks to do. This appears
to demonstrate that autistic individuals maintain a maladap-
tive degree of inward-focused attention. One would
therefore expect that treatments that lead to recovery would
result in the normal occurrence of deactivation when the
individual is engaged in tasks.
It is interesting to consider further the timing of the early
disinterestin, or aversion to social stimuli. Typically
developing infants exhibit intense motivation for social
interaction (e.g. Trevarthen and Aitken 1994; Yarrow et al.
1975); however, children with autism seem, generally, not
to develop the core deficit of social disinterest/aversion
until they are more than six months old. So for some
children it may not be, as Dawson suggested, that
interpersonal interactions fail to become motivating, but
that, having been motivating early on, they cease to be so
by the end of the first year of age. Perhaps autism is a
disease that has its onset or first clinical expression during
the first year rather than already by birth, as is usually
assumed. Or perhaps social engagement, initially reward-
ing, becomes gradually less so because of some aversive
accompaniment, such as excessive phasic aversive arousal
and/or sensory overload due to unstable activating systems
charged with the control of excitation/inhibition balance.
Early intervention might seek to render these interactions
less aversive by controlling external factors that modulate
arousal and sensory stimulation, and by attempts at
desensitization.
Whatever underlying deficit causes the experience-
expectant systems to be deprived of input, intervention
would work by forcing attention to the instructionally- and
socially-relevant aspects of the environment, thereby
normalizing the crucial early input. Typical infants have
pre-set and unobstructed biases that amplify features to
which attention should be paid, including speech, faces, and
gestures. These attentional biases facilitate perceptual
processing, leading to imitation, and rapid learning, and
culminating in expertise. If this normal attentional bias is
absent or obstructed, early intervention might force the
child to attend to these stimuli. In this view, treatment
bypasses the abnormal motivation system, possibly without
ever fully correcting it, or else compensates for the
obstruction by amplifying inputs that would otherwise be
too weak to overcome the biological obstruction. In other
words, treatment prevents the childs neurologically-based
deficit in social orienting from disrupting further neurolog-
ical development (Mundy and Crowson 1997) by prevent-
ing the child from missing out on critical, early social
learning. In recovered children, social orienting presumably
becomes autonomous at some point and no longer
dependent on their attention being specifically directed
during interventions.
The accelerated head growth in many children with ASD
in the second year of life may reflect or contribute to a
failure of this experience-expectant learning. Experience-
expectant learning may work by overproducing synapses to
be pruned. The overgrowth of the brain that peaks by the
second year might reflect a failure of this pruning while an
obstruction model would be appropriate if metabolic
abnormalities rather than failure of synaptic pruning were
at play (Herbert and Anderson 2008). If most underlying
cognitive systems are potentially intact or have functional
or metabolic changes that are reversible, then future
research might show that the brains of recovered children
appear similar to those of children with no history of
autism.
2. Promoting reinforcement value of social stimuli
A related process is helping the child to associate adults,
and then peers, with reward value, promoting motivation to
attend to other people. Most behavioral programs utilize
conditioning techniques that begin by rewarding the child
with primary reinforcers or objects and experiences that
have already acquired reward value for the child (e.g. food,
tickles, breaks to do preferred activities). Dawson and
Zanolli (2003) and Dawson (2008) speculate that this
allows the adult to acquire reward value for the child. But
since the reward value of the adult does not extinguish
when the primary reinforcers are withdrawn, the question
arises of whether the learning process involved is best
described as conditioning of someone with absent social
motivation or, instead, recovery of obstructed motivation.
By explicitly pairing attention and response to other
people with reinforcers that create emotional reactions, the
child may be described as acquiring what Grossberg and
Seidman (2006) refer to as drive representationof these
social stimuli. Hypothetically, instructions to the prefrontal
and sensory cortices amplify the signal on any incoming
sensory stimuli to which the child is expected to have an
emotional reaction. A drive representation is an expectation
that the child will have a positive emotional reaction to a
class of stimuli. Once classical conditioning takes place and
a child independently experiences emotional arousal in
conjunction with social stimuli apart from reinforcement,
Neuropsychol Rev (2008) 18:339366 353353
this circuit is presumably created between the amygdala
and the prefrontal cortex. In effect, this mechanism creates
the biases that are pre-set in typical infants but that are not
originally present or accessible in the autistic infant.
Classical conditioning may have more profound effects in
very young children as their brains develop salience maps
of the world that will guide them for the remainder of their
lives. This may allow the connection between social stimuli
and reinforcement not to become extinguished once the
explicit pairing ceases. It is also possible that by mere
repetitive orienting and responding toward social stimuli,
the social motive takes on functional autonomy, as can
often be seen in the persistence of unreinforced habitual
behaviors.
These first two proposed mechanisms imply that
underlying cognitive systems are initially intact in an
autistic child but that the emotional systems engaging and
motivating social attention are not. In this scenario,
controlling the focus of the childs attention and pairing
reinforcers with socioemotional stimuli is central to
treatment success.
3. Early intervention provides an enriched environment
A similar possibility for a mechanism underlying
effective intervention is that it creates an enriched environ-
ment for the child (Dawson 2008). Consistent with the
notion that autism comes about when experience-expectant
stimuli are not encountered, studies of Romanian adoptees
have shown that children who experience an absence of
stimulation are at substantial risk for developing some
autistic symptoms. Approximately one-third of the envi-
ronmentally-deprived Romanian adoptees show autistic
traits (Rutter et al. 1999). Rutter et al. (1999) note that
these symptoms seem to be associated with prolonged
perceptual and experiential deprivation(pp. 546). The
deprivation might lead to the extinction of the normal, early
predisposition to seek and enjoy social interactions. A
hallmark sign of autism, the restricted and repetitive
movements and activities, are also commonly observed in
animals kept in small cages, but not in enriched environ-
ments (Lewis et al. 2007), consistent with the idea that they
are the result of deprivation. Of course, in the case of
children with autism the deprivation is neurologically,
rather than environmentally, imposed. However, the fact
that even under conditions of environmental deprivation
that are apparently far more severe than those that autistic
behavior imposes on children with ASD, the full autistic
syndrome fails to appear, indicates that environmental
deprivation, though it may contribute to, cannot account
for the bulk of autistic symptomatology.
In addition, it seems to be precisely during the earliest
months after birth that the deprivation is least marked, or
minimally observable. The degree of deprivation of normal
experience in hospitalism and certain orphanages seems to
be far more severe than that which autistic children
experience in their first year of life, and yet it is deprivation
during the first year that has the most severe and enduring,
deleterious consequences for mental development. None-
theless, the prognosis for children who suffered early social
deprivation is far better than that for children with incipient
autism. Few of them become classically autistic, and their
development seems to be suspended during the deprivation
rather than permanently impaired. In other words it is
possible to overrate the negative effects on the development
of key brain areas of environmental restriction. Held and
Hein (1963) deprived newborn kittens of any opportunity to
explore the environment or even to locomote by harnessing
them to other kittens, who did all the moving, for the first
6 weeks of their lives. When the experimental kittens were
unharnessed, they were unsteady, tentative and insecure. As
little as 48 h later, they were indistinguishable from their
control age-mates. At least some developmental skills can
develop absent the expected environmental opportunities.
Perhaps mental skills are more vulnerable than motor skills.
However, recovery should not be considered impossible
because certain brain areas are presumed to have failed to
pursue a normal maturational course early in life.
Like the first two proposed mechanisms, this one implies
that the childs underlying cognitive systems are intact but
his/her motivation and emotional response are dampened.
Treatment compensates for this dampened motivation by
creating a highly emotional and perceptually-rich environ-
ment that causes the child to experience the same (or near
normal) frequency and intensity of emotion as other
children. Such emotional experiences draw the childs
attention outward. Grossberg and Seidman (2006) proposed
that individuals with autism have a dampened amygdala
response, meaning that the intensity of a stimulus will have
to be much greater than is typically required in order to
provoke an emotional reaction. Intervention therapists
typically used heightened affect when interacting with
children with ASD, create and emphasize emotional
situations for the child, and, when teaching cognitive skills,
use objects that hold emotional value for the child (e.g.,
food, tickles, favorite toys, i.e. reinforcers). Thus, what may
appear to be an enriched environment is approximating a
normal environment for a child with autism.
In addition, enriched environments may even prolong
critical periods during which neurons are maximally
sensitive to modification by experience (Hensch 2004).
This is potentially important, since effective early interven-
tion is often not started until after the third birthday, well
beyond what evidence (reviewed by Dawson and Zanolli
2003) suggests is the critical period for automatic face
processing as well as phoneme discrimination. On the other
hand, the deprivation presumably experienced by inatten-
354 Neuropsychol Rev (2008) 18:339366
tive autistic children may itself prolong certain critical
periods. It is possible that a lack of competition prevents
synapse elimination and extends the sensitive period for
many circuits. For example, rats reared with a modulated
but limited repertoire of sounds experience early closing of
critical periods before functional maturation is achieved. In
contrast, rats reared with continuous, unmodulated sounds
experience prolonging of critical periods indefinitely
(Chang and Merzenich 2003).
The idea of providing an enriched environment is not
inconsistent with the normalization of input if the untreated
autistic environment is one of functional deprivation. One
finding that argues against this explanation is that animals
and children suffering severe deprivation tend to have
smaller brains and even frank atrophy, which has not been
reported in autism.
4. Early intervention provides mass trialing/practice
Animal models amply demonstrate that intensive train-
ing can overcome brain-damaged-induced learning deficits
and even reverse hippocampal hypoplasia (Loupe et al.
1995). In the intensive training conducted by Loupe et al.
(1995), it was crucial to start with easy discriminations and
proceed incrementally with gradually more difficult ones,
as is done in effective behavior therapy for children. From
the material in the foregoing section, we will proceed under
the assumption that the best therapy, the most likely to
promote recovery and reverse neurological impairment, is
instituted early (before age 4 years and the earlier the
better), is intense (20+ h a week), incorporates structured
teaching using behavior principles, administers large doses
of positive affect designed to promote social engagement
with adults and later with peers, and involves parents to
directly administer treatment or help with generalization
and maintenance of skills and to motivate positive affective
interactions. One aspect of successful early intervention is
that it is intensive; successful early intervention seems to
generally entail 2040 h per week (Dawson 2008); this
provides mass trialing, or repetitive exposure to stimuli
and repetitive practice in acquiring skills that typically
developing children do not require. Studies on expertise,
rehabilitation of acquired injury, and early intervention for
developmental or early onset disorders in humans, all
demonstrate that intense repetition of a set physical or
cognitive exercises leads to some amount of neural
reorganization, either through increased synaptic connec-
tions or alterations in the cortical map (Sur and Rubenstein
2005). Children with autism may need extreme amounts of
practice or exposure because: (a) the child may have a
deficit in implicit learning, (b) the child may have difficulty
attending or discriminating because of a relatively undif-
ferentiated cortex or other biological interferences with
higher order functions, (c) the child may not benefit from
observation or imagination due to a simulation deficit and
needs explicit teaching, or (d) the child may have
underdeveloped areas of the brain that require extra practice
to bring them online.
(a) Rubenstein and Merzenich (2003)haveproposedthat
environmental factors affect the neural circuits of young
children at-risk for autism, causing premature termina-
tion of critical periods before their neural maps are fully
differentiated; that is, before neurons have selected their
permanent repertoire of inputs from among a wider
array of possibilities. This hypothesis carries two sets of
implications. Although the brain is capable of learning
throughout life, critical periods represent a massive
sensitivity of neuronal properties to modification by
experience (Hensch 2004). When a critical period is
open, a child merely has to be exposed to stimuli such
as speech to learn from it, even during sleep (Cheour et
al. 2002) whereas after it has expired, a child must
deliberately attend to material in order to learn from it
(e.g., second language learning beyond early childhood,
unlike first language learning, is effortful). Consequent-
ly, whereas typically-developing children will implicitly
learn what they need to about the world via simple
exposure, autistic children may need to be formally
taught nearly everything in a tightly controlled envi-
ronment that ensures attention and effortful learning
(see Renner et al. 2000 for a review on implicit learning
deficits in autism).
(b) A secondary consequence of neural maps being relatively
undifferentiated might be chronic overarousal (Goodwin
et al. 2006;Huttetal.1965; Kinsbourne 1987;
Rubenstein and Merzenich 2003) as well as difficulty
attending to particularly salient environmental stimuli
because of reduced signal/noise ratios. As a result of
this lack of perceptual differentiation, areas of the brain
would begin to respond broadly to stimuli rather than
selectively to the specific stimuli that would normally
engage each area of the brain. This would potentially
flood the brain with stimuli to which it will respond
(with both baseline and stimulus-induced electrical
activity heightened and disorganized, placing the child
at risk for seizures). Children may attend to all
environmental signals, experience abnormal signal
modulation, and have difficulty blocking irrelevant
stimuli, thus making it hard to attend selectively to
what is salient. Support for this hypothesis comes from
an animal model. The primary auditory cortex of rats
reared in continuous 70dB acoustic noise continues to
show the immature pattern of broad, high frequency
tuning curves and imprecise tonotopy characteristic of
the earliest stage of auditory development (Chang and
Merzenich 2003)a pattern similar to that observed in
Neuropsychol Rev (2008) 18:339366 355355
high functioning autistic participants in psychoacoustic
experiments (Plaisted et al. 2003). Furthermore, per-
ceptual training normalized this pattern in these same
rats as adults, whereas passive exposure uncoupled with
reward did not reverse the effects (Zhou and Merzenich
2007). These findings demonstrate that adult cortex
remains plastic for attended, rewarded stimuli. An
effective early intervention environment would be one
that generally amplifies all informative signals in the
childs environment, teaching discrimination to the
undifferentiated cortex through rewarded discrimination
learning. It also suggests that the notion of loss of
plasticity after the end of critical periods may inappro-
priately deflect potential therapeutic opportunities.
(c) A third possibility is that autistic children do not
automatically mimic or simulate the actions of others as
do typically developing infants and children. Simulation
may underlie imaginative play (Goldman 2006), which
is disrupted in individuals with autism, as evinced by
their reduced amount of pretend play (Charman et al.
1997). Mental practice, for example, is said to be as
effective in increasing synaptic connections and
expanding cortical representations as physical practice
under many conditions (Jackson et al. 2003). In short, it
is possible that typically-developing children benefit
from observation and imagination, in a way that
children with autism do not. Imagining previously-
observed signals and actions may give normal child-
rens brains extra practice, allowing the proper amount
of exposure for neural development. Children with
autism, on the other hand, may only benefit from
actions as they are being enacted and stimuli as they are
being directly experienced, meaning that they require
the enhanced direct experience with cognitive and
sensorimotor experiences provided by structured teach-
ing. This lack of automatic delayed and immediate
mimicry has been related to the mirror neuron
system, a set of neurons distributed in several areas
of cortex, that have been suggested to be functionally
disordered in individuals with autism (see Iacoboni and
Dapretto 2006, for a review). Typical individuals, but
not autistic individuals, show activation in these areas
that is similar whether they are experiencing a stimulus
or enacting a behavior, or whether they are watching
someone else experience a stimulus or enact a behavior.
It seems to us more parsimonious to regard this as an
effect of early social disinterest, rather than suggesting
that a system which is not morphologically, neuro-
chemically, or anatomically distinct is selectively
abnormal and causes social disinterest. Particularly
given growing documentation of widespread connec-
tivity abnormalities, it is more likely that mirror
neuron systemdysfunction is secondary to much more
widespread processing disturbances or a preceding
deficit in social motivation, depriving it of input. But
in either case, dysfunction in this system is consistent
with the lack of mimicry that preliminary research
suggests is the case in autism (McIntosh et al. 2006).
(d) Yet another possibility is that in children with autism,
particular neural systems or areas are underdeveloped,
and need enhanced practice and experience in order to
bring systems online. The concept of constraint-induced
movement therapy (i.e.forcing use of a damaged system;
e.g., Taub et al. 2004) has recently entered the literature
on cognitive rehabilitation (Sohlberg and Mateer 2001).
Constraint-induced movement therapy, which forces
individuals to rely on their damaged (as in the case of
stroke patients) or dysfunctional (as in the case of
children with cerebral palsy) motor system by restrain-
ing the spared limb, has been shown to result in both
restoration of lost cortical representations and acquisi-
tion of new representations (Johansen-Berg et al. 2002;
Liepert et al. 2000). Early intervention that emphasizes
extreme amounts of practice may be conceptually quite
similar. Just as a normal system may become enhanced
with extreme amounts of practice, a damaged system
may reach normal levels of functioning with extreme
amounts of practice. If an autism cascade begins as a
structural or connective defect of some sort, interven-
tion may force use on a damaged attentional, social-
emotional, or language system until the systems
cortical representation grows enough to function with-
out continued treatment.
5. Compensatory input
Alternatively, there may be irreversible damage to
underlying neural systems responsible for key behaviors
such as language and face processing. If so, the only route
to recovery would be to teach the child early on to
compensate for this damage by learning alternative strate-
gies for mastering these pivotal skills, so as to recruit areas
of the brain that are not typically used for such functions. In
this case, fundamental building blocks to development are
acquired in an alternative way that allows for nearly typical
development of surface behaviors, but involves substantial
alterations in the cortical map of cognitive processes or
neural representations of information.
Interventions that lead to effective change in one or two
pivotal skills that are fundamentally disordered in autism
might lead to collateral changes in other prominent symptoms
and skills (Koegel et al. 1999). The more sophisticated
cognitive and emotional processes that children with optimal
outcomes go on to master may only require foundation skills
such as language, face-processing, and imitation upon which
to build, regardless of how these foundation skills were
initially developed. This possibility implies that underlying
356 Neuropsychol Rev (2008) 18:339366
cognitive systems representing language and social skills are
damaged in an autistic child but that other aspects of
cognition are intact (and therefore recovery would be
precluded by comorbid mental retardation). In these success-
ful children, intact parts of the brain may take over in
representing these pivotal functions (just as left hemisphere
stroke victims sometimes show significant right hemisphere
activity taking over for language) (Kinsbourne 1971;Mussol
et al. 1999). In this scenario, acquiring a basic set of
foundational skills, necessary for further development, is the
mechanism central to early intervention success.
This possibility is illustrated by considering how young
children with autism learn language and social skills. Typical
children, acquire these concepts and skills implicitly (Church
et al. 1986; Karmiloff-Smith 1992). However, intervention
programs make the learning of these skills explicit. Doupe
and Kuhl (1999) suggested that the act of learning itself may
limit the extent to which one can learn to vocalize specific
phonemes. Acquiring these abilities through the conscious
effort most children apply to math and reading, but not
conversation or imaginative play, may bypass the normal
course of cognitive development, leading to atypical cortical
representation of these skills. In other words, the alternate
strategies generally used by children with autism to acquire
communicative and social abilities may lead to compensato-
ry, rather than normalized, functional systems in the brain.
If compensation underlies recovery from autism it should
be accompanied by changes in the localization of function of
skills that were emphasized by therapy in recovered children.
Indeed, preliminary evidence supports this idea. Typical
individuals show unique activation in the fusiform face area
(FFA) when looking at faces. However, individuals with
autism consistently show hypoactivation in this region
(Schultz et al. 2000;Pierceetal.2001). Schultz et al.
(2000) have interpreted these findings as a reflection, rather
than a cause, of the tendency of autistic people not to look at
faces. A popular theory regarding the FFA is that it is linked
to expertise (Gauthier et al. 2000), and although most of us
become face experts by a very young age, Schultz et al.
(2003) argue that people with autism, due to their lack of
social attention, do not. Expecting that increased experience
with faces might activate the fusiform face area, Bolte et al.
(2006) trained 10 high-functioning autistic adults in facial
affect recognition. While the group showed significant
behavioral improvements, these improvements did not lead
to increased post-training activation of the FFA. Instead, they
led to increased activation in the superior parietal lobule
(Bolte et al. 2006). Other studies that have found activation
in the precuneus region, or retrosplenial cortex, in autistic
children (Wang et al. 2004) and adults (Schultz et al. 2003)
in response to familiar faces. This region may represent a
higher-order processing system that is unique to individuals
with autism (Schultz et al. 2003).
The possibility of alternate specialization in the autistic
brain is consistent with the idea that regional specialization
is sensitive to experience (Jacobs 1999). The evidence cited
above suggests that treatment-enhanced ability of autistic
individuals to recognize faces and facial affect may involve
compensatory pathways and activation, and thus neuro-
imaging studies should show different degrees or location
of activation in processing this kind of information. To date,
no study has examined these processes in recovered
children. Evidence from successful treatment of dyslexia
(Aylward et al. 2003; Richards et al. 2000; Shaywitz et al.
2004, Simos et al. 2002; Temple et al. 2003) demonstrates
both normalization of cerebral activity and compensation
by recruiting additional brain areas; furthermore, this
plasticity has been observed across the life span (e.g., Eden
et al. 2004; Shaywitz et al. 2004; Simos et al. 2002). Of
course, one might expect later-acquired skills such as
reading, as opposed to skills usually acquired very early,
such as face processing expertise and basic language skills,
to show an extended period of possible effective plasticity.
6. Effective intervention suppresses interfering behaviors
Behavioral treatment may bring about functional recov-
ery in some children with autism by suppressing those of
the childs behaviors that interfere with attention to his/her
environment, especially the repetitive behaviors that thera-
pists call self-stimulatory. This may work by suppressing
the abnormal cortical input that restricted and repetitive
behaviors induce, thereby preventing them from taking up
valuable cortical space, or from altering the neurochemical
balance in the brain, such as, by reducing brain-derived
neurotrophic factor (BDNF) levels in the hippocampus
(Branchi et al. 2004). Alternatively, interrupting the childs
repetitive behaviors may simply make him/her available for
teaching and receiving meaningful input from his/her
environment. If the repetitive behaviors are not interrupted,
the childs potential to benefit from meaningful input will
be diminished as more and more processing capacity is
occupied by meaningless input and he/she loses neuro-
plastic degrees of freedom(Lewis 2004). At the same
time, the child will miss out on input and experiences
necessary for normal neural and social development.
Turner (1999) reviewed the literature about the possible
functions of repetitive behaviors in autism, including the
arousal-reduction hypothesis (Kinsbourne 1980,1987); the
operant hypothesis, according to which stereotyped behav-
iors are maintained by their sensory consequences, attention
elicited from caregivers, or escape from aversive tasks; and
the executive hypothesis, in which stereotyped behaviors
result from impairments in initiating new behaviors or in
inhibiting ongoing behaviors. A variant of the arousal and
operant hypotheses is that repetitive behaviors are a
response to sensory overload which overwhelms discrimi-
Neuropsychol Rev (2008) 18:339366 357357
nation in proprioceptive as well as other sensory channels,
with the movements being an attempt to ramp up physical
stimulation to restore a sense of the location of the physical
body in space. Lewis et al. (2007) also review animal
models of stereotyped behavior, including CNS insults,
pharmacological interventions, and rearing in restricted
environments. These attentional mechanisms are suggested
to result in functionally impoverished environments. The
hypotheses postulated above carry different implications for
the treatment of stereotyped behaviors. The arousal hy-
pothesis implies that behavioral limitations are at least in
part state dependent. It would divert remedial efforts toward
manipulation of the environment, for instance avoiding
novelty and stress, or attempting to acclimate the individual
to unavoidable uncertainties. Many deviant behaviors
would then be recognized as being attempts at compensa-
tion. If stereotypic behaviors serve a de-arousing purpose,
then the child should not be deprived of these behaviors
until more socially-acceptable maneuvers are successfully
substituted (Kinsbourne 1980). Another implication of this
hypothesis is that attempts at environmental enrichment
would be quite counterproductive, since they might
increase arousal levels. In contrast, if the stereotyped
behaviors in some children with ASD arise for the same
reasons as in animals reared in restricted environments,
then providing enriched environments (or forcing attention
to the normal environment, which might have the same
result) should reduce these behaviors. And if the repetitive
behaviors are supported by their consequences, then
operant procedures to change the consequences (e.g. not
allowing escape from tasks, preventing the sensory con-
sequences) should reduce the behaviors. What supports these
behaviors may differ between behaviors, between children,
and within children over time. A behavior initially caused by
one factor, for example, may come to be supported by
secondary consequences. Advances in functional behavior
analysis allow therapists to study the antecedents and
consequences of these behaviors for each child, at one point
in his/her development. Difficult as this makes theory, this
focus on individual differences in the purposes or causes of
specific behaviors, seems likely to be productive.
7. Successful early intervention reduces stress and stabil-
izes arousal
Another contender for the critical mechanism underlying
the success of behavioral intervention is that it structures
and organizes the childs world in such a way that it
normalizes the childs arousal levels, thereby allowing
learning to take place. Kinsbourne (1987) proposed that
social stimuli are selectively avoided by individuals with
autism because social interactions are, by nature, the most
unpredictable. This unpredictability, he argued, creates an
untenable level of arousal for children with autism, because
they have unstable arousal systems, causing them to seek
comfort in objects and routines which are generally de-
arousing. Behavioral intervention may structure social
interactions in such a way that they become more
predictable and therefore less arousing. This would make
social interactions less aversive. Recent work documenting
connectivity abnormalities may support this arousal model
since unpredictability can overwhelm the reduced capacity of
the autistic brain to coordinate complex and rapid stimuli,
leading to overload-related stress. It is also possible that as the
child grows, rather than turning to a nurturing social
environment for soothing, he/she may learn to self-regulate
by engaging in repetitive, self-stimulatory behaviors, thus
making him/her increasingly less available to the outside
world at the risk of being overwhelmed. Making the
environment more predictable might lower arousal and
therefore decrease the need for the de-arousing repetitive
behaviors that interfere with learning. On the other hand,
forcing a child into highly arousing social situations (face to
face interaction with others for hours per day) may create
habituation and lower stress in that way.
Chronic stress can instigate developmental brain damage
in several different ways. This cascade could be stopped
early in development and the environment made able to
compensate for the childs biological overarousal, either by
making social interaction more predictable, or by desensi-
tizing the child to the unpredictability. This theory implies
that the children with autism who recover have cognitive
systems that are initially intact but that due to chronic
overarousal, the children are initially too stressed to attend
and learn as they otherwise might. This theory leads to
direct predictions that in early childhood, particularly before
effective intervention has begun, signs of autonomic over-
arousal, overreactivity, or instability should be detectable.
8. Boosting recovery via biomedical treatment
There is currently no evidence that biomedical interven-
tion alone can result in recovery from autism. However,
such intervention may boost the effectiveness of education-
al interventions. A child who is sleep-deprived, experienc-
ing gastrointestinal distress, eating a self-restricted
imbalanced diet, underactive, or suffering from depression
and anxiety may not receive the full benefit of behavioral
treatment or education. Slow wave sleep has been shown to
enhance critical period plasticity in the visual system
(Dang-Vu et al. 2006) and it is possible that it does so for
additional systems. Indeed, in mammals, high levels of
sleep coincide with the rapid phases of brain development,
and decline when brain maturation has occurred. Sleep-
deprived rats show significant decreases in the size of the
cerebral cortex and brainstem (Mirmiran et al. 1983). More-
over, sleep-deprived rats (as opposed to rats whose sleep
cycles were undisturbed) showed no plasticity benefits from
358 Neuropsychol Rev (2008) 18:339366
exposure to an enriched environment (Mirmiran et al.
1983). These findings suggest strongly the need for optimal
sleep management for young children. On the positive side,
exercise has been shown to increase BDNF levels and
generally promote neural plasticity (Cotman and Berchtold
2002; Widenfalk et al. 1999) as well as improving cognitive
and brain function (Kramer and Erickson 2007). Thus,
treatment for such ancillary symptoms may improve the
benefit the child receives from behavioral intervention.
Another state change that has been noticed in children
with ASD is improved behavior with significant fevers
(Curran et al. 2007). Parent report has confirmed reductions
in adverse behaviors with fever. Despite the significance of
this observation, it would be even more important if
anecdotal reports of increased emotional contact and speech
with fevers could be confirmed. This might lead to a better
understanding of state changes that promote normal
behaviors and the underlying chemistry of autism. Finally,
there are multiple reports of autistic children speaking in
conditions of perceived emergencies, starting with Rimlands
1964 book. While these otherwise mute or almost-mute
children did not produce complex, advanced speech, they
did produce utterances (look out,take it out,Idont
want to go) that were thought to be beyond their ability.
Assuming these reports are true, it bolsters the motivational
theory to explain at least some autistic behaviors.
Several lines of research lend hope to the idea that
biomedical treatments may someday improve the prognosis
for a larger majority of children diagnosed with ASD.
Many children with ASD may experience some form of
immune compromise (Warren et al. 2005). Herbert and
Anderson (2008) suggest that early immunological insults
to the brain, such as by toxicants and infectious agents, may
not be eliminated from the body if encountered during
critical periods of early development. If viruses or heavy
metals penetrate the nervous system they may stimulate an
oxidative stress response which could lead to neural
inflammation. Inflammation and oxidative stress could
interfere with optimal neural functioning through multiple
mechanisms. By contributing to excitotoxicity and subop-
timal cellular energetics they could exacerbate the neuro-
chemistry underlying the stress response and contribute to
excessive arousal, as well as to a more general phenomenon
of cortical noise with decreased signal-to-noise ratio that
could contribute to abnormal thresholding and diminished
specificity in response to sensory stimulation (Anderson et
al. 2008) The astroglial activation component of immune
activation may well lead to the hypoperfusion often seen in
children with ASD (e.g. Degirmenci et al. 2008), since
activated astroglia are enlarged and can reduce brain
capillary lumen by as much as 50%, reducing oxygen
support of brain tissue, increasing the difficulty of
eliminating waste products to the blood system, and hence
and impairing the cellular activities associated with neural
activity and synchronization (Aschner et al. 1999). Over
time, this could result in various areas of the brain
developing in poor relation to one another, with each area
of the brain perhaps developing hypersensitivities or special
properties, but making it difficult for multiple neural
systems to work in concert (see Muller 2007 for a review
on lack of synchronicity in autism). If this inflammation
could be controlled early in life, it might prevent such
atypical development from taking place. This might be
accomplished by agents that reduce microglial and astro-
glial activation, address the triggers for this activation, or
that counteract the consequent hyperglutaminergic state.
This scenario is consistent with the idea that intrinsic bias
toward social motivation is obstructed rather than absent in
children affected with this type of pathophysiology.
A recent study reversing the symptoms of Retts
Syndrome in adult mice (Guy et al. 2007) raises the
possibility that biological treatment may not even need to
occur early in life. They found that activating MeCP2 in
adult affected mice resulted in phenotypic reversal of the
syndrome. This demonstration that defective neurons may
be repaired even in adulthood, and that developmental
damage done during brain formation may sometimes be
reversible, is a further caution to avoid too rigidly holding
that after critical periodsdeficits are totally fixed.
However, neuronal circuits that control behavior are
largely shaped during critical periods in the first few years
of postnatal life. Another possibility for future treatment is
that critical periods may be extended, or even reopened, via
pharmacological intervention to treat children with autism.
For example, autistic children do not experience the period
of high serotonin synthesis during childhood that typically
developing children do (Chugani 2004). Serotonin is critical
to postnatal synaptogenesis, and so one possibility would be
to treat very young children with serotonin agonists in an
attempt to replicate for autistic children a more typical period
of early brain plasticity (Chugani 2004). Similarly, activity-
dependent development of sensory systems has been shown
to be dependent upon GABA neurotransmission and
treatment with GABAergc drugs extend the time course of
the critical period for vision (Hensch et al. 1998). As
research progresses as to the timecourse of various neuro-
chemical developmental processes in different subtypes of
autism, more potential pharmacological interventions aimed
at modulating experience-induced synaptic plasticity in
young children may present themselves. Pharmacological
interventions may be particularly potent when delivered
between 12 and 24 monthsan active period of synapto-
genesis when children with autism are frequently observed to
regress and/or become symptomatic.
Genes that control activity-regulated synaptic develop-
ment and function are affected in some autistic children
Neuropsychol Rev (2008) 18:339366 359359
(Garber 2007; Morrow et al. 2008; Sutcliffe 2008; Zoghbi
2003). Normalizing the malfunctioning control genes or
providing the missing gene product, of course, would be a
direct treatment for such children. However, children so
affected may not be among the ones for whom intense
behavioral intervention can produce recovery. The children
in the Morrow study for whom information is given appear
to be severely affected, with comorbid MR and sometimes
seizures, as might be expected with a widespread malfunc-
tion of synapses. Most of the mechanisms suggested in this
paper would probably not produce recovery for such
children, although treatment could certainly still produce
improvement. Geneenvironment interactions may also
affect synaptic functioning; for example, in addition to the
multiple candidate genes impacting calcium channels,
multiple ubiquitous environmental toxins targeting these
same channels could also impair function both prenatally
and postnatally (Pessah and Lein 2008). This may be
pertinent in less severe cases of autism. If the contribution
of such environmental triggers in the setting of genetic
vulnerability is substantial, reducing exposure to environ-
mental toxins may decrease gene penetrance and increase
receptivity to behavioral intervention.
Conclusions and Future Directions
The gold standard in treatment evaluation is the randomized
prospective study. Despite the absence of such studies in
the field of treatment of autistic children, we are able to
draw some tentative conclusions.
Recovery in children with ASD through behavioral and
educational interventions seems possible in a significant
minority of cases. Ideally, treatment methodologies are based
on an understanding of the underlying brain abnormalities
and dynamic issues. In autism treatment we are compelled to
reason in the opposite direction. Having determined what
seems to work empirically, we suggest which biobehavioral
mechanisms might underlie their success. There are many
possible psychological and neurobiological mechanisms
through which this improvement can come about. We have
listed some that broadly fall into the categories of intensive
practice (treating to weakness), environmental enrichment
and stress/anxiety reduction coupled with reinforcements
that guide attention outward into the physical and social
environment, as well as the possibility of increasing
receptivity to behavioral interventions by reducing the
severity of treatable biological processes that impair
neural functioning. These efforts appear most promising
when implemented early in life, even before the autistic
symptoms have fully presented.
In addition to the more fundamental questions about the
biological causes of autism, many questions remain about
how behavioral intervention can work, answers to which
may provide basic information not only about autism but
about neuroplasticity in general.
Which children have the potential for recovery through
behavioral means, and how many are there? Recovery may
occur through spontaneous reorganization of the brain,
through behavioral adjustments that circumvent permanent
brain impairments, through brain reorganization facilitated
by behavioral interventions, and/or through facilitation of
behaviorally-induced brain reorganization through reduc-
tion of biological barriers to learning. What genetic,
physiological, or developmental factors may predict recov-
ery? Are there structural or neurotransmitter defects from
which it is possible to recover through behavioral means
and others from which it is not? Different cognitive or
affective systems may have more or less potential for
reorganization or normalization, and thus, an individual
childs outcomes may depend upon the nature of the initial
neurological impairments. Children from consanguineous
or multiplex families may have a somewhat different set of
conditions (Morrow et al. 2008) and therefore their
potential for recovery may differ. Does a regressive course
have a different probability of recovery? Some evidence
suggests that regressive course may have a slightly worse
outcome, in general (Rogers 2004), although the data are
inconclusive (Werner et al. 2005), and yet many of the
recovered children in the Fein et al. (2005) and Zappella
(2005a,b) series seem to have had a regressive course; how
can these findings be reconciled?
Does any sort of matching factor play a role? Certain
treatment protocols, and certain therapists, may emphasize
varying levels of factors such as positive affect and reward
value for adults, teaching fundamental cognitive skills,
forcing attention to the environment in a continuous way,
etc. Some of these may have stronger effects on certain
phenotypes of the disorder.
What is the critical time period for intense intervention
to begin? Is there a zone of modifiability(Ramey and
Ramey 1998) during which the developmental trajectory
can be maximally impacted?
Is behavioral intervention necessary for such recovery or
are there other interventions that might have the same
result? Do some children with ASD achieve recovery with
no specific intervention, merely through maturation, be-
cause of the type of ASD they have?
Another question that has not been well addressed, either
empirically or even theoretically, concerns the nature of the
predictor variables. Firm data support the predictive value
of motor development, IQ, receptive language, and suggest
the probable predictive value of joint attention, social
interest, and play. But what do these predictive factors
indicate? If they are gateways to further learning (as would
be easily imagined for receptive language and joint
360 Neuropsychol Rev (2008) 18:339366
attention), then treating them directly should improve
outcome. However, if they are markers of underlying
CNS integrity (as might be imagined for motor skills), then
treating them would not have much effect (analogous to
treating pain that indicates a serious underlying condition).
What can we learn from the residual vulnerabilities of
the recovered children? Although data are meager, so far
they suggest that recovered children are subject to difficul-
ties with higher-level language pragmatics (e.g. discourse),
attention, tics, anxiety and depression. Does this reflect the
comorbidity of ASD with several of these disorders?
Simonoff et al. 2008 found ASDs share high comorbidity
with social anxiety, ADHD, and oppositionality. Or does it
suggest that problems with attention and anxiety are central
to ASD (Kinsbourne 1987) and persist when other parts of
the syndrome resolve? Do these problems need to be
treated in their own right, regardless of the autistic
comorbidity, and are they treatable with standard therapeu-
tic methods?
When recovered children perform language, social, or
academic tasks to normal levels, are they using the same
neural networks to the same level of activation as children
with no ASD history? Is normalization or compensation
more prominent, in different tasks, and in different children?
As the recovered children enter adolescence and then
adulthood, are any at risk for regressing back into their
ASD symptomatology? So far, our studies and those of the
UCLA group indicate that this does not happen, but the
research is certainly insufficient for a definite conclusion.
Research that examines functioning in persistent or
recovered ASD, either through behavioral/cognitive testing
or through physiological or neuroimaging methods should
specify the treatment that their participants received. This
will help untangle the effects of intervention on behavior
and the brain, and assist our understanding of the critical
differences between ASD itself and ASD in its treated state.
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... Autism spectrum disorders (ASDs) are generally regarded as lifelong conditions, affecting communication, relationships, adaptive skills, academic and vocational attainment [1]. However, recent research indicates that a percentage ranging from 3% to 25%, depending on the study, several years after the original diagnosis no longer fulfil the diagnostic criteria of autism [2][3][4][5][6]. In a follow-up study, Kelley, Naigles and Fein [7] examined a sample of children with optimal outcomes aged 8-13 years and found that these were comparable to those with the typical development group on all language measures and showed psychiatric vulnerability only in attention regulation. ...
... Also, other authors who have dealt with younger children (from 5 to 9 years old) with optimal outcomes, found residual pragmatic and semantic language deficits, while grammatical skills were intact [8][9][10]. Other studies on the developmental trajectories of people with an original diagnosis of autism have found adequate adaptive social-communication skills, effective experiences of inclusion in regular education classrooms [2], normal intellective functioning and an absence of typical autism symptomatology [5]. ...
Article
Full-text available
Autism spectrum disorders are generally regarded as lifelong conditions, affecting communication, relationships, and adaptive skills. Studies on the developmental trajectories of people out of autism have found adequate adaptive social-communication skills, effective experiences of inclusion in regular education classrooms, normal intellective functioning, and an absence of typical autism symptomatology. It therefore seems plausible to start reading the 'after autism' psychopathological conditions in a continuum that features several possible clinical and non-clinical phenotypes. The present retrospective research aimed to examine the different developmental trajectories of 17 children with an original diagnosis of autism, evaluated in a follow-up approximately 5 years after the end of the therapy. The stability of the optimal outcomes is evidenced by the absence of clinical diagnostic criteria for autism spectrum disorder. However, some difficulties persisted in adaptive functioning, especially in the social domain, consistent with the dysfunctional core that characterized the clinical features of autism in childhood. Furthermore, many of the participants showed residual relational atypia, such as alterations in pragmatic communication, or a psycho-affective disorder, or specific developmental disorders. The presence of some residual atypia provides important food for thought, not only in orienting any therapy with which continue to support older children, but also for a greater understanding of the pathological core towards which has evolved the original diagnosis of autism.
... Helles et al. (2015) found that individuals displaying loss of ASD diagnosis had milder symptom presentations at an earlier time compared with individuals displaying persistent ASD. Studies investigating predictors of persistence across the autism spectrum suggest that receiving an early diagnosis and/or early intervention and having higher IQ and/or language skills are associated with loss of ASD diagnosis (see Helt et al., 2008 for review). ...
Article
Background The aim was to examine diagnostic persistence of Autism Spectrum Disorder (ASD) in individuals without intellectual disability from childhood to emerging adulthood. Method We assessed 38 children with estimated full-scale intelligence quotient (IQ) >70 who were diagnosed with ASD at baseline (Mage=12.0, SD=2.3, 84% male), and re-assessed two (n=37, Mage=14.2, SD=2.4, 84% male) and 10 years (n=23, Mage=21.7, SD=2.4, 78% male) later. Results At two-year follow-up, all participants still met diagnostic criteria for ASD according to the Diagnostic and Statistical Manual for Mental Disorders – fourth version (DSM-IV). At 10-year follow-up, 65% met diagnostic criteria for ASD according to DSM-IV, 48% met diagnostic criteria according to the Diagnostic and Statistical Manual for Mental Disorders – fifth version (DSM-5), 57% met the ASD cut-off on the Autism Spectrum Quotient 10-item (AQ-10), and 78% met either DSM-IV criteria or cut-off on the AQ-10. Higher IQ in childhood predicted loss of ASD diagnosis according to DSM-IV criteria (Hedges g = 1.30). A higher proportion of girls compared to boys displayed loss of ASD diagnosis according to DSM-IV criteria. Conclusions These findings suggest that ASD traits among individuals without intellectual disability may wane into emerging adulthood and that loss of ASD diagnosis is associated with higher IQ and being a girl. Diagnostic re-evaluations may be warranted for some individuals diagnosed with ASD as children or adolescents.
... In addition to method intensity, we examined whether other factors could mediate the observed decrease in scores. Intellectual quotient and verbal IQ (VIQ) language development skills, nonverbal communication skills and motor skills have already been associated with optimal ASD outcomes [39][40][41][42][43]. We wondered if the age of the participants, sex, severity of ASD, or comorbidity naturally could have an impact on their behavioural and developmental skills. ...
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Full-text available
Background The Intensive, Interactive, and Individual (3i) intervention approach aims to decrease the severity of autism spectrum disorder (ASD) using intensive developmental play therapy (3i). We performed a retrospective study of 90 children who were enrolled for 2 years in the 3i approach to assess changes and predictors of changes in ASD severity at follow-up (FU). Methods The ASD severity of all patients (N = 119) who began 3i intervention between 2013 and 2018 was systematically measured using the childhood autism rating scale (CARS) and autism diagnosis interview-revised (ADI-R). Among them, 90 patients (mean age 5.6 ± 3.7 years) had a second assessment at the 2 year FU. CARS and ADI-R scores after 2 years of 3i intervention were compared to baseline scores using paired student’s t-tests. We used multiple linear regression models to assess the weight of baseline variables (e.g., age, oral language, sex, treatment intensity) on changes at the 2 year FU. Results Mean CARS and ADI-R subscores (interaction, communication, repetitive behaviour) decreased significantly by 20, 41, 27.5 and 25%, respectively (effect sizes: d > 0.8). Moreover, 55 and 46.7% of participants switched to a lower category of ASD severity based on the CARS scale and ADI-R interview, respectively. Multiple linear models showed that (i) a higher treatment intensity (more than 30 h per week) was significantly associated with a greater decrease (improvement) in the ADI-R interaction score; (ii) patients categorized as verbal subjects at baseline were associated with a better outcome, as ascertained by the CARS, ADI-R interaction and ADI-R communication scores; and (iii) older patients were significantly associated with a greater decrease in the ADI-R interaction score. However, we found no impact of sex, severity of ASD or comorbidities at baseline. Conclusion This study performed on 90 children suggests that 3i therapy may allow for a significant reduction in ASD severity with improvements in interaction, communication, and repetitive behaviours. A study using a control group is required to assess the efficacy of 3i play therapy compared to other interventions.