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Parental Recognition of Developmental Problems in Toddlers with Autism Spectrum Disorders

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Symptoms of Autism Spectrum Disorders (ASD) begin to manifest during the first 2 years; there is limited evidence regarding type and timing of symptom onset. We examined factors related to parental age of recognition (AOR) of early abnormalities and the association between AOR and diagnosis and levels of functioning at 2 and 4 years in 75 toddlers with ASD. Results suggest significant differences between autism and PDD-NOS in the AOR and type of first concerns. Early social and motor delays as well as maternal age was associated with AOR. Later AOR was associated with poorer social-communicative and nonverbal cognitive functioning at 2 and 4. The findings are discussed in a context of identifying distinct developmental trajectories within the autism spectrum.
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ORIGINAL PAPER
Parental Recognition of Developmental Problems in Toddlers
with Autism Spectrum Disorders
Katarzyna Chawarska Æ Rhea Paul Æ Ami Klin Æ
Sarah Hannigen Æ Laura E. Dichtel Æ Fred Volkmar
Ó
Springer Science+Business Media, LLC 2006
Abstract Symptoms of Autism Spectrum Disorders
(ASD) begin to manifest during the first 2 years; there
is limited evidence regarding type and timing of
symptom onset. We examined factors related to
parental age of recognition (AOR) of early abnorma-
lities and the association between AOR and diagnosis
and levels of functioning at 2 and 4 years in 75 toddlers
with ASD. Results suggest significant differences
between autism and PDD-NOS in the AOR and type
of first concerns. Early social and motor delays as well
as maternal age was associated with AOR. Later AOR
was associated with poorer social-communicative and
nonverbal cognitive functioning at 2 and 4. The
findings are discussed in a context of identifying
distinct developmental trajectories within the autism
spectrum.
Keywords Autism PDD-NOS Infants Age of
recognition Regression
Introduction
Despite the wide acceptance that symptoms of Autism
Spectrum Disorders (ASD) manifest during the first
2 years of life, there is still very limited evidence
regarding the timing of onset and the nature and
severity of the primary symptoms. Studies on parental
perception of symptom onset as well as analysis of
video diaries (e.g., De Giacomo & Fombonne, 1998;
Werner & Dawson, 2005) suggest that some children
may be exhibiting abnormal behaviors and delays
within the first postnatal months, while in others the
concerns arise after a period of more or less typical
development and begin sometime in the second or
even third year of life (see Chawarska & Volkmar,
2005 for a review).
Age of Recognition
Consistent with previous reports (e.g. Rogers &
DiLalla, 1990; Volkmar, Stier, & Cohen, 1985), more
recent studies suggest that the vast majority of parents
of children with ASD notice abnormalities during the
course of the first 2 years of life (Baghdadli, Picot,
Pascal, Pry, & Aussilloux, 2003; De Giacomo &
Fombonne, 1998; Tolbert, Brown, Fowler, & Parsons,
2001). De Giacomo and Fombonne administered the
Autism Diagnostic Interview-Revised (ADI-R) (Lord,
Rutter, & Le Couteur, 1994) to 82 parents of children
with ASD (mean age 6 years). On average, parents
began to recognize that their children were experienc-
ing problems at around 19 months, with approximately
30% of parents noticing first abnormalities prior to the
first birthday, and 80% by the age of 2 years. Similar
results have been reported with a French sample of
ASD children of a comparable age, in which the
average AOR was 17 months, with 38% of parents
concerned by 12 months, and 78% noticing abnormali-
ties by 24 months (Baghdadli et al., 2003).
K. Chawarska (&) R. Paul A. Klin
S. Hannigen L. E. Dichtel F. Volkmar
Yale Child Study Center, Yale University School
of Medicine, New Haven, CT 06520, USA
e-mail: katarzyna.chawarska@yale.edu
R. Paul
Department of Communication Disorders, Southern
Connecticut State University, New Haven, CT, USA
J Autism Dev Disord
DOI 10.1007/s10803-006-0330-8
123
Leading Reasons for Parental Concerns
Amongst the most common and often first noted
concerns are delays in speech and language develop-
ment, followed by abnormal social responsivity level,
medical problems, and nonspecific difficulties related
to sleeping, eating and attention (De Giacomo &
Fombonne, 1998). In young children, concerns regard-
ing unusual interests and stereotyped behaviors rarely
trigger parental concerns, most likely due to their
relatively mild manifestations in infancy or a later
onset. Parental concerns sometimes emerge in
response to unusual rate of progress (e.g., delays in
reaching developmental milestones), apparent slowing
of development (e.g., if babbling is not followed by
emergence of the first words), or loss of previously
acquired skills (Siperstein & Volkmar, 2004). Regres-
sion is usually reported in 20–33% of cases (Goldberg
et al., 2003; Rapin & Katzman, 1998; Werner &
Dawson, 2005) and can involve loss of words, vocal-
izations, nonverbal communication skills (e.g., eye
contact, gestures), social dyadic interaction skills,
imitation, or pretend play (Davidovitch, Glick, Holtz-
man, Tirosh, & Safir, 2000; Goldberg et al., 2003;
Luyster et al., 2005). Parental reports of regression do
not necessarily indicate normal development prior to
the perceived loss of skills nor would early abnormal-
ities preclude regression (Lord, Shulman, & DiLavore,
2004; Siperstein & Volkmar, 2004; Werner & Dawson,
2005; Wilson, Djukie, Shinnar, Dharmani, & Rapin,
2003). The perception of regression, however, appears
to be specific, though clearly not universal, to ASD
(Luyster et al., 2005; Siperstein & Volkmar, 2004).
Factors Affecting Age of Recognition
The concurrent presence of mental retardation, delays
in motor milestones, significant speech delays, and
medical problems tends to trigger the onset of parental
concerns earlier compared to cases in which ASD is
not accompanied by these challenges (De Giacomo &
Fombonne, 1998). Presence of perinatal complications
and sensory deficits has also been associated with
earlier recognition (Baghdadli et al., 2003). Factors
that have not been found to influence the AOR include
birth-order, social class, and gender (De Giacomo &
Fombonne, 1998). More recently, growing appreciation
of the genetic factors in autism and increased risk for
ASD in younger siblings of the affected children might
sensitize parents to early signs of vulnerability and
contribute to earlier recognition of developmental
problems (Klin et al., 2004; Zwaigenbaum et al., 2005).
Age of Recognition and Developmental Outcome
To date, a handful of studies have attempted to examine
the predictive relationship between age of recognition
and the child’s outcome; however, the studies produced
rather mixed results. When outcome is defined in terms
of IQ level, some researchers suggest no relationship
(Rogers & DiLalla, 1990; Volkmar et al., 1985), while
others report that earlier onset is related to greater
severity of cognitive impairment (Short & Schopler,
1988). If the issue of outcome, still defined as IQ level, is
cast around regression as a form of later onset or
recognition, the evidence is also mixed. Some studies
suggest poorer long-term outcome in children with
reported loss of skills (Christopher, Sears, Williams,
Oliver, & Hersh, 2004;Kurita,1985; Rogers & DiLalla,
1990; Tuchman, & Rapin, 1997). This is particularly true
in the rare syndrome of Childhood Disintegrative
Disorder (Volkmar, Koenig, & State, 2005). Others
however, report that in the short term (at 24 months),
there appear to be few differences in terms of verbal
and nonverbal developmental skills between children
with and without loss of skills (Werner, Dawson,
Munson, & Osterling, 2005). Similarly, the relationship
between language levels and AOR is unclear. Rogers
and DiLalla examined the relationship between age at
parental recognition of social difficulties and levels of
social, cognitive, and communicative outcome in young
children with autism and PDD-NOS (average age
45 months), and found that children with the poorest
language outcome began manifesting social problems in
thesecond,butnotinthefirstorthird,yearoflife.
Reports regarding the relationship between AOR
and severity of autistic symptoms are mixed as well.
Some researchers find no relationship between severity
of symptoms as measured by the ADI-R or clinical
diagnosis (i.e., autism versus PDD-NOS) (De Giacomo
& Fombonne, 1998) and the parentally reported age of
onset, or between CARS scores and the AOR (Rogers
& DiLalla, 1990). Others however, report a modest
relationship between an earlier AOR (<18 months)
and more severe autistic symptoms as measured by the
CARS (Baghdadli et al., 2003; Short & Schopler, 1988).
Still others argue that those with later onset, as defined
by parental report of regression or loss of skills, have
poorer social-communicative skills at the age of
3 years, as compared to those with an earlier recog-
nized symptom onset (Luyster et al., 2005).
Limitations of Previous Studies
The empirical evidence regarding parental recognition
of developmental abnormalities and its relationship to
123
J Autism Dev Disord
outcome is inconsistent. This is not surprising given the
heterogeneity of sampling procedures as well as
differences in analytic and methodological approaches
adopted in the aforementioned studies. Information
regarding the timing and type of first symptoms has
often been collected years after the onset of recogni-
tion, ranging from fewer than 2 to more than 30 years.
The long interval separating AOR and the time of
parental report might lead to the ‘telescoping effect’
(Cooper et al., 2001), that is, a tendency of parents, as
children grow older, to report a later age of symptom
recognition. Furthermore, some researchers relied on a
review of medical records or questionnaires, while
others collected data through standard parent inter-
view procedures. In some studies, parental report and
estimates based on expert opinion were combined.
While the sample in some studies included clients
living in a residential facility, others focused on clients
receiving care in specialized clinics, which most likely
resulted in highly variable rates of genetic and neuro-
logical problems across samples. There is also great
variability of methods used to ascertain IQ informa-
tion, both within and between samples (e.g., due to a
wide age range in the same sample, level of cognitive
functioning might be measured by developmental or
IQ tests, depending on the age of the subjects).
Information regarding social and communicative func-
tioning was often obtained through parent interview,
with fewer studies relying on observational scales such
as CARS or the ADOS. Drawing inferences regarding
the relationship between AOR and outcome, however
broadly defined, might have also been complicated by
the fact that in the majority of cases, information
regarding AOR and outcome was collected simulta-
neously, leading to possible confounds.
Present Study
The age of parental recognition (AOR) of develop-
mental problems is typically distinguished in the
literature from the age of symptom onset, and the
former is regarded as representing the upper-bound
limit to the actual age of symptom onset (Volkmar,
Stier, & Cohen, 1985). Thus, determining factors that
delay or precipitate the onset of parental concerns is
important, as they are likely to affect the age at which
the child accesses appropriate early assessment and
intervention services. Furthermore, examining the
timing and type of parental concern might offer insight,
albeit indirectly, into the question of the endopheno-
types present within the autism spectrum. The present
study revisits the question of parental recognition of
developmental problems in ASD. The study provides
an improvement over earlier investigations by (1)
shortening the time elapsing between the onset of
concerns and the direct assessment by including only
children diagnosed prior to the 3rd birthday; (2)
providing prospective assessment of the outcome at
the age of 4 years; (3) employing of direct and
standardized assessment measures of the child’s func-
tioning; and (4) increasing homogeneity of the sample.
Presence of major perinatal complications or postnatal
health problems is likely to trigger concerns regardless
of the presence of social-communicative impairments,
and thus, confound information regarding the early
course of ASD. In the present study, we constrained
the impact of some of these factors by including only
children without a history of significant medical prob-
lems or serious complications associated with preg-
nancy or delivery, including prematurity. This resulted
in a less medically compromised and more homoge-
nous sample.
Furthermore, in our study the AOR ranged from
birth to 26 months, spanning across several important
developmental epochs including the onset of dyadic
and triadic social interactions, as well as nonverbal and
verbal communication. Guided by the developmental
milestones that are highly relevant to studies of ASD,
we examined the AOR not only as a continuous
variable, but also compared groups with the onset of
parental concerns during the pre-verbal phase of
development (birth—10 months, AOR1), early verbal
(11—17 months, AOR2), and verbal phase (18 months
and older, AOR3). These intervals also roughly map
onto the periods of social development that involve
primarily dyadic interactions (AOR1), emergence of
joint attention (AOR2), and beginnings of more
complex and integrated social, symbolic, and commu-
nicative development (AOR3).
Two main questions guided our analytic approach.
First, we examined factors that influence the timing of
parental recognition of developmental problems,
including severity of autistic symptoms, concomitant
cognitive delays, and parental knowledge of develop-
ment. The pathogenic factors responsible for social
dysfunction might be present from birth, though
symptom severity and temporal pattern of expression
may vary depending on the genetic and neurodevel-
opmental load as well as environmental factors. Such
differences could result in triggering parental concerns
at different times and perhaps for different reasons.
Conversely, if the AOR is confounded by parental
denial, lack of experience with typical developmental
trajectories, or issues related to retrospective reporting,
we would find no relationship between the AOR and
the child’s developmental history and presentation at
123
J Autism Dev Disord
the time of diagnosis. We hypothesized that parental
age of recognition reflects, at least to some extent, their
child’s unique developmental trajectory and thus, we
expected to identify a set of factors that will differen-
tiate the earlier AOR groups from those whose parents
noted abnormalities later. Second, we examined
whether there is a relationship between AOR and
developmental outcome several years later. We
hypothesized that the different AOR groups are
related to different phenotypic variants of the autism
spectrum, and thus, differences in AOR will be
predictive of outcome defined in terms of clinical
diagnosis as well as cognitive, communication, adap-
tive, and social functioning.
Method
Participants
Seventy-five toddlers underwent a comprehensive
evaluation prior to their 3rd birthday as part of a
longitudinal study on early social-cognitive develop-
ment. The inclusion criteria were: gestational age at
least 34 weeks and the absence of visual or auditory
impairments or seizures at the time of enrollment into
the study. At Time 1, all children underwent a
comprehensive assessment, which included the Mullen
Scales of Early Learning (Mullen, 1995) and the
Autism Diagnostic Observation Scales–G, Module 1
(ADOS-G; Lord et al., 2000). Parents were inter-
viewed with the Vineland Adaptive Behaviors Scales-
Expanded (Vineland, Sparrow, Balla, & Cicchetti,
1984) and Autism Diagnostic Interview-Revised (Lord
et al., 1994). At Time 1, all children were diagnosed by
the study clinicians (FV, AK, RP, and KC) as having
an autism spectrum disorder. Following the assess-
ment, all children were referred to early intervention
services and were re-evaluated around their 4th birth-
day using the same set of assessment procedures.
Based on the consensus clinical diagnosis of two
clinicians, at the age of 4 years, 51 children were given
the diagnosis of autism, and 24 the diagnosis of PDD-
NOS (see Table 1 for sample characterization).
The vast majority of the participants were Caucasian
(94%) with African Americans and Asians represent-
ing 4% and 1%, respectively. There were no differ-
ences between the diagnostic groups in terms of
parental educational level or maternal age at the time
of the child’s birth. The diagnostic groups were also
similar in terms of gestational age and the onset of the
major developmental milestones, but children with
PDD-NOS tended to have a marginally lower birth
weight. In both groups, approximately 40% of children
were firstborn and of the 75 children, 45 (60%) had
older siblings. In 44% (20 of the 45) of these cases,
parents reported that the older sibling(s) had some
developmental problems including ASD, speech and
language delays, sensory problem, and motor delays.
Within this group of siblings with developmental
problems, 24% (11 of the 45) carried a diagnosis of
ASD.
Procedure
Information regarding the age of parental recognition
was ascertained at the time of the first assessment and
prior to the 3rd birthday using the toddler version of the
(ADI-R) (Lord et al., 1994). The interview was
conducted by an experienced interviewer blind to the
child’s developmental level and diagnostic status. On
average, the time elapsed between the AOR and the
ADI-R interview was 13.5 months (SD =7.04, range:
.84–34) and did not differ between the diagnostic
groups. The ADI-R was conducted independently of
the child’s direct assessment the day before feedback
regarding the diagnosis and other findings were dis-
cussed with the parent. Through the ADI-R we also
collected information about the type of concerns and
their priority. The list of concerns includes (1) speech
and language delays and abnormalities (S&L), (2)
medical problems (e.g., seizures) and motor delays
(Medical/Developmental), (3) social abnormalities man-
ifesting as lack of interest in people (Social), (4)
nonspecific problems related to sleep, eating, aggres-
sion, or activity level (Nonspec), and (5) stereotyped
behaviors (SB), as well as the (6) ‘Other’ category
including family issues, etc. In addition, information
regarding parental perception of loss of skills was
derived directly from the ADI-Toddler form in all but
19 cases. For these 19 participants, parents were
administered a short version of the ADI- R Research
Short Form (Lord, Rutter, & LeCouteur, 1994)thatdid
not contain the regression questions. Consequently,
information regarding parental perception of loss of
skills was obtained from the medical and developmental
history collected by a psychiatrist during the first visit.
For the purpose of this study, regression was defined
broadly as a loss of any skills including speech, social
engagement, play or motor skills. Information regarding
maternal age, history of infertility, course of pregnancy
and the child characteristics (birth order, birth weight,
gestational age, risk status) was obtained through a
parent questionnaire. The pregnancy complication var-
iable was created by summing up all the complications
in the following categories: diabetes, hypertension,
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J Autism Dev Disord
problems with thyroid, liver, heart, and other organs,
infections including sexually transmitted diseases,
measles, and viral infections, swelling, and X-ray
exposure.
Results
Age of Recognition
The mean age of onset of parental concerns in the
group with Autism was 14.7 months (SD = 6.5) and
was comparable to that reported in the PDD-NOS
group (mean = 14.9 months, SD = 5.6). The ADI
specifies the domain of primary concern, but also
allows for coding multiple concerns (up to three have
been used in this study). For the purpose of this
analysis we focus on the overall frequency of various
concerns rather than their priority (see Table 2).
Concerns regarding language development and
social relatedness were the most frequent and were
equally prevalent in both diagnostic groups. However,
parents of children with autism were significantly more
likely to report their children as having medical
problems and motor delays (/ = .28), as well as
unusual autistic-like stereotyped behaviors (/ = .36),
than parents of children with PDD-NOS. In compar-
ison, children with PDD-NOS had more nonspecific
problems related to sleeping, eating, and activity level
(/ = .25). The effect sizes for these effects ranged from
medium to large.
Determinants of AOR: Maternal and Child
Characteristics
To examine whether age of recognition was related to
familial risk status, parental experiences, and child
characteristics either prior to, or at the time of the
assessment, we compared the AOR groups on a
number of variables (see Table 3).
Prior to the main series of analyses we examined
whether AOR and the age of the assessment were
associated. Children with an earlier AOR might have
been assessed at a younger age, which in turn might
have impacted their scores on the standard assessment
instruments, introducing additional variance into the
model. A between-group ANOVA on the age at Time
1 assessment indicated a marginally significant differ-
ence in age at Time 1, F (2, 72) = 2.71, P < .073. A
planned contrast comparing the age in AOR1 with
AOR2 and AOR1 with AOR3 revealed that AOR
Table 1 Sample characterization at Time 1
Characteristic Autism (N = 51) PDD-NOS (N = 24) P-value
Age at T1 (months) 28.5 (4.7) 27.8 (5.7) .05
Time between AOR and ADI-R (months) 13.8 (7.4) 12.9 (6.4) ns
Pregnancy complications .62 (.78) .52 (.73) ns
Birth weight (g) 3445 (571) 3179 (550) .062
Gestational age (weeks) 39.3 (2.3) 39.1 (1.7) ns
Social smile (months) 2.6 (1.5) 2.2 (1.3) ns
Walked (months) 13.5 (2.5) 13.8 (2.4) ns
% Firstborn 39 42 ns
% Children having one or more siblings with developmental
problems of any kind (N = 45)
a
14 (45%) 6 (43%) ns
% Children with one or more siblings
with ASD (N = 45)
a
7 (23%) 4 (29%) ns
Maternal education (years) 16 (2) 16 (2) ns
Paternal education (years) 16 (2) 16 (2) ns
Maternal age (years) 34 (5) 34 (5) ns
Mullen receptive language DQ
b
40 (23) 63 (25) .001
Mullen expressive language DQ
b
49 (21) 66 (18) .001
Mullen visual reception DQ
b
72 (18) 84 (16) .01
ADOS Soc/Com Score 18.6 (2.8) 14.2 (4.6) .001
a
Percentage based on a sub-sample of children who had siblings who had siblings at the time of the second assessment (N = 60)
b
Age Equivalent/Chronological age*100
Table 2 Frequency of parental concerns in autism and PDD-
NOS groups
Concerns (%) Autism PDD-NOS v
2
P-value
Speech and language
delays
70.6 79.2 .61 ns
Social difficulties 60.8 41.7 2.4 ns
Medical problems,
developmental delays
29.4 4.2 6.19 .013
Stereotyped behaviors 17.6 0 4.81 .028
Nonspecific problems 5.9 33.3 9.82 .002
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J Autism Dev Disord
groups 1 (mean = 26.5 months, SD = 5.4) and 2
(mean = 27.5 months, SD = 5.5) did not differ from
one another, but the AOR3 group was tested at a
slightly older age (mean = 29.7 months, SD = 4.2), F
(1, 72) = 4.46, P < .05 than the AOR1 group. Thus, the
age at Time 1 assessment was included in subsequent
analyses as a covariate. A series of between-group
ANOVAs was conducted with planned contrasts
whenever applicable (see Table 3).
Children in the AOR1 had delays in the emergence
of social smiling (d = .85) and were more likely to start
walking independently at a later age (d = .65) as
compared to the two other AOR groups (see Table 3).
Children in the AOR3 group had mothers who were
older than mothers of children in AOR1 (d = 1.13) and
AOR2 (d = .88). These mothers were also more likely
to have a history of infertility treatment either with this
or previous pregnancies as compared with mothers in
the AOR1 (/= .34), but not the AOR2 group.
Children in the AOR3 group also had significantly
lower scores on the Mullen Receptive Language scale
than children in AOR1 and AOR2 (d = .77 and .67,
respectively). Effect sizes ranged from medium to
large. Factors that were not related to the AOR
grouping were gestational age and birth weight, non-
verbal levels of functioning (Visual Reception and Fine
Motor scales of the Mullen), level of play skills and
stereotyped behaviors as measured by the ADOS, as
well as adaptive levels of functioning. There was a
marginal increase in the ADOS social-communication
scores in the AOR3 group, but the results failed to
reach statistical significance. There were no differences
between the AOR groups in terms of the percentage of
children with older siblings with developmental prob-
lems. In the AOR1, 2, and 3 there were approximately
45%, 58%, and 36% of children with older siblings
experiencing some problems, respectively. These per-
centages dropped to 27%, 36%, and 36%, respectively,
when only older siblings with ASD were considered.
Age of Recognition and Clinical Diagnosis
Whereas the average AOR did not differ between
groups, examination of the frequency distributions of
the cases in the three recognition groups (AOR1,
AOR2, AOR3) indicated that approximately 50% of
children diagnosed at 4 years with autism triggered
parental concerns at or after 18 months. However, in
the group diagnosed with PDD-NOS, 54% of parents
reported concerns between 11 and 18 months. Three
one-way v
2
-tests for proportional distribution of the
frequencies within each of the groups indicated that in
AOR1 group there were significantly more children
who received the eventual diagnosis of autism (12 of
the 15, 80%) than PDD-NOS (3 of the 15, 20%),
v
2
= 5.4, P < .02. The proportion of children diagnosed
with autism and PDD-NOS was very similar in the
AOR2 group (14 of the 27, or 52% AUT, 13 of the 27,
Table 3 Characteristics of the three AOR groups: maternal and child factors
Characteristics AOR1 AOR2 AOR3 P-value Contrast
<11 months 11–18 months >18 months
N =15 N =27 N =33
Child age (months) 5.3(3.2) 13.6 (1.8) 20.1(2.9)
Maternal age (years) 32(3) 32(5) 36(4) .01 1 = 2 < 3
Infertility hx. (%), (N = 26) 7.1% 26.9% 48.5% .05
Pregnancy complications 46 (.74) .62 (.88) .61 (.67)
Firstborn (%), (N = 30) 40% 56% 27% .084
Sibling Risk Status (N = 45)
a
44% 57% 36%
GA (weeks) 39.8 (2.1) 38.8 (3.0) 39.3 (1.5)
BW (g) 3422 (449) 3278 (3.0) 3399 (508)
Social smile (mo) 3.50 (2.1) 2.04 (1.2) 2.60 (1.1) .02 1 > 2 = 3
Walked (months) 15.0 (3.5) 13.1 (2.2) 13.3 (1.7) .05 1 > 2 = 3
Mullen VR DQ 85 (22) 78 (18) 70 (13)
Mullen FM DQ 78 (13) 78 (16) 70 (12)
Mullen RL DQ 59 (36) 52 (26) 37 (18) .02 1 = 2 > 3
Mullen EL DQ 57 (27) 60 (23) 49 (18)
ADOS Soc/Com 16.1 (3.9) 16.3 (4.5) 18.5 (3.2) .07
ADOS Play 2.93 (1.4) 3.33 (1.0) 3.39 (.93)
ADOS SB 2.9 (1.8) 3.4 (1.9) 3.9 (1.8)
Vineland Com 73 (12) 72 (9) 69 (8)
Vineland DSL 71 (11) 71 (9) 67 (6)
Vineland Soc 67 (11) 67 (9) 65 (8)
Vineland Motor 82 (15) 83 (13) 80 (12)
a
Risk status included diagnosis of ASD, learning or language difficulties, sensory issues, and other delays
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J Autism Dev Disord
or 48% PDD-NOS), but in the AOR3 group, there
were again significantly more autism (25 of the 33,
76%) than PDD-NOS (8 of the 33, 24%) cases,
v
2
= 8.75, P < .003. These findings suggest an associa-
tion between severity of the social disability as judged
by an experienced clinician and the AOR. The
likelihood of receiving a diagnosis of autism at the
age of 4 was very high for those children whose parents
noted concerns very early, as well as for those who
noticed abnormal behaviors after 18 months. Children
whose parents expressed first concerns between 11 and
18 months were equally likely to receive diagnosis of
autism or PDD at the age of 4.
Relationship between Age of Recognition, Loss
of Skills, and Clinical Diagnosis
Parents reported a loss of skills in 30.6% (N = 23) of
cases. The loss tended to occur more frequently in the
second year of life, with 35% (N = 8) occurring
between 11 and 18 months and 52% (N = 12) at
18 months or thereafter. Prior to 11 months there
were only 3 (13%) cases of reported loss of skills.
Parents of children with autism reported loss (87%,
N = 20) significantly more frequently than those with
PDD-NOS (13%, N =3;v
2
= 5.47, P < .019, / = .27).
Whereas children whose parents reported regression in
the preverbal (AOR1) and early verbal (AOR2)
phases were not significantly different with regard to
diagnosis, in the AOR3 group 48% (N = 12) of cases
with autism reportedly experienced loss of skills as
compared to 0% of the PDD-NOS cases, (v
2
= 6.03,
P < .014, / = .43).
To further examine the relationship between loss of
skills and age of reported abnormalities, we conducted
a series of analyses comparing children diagnosed with
autism with and without reported loss of skills. The
leading question was whether those with reported
regression differed in terms of verbal, nonverbal,
social-communicative, or adaptive functioning from
children without regression. The numbers of children
in the younger AOR groups were insufficient to
warrant a full-model analysis so we examined this
question only for the AOR3 group. A series of
ANOVAs with loss as a between-group factor revealed
that children with autism with (N = 12) and without
loss (N = 13) in the AOR3 group performed compa-
rably on the Mullen and Vineland scales (see Table 4),
and received very similar scores on the ADOS sociali-
zation and communication scales combined. They also
had comparable scores on the Play and Stereotyped
Behaviors scales on standard assessment instruments.
Thus, children whose parents registered concerns at or
after 18 months were comparable in terms of their
performance on the standard assessment instruments
and received the same clinical diagnosis, regardless of
the presence or absence of a perceived loss of skills.
Relationship between the Age of Recognition
and Functioning at 4 years
Children were re-evaluated on average at the age of
52 months (SD = 5), 50 months (SD = 4), and
51 months (SD = 4) in the AOR groups 1–3, respec-
tively. To examine the association between AOR and
the level of functioning at the age of 4 we computed a
series of Pearson r correlations. No significant corre-
lation was found for the indices of adaptive functioning
as measured by the Vineland standard domain scores
or the Mullen expressive and receptive language as
well as fine motor scores. However, there was a
medium but significant positive association between
the AOR and the ADOS social and communication
scores (r = .27, P < .02), ADOS-G Play and Imagina-
tion score (r = .28, P < .02), and Mullen Visual Recep-
tion scores (r = –23, P < .05). The results suggest that
later age of parental recognition was associated with
worse outcome in terms of social and communicative
functioning as measured by the ADOS and poorer
nonverbal cognitive skills as measured by the Mullen
Visual Reception scale.
Discussion
In this study we report on the factors related to
parental recognition of developmental problems in the
group of children diagnosed with ASD prior to the age
Table 4 Mean (SD) Mullen, ADOS-G, and Vineland scores of
children with autism with and without reported loss of skills at 18
months or thereafter
Scale Autism: no
loss
Autism: reported
loss
N = 13,
M (SD)
N = 12,
M (SD)
Mullen VR 67.4 (15.1) 67.5 (12.3)
FM 69.8 (12.0) 66.3 (10.5)
RL 29.2 (12.2) 33.5 (14.2)
EL 40.6 (12.7) 46.2 (17.9)
ADOS Social & Comc. 19.7 (1.7) 18.8 (3.2)
Play 3.8 (0.4) 3.3 (1)
Stereotyped
Beh.
4.4 (1.7) 4.3 (1.5)
Vineland Communication 64.6 (5.5) 67.5 (6.6)
DLS 65.5 (7) 66.4 (5)
Socialization 64.2 (7.0) 61.7 (6.7)
123
J Autism Dev Disord
of 36 months. Consistent with other reports (Hoshino
et al., 1987; Rogers & DiLalla, 1990), parental AOR
did not appear to simply represent the time that
parents become aware of the difficulties. There were
tangible differences among children who, according to
their parents’ report manifest abnormalities in the
three phases of development we identified: preverbal/
dyadic interaction (birth-11 months); emerging verbal/
triadic social interaction (12–17 months); and symbolic
thought and verbal communication (18 months and
older).
Parents first noticed abnormalities on average
around 14 months, which is a somewhat earlier age
than reported in other studies (Baghdadli et al., 2003;
DeGiacomo & Fombonne, 1998; Rogers & DiLalla,
1990; Volkmar et al., 1994). This is likely to be due to a
relatively short lag between recognition and assess-
ment leading to a diminished impact of ‘forward
telescoping’, a phenomenon reported by others
(Cooper, Kim, Taylor, & Lord, 2001). We expected
that ascertaining information regarding AOR rela-
tively shortly after the onset of concerns would result
in a greater proportion of parents reporting concerns in
the first year of life. However, consistent with reports
on older children (e.g., Bahdadli et al., 2003; Rogers &
DiLalla, 1990), the AOR was distributed across the
first 2 years, with 56% of parents noticing some
abnormalities prior to 18 months. This finding may
suggest that we tapped the upper limit of the parents’
ability to recognize more subtle signs of ASD early in
development (see Chawarska, Klin, Paul, & Volkmar,
2007), highlighting the necessity for development of
highly sensitive behavioral and biological measures of
markers for ASD in the first year of life. However, it is
also possible that some children with ASD do not show
signs of the disorder in the first year of life; instead,
ASD-specific symptoms appear in the second year at
critical point in development at which earlier develop-
mental trajectories need to become integrated in order
to enable the emergence of higher levels of social and
symbolic behaviors.
Consistent with other studies (De Giacomo &
Fombonne, 1998), parents of children with autism
and PDD-NOS alike were most often concerned about
their child’s social development and speech difficulties.
However, parents of children who were later diagnosed
with autism had more concerns related to problems
such as delayed motor milestones and the presence of
unusual sensory and stereotypic behaviors than parents
of children diagnosed with PDD-NOS. In contrast,
concerns regarding problems not specific to autism,
such as problems with sleep, feeding, and overall
activity level were more frequent in the PDD-NOS
group. While this finding is intriguing and might
suggest differences in the earliest expression of social
disability in autism and PDD-NOS, it is also possible
that more severe social, communication, and develop-
mental difficulties overshadowed reporting of co-existing
but perhaps less pressing problems in these domains.
The finding however, identifies potential areas of
functioning related to arousal regulation and temper-
amental qualities that should be monitored closely in
prospective studies of younger siblings at risk for ASD.
In addition, primary concerns differed depending on
the timing of parental recognition. Children with
symptoms recognized the earliest tended to have
delayed onset of social smiling and independent
walking. The exclusion of children with a history of
prematurity, seizures, and sensory impairments possi-
bly diminished the relationship between AOR and
factors related to pre- perinatal or health issues.
Consistent with other reports (Baghdadli et al., 2003;
De Giacomo & Fombonne, 1998) birth order was not
associated with the age of recognition. Moreover,
having an older child with developmental difficulties,
including ASD, did not result in an earlier onset of
concerns in our sample. The latter finding is surprising,
as these parents should be particularly sensitized to
developmental vulnerabilities in younger siblings. It is
possible that at the time that our sample was first
collected between 2000 and 2003, the issue of an
increased genetic risk for ASD in younger siblings had
not been yet widely publicized, hence, its limited effect
on the AOR.
The oldest AOR group differed from the two other
groups in several important ways. Mothers of children
in the AOR3 group were significantly older than in the
two other groups; they were also more likely to have a
history of infertility treatment. To the best of our
knowledge, this is the first study reporting a relation-
ship between later recognition and higher maternal
age. While intriguing, the significance of this finding is
not clear. On the one hand, older mothers, especially
those who faced infertility problems, might be more
tolerant of the child’s developmental incongruities, and
thus, to register the signs of difficulties later than
younger mothers. On the other hand, maternal age of
35 or higher has been associated with a greater risk for
autism (Croen, Grether, & Selvin, 2002; Gillberg et al.,
1990; Glasson et al., 2004). This relationship is often
conceptualized as reflecting an interaction between an
increased risk of complications during labor and
delivery in older mothers and the child’s inherent
genetic vulnerabilities (Glasson et al., 2004), and thus
represents aspects of a complex gene-environment
interaction in ASD (Rutter, 2005). The clarification of
123
J Autism Dev Disord
the relationship between parental factors including
childbearing age as well as pre- and perinatal factors
and possible endophenotypic variations within the
autism spectrum would be best addressed prospectively
through studies of infants at risk for ASD and other
developmental disorders.
One of the important questions often posed in the
context of studies of ASD recognition is whether
children with recognizable abnormalities early on end
up with more profound social and other difficulties as
compared to those with later manifestations of the
disorder. This hypothesis is based on the assumption
that an earlier disruption of the developmental
sequence leads to a greater impairment downstream
in development. On the other hand, these children
might have more time to develop alternative compen-
satory strategies as compared to those with later onset,
and thus, on a short run, outperform those with the
later onset, and consequently, a shorter period of time
between the ‘onset’ and assessment. Still another
possibility is that different subtypes of ASD follow
their individual developmental trajectories reflected,
amongst other factors, in the time when problems
begin to manifest behaviorally. We addressed the issue
of the relationship between AOR and the clinical
presentation on several levels.
First, we examined the association between the
timing of the AOR and clinical diagnosis at the age of
4. In ASD, expert clinical opinion constitutes the
diagnostic gold standard, especially in younger chil-
dren. The diagnosis relies on integration of information
from multiple sources and examining the child’s profile
of skills across a number of key areas (Chawarska &
Volkmar, 2005; American Psychiatric Association,
1994; Klin, Chawarska, Rubin, & Volkmar, 2003).
The results indicate that children who were identified
by their parents as having problems between birth and
10 months were four times more likely to be later
diagnosed with autism than with PDD-NOS. However,
those manifesting abnormalities identified by parents
between 11 and 18 months were equally likely to
receive a diagnosis of autism as PDD-NOS at 4 years.
Finally, all children in the group with concerns arising
at or after 18 months received a diagnosis of autism at
the age of 4. This finding suggests a strong and nonlin-
ear relationship between the age of parental recogni-
tion and clinical diagnosis assigned 2–3 years later.
Second, we examined the relationship between the
time of recognition and the child’s cognitive, social-
communication, and adaptive skills at the age of
2 years. There were relatively few differences between
the AOR groups in performance on standard assess-
ment measures. Consistent with other reports on young
children (Rogers & DiLalla, 1990), the three groups
did not differ in terms of nonverbal cognitive skills or
the levels of adaptive functioning in the areas of
communication, socialization, daily living, and motor
skills. The vast majority of children in our study had
very significant delays in expressive language so the
differences between groups were not statistically
significant. However, the oldest AOR group had
significantly lower receptive language skills based on
the Mullen assessment. The Receptive Language scale
of the Mullen taps into understanding of verbal
communication; however, at earlier ages it focuses on
pre-verbal development, including attention to speech,
response to name, as well as understanding of com-
municative gestures. These behaviors are typically
associated with social-communicative abnormalities in
ASD in the second year of life.
Third, we found a moderate relationship between
AOR and the level of functioning at 4 years. Children
whose parents reported later onset of abnormalities
tended to have worse outcome in terms of social and
communicative functioning, symbolic play skills and
nonverbal cognitive levels. These results are inconsis-
tent with those reported by Baghdadli et al. (2003)
where earlier age of recognition was modestly associ-
ated with more severe autistic symptoms (measured by
the CARS), lower adaptive skills (Vineland) and
greater deficits in speech (ADI-R). However, their
sample was older at the time of assessment, but more
importantly, consisted of 39% of cases with neurolo-
gical, genetic, perinatal conditions, and auditory defi-
cits, leading to a presumably higher rate of cognitive
impairments and an inverse relationship between
AOR and the outcome. On the other hand, Tolbert
and colleagues (Tolbert et al., 2001) reported no
association between age of onset and clinical presen-
tation, as measured by the CARS and the Aberrant
Behavior Checklist (ABC) in a cohort of older insti-
tutionalized adults. Studies that focus on younger
children, however, report findings that are more in
line with ours. Rogers and DiLalla (1990) reported
poorer language outcome in children recognized in the
second but not in the first year of life. More pro-
nounced impairment in social-communicative skills
were also reported at 36 months in children with later
onset combined with regression as compared with
those manifesting symptoms earlier and not experi-
encing regression (Luyster et al., 2005).
The vast majority of studies on regression focus on
comparing children with and without loss of skills
(however defined), with less regard to the age when the
reported regression occurred. In the present study we
were able to examine whether children whose parents
123
J Autism Dev Disord
reported regression at 18 months or thereafter, dif-
fered from those who reported onset of problems
during this time period, but without any loss of skills.
The results suggest that the two groups were indistin-
guishable in terms of clinical diagnosis (all were
diagnosed with autism), verbal and nonverbal cognitive
skills, social and communication skills, play, stereo-
typed behaviors, and adaptive skills. Similar findings
with regard to adaptive functioning (Vineland) and
constellation of symptoms (ABC) have been recently
reported in a retrospective study of older children
(Siperstein & Volkmar, 2004). This suggests that while
there is a strong association between this age period
and reports of regression, behaviorally, these children
are not distinguishable at the age of 2 from those with
an identical AOR but without reported loss of skills.
This finding posits an interesting question whether
cases with and without reported loss in fact represent
different phenotypic variations. The time when par-
ents report regression most frequently coincides with
a period of important transitions across a number of
key developmental areas including a change from
prelinguistic to primarily verbal expression of inten-
tions, expansion of expressive and receptive vocabu-
lary, the development of representational, memory,
and imitation skills, categorization, symbolic play,
social interactions, and development of sense of self
(see Courage & Howe, 2002 for a review). It may be
possible that some children with autism do not show
striking developmental delays and abnormalities early
on (though some delays might be present), but they
fail to successfully complete the stage of development
at which the early emerging skills become integrated
and transformed. For instance, in some children with
autism the early social behaviors such as smiling and
mutual gaze may emerge typically (Werner & Daw-
son, 2005), but around 18 months these skills fail to
connect to more specific communicative patterns
when language and symbolic thought begin to medi-
ate the early purely affective interaction and enmesh
them in a more symbolic context (Bloom, 1997). This
transition from affective to symbolic communication
may constitute a pivotal point in development that is
uniquely vulnerable to the kind of disruption that
characterizes a later-emerging form of autism. The
later-emerging form of autism may be an example of
a failure to link emerging skills into a meaningful
network that comprises social-symbolic communica-
tion. This perspective may help to understand the
phenomenon of regression, which is most often
defined as loss of expressive skills. That is, expressive
skills may emerge through basic developments such as
the ability to produce speech-like vocalizations, which
appears to be a highly buffered and not easily disturbed
developmental system. For instance, infants with hearing
loss vocalize and babble like typical babies; however,
they lose these skills at the point in development at which
production becomes linked to perception and deaf
infants lack the auditory feedback linked to their own
productions (Oller, Levine, Cobo-Lewis, Eilers, & Pear-
son, 1998). The loss of early-acquired speech-like pro-
ductions in toddlers with ASD may occur in a similar way
when the connections necessary to link these expressions
to a network of symbolic communication fails. Thus, the
actual number of true regression cases might be much
lower than previously reported (Siperstein & Volkmar,
2004), and their relationship with Childhood Disintegra-
tive Disorder needs to be clarified.
Taken together, these findings suggest that there
might be several distinct pathways to a diagnosis of
autism and PDD-NOS. Further identification of the
various developmental trajectories, their relationship
with phenotypic subtypes, and the role of underlying
neurobehavioral and genetic mechanisms in the path-
ogenesis of ASD will have to be addressed through
large prospective longitudinal studies of high-risk
cohorts of infant siblings.
Acknowledgments This study was supported by the NAAR
grants and NIMH Grant # U54 MH66494 awarded to Fred
Volkmar, Katarzyna Chawarska, Ami Klin, and Rhea Paul. We
would like to thank the children and their parents who
participated in the study.
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Existing screening instruments for Autism Spectrum Disorder (ASD) might be prone to detect a male manifestation of ASD. Here, we examined the 17 items from the ASD domain in the Autism-Tics, ADHD and other Comorbidities inventory (A-TAC) for Differential Item Functioning (DIF). Data were obtained from the Child and Adolescent Twin Study in Sweden (CATSS) in which parents have responded to the A-TAC. Information regarding a registered diagnosis of ASD were retrieved from the National Patient Register. The cohort was divided into a developmental sample for evaluation of DIF, and a validation sample for examination of the diagnostic accuracy of the total ASD domain, and a novel male and female short form. Our main finding included the identification of DIF for six items, three favouring males and three favouring females. The full, 17 item, ASD domain and the male and female short form showed excellent ability to capture ASD diagnoses in both males and females up to the age of nine years. The full ASD domain in A-TAC is psychometrically largely equivalent across sex and the limited differences between males and females diminish the need for a sex-specific scoring when utilizing the 17 item total score.
... ASD is a heterogeneous, lifelong, neurodevelopmental disorder characterized by persistent deficits in social communication and social interaction across multiple contexts, restricted/repetitive patterns of interests/behavior, and sensory dysfunction. 1 These characteristics often present during the child's early development as significant deficits in communication, social behavior and cognitive and adaptive functioning. 1 ASD is often accompanied by comorbid conditions, including intellectual disability (ID), attention deficit hyperactivity disorder (ADHD) and obsessive compulsive disorder (OCD). [2][3][4] It is a disorder that cannot be easily identified by either the parents or the doctor in the early stages, but atypical behaviors can usually be observed after the age of 6 months. 5-7 ...
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Autism spectrum disorder (ASD) is a multifactorial neurodevelopmental disorder which has attracted the interest of researchers in many scientific fields. The prevalence of a disease or a disorder is important for healthcare and socioeconomic reasons. According to the World Health Organization (WHO), currently, 1 in 160 children is born with ASD (0.63%), possibly a conservative estimate, as many studies have reported a prevalence higher than 1%. Even so, the WHO rate is approximately 14 times higher than that reported in the first epidemiological study on ASD, which was conducted in the UK 50 years ago. It is currently estimated that approximately 60 million people worldwide have ASD. Diagnosis and documentation of these individuals is challenging, due to the nature of the disorder and its broad spectrum. Many countries have no epidemiological data on ASD and several epidemiological studies on ASD record significant methodological limitations, but the currently available data indicate that the prevalence of ASD has risen over the years. The interpretation of this trend remains uncertain, but several factors have been documented that may have contributed to this apparent increase, including revision of the diagnostic criteria, overdiagnosis, scientific advances, accessibility to services, increase in social awareness, and improvement in the methodology applied in the epidemiological studies, in addition to environmental and other factors.
... Accumulating evidence indicates that up to 83% of children with ASD have varying degrees of poor motor skills and delayed motor development as compared with typically developing children [5][6][7][8][9][10][11][12]. Such motor dysfunction or deficits have been observed on measures of gross and fine motor skill, coordination, balance, gait pattern, postural control, joint flexibility and movement speed [13][14][15]. Motor skill deficits can reduce the opportunities for participation in physical activity, increasing the rate of sedentary-related diseases [16] and possibly contributes to social isolation, anxiety, and emotional challenges for children with ASD and their families [17]. Therefore, it is important to monitor motor competence in children with ASD and address motor skill deficits through targeted interventions. ...
... Many of such studies have focused on follow-up of young children referred for clinical ASD assessment or children who received community-based ASD screening; most used Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV) (13) or Fourth Edition, Text Revision (DSM-IV-TR) (14) diagnostic categories. While sample sizes were small in most studies, high stability rates (72-100%) have been reported when first assessments occurred near the second birthday and follow-up assessments occurred from about 1-7 years later (1,(15)(16)(17)(18)(19)(20)(21). In a study of 172 2-year-olds referred for clinical assessment to rule out autism and followed to age 9 years, Lord et al. (1) reported the highest ASD diagnostic stability rates for children diagnosed with autism, as opposed to Pervasive Developmental Disorder-Not Otherwise Specified (PDD-NOS), at 24 months (using DSM-IV criteria). ...
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Given the importance of early detection, it is critical to understand the non-linearity in manifestation of ASD before age 24 months, when ASD symptoms are beginning to consolidate, through the age of 36 months when stability of ASD diagnosis is reportedly high into school-age when increased demands may challenge previously successful compensatory processes and permit first ASD detection. We employed a prospective, longitudinal design focused on children with an older sibling with ASD (n = 210) who received diagnostic evaluations at mean ages of 15.4 months (Time 1), 36.6 months (Time 2), and 5.7 years (Time 3) to examine: (1) diagnostic stability, (2) developmental trajectories associated with different patterns of ASD vs. non-ASD classifications, and (3) predictors of classification group over time. Clinical best estimate (CBE) diagnosis of ASD or non-ASD was made at each time point. Linear mixed-effects models were implemented to examine differences in developmental trajectories of stable and dynamic diagnostic groups. Multinomial logistic regression analyses were used to examine predictors of the likelihood of belonging to each CBE diagnostic classification group. Results revealed that sensitivity and stability of an ASD diagnosis significantly increased from Time 1 (sensitivity: 52%; stability: 63%) to Time 2 (sensitivity: 86%; stability: 68%). Different developmental trajectories of autism symptom severity and non-verbal and verbal IQ were observed across groups, with differences first observed at Time 1 and becoming more pronounced through Time 3. Presence of restricted and repetitive behaviors as well as limitations in initiation of joint attention and expressive language skills differentially predicted the likelihood of belonging to the different CBE diagnostic classification groups. Results suggest that ASD symptoms may emerge or attenuate over time, with some children meeting diagnosis at follow-up, and other children no longer meeting diagnostic criteria. From a systems perspective, diagnostic non-linearity may be viewed as a dynamic developmental process, where emergent properties arising from various biological, genetic, and experiential factors interact, culminating in phenotypic phenomena that change over time. Clinical implications include extending universal ASD and social communication screening into school-age, supporting families' understanding of diagnostic shifts, and ensuring unbiased diagnostic decision-making when following children with ASD.
... Autism spectrum disorder (ASD) is a neurodevelopmental disorder in which the affected individuals demonstrate deficits in social communication and interaction, as well as restricted, repetitive patterns of behavior (Livanis et al., 2017). Over half of children with ASD have a difficult time living independently from their family or require special services later in adulthood (Chawarska et al., 2007;Howlin et al., 2004). The lifelong societal cost for an individual with ASD was estimated to be $3.6 and $1.4 million in the USA and in the UK, respectively. ...
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Autism spectrum disorder (ASD) is reportedly more prevalent in urban areas partly because of better accessibility and affordability to healthcare. With universal health insurance coverage in Taiwan, a previous study has shown no urban–rural disparity in the utilization rate of a child’s preventive healthcare. Under this circumstance, we followed a birth cohort of 176,273 live births from 2006 to 2015 to detect the differences in ASD incidence between urbanicities. After adjusting for socioeconomic factors, children were 1.28 (95% confidence interval (CI): 1.13–1.44) and 1.54 (95% CI: 1.36–1.75) more likely to acquire ASD in satellite and urban areas compared with those in rural areas, respectively. A gradient association between parental educational attainment and ASD incidence was also noted. Greater ASD incidences in more urbanized areas and more advanced educated parents’ children were detected under a circumstance with low barriers to healthcare.
... The ADI-R may furthermore be subject to retrospective recall biases or may be affected by inaccurate caregiver memory, particularly if the caregiver was not concerned about their child's behavior in earlier childhood (16). This is reflected by low agreement between diagnoses based on ADI-R and those based on ADOS, particularly for older and atypical cases (7,(17)(18)(19)(20)(21). ...
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Diagnosing autism spectrum disorder (ASD) requires extensive clinical expertise and training as well as a focus on differential diagnoses. The diagnostic process is particularly complex given symptom overlap with other mental disorders and high rates of co-occurring physical and mental health concerns. The aim of this study was to conduct a data-driven selection of the most relevant diagnostic information collected from a behavior observation and an anamnestic interview in two clinical samples of children/younger adolescents and adolescents/adults with suspected ASD. Via random forests, the present study discovered patterns of symptoms in the diagnostic data of 2310 participants (46% ASD, 54% non-ASD, age range 4–72 years) using data from the combined Autism Diagnostic Observation Schedule (ADOS) and Autism Diagnostic Interview—Revised (ADI-R) and ADOS data alone. Classifiers built on reduced subsets of diagnostic features yield satisfactory sensitivity and specificity values. For adolescents/adults specificity values were lower compared to those for children/younger adolescents. The models including ADOS and ADI-R data were mainly built on ADOS items and in the adolescent/adult sample the classifier including only ADOS items performed even better than the classifier including information from both instruments. Results suggest that reduced subsets of ADOS and ADI-R items may suffice to effectively differentiate ASD from other mental disorders. The imbalance of ADOS and ADI-R items included in the models leads to the assumption that, particularly in adolescents and adults, the ADI-R may play a lesser role than current behavior observations.
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To date, a deficit-oriented approach dominates autism spectrum disorder (ASD) research, including studies of infant siblings of children with ASD at high risk (HR) for the disabilities associated with this disorder. Despite scientific advances regarding early ASD-related risk, there remains little systematic investigation of positive development, limiting the scope of research and quite possibly a deeper understanding of pathways toward and away from ASD-related impairments. In this paper, we argue that integrating a resilience framework into early ASD research has the potential to enhance knowledge on prodromal course, phenotypic heterogeneity, and developmental processes of risk and adaptation. We delineate a developmental systems resilience framework with particular reference to HR infants. To illustrate the utility of a resilience perspective, we consider the “female protective effect” and other evidence of adaptation in the face of ASD-related risk. We suggest that a resilience framework invites focal questions about the nature, timing, levels, interactions, and mechanisms by which positive adaptation occurs in relation to risk and developmental pathways toward and away from ASD-related difficulties. We conclude with recommendations for future research, including more focus on adaptive development and multisystem processes, pathways away from disorder, and reconsideration of extant evidence within an integrated risk-and-resilience framework.
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This study aimed to explore the rates of motor difficulties in children from the Australian Autism Biobank, and how early motor concerns impacted on children functionally. Children with autism aged 2–7 years, including 441 with a Vineland Adaptive Behavior Scale (VABS-II) motor subscale and 385 with a Mullen Scales of Early Learning (MSEL) fine motor subscale were included (n total = 514; 80% male). Approximately 60% of children on the MSEL and ~ 25% on the VABS-II had clinically significant motor impairments. More children with delayed sitting and walking motor milestones had early childhood parent reported motor difficulties (p < 0.001). Early motor delays or concerns may assist identifying individuals who will likely benefit from early ongoing developmental monitoring and early support.
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