Cognitive Rehabilitation Interventions for Executive
Function: Moving from Bench to Bedside
in Patients with Traumatic Brain Injury
Keith Cicerone1, Harvey Levin2, James Malec3, Donald Stuss4,
and John Whyte5
& Executive function mediated by prefrontally driven distrib-
uted networks is frequently impaired by traumatic brain in-
jury (TBI) as a result of diffuse axonal injury and focal lesions.
In addition to executive cognitive functions such as planning
and working memory, the effects of TBI impact social cogni-
tion and motivation processes. To encourage application of
cognitive neuroscience methods to studying recovery from
TBI, associated reorganization of function, and development of
interventions, this article reviews the pathophysiology of TBI,
critiques currently employed methods of assessing executive
function, and evaluates promising interventions that reflect
advances in cognitive neuroscience. Brain imaging to identify
neural mechanisms mediating executive dysfunction and re-
sponse to interventions following TBI is also discussed. &
The National Institute of Neurological Disorders and
Stroke (NINDS) is encouraging a shift in research objec-
tives from diagnosis and descriptive analysis of neuro-
psychological assessment of the cognitive impairments
in traumatic brain injury (TBI) to the development
of evidence-based interventions in the evaluation and
treatment of patients with TBI. To further that goal, an
NINDS workshop highlighted a limited set of neurolog-
ical conditions in which progress in the rehabilitation
of higher thought processes would benefit from formal
partnerships between basic cognitive neuroscientists
and clinicians in assessing residual capacity within spec-
ified lesioned circuits and potential for functional re-
turn. In this article, the TBI cognitive rehabilitation
working group provide a comprehensive analysis of
the pathophysiology of TBI, the resulting executive
function (EF) deficits in adults, the current methods
used to assess these impairments, and promising strate-
gies for enhancing both the quality of research and cog-
PATHOPHYSIOLOGY OF TBI IN RELATION
The prefrontal areas and frontal systems are particularly
vulnerable to TBI, which produces primary brain damage
of two broad types: diffuse axonal injury (DAI) and focal
cortical contusions (FCCs). DAI is a microscopic shear-
ing injury of axons and small blood vessels that occurs
throughout the brain but disproportionately involves the
deep frontal white matter (Povlishock, 1993). DAI may
also involve subcortical structures with critical frontal pro-
jections, such as the ventral tegmental area of the mid-
brain (Adair, Williamson, Schwartz, & Heilman, 1996) and
the anterior or medial thalamus. Prefrontal, but not extra-
frontal hypometabolism, measured by resting positron
emission tomography (PET) correlated with executive,
behavioral, and memory dysfunction in TBI patients with
DAI (Fontaine, Azouvi, Remy, Bussel, & Samson, 1999).
FCCs are caused either by a direct blow to the skull
transmitted to the brain or by powerful acceleratory/
deceleratory inertial forces causing the brain to be
abraded by adjacent skull (primarily the ridges and con-
fines of the anterior fossa and middle fossa). These
contusions are primarily confined to the basal frontal
and anterobasal temporal regions (Gentry, Godersky, &
Thompson, 1988). Dorsolateral prefrontal cortex (DLPFC)
FCCs are less common, but the functions associated
with this region may be compromised by disconnection
effects secondary to DAI. That is, secondary damage to
frontal systems after focal injury may result from (a)
delayed neuronal injury (as occurs after diffuse injury)
including the effects of excitoxicity and inflammation,
(b) herniation syndromes (especially frontal transfalcine
herniation that may compromise medial frontal lobes
and anterior cerebral artery perfusion) and (c) hypoxic–
1JFK Johnson Rehabilitation Institute,2Baylor College of Medi-
cine,3Mayo Clinic,4Baycrest and University of Toronto,5Moss
Rehabilitation Research Institute, Philadelphia
D 2006 Massachusetts Institute of Technology Journal of Cognitive Neuroscience 18:7, pp. 1212–1222
The effects of TBI on EF are dynamic in the sense
that these abilities are impaired immediately after injury
and recover at a variable rate depending on severity of
focal and diffuse effects. Traditionally, the initial period
of recovery following the resumption of consciousness
has been referred to as posttraumatic amnesia (PTA)
because of an obvious absence of the capacity to form
new memories. However, many other cognitive pro-
cesses including EF are also initially disrupted by TBI
(Stuss, Binns, et al., 1999).
EXECUTIVE FUNCTION: BACKGROUND
Terms such as EF, the dysexecutive syndrome, the su-
pervisory system, and frontal lobe functions are chal-
lenging to define and measure. The following schema
divides what has been loosely termed ‘‘executive func-
tions’’ into four more clearly defined and circumscribed
domains that follow anatomy and evolutionary develop-
ment: (1) executive cognitive functions, (2) behavioral
self-regulatory functions, (3) activation regulating func-
tions, and (4) metacognitive processes (Stuss, in press).
Executive Cognitive Functions
Evolutionary theory of cortical architectonics proposes
two major functional/anatomical dissociations within the
frontal lobes (Pandya & Yeterian, 1996). The DLPFC is
part of the hippocampal archicortical trend and is in-
volved in spatial and conceptual reasoning processes.
Much of what is known about EF is based on patients
with DLPFC lesions (Milner, 1963). However, it is also
important to recognize that because of the interconnec-
tivity between the lateral frontal and posterior regions,
diffuse pathology such as axonal injury can also cause
dysfunction in executive cognitive functions.
Executive cognitive functions are involved in the
control and direction (planning, monitoring, activating,
switching, inhibiting) of lower level, more modular,
or automatic functions. Working memory, a limited
capacity process for the short-term storage, monitoring,
and manipulation of information (Baddeley, 1992) and
inhibition (Bjorklund & Harnishfeger, 1990) are funda-
mental, age-related processes that mediate EF (Miller
& Cohen, 2001).
Behavioral Self-regulatory Functions
The ventral (medial) frontal region is part of the paleo-
cortical trend emerging from the caudal orbitofrontal
(olfactory) cortex, closely connected with limbic nuclei
involved in emotional processing (Nauta, 1971), includ-
ing the acquisition and reversal of stimulus–reward
associations (Rolls, 2000). The ventral prefrontal cortex
(VPFC) is involved in reward processing, including
behavioral self-regulation in situations where cognitive
analysis, habit, or environmental cues are not sufficient
to determine the most adaptive response (Eslinger &
Activation Regulating Functions
Activation plays a key role in self-regulation by providing
initiative and energizing behavior at a level appropriate
to the situation and to attaining the individual’s goals.
More limited medial pathology results in disorders of
activation and drive, clinically known as apathy or abulia.
The frontal poles (possibly more particularly on the
right) are most recently evolved and appear to bridge
self-regulatory and executive cognitive functions be-
cause of their unique position to integrate executive
cognitive functions and emotional or drive-related in-
puts. The frontal poles are involved in metacognitive
aspects of human nature: personality, social cognition,
autonoetic consciousness, and self-awareness as re-
flected by the accuracy of evaluating one’s own abilities
and behavior in relation to objective performance and
reports by others.
In summary, we emphasize four domains of EFs for
several reasons: (a) The term executive function has his-
torically referred specifically to cognitive abilities such
as planning, switching, and monitoring that are related
to the DLPFC, and for the sake of operational clarity
should be retained as such. (b) Other important be-
havioral processes, which have been relatively ignored
and lumped within the general term as ‘‘executive,’’ de-
pend on systems that are anatomically proximal to the
DLPFC. (c) Our proposed distinctions do relate to dif-
ferent anatomical regions and systems with distinct
behavioral associations. (d) Most importantly, such an-
atomical/behavioral definitions are essential in under-
standing the sequelae of TBI and the development of
ASSESSMENT OF EXECUTIVE FUNCTION
Objectives of Assessment
The objective for assessment of function after TBI is
to isolate deficient processes to guide rehabilitation.
The most commonly used assessment methods in both
research and clinical practice (i.e., Trail Making Test,
Stroop, Wisconsin Card Sorting Test [WCST]) were de-
veloped to differentiate populations with and without
gross cerebral pathology and do not reflect the con-
temporary cognitive neuroscience perspective of brain/
behavioral systems. Whereas many of these assess-
ment measures are sensitive to damage in the DLPFC
system, their specificity is low. Promising experimental
Cicerone et al.1213
measures of behavioral self-regulatory and metacogni-
tive processes are in development in various laboratories
but are not yet widely used.
Levels of Analysis in Assessment
Rehabilitation research distinguishes the impairment
level (e.g., planning deficit measured by a test) from
the activity or participation level, which in the present
context refers to performing a task in everyday activities
that involves EF more generally defined (e.g., planning a
meeting). Participation also refers to categories of in-
volvement in society (e.g., having a job, friends, and
other important relationships). These different levels of
analysis are interrelated in complex ways (Whyte, 1997).
Elemental cognitive processes or operations may be
combined in the operation of an EF system (impairment
level), but real-world tasks (activity level) invariably
require the coordinated operation of multiple sensory,
cognitive, and motor systems, even when the task is
thought of as tapping executive skills. Multiple tasks and
activities combine to determine the overall level of par-
ticipation in addition to the contribution by an execu-
The following sections on assessment of adults with TBI
are divided according to the four anatomical/behavioral
distinctions described above. Sections on intervention
follow the discussion of assessment. EF in children after
TBI has been reviewed recently (Levin & Hanten, 2005).
ASSESSMENT OF EXECUTIVE FUNCTION
All measures reviewed in this article have also been
demonstrated to be sensitive to impairment to a greater
or lesser degree after at least moderate to severe TBI.
Although the right and left dorsolateral frontal areas
function in parallel in some ways and asymmetrically in
others, lateralized distinctions are not as relevant to the
diffuse effects of TBI.
Executive Cognitive Functions
The following measures are most frequently used as
executive tests: WCST, Trail Making Test Part B, and
specific measures within verbal fluency tasks. They have
been shown to be related to focal DLPFC lesions (but
not generally to orbitofrontal/ventral medial pathology)
provided that other processes that could affect perform-
ance are covaried.
Strategic aspects of encoding and retrieval in word list
learning tests and working memory are other examples
of executive cognitive functions. In memory assessment,
one should distinguish between basic associative pro-
cesses of cue–engram interaction (mediated by medial
temporal lobe/hippocampal structures) and strategic
processes related to the encoding and retrieval of these
associations (mediated by the DLPFC primarily). Memo-
ry deficit after TBI can be secondary to impairment of
both associative and strategic processes that can be
differentiated by tasks such as the California Verbal
Learning Test (CVLT) through serial position learning,
semantic organization, interference effects, cued recall,
recognition, monitoring, and response bias. The role of
the frontal lobes in working memory is in the manipu-
lation and control of information held online. The latest
updates of the Wechsler instruments have added new
tasks stressing manipulation and control, and allow for a
separate ‘‘working memory’’ composite score. Executive
processing in acquiring visuospatial information is less
well understood, and, consequently, there is a paucity of
measures that examine learning strategies and working
memory manipulation of visuospatial stimuli.
Another set of cognitive processes falling within the
broad rubric of executive cognitive functions are mech-
anisms of attention/intention, such as sustained atten-
tion, inhibition of irrelevant information (distractibility),
monitoring of information, and variability in reaction
time (RT) performance. Different tests of attention as-
sess inhibition and monitoring, using errors and RT as
dependent measurements. The right frontal region is
important for performance on Continuous Performance
Tests, especially when the target complexity is increased
(i.e., respond to ‘‘O’’ following ‘‘X’’; Pardo, Fox, &
Raichle, 1991), and the task is slowed. The Sustained
Attention to Response Task (SART; Robertson, Manly,
Andrade, Baddeley, & Yiend, 1997) and the Elevator
Counting Test (Robertson, Ward, Ridgeway, & Nimmo-
Smith, 1991) are modern tests of sustained attention. A
key impairment found after focal frontal pathology, and
following TBI, is increased variability of performance
both within a testing session and across sessions (Stuss,
Murphy, Binns, & Alexander, 2003). This fluctuation in
top-down control is most visible in more complex tasks,
including those involving RT and memory tasks.
To bridge the gap between laboratory tasks of exec-
utive cognitive functions and functional outcome mea-
sures of everyday activities, investigators have studied
naturalistic actions under controlled conditions. Based
on a hypothesized disturbance of supervisory attention
associated with reduced planning, working memory,
and resistance to interference, Schwartz et al. (1998) de-
signed the Multi-Level Action Test (MLAT) to assess
everyday, sequential activities such as packing lunch in
a lunchbox. These investigators tested 30 TBI patients
undergoing rehabilitation under four conditions in
which the presence of distractors was orthogonal to
the addition of a second, concurrent action that in-
creased the demand on working memory. Although
the patients had a higher rate of errors than uninjured
subjects, the TBI group was not more susceptible to
interference by distractors or the addition of a concur-
rent task. Although performance by the TBI patients
was not related to the presence of frontal lesions, it
1214Journal of Cognitive Neuroscience Volume 18, Number 7
was moderately correlated with a measure of functional
outcome. This naturalistic approach was also evident in
a study of planning activities in which the representation
of various actions or ‘‘script’’ was assessed by a card
sorting technique that evaluated the patient’s sequenc-
ing of steps and by a spontaneous generation task in
which the patient explained the steps necessary to plan,
initiate, and complete each activity (Cazalis, Azouvi,
Sirigu, Agar, & Burnod, 2001). In both tasks, 12 patients
with severe TBI who were at least 6 months postinjury
had slower performance than uninjured subjects. On
the card sorting task, the TBI patients (but not controls)
had intrusions of a given action from one script to
another but they were not more susceptible to intru-
sions and the degree of impairment did not differ for
routine (e.g., preparing to go to work in the morning)
versus nonroutine (e.g., taking a trip to Mexico) or
novel (e.g., opening a beauty salon) scripts. Performance
summed across both of the script tasks was correlated
with a measure of dysexecutive functioning in everyday
activities (Baddeley, Della Sala, Papagno, & Spinnler,
1997). These studies suggest that naturalistic tasks can
reveal executive cognitive deficits in patients at least
6 months after TBI. It is unclear whether naturalistic
measures increment the information obtained from lab-
oratory tasks and are useful in evaluating the effects of
Behavioral Self-regulatory Functions
Patients with damage to the inferior medial frontal cor-
tex have difficulty in understanding the emotional con-
sequences of their behavior despite intact performance
on commonly used neuropsychological tests of execu-
tive cognitive functioning, and performing normally in
structured situations (Eslinger & Damasio, 1985). Assess-
ment of these behavioral self-regulatory functions tends
to be more experimental in nature and includes gam-
bling tasks and naturalistic multiple subgoal tasks.
Because of the role of the VPFC in emotional pro-
cessing (basic drives and rewards that inform and direct
high-level decision making), tests assessing the acquisi-
tion and reversal of stimulus–reward associations can
be used (Rolls, 2000). Reversal learning is dissociable
from the impairment in attentional (extradimensional)
set shifting found after DLPFC lesions (Dias, Robbins, &
Roberts, 1996), reinforcing the distinction between ex-
ecutive attentional and affective/emotional behavioral
measures. The Behavioral Dyscontrol Scale (Grigsby,
Kaye, Baxter, Shetterly, & Hamman, 1998) has also been
shown to be sensitive in cases of TBI (Leahy, Suchy,
Sweet, & Lam, 2003).
Activation Regulating Functions
Damage to left or right medial (anterior cingulate and
superior) frontal regions results in poor capacity to
generate and maintain actions or mental processes. Pa-
tients with damage in this region are slow in more de-
manding RT tasks, deficient in generating lists of words
(particularly in the first 15 sec), and have problems
maintaining a selected target such as in the Stroop
interference test. Patients with DLPFC lesions are often
impaired on the same tasks. For EF tasks, superior me-
dial frontal regions appear ‘‘upstream’’ from the DLPFC,
providing activation and drive to organize and sustain
action without necessarily providing the content of ac-
tion. Measures most frequently used to assay activation
and drive are verbal fluency tasks and the Stroop test.
These tasks lack specificity, as they are also sensitive to
impairment in nonexecutive cognitive functions.
The frontal polar region has been related to theory of
mind and self-awareness, humor appreciation, and epi-
sodic (autonoetic or self-knowing) memory (Stuss, Gallup,
& Alexander, 2001). Self-awareness implies a metacogni-
tive representation of one’s own mental states, beliefs,
attitudes and experiences. Making inferences about the
world and empathizing with others are fundamental to
accurate social judgment and appropriate social behavior.
The neuropsychological assessments in this domain
include reactions to verbal and cartoon humor, visual
perspective-taking tasks, and comparison of perform-
ance on remember–know memory tasks. It is impor-
tant to recognize that for some individuals these tasks
can be solved on the basis of factual knowledge, not
inference. Family reports often precisely describe the
changes in behavior that have occurred such as lack of
empathy, unconcern, and inability to appreciate humor
that requires self-reflection.
Currently available tests of EF typically lack specificity,
even when they are sensitive. The few tasks that ap-
pear to differentiate processes more specifically lack ap-
propriate normative data. There is a need to develop
new tests that target the aforementioned EF domains,
establish their validity, including their relation to daily
functioning and participation in complex activities in
INTERVENTIONS FOR EXECUTIVE FUNCTION
IN TBI PATIENTS: CONCEPTUAL ISSUES
IN DESIGNING INTERVENTIONS
Level of Analysis
Studies must consider the hypothesized mechanism
of treatment because this will bear on the appropriate
level of analysis at which to assess treatment impact.
Some treatments (e.g., pharmacologic interventions,
Cicerone et al.1215
‘‘direct remediation’’ treatments) may seek to amelio-
rate the underlying executive process impairments and
impact impairment-level outcome measures. Other in-
terventions, however, may seek to train compensatory
strategies for overcoming EF impairments (e.g., cuing
or reminding devices). In such instances, one may not
hypothesize any meaningful change in the executive
processes themselves, but may predict improvement in
tasks that were secondarily compromised by the execu-
One option is a program of sequential studies that
seeks to trace the impact of treatment into progressively
more complex domains. In this approach, one might
first study treatment effects only at the level most closely
linked with the proposed treatment mechanism, be-
cause if the treatment is ineffective even here, it is
unlikely to be productive to search for larger and more
general effects. A second wave of research can be
conducted in which subjects with a few other confound-
ing deficits are studied, with activity level outcomes
as the treatment target. Finally, a less highly selected
group can be studied, potentially combining several
treatments aimed at several coexisting impairments,
with an assessment of their combined treatment im-
pact (Whyte, 1997, 2002). Alternatively, one can assess
multiple levels of treatment outcome simultaneously
from the beginning and examine the interrelationships
among treatment responses at multiple levels (Whyte
et al., 2004). Which approach to take depends largely
on practical considerations such as whether it is more
difficult to identify appropriate subjects or more diffi-
cult to collect large volumes of data on each subject
(Whyte & Hart, 2003).
Crossover designs may be particularly useful in the
chronic phase when spontaneous recovery is slow or
absent, assuming that the mechanism of treatment can
safely be assumed to be reversible upon discontinuation.
Such designs necessitate smaller samples than parallel
group designs, but require a lengthier involvement of
each subject. Crossover designs are more difficult to use
in the acute period because the pace of recovery may
change substantially between treatment phases. Within-
subject designs are also not feasible for practice-based
treatments or compensatory strategy interventions,
where subjects are unlikely to ‘‘unlearn’’ the interven-
tion after crossover (Woods, Williams, & Tavel, 1989).
Parallel group designs are more appropriate in these
contexts but will face the challenge of establishing
groups with comparable prognosis, requiring either
relatively large sample sizes or careful prognostic strat-
ification. Additional study designs such as multiple base-
lines across behaviors or multiple baselines across
subjects may also be appropriate depending on the
hypothesized mechanism of treatment effect.
There are no medications that currently meet a practice
standard for treatment of executive deficits in TBI or,
for that matter, any other cognitive impairment in this
population. Because of the rich catecholaminergic inner-
vation of the prefrontal cortex (Camps, Cortes, Gueye,
Probst, & Palacios, 1989), medications that modulate
these neurochemical systems (particularly dopamine)
might have treatment potential for executive deficits.
Moreover, dopaminergic interventions modulate work-
ing memory and EF in animal models (Robbins &
Everitt, 1995), in healthy elderly individuals (Kimberg,
D’Esposito, & Farah, 1997), and in individuals with TBI
(McDowell, Whyte, & D’Esposito, 1997).
Structural and Functional Imaging
Major advances have been made in recent years in un-
derstanding recovery after TBI, using both structural and
functional imaging techniques in conjunction with be-
havioral evaluation. Functional brain imaging, including
PET and functional magnetic resonance imaging (fMRI)
have begun to elucidate mechanisms mediating indi-
vidual differences in recovery from injuries of similar
severity. Functional imaging studies can also be used to
indicate how brain reorganization of neural systems
underlies functional recovery (Perlstein, Dixit, Carter,
Noll, & Cohen, 2003). These imaging techniques could
also be used to assess the impact of rehabilitative ef-
forts. Structural measurements such as ventricular size
and regional atrophy can identify pathology in the ab-
sence of clear focal damage. Diffusion tensor imaging
(DTI), which can detect disruption of white matter con-
nections in diffuse TBI (Huisman et al., 2004), is poten-
tially a useful biomarker for severity of tissue injury.
INTERVENTIONS FOR EF DEFICITS IN
ADULTS AFTER TBI: CURRENT PRACTICE
Impairments of EF can represent a distinct challenge
to the rehabilitation process. In many cases, remedial
interventions for acquired cognitive impairments em-
phasize the acquisition of specific compensations in
controlled situations. Responsibility for the selection
and application of compensatory strategies may initially
rely on the therapist, with the assumption that the
patient will be capable of implementing these compen-
sations independently with adequate practice. In con-
trast, disturbances of EF are most likely to be evident
when the patient is required to assume responsibility
for the application of compensatory strategies (Shallice
& Burgess, 1991) or to cope with novel situations
(Godefrey & Rousseaux, 1997). Disturbances of EF often
coexist with impaired self-awareness, representing an
additional challenge to rehabilitation.
1216Journal of Cognitive Neuroscience Volume 18, Number 7
Recognizing the interplay of executive cognitive, be-
havioral self-regulatory activation, and metacognitive
processes, as well as the lack of specific assessment
techniques for parsing these processes, clinicians widely
endorse global functional assessments and ‘‘holistic’’
rehabilitation. For instance, functional assessment in
clinical populations has focused on complexes of be-
haviors (such as pragmatic communication skills, other
social skills, and adaptive behaviors) using self-report
or rating scales, such as the Awareness Questionnaire
(Sherer, Bergloff, Boake, High, & Levin, 1998), the Pa-
tient Competency Rating Form (Prigatano & Altman,
1990), the Neurobehavioral Rating Scale (Levin et al.,
1987), and the Mayo-Portland Adaptability Inventory
(Malec, 2004). Such assessment has focused on func-
tional behaviors with the premise that these behav-
iors are the final common pathway for a variety of EF
In rehabilitation, these behavioral complexes are tar-
gets of interventions that are equally general and multi-
modal. Such holistic rehabilitation efforts are directed
at simultaneously addressing the complex of cognitive,
metacognitive, behavioral, and emotional dysfunctions
that may result from disruption of the proposed ana-
tomic/behavioral systems. Only a small number of
studies have examined the efficacy of rehabilitation
interventions that target specific aspects of executive
The review of specific studies of interventions for EF
deficits is organized according to our previous distinction
among the domains of executive cognitive functions,
behavioral and emotional self-regulatory functions, acti-
vation self-regulatory functions, and metacognitive pro-
cesses. Although these distinctions may correspond to
specific anatomic substrates, these anatomic–behavioral
relationships have typically not been specified in the re-
Interventions for Problem-solving Deficits
Three prospective, randomized controlled trials of in-
terventions directed at problem-solving deficits have
been conducted. Von Cramon, Matthes-Von Cramon,
and Mai (1991) trained patients to reduce the complex-
ity of a multistage problem by breaking it down into
manageable subgoals. Training was provided to 37 sub-
jects (including some subjects with cerebral insult other
than TBI), who were identified as poor problem solvers
on formal tests of planning and response regulation.
Twenty participants received an intervention directed
at remediation of EF deficits, whereas 17 participants
received an alternative intervention consisting of mem-
ory retraining. The experimental intervention included
training in problem orientation, problem definition and
formulation, generation of alternatives, decision making,
and solution verification. When compared with memory
training, the participants who received the problem-
solving training demonstrated significant gains on mea-
sures of planning ability and improvement on behav-
ioral ratings of EF, such as awareness of cognitive
deficits, goal-directed ideas, and problem-solving.
Levine et al. (2000) developed a formalized, staged
intervention for executive dysfunction, referred to as
goal-management training (GMT), based on Duncan,
Emslie, Williams, Johnson, and Freer’s (1996) theory of
goal neglect and similar to the algorithm employed by
Von Cramon et al. (1991). Training to evaluate the
current problem state (‘‘What am I doing?’’) was fol-
lowed by specification of the relevant goals (the ‘‘main
task’’), and partitioning of the problem-solving process
into subgoals (the ‘‘steps’’). Participants were then
assisted with the learning and retention of goals and
subgoals (‘‘Do I know the steps?’’) and finally taught
to self-monitor the results of their actions with the
intended goal state (‘‘Am I doing what I planned to
do?’’), and in the event of a mismatch the entire process
The GMT consisted of a single session in which par-
ticipants were instructed to apply the problem-solving
algorithm to two functional tasks (proofreading and
room layout) that involved keeping goals in mind,
analysis of subgoals, and monitoring outcomes. Patients
in the motor skills training condition practiced reading
and tracing mirror-reversed text and designs; a trainer
provided general instruction and encouragement, but
the treatment procedure did not include any processes
related to GMT. Treatment effectiveness was assessed
on several paper-and-pencil tasks that resembled the
training tasks and were intended to simulate the kind of
unstructured everyday situations that might elicit goal-
management deficits. Participants who received the
GMT demonstrated significant reduction in errors and
prolonged time to task completion (which was inter-
preted as an indication of their increased care and
attention to the tasks) on two of the three outcome
measures. The entire treatment in this study consisted
of 1 hr of intervention, which may be adequate to
suggest the putative efficacy of GMT but provides little
evidence of its clinical effectiveness.
Rath, Simon, Langenbahn, Sherr, and Diller (2003)
evaluated the effectiveness of an ‘‘innovative’’ group
treatment focused on the treatment of problem-solving
deficits (n = 27), compared with a ‘‘conventional’’ neu-
ropsychological group treatment (n = 19), for patients
with TBI. The participants were selected from a large
outpatient neuropsychological rehabilitation program
as being ‘‘higher functioning’’ but with documented,
persistent impairments in social/vocational functioning,
an average of 4 years postinjury. Both groups received
2 to 3 hr of small group intervention per week for
24 weeks. The conventional treatment consisted of
group exercises intended to improve cognitive skills
and support for coping with emotional reactions and
changes after injury. The problem-solving intervention
Cicerone et al.1217
focused on the development of emotional self-regulation
strategies as the basis for maintaining an effective prob-
lem orientation, along with a ‘‘clear thinking’’ compo-
nent that included cognitive-behavioral training in
problem-solving skills, a systematic process for analyzing
real-life problems, and role-play of real-life examples of
problem situations. Both groups showed significant im-
provement of their memory functioning after treatment.
Only the problem-solving group treatment resulted in
significant beneficial effects on measures of executive
cognitive functioning, self-appraisal of clear thinking
and emotional self-regulation, and objective observer
ratings of interpersonal problem-solving behaviors in
naturalistic simulations. These gains were maintained
at 6 months after treatment, but did not translate into
significant improvements on a measure of community
Rath et al.’s (2003) inclusion of a treatment compo-
nent directed specifically at patients’ developing im-
proved emotional self-regulation in the context of the
cognitive intervention is innovative and particularly rel-
evant to the clinical treatment of patients with EF
deficits after TBI. Moreover, the study included behav-
ioral observations of participants’ actual interpersonal
behaviors in naturalistic situations. Given the lack of
an established relationship between psychometric mea-
sures of executive cognitive functioning and everyday
behaviors, and the well-known potential for dissociation
between verbal self-appraisal and actual behavior after
frontal lobe damage, the use of real-life behavioral ob-
servations to assess treatment outcomes is well advised.
Fox, Martella, and Marchand-Martella (1989) con-
ducted a small observational study of remediation for
‘‘real-life’’ problem-solving skills. The treatment con-
sisted of cuing and feedback to develop effective prob-
lem solutions, using verbal analogs of problem situations
in four general areas of everyday life relevant to com-
munity placement and adjustment (e.g., community
awareness and transportation, using medications, and
responding to emergency situations). Training was pro-
vided to three participants with TBI within a residential
rehabilitation facility; three subjects within the same
facility served as untreated controls. Throughout the
course of training, appropriate verbal responses to
analogous problem situations showed significant in-
creases. The participants who received the treatment
also demonstrated generalization to simulated interac-
tions conducted in the natural environment, whereas
the untreated subjects showed essentially unchanged
performance. This use of ecologically relevant problems
and situational simulations in this area of cognitive
remediation appears promising.
Interventions for Working Memory Deficits
Impairments of higher level cognitive functions include
difficulties with the effective allocation of attention and
the organization of multiple task demands. Impairments
in the ‘‘central executive’’ component of working mem-
ory, identified by poor dual-task performance, have been
shown to be related to behavioral indices of executive
dysfunction (Baddeley et al., 1997). There is also evi-
dence that interventions derived from, and directed at,
the central executive component of working memory
can be effective in remediating the subjective and ob-
jective attention difficulties in patients with mild TBI
One study in post-acute TBI patients based on
Baddeley et al.’s (1997) model of the central executive
demonstrated a beneficial effect of a single 2.5-mg dose
of bromocriptine, a D2 agonist, on efficiency of the
central executive but not on the corresponding working
memory buffers, in a dual task paradigm (McDowell,
Whyte, & D’Esposito, 1998). That is, dual task perform-
ance improved without improvement in the two tasks
when performed alone.
Interventions for Behavioral
and Emotional Regulation
These interventions emphasized the need for patients to
anticipate and monitor the outcomes of their behavior.
In most cases, the goal of remediation was not the
training of task-specific performance, but the training
and internalization of regulatory cognitive processes.
Several studies have relied on external cuing or en-
vironmental restructuring to modify specific behaviors.
Lengfelder and Gollwitzer (2001) noted that the auto-
matic control of habitual behavior remains relatively
intact after frontal lobe damage. They argued that
patients with frontal lobe dysfunction might therefore
benefit from linking situational cues to goal-directed
behavior through the use of ‘‘implementation inten-
tions’’ (e.g., ‘‘if situation y arises, I will perform the
goal-directed behavior z’’) that do not require conscious
deliberation. Among 34 patients with frontal or non-
frontal brain injuries, implementation intentions were
found to improve the efficiency of reactions on a dual
task. The effectiveness of the intervention was not re-
lated to whether patients had frontal or nonfrontal
lesions, but was related to the presence of impaired
planning and self-regulation. Manly, Hawkins, Evans,
Woldt, and Robertson (2002) developed an intervention
that was again based on the Duncan et al. (1996) theory
of goal neglect. Ten participants with TBI were required
to perform a complex task comprising multiple ele-
ments, with or without provision of an external auditory
stimulus intended to interrupt their activity and cue
them to consider their overall goal. Without the exter-
nal cues, participants performed more poorly than
healthy controls, in large part due to their perseveration
on one aspect of the task and failure to allocate suffi-
cient time to the multiple task components. Significant
improvement and normalization of task performance
1218Journal of Cognitive NeuroscienceVolume 18, Number 7
was obtained with provision of the external cue, sug-
gesting that environmental cuing could facilitate behav-
ioral regulation during complex task performance.
Burke, Zencius, and Weslowski (1991) described the
effective use of external compensatory strategies to sup-
port patients’ performance of relevant functional tasks
(e.g., checklists for cuing and monitoring completion of
job steps). Alderman, Fry, and Youngson (1995) utilized
a program of prompts and rewards to enable a patient to
exert control over inappropriate behaviors through in-
creased self-monitoring. This was effective in reducing
the frequency of inappropriate behaviors within both
the treatment and community environments.
Few studies have explicitly addressed the remediation
of impairments in emotional regulation after TBI. Medd
and Tate (2000) conducted a prospective controlled trial
to examine the effectiveness of a cognitive–behavioral
program of anger management for 16 participants with
acquired brain injury. Participants in the treatment con-
dition received a stress-inoculation procedure modified
to include information relevant to individuals with ac-
quired brain injury. Modifications included training in
the relationship between brain injury and subsequent
anger management difficulties. Participants in the no-
treatment control group monitored their anger for
8 weeks. The participants receiving anger-management
training showed a significant decrease in the negative,
outward expression of anger, although there was no
change in participants’ self-reported awareness of prob-
lems with emotional control as a result of treatment.
There is evidence to suggest that disturbances of
emotional regulation after orbitofrontal injury may be
particularly refractory to treatment. Although training
under a routinized, external structure has been shown
to be effective in changing behaviors specific to the
situations in which they had been trained, this im-
provement was not apparent in novel situations and
the patients continued to exhibit disturbances in their
emotional and social behavior (Cicerone & Tanenbaum,
Interventions for Activation
Sohlberg, Sprunk, and Metzelaar (1988) treated a pa-
tient with traumatic frontal-lobe damage who exhibited
decreased initiation and range of affect. The therapist
provided the patient with intermittent external cues
(such as placing an index card in front of the subject
with an instruction to initiate conversation) that placed
little demand on internal self-monitoring, to increase
verbal initiation and response acknowledgments. Both
behaviors increased during application of the external
cuing procedure; the patient’s verbal initiation de-
creased when the external cuing procedure was with-
drawn, although the level remained above baseline.
To our knowledge, there have been no other studies,
and certainly no randomized control studies, of cogni-
tive remediation related to disturbances of behavioral
drive or activation.
One pharmacologic trial evaluated dopamine agonist
therapy for deficits in clinical motivation in 11 patients
with TBI or subarachnoid hemorrhage (SAH), 2 months
to 5 years after injury. Bromocriptine was administered
starting at 2.5 mg/day, increased by 2.5 mg/day per week
to a maximum of 10 mg/day. Clinical ratings of sponta-
neity and responsiveness to incentives, but not mood,
improved with drug treatment for all patients (Powell,
Collin, & Sutton, 1996).
Planning, Inhibition, and Self-monitoring
Interventions in this area have typically been conceptual-
ized in terms of fostering the internalization of strategies
for effective self-monitoring and self-regulation. Cicerone
and Wood (1987) used a self-instructional training proce-
dure to treat a patient with traumatic frontal-lobe dam-
age who exhibited executive dysfunction four years post
injury. The training procedure included three stages of
self-verbalization, progressing from overt verbalization
through faded verbal self-instruction to covert verbal
mediation of appropriate responses. The three stages of
self-instructional training were provided over an 8-week
period, followed by 12 weeks of treatment to promote
the application of self-regulation strategies in the pa-
tient’s everyday functioning. Over the initial course of
self-instructional training, there was a dramatic reduc-
tion in task-related errors as well as more gradual re-
duction and eventual cessation of off-task behaviors.
Generalization to the patient’s functional, real-life behav-
iors was observed only with the additional instruction
and practice in the application and self-monitoring of
the verbal mediation strategy to his or her everyday be-
haviors. Cicerone and Giacino (1992) replicated this
intervention with six patients, using a multiple-baseline
across-subjects design. The participants were all at least
1 year since the onset of their injury or illness, all had
evidence of damage to the frontal lobes and were se-
lected for the intervention because they exhibited im-
paired planning and self-monitoring on the basis of family
observations and therapist reports, as well as evidence
of impaired performance on at least one of three neuro-
psychological measures of executive cognitive function-
ing. Five of the six patients showed marked reduction
of task-related errors and perseverative responses, sug-
gesting that the effectiveness of training was related to
the patients’ improved ability to inhibit inappropriate
Ownsworth, McFarland, and Young (2000) evaluated a
group intervention directed at improving participants’
self-regulation abilities and self-awareness. Participants
receiving the treatment consisted of 21 patients with
Cicerone et al.1219
acquired brain injury (16 with TBI). Sixteen patients
had documented frontal lobe damage and all exhibited
severe cognitive impairments and poor self-awareness
when evaluated an average of 8.6 years after injury. The
intervention incorporated elements of problem-solving
training, role-plays, and training in compensatory strat-
egies over a 16-week period. Following treatment, par-
ticipants exhibited reliable clinical improvement on
measures reflecting their knowledge and use of self-
regulatory strategies and the self-rated effectiveness of
strategies in their daily functioning, and these gains were
maintained after six months.
The study by Ownsworth et al. (2000) noted that im-
provements in self-regulatory strategies was associated
with increased awareness of deficit and anticipatory
awareness of situations wherein the patients might ex-
perience difficulty. Two additional studies of patients
with TBI suggest that having subjects predict their task
performance and providing them with tangible feed-
back may reduce discrepancies between their predicted
and actual performance (Rebmann & Hannon, 1995;
Youngjohn & Altman, 1989). In both of these latter
studies, the primary effect of the intervention was re-
lated to modification of patients’ predictions rather than
a change in actual task performance, suggesting an
impact on their self-monitoring and self-appraisal. How-
ever, evidence also suggests that interventions can pro-
duce improvements in behavioral functioning without
accompanying increases in participants’ awareness of
deficit (Medd & Tate, 2000).
KEY ISSUES AND QUESTIONS RELATING TO
TREATMENT FOR EXECUTIVE DYSFUNCTION
IN TBI PATIENTS
There is a need to better specify the patient samples and
nature of impairments being addressed. Relevant patient
characteristics might include the presence and location
of focal cerebral lesions, nature and severity of executive
dysfunction, and the presence of comorbid cognitive
impairments. There is also a need for continued devel-
opment of appropriate outcome measures and efforts
to ensure that interventions translate into meaningful
changes in real-world functioning.
Executive function has assumed too broad a connota-
tion for the adult developed brain. Within this broad
term, a more precise classification of the four domains
(executive cognitive, behavioral self-regulatory, activation-
regulatory, and metacognitive) based on documented
anatomical/behavioral distinctions is possible with the
recommendation that these domains should be assessed
in TBI patients. Pressing questions for future research
include the following:
1. Can sensitive and specific measurement techniques
be developed that define the impairment of executive
cognitive, behavioral self-regulatory, activation-regulatory,
and metacognitive processes? How are these behavioral
measurements related to functional activities and societal
2. Is rehabilitation that targets impairments in specif-
ic EF domains effective in changing both the specified
impairments and associated activities and participation?
3. Alternatively, is holistic or multimodal rehabilitation
more effective than specifically targeted rehabilitation in-
terventions in improving activities and participation?
4. Is an approach combining the targeted and multi-
modal approaches the most effective?
5. How can structural and functional brain imaging
be used to elucidate the mechanisms mediating changes
in EF performance resulting from cognitive rehabilita-
tion? Could imaging techniques be useful in selecting
patients who will benefit from specific cognitive and
This project was supported by NINDS. This article has been
developed from the research and discussions carried out by
the NINDS Cognitive Rehabilitation Initiative Working Group
(see September 23–24, 2004, workshop Executive Sum-
mary at www.ninds.nih.gov/news_and_events/proceedings/
We thank Emmeline Edwards, Robert Finkelstein, and Mary
Ellen Michel for excellent comments on an earlier version
of this manuscript; we also thank Biao Tian and Rebecca
Desrocher for editorial assistance and help in reformatting this
Reprint requests should be sent to Emmeline Edwards, Deputy
Director for Extramural Research, National Institute of Neuro-
logical Disorders and Stroke, 6001 Executive Boulevard, Room
3305, Bethesda, MD 20892-9531, or via e-mail: email@example.com.
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