International Conference on the Effectiveness of
Rehabilitation for Cognitive Deficits.
Cardiff, Wales, 17th-19th September 2002.
http://www.cardiff.ac.uk/psych/ercd/index.html
ABSTRACTS
1. History & Conceptual Issues
Professor George Prigatano
A History of Cognitive Rehabilitation
Attempts to help patients improve their cognitive functioning following various brain
lesions have been documented since the mid-1800's, with initial efforts focusing primarily
on the problem of aphasia. However, the care of soldiers from World War I and II, as well
as from the Israeli conflicts, provided great impetus to this endeavor, and other
disturbances now became the area of focus (e.g., memory impairments, visuospatial
problem solving disturbances, apraxia, problems with abstract reasoning, etc.). The work
of Kurt Goldstein, Walther Poppelreuter, A.R. Luria, Oliver Zangwill, Yehuda Ben-Yishay,
and Leonard Diller were paramount to this endeavor. The refinement of neurosurgical
procedures, which resulted in large numbers of patients surviving traumatic brain injury,
further fostered modern day efforts at neuropsychological rehabilitation, for which
cognitive rehabilitation is one component. This paper will summarize aspects of the
"useful past", which may be helpful to our present day efforts to improve higher
integrated brain functions and teach adaptive, compensatory techniques following various
forms of brain injury. Appreciating the fact that higher integrated brain functions reflect
an integration of many processes involved in problem solving (such as emotion and
motivation) helps form questions that, when answered, have a meaningful impact on
patient care. Any evidence-based approach to evaluating cognitive rehabilitation must
truly assess the "scientific evidence for efficacy" and the patient and family satisfaction
with services (i.e., their willingness to pay for the services rendered). Clinical
neuropsychologists are presently leading many cognitive rehabilitation efforts and are
describing for the first time, how evidence-based procedures and cost outcome research
methodologies may be applied to this important area of study.
Professor Keith Cicerone
The Validity of Cognitive Rehabilitation: Strategies for Evaluating Effectiveness and
Translating Research into Clinical Practice
Impairments of cognitive functioning are a significant cause of disability after traumatic
brain injury (TBI) and stroke, and interventions to reduce cognitive disability are a
common component of brain injury rehabilitation. However, there is continued concern
and controversy regarding the conceptual basis for cognitive rehabilitation (e.g., Ylvisaker,
Hanks & Johnson-Greene, 2002), the evidence that cognitive rehabilitation is effective, and
the appropriate methods for evaluating effectiveness.
Underlying all of these clinical, research and methodological concerns is the question of
the validity of cognitive rehabilitation, in other words, are the intentions of cognitive
rehabilitation consistent with the results of cognitive rehabilitation. For example, concerns
regarding the conceptual framework for cognitive rehabilitation and basis for specific
interventions cannot be adequately evaluated, including the clinical judgment of
effectiveness for an individual patient, unless the methods to evaluate outcome are
congruent with the objectives and rationale for the intervention. Attempts to evaluate the
validity of cognitive rehabilitation need to distinguish between efficacy and effectiveness
research. Efficacy refers to the evidence suggesting that an intervention can work, and is
usually demonstrated under highly constrained circumstances. Effectiveness refers to the
evidence that an intervention does work, and may be more directly relevant to clinical
practice. These issues will be discussed in relation to the evidence-based review of
cognitive rehabilitation completed by the Brain Injury-Interdisciplinary Interest Group of
the American Congress of Rehabilitation Medicine (Cicerone et al., 2000). This systematic
review evaluated 171 studies which were classified according to the level of evidence: (I)
well designed, prospective, randomized controlled trials (II) well designed observational
studies including prospective non-randomized cohort analyses; retrospective case-control
studies; or clinical series with well-designed controls (III) clinical series without
concurrent controls, or studies that utilized appropriate single-subject methodology.
Specific recommendations were established for the remediation of visuospatial and
language impairment following stroke, compensatory memory strategy training,
interventions for functional communication deficits, remediation of attention and problem
solving deficits during post-acute rehabilitation, and comprehensive-holistic
neuropsychological rehabilitation following TBI. Methodological issues will be illustrated
by discussion of the 29 Class I studies from that review, plus additional Class I studies
reviewed since then, which demonstrate significant variations in outcome when the
effectiveness of cognitive rehabilitation is compared with different forms of alternative
treatment. Finally, this presentation will discuss principles that inform the translation of
evidence-based reviews into clinical practice.
Cicerone KD, Dahlberg C, Kalmar K, Langenbahn DM, Malec JF, Bergquist TF, Felicetti T,
Giacino JT, Harley JP, Harrington DE, Herzog J, Kneipp S, Laatsch L, Morse PA. Evidence-
Based Cognitive Rehabilitation: Recommendations for Clinical Practice. Archives of Physical
Medicine and Rehabilitation. 2000; 81:1596-1615.
Ylvisaker M, Hanks R, Johnson-Greene D. Perspective on rehabilitation of individuals
with cognitive impairment after brain injury: rationale for reconsideration of theoretical
paradigms. Journal of Head Trauma Rehabilitation, 2002; 17:191-209.
Professor Derick Wade
The WHO Model as a Framework for Rehabilitation
Models or representations of how the world appears to work are vital, because all human
decisions and actions are determined by such frameworks. Rehabilitation has suffered
from being conducted for many years either in the absence of any model, or using a
restricted model such as the 'medical model' (whatever that may be) or the 'social model'
(an equally ill-defined model). However, there is one coherent and comprehensive model
which should form the framework for all rehabilitation, namely the World Health
Organisation's International Classification of Functioning (WHO ICF) model.
This model in practice is best considered as a systems analytic model, with there being at
least four systems or levels with three more intervening systems. The four levels at which
an illness can be described, and the four systems are: the organ, where abnormalities or
changes are referred to as pathology (and are classified using the International
Classification of Diseases; ICD); the person (or organism as a whole), where changes can
be referred to as impairments; the person's interaction with their environment (i.e. their
behaviour) where we now refer to (limitations on) activities; and the person's social
position (i.e. their social roles and status) where we now refer to (limitations on)
participation. The three intervening variables, and three other systems are: personal
context, the person's individual attitudes, expectations etc that will be based to a great
extent upon previous experiences; physical context, referring to both objects and also
people but only considered for their ability to provide support; and social context,
referring to the people that interact with the person on a social basis.
This model provides many insights into rehabilitation (and other aspects of health care)
[Wade, 2001]. For example one cannot refer to 'cognitive disability' or 'physical disability'.
Disability, now termed limitation on activities, refers to behaviour that is in some way
constrained or altered. The cause of that change or limitation might be cognitive
impairments or motor impairments (but equally might be other factors such as the social
context). One can state that certain behaviours or limitations on activities are more (or less)
likely in the presence of motor or cognitive impairments, and conversely one might state
that certain behaviours are more likely to be limited by certain cognitive or motor
impairments.
Therefore when considering a specific disability that might arise from a cognitive
impairment it is important not only to consider ameliorating or reducing the underlying
cognitive impairment, but also to consider how the activity could be improved even if the
impairment remains unchanged, for example by manipulating the physical or other
contexts, or by practicing the activity repeatedly, or by teaching an alternative strategy to
achieve the same goal. The WHO ICF model encourages rehabilitation clinicians to think
more broadly, considering the patient as a whole and not simply focusing on their disease,
impairment, disability or limited participation alone.
Professor Catherine Mateer
Neuropsychological Rehabilitation: Fundamental Characteristics And Functional
Significance
Until the early 1980's, rehabilitation with respect to mental abilities tended to involve
treatments of acquired disorders of speech and language, and of visual and spatial
perception. This reflected the dominance of stroke as an aetiology for patients seen in
rehabilitation. With increasing survival rates from traumatic brain injury and other
neurological conditions, and the development of both clinical neuropsychology and
cognitive neuroscience, acquired cognitive impairments were better recognized and
understood, and rehabilitation specialists became more interested in addressing problems
in the domains of attention, memory, and executive function. This direction was further
fostered by the growing evidence that problems with cognitive, behavioural, emotional,
and interpersonal functioning contributed substantially to levels of community
independence, disability, and handicap, and to the effective reintegration of patients into
family, home, school, and work.
The new direction in treatment focus required the development of new models for
cognitive intervention. Other domains of intervention, for example with speechand
language impairments, had at least begun to develop reasonable taxonomies for
conceptualizing the disorders with respect to underlying structures, assessment and
intervention. In contrast, there was little by way of the rehabilitation literature with
respect to conceptualizing acquired disorders of attention, memory, and executive control
functions, other than the historic, but pioneering work of a few individuals such as
Alexander Luria, Ritchie Russell, and Kurt Goldstein. There were also no standards
established with respect to the fundamental characteristics of effective cognitive
rehabilitation, the best methods of delivery, or the mechanisms for conceptualizing and
determining whether interventions were effective.
Although many issues and questions remain, the field has moved forward quickly in the
last two decades. A number of basic assumptions and well-established principles for
ethical and effective rehabilitation have been established. 1) Interventions that address
cognitive impairments must been seen as a collaborative enterprise involving patients,
family, professionals, and communities. 2) Interventions must be goal oriented and
address practical and meaningful aspects of the person's everyday life. 3) Cognitive
interventions are dynamic and often involve a combination of activities designed to
maximize areas of cognitive functioning, to increase insight and awareness, and to identify
and implement effective internal and external compensatory strategies. 4) Cognitive
abilities are interlinked with behavioural, emotional and psychosocial functioning and
must be addressed in any effective treatment program. 5) Effective neuropsychological
rehabilitation relies on a broad theoretical base incorporating frameworks, models, and
methodologies from many different fields of scientific, medical, neuropsychological,
social, and ethical inquiry.
Professor Max Coltheart
Justifying a Cognitive Approach to Rehabilitation
Cognitive neuropsychology is that branch of cognitive psychology which uses data from
people with disordered cognition in order to develop, test and extend theories about
normal cognition. In addition it uses such theories to interpret the patterns of preserved
and impaired cognitive abilities in people with cognitive disorders (Coltheart, 2002).
The theories of cognition which cognitive neuropsychology uses are modular: that is, they
offer descriptions of what the particular information-processing components are that make
up the cognitive system responsible for a person's performance in some particular
cognitive domain. These descriptions are sufficiently explicit that they define what the
actual functions of the components are, and so they tell us what tasks should be used to
assess whether any particular component of the system is functioning normally or not.
Cognitive neuropsychology thus automatically provides a guide to rational assessment.
Examples of assessment batteries derived from theories in this way are PALPA (for
assessing language; Kay, Lesser & Coltheart, 1992) and BORB (for assessing visual
perception and recognition; Riddoch & Humphreys, 1993). This kind of assessment allows
targeted therapy programs to be devised. What it does not provide, at least not currently,
are ideas regarding what form the targeted treatment should take. This is left up to the
experience and ingenuity of the therapist. Perhaps in the future cognitive theories will
have something more to say about exactly how each information-processing module in a
system carries out its job, and that might provide some help regarding the choice of
treatment method.
A second virtue of the application of cognitive neuropsychology to treatment is that it
compels the recognition that disorders in any particular cognitive domain must be
heterogeneous, i.e. will exist as distinct subtypes. Reading, for example, is a cognitive
activity that depends upon a modularly-organised cognitive system; damage to any
module in that system will result in impaired reading, but what is impaired about reading
(and hence what needs treatment - and hence what treatment is appropriate) will vary as a
function of which module or modules are abnormal. It is therefore completely implausible,
for example, to claim that all or nearly all cases of developmental dyslexia are due to
cerebellar dysfunction (see http:// www. ddat.co.uk/), or that all or nearly all are due to a
predilection for thinking in visual terms (see http://www.dyslexia.com/program.htm), or
that all or nearly all are due to an impairment in the auditory processing of brief or
rapidly-changing auditory stimuli (see http://www.scientificlearning.com/). Nevertheless,
such claims are made by those offering treatment programs based on one or other of these
(contradictory) ideas. The typical implication that the program is suitable for all or nearly
all children with developmental dyslexia thus has no scientific justification.
Coltheart, M. (2002). Cognitive Neuropsychology. In Wixted, J. (Ed.) Stevens' Handbook of
Experimental Psychology, Third Edition - Vol 4. John Wiley & Sons.
Kay, J., Lesser, R. and Coltheart, M. (1992) PALPA: Psycholinguistic Assessments of Language
Processing in Aphasia. Hove: Lawrence Erlbaum Associates.
Riddoch, M.J. & Humphreys, G.W. (1993). BORB: Birmingham Object Recognition Battery.
London: Psychology.
2. Spoken Language Deficits
Professor David Howard
Language Production and Comprehension: Processes and the Brain
This talk will consider the information processing components of language production
and comprehension. I will argue that both language production and comprehension
involve a sequence of stages, and that production and comprehension are largely
independent. Then, I will summarise our knowledge of the functional localisation of these
processes in the brain, using mainly data from PET and fMRI studies of normal language
processing. Data from brain lesions will be briefly considered, as well as the limitations in
knowledge gained from these processes. I will argue that both language production and
comprehension involve complex and interacting brain systems, distributed over the
cerebral cortex. The nature of the processing taking place in different brain regions is not
yet fully understood.
Dr Lyndsey Nickels
Tried, tested and trusted? Language Assessment for Rehabilitation
This paper will provide a critical review of clinical assessments used to evaluate acquired
language impairments. It will review assessments aimed at examining both language
functions ('impairment' based approaches), and language activities ('functional' measures).
In particular it will discuss the adequacy of these assessments as tools in the rehabilitation
process. For example, are the assessments clinically practical? Do they lead to a clear
description of the language function? If they are to be used to measure treatment efficacy,
do they have good test-retest reliability and are they sensitive to change? Finally, the
question will be raised as to whether there is any relationship between performance on
measures of language function and degree of impairment in
language activities.
Professor Anna Basso
Language Therapy: does it help?
In 1972, Darley wrote, "Does language rehabilitation accomplish measurable gains in
language function beyond what can be expected to occur as a result of spontaneous
recovery?" (p. 4). After reviewing the existing evidence he expressed the hope that
researchers would introduce "a rigor of procedure" such that in 10 years time "the
profession will enjoy substantial agreement about the nature of language breakdown and
what can be best done for it" (p. 20). In this presentation I hope to demonstrate that 30
years after Darley's urging we have a sufficiently rigorous and positive answer to the
question.
In the years following Darley's paper numerous and more rigorous studies on efficacy of
aphasia therapy have been published. To control for the effect of spontaneous recovery,
some researches studied the effect of aphasia therapy in chronic patients. Other studies
introduced a control group of non-rehabilitated patients; still others compared different
therapeutic methods. Results were not unequivocal: therapy was found to be effective in
some studies but no significant difference between treated and untreated patients was
found in others. It must, however, be stressed that a positive result is more "powerful"
than a negative one, which only demonstrates that a significant effect has not been found.
Moreover, a careful rereading of the literature demonstrated that long-lasting aphasia
therapy was always effective and that no difference between treated and untreated
patients was found when therapy was short-lived.
The methodological difficulties of randomised clinical trials are enormous. Ethical
considerations, for example, make it difficult to randomly select a no-treatment group. To
overcome the limits of such a methodology, meta-analyses were introduced, as it happens
in the field of medical and social sciences. They allow calculating treatment efficacy on the
basis of all available evidence. Results of the meta-analyses clearly indicate that treated
patients improve more than untreated patients. Robey (1998), for example, reviewed 55
studies and found a significant effect of therapy. He also considered the effect of amount
of therapy and found that it was positively related to magnitude of change. The Cochrane
review (Greener et al., 1999), on the other hand, only considered studies comparing
vascular patients randomly allocated to the treatment and no-treatment groups. Under
these conditions, only 2 studies were considered eligible and a meta-analysis could not be
performed. It will be concluded that intensive or prolonged aphasia therapy has been
proven to be effective and that it is now time to ask more specific questions.
Darley LD (1972) The efficacy of language rehabilitation in aphasia. Journal of Speech and
Hearing Disorders, 37, 3: 21.
Greener J, Enderby P, and Whurr R (1999) Speech and language therapy for aphasia
following stroke (Cochrane review). In The Cochrane Library, issue 4. Oxford: Update
Software Ltd.
Robey RR (1998) A meta-analysis of clinical outcomes in the treatment of aphasia. Journal
of Speech, Language, and Hearing Research 41, 172-187.
Dr Jane Marshall
Can Therapy Reduce The Disabilities/Handicap Arising From Language Impairments?
This talk will begin by exploring the relationship between language impairments,
disabilities and handicap (activity/participation). It will suggest that this relationship is
often opaque and unpredictable. So, for example, we would predict that a deficit in the
processes which map lexical semantic onto lexical phonological information would impair
spoken word production. Effects on activity/participation might reduce ability to take part
in conversation and consequent loss of social roles. However, this will be influenced by
numerous extraneous variables, with the result that different people with equivalent
production impairments may have very different levels of activity/participation.
Implications for the practice and evaluation of therapy will be considered.
The talk will then review published group and individual therapy studies. I will argue
that many, if not most studies to date have focussed on the impairment level, often with
minimal consideration of effects on activity/participation. With this limitation in mind,
three sub questions will be addressed: (1). Can therapy aiming directly to reduce the
language disability improve activity/participation? (2). Can therapy aiming to develop
alternative communication strategies, such as gesture and drawing, improve
activity/participation? and (3). Can therapy aiming to change the behaviours of those in
the environment of aphasic people improve activities/participation?
The talk will also briefly consider whether therapy directed at the level of activity/
participation might have an impact on the person's language impairment. Methodological
difficulties, particularly with respect to measuring change in activity/participation, will be
considered.
3. Executive Deficits
Dr Paul Burgess
The Functional and Anatomical basis of Executive Disorders
Many of the symptoms that clinicians involved in rehabilitation find particularly difficult
to treat are associated with damage to the frontal lobes and other parts of the brain that are
highly interconnected with them. There are a very large number of these symptoms (e.g.
apathy, disinhibition, planning problems, confabulation, lack of insight and so on), which
are collectively referred to "dysexecutive symptoms". These problems are not only
problematic in themselves, but they can also affect a patient's ability to benefit from
therapy aimed at ameliorating other forms of deficit (e.g. physical therapy), and is often
associated with a generally poor response to treatment. Considerable treatment advances
have been made in this area in the last few years. However in order to develop new
methods, and in some cases to explain the success or failure of existing ones, we need to
understand the causes of the particular symptoms. For this reason rehabilitation can only
proceed as fast as our knowledge about the basic brain systems that are damaged will
allow. This presentation therefore has four aims: (1) To describe some of the latest findings
about the functional anatomy of the frontal lobes, (2) to describe the main clusters of
frontal lobe symptoms, how they relate together, and their relative importance from the
patients' and relatives' points of view (3) explain the main theories of how the frontal lobe
executive system works and how they relate to the symptoms you can expect to see dayto-day, and (4) give some "blue-sky" predictions about which therapeutic methods might
be worth pursuing based on these theories.
Professor John Crawford
Assessment of Executive Deficits
A very brief outline of the behavioural features of patients with executive dysfunction will
be presented. Executive deficits typically have a much more profound effect on recovery
and adjustment than the more circumscribed deficits that arise from posterior lesions.
However, the behavioural features have proven hard to capture formally. This overview
of assessment methods will focus on practical methods and issues in clinical assessment
rather than on experimental techniques. Coverage of clinical tests will begin with the old
warhorses of clinical assessment. Tests of verbal and non-verbal fluency will be reviewed
(these will include standard phonemic and semantic fluency but also tasks designed to
impose a greater executive load (e.g. alternating & homophone fluency). Tests that require
shifting cognitive set (e.g., Wisconsin Card Sorting Test, modified Wisconsin, and the
more recent Brixton Spatial Anticipation Test) will also be evaluated. As part of this
evaluation, provisional results from a large meta-analysis of executive tasks will be
presented. The need to consider a patient's premorbid ability when assessing executive
functioning will be discussed using homophone fluency as an example. Problems and
solutions associated with the measurement of change in executive functioning will also be
covered, using the Brixton as an example. With some exceptions, standard clinical tests
used to assess executive problems suffer from being too structured and examiner-led; as a
result they can fail to capture the core problems of initiation, planning, and selfmonitoring. On the other hand tasks used in work with individuals must have very sound
psychometric properties e.g. internal consistency and inter-rater reliability etc.;
unstructured tests can have problems in this regard. A battery of tests that strikes a good
balance between these competing demands is the Behavioural Assessment of the
Dysexecutive Syndrome (BADS). It also has the advantage that it more explicitly reflects
contemporary theory. Selected subtests of this battery will be reviewed. The BADS will
also be used to illustrate the importance of demonstrating the ecological validity of our
measures. Finally, rating scales and questionnaire methods of assessing executive
problems and disability will be covered (including the DEX, PRMQ and FrSBe).
Dr Jonathan Evans
Can Impaired Executive Functions be Restored or Retrained?
Addressing the question of whether executive functions impaired by injury or disease can
be restored or retrained is made difficult by the lack of theoretical consistency in the
concept of executive function. This theoretical inconsistency is probably partly responsible
for the relative lack of credible studies of treatments for executive dysfunction. However,
central to most models of executive functioning are notions of planning, problem solving,
or goal management. This paper therefore provides a review of studies with an explicit
aim of restoring or retraining these cognitive skills. Methodological difficulties, such as the
problems associated with repetition of tests executive function, are also a major limiting
factor in the evaluation of interventions, and will be discussed. Stem-cell based neural
replacement therapies offer hope for the future, but the specific impact on executive
functioning of such treatments, with or without cognitive retraining, remains to be
established. A very small number of studies of pharmacological agents have also
produced positive results in improving planning and problem solving skills, but small
numbers of participants and lack of evidence for generalisation of treatment-related
cognitive improvements means that routine prescription of such agents is a long way off.
A relatively small number of studies of cognitive retraining programmes using therapy
tasks designed to exercise cognitive skills associated with planning, problem solving and
goal management have also reported positive results with people with acquired brain
injury and also people with schizophrenia. Again, however, methodological limitations
and lack of evidence of generalisation to social, domestic or vocational functioning
severely limit the conclusions that can be drawn.
A theoretically coherent programme of methodologically rigorous research examining the
biological, cognitive and functional consequences of executive function retraining
approaches is desperately needed.
Dr Andrew Worthington
Rehabilitation of Executive deficits: The Effect on Disability
Executive abilities are complex cognitive processes underlying many everyday living
skills. Brain injury can result in dysexecutive deficits that compromise these processes and
cause pervasive disabilities, affecting competence and relationships at home, at leisure and
in the workplace. Disturbances of social conduct and adaptive behaviour associated with
executive dysfunction constitute the most significant obstacle to reintegration after brain
injury. Despite this, the development of treatments for executive disorders currently
remains in its infancy. In part, this is due to the elusiveness of executive disturbance to
traditional means of neuropsychological investigation, and the absence of a standard
conceptual approach to assessment and treatment. Cognitive neuropsychology, in
particular, has been slow to embrace the complexity of executive functioning with the
result that clinical interventions have often been instigated on dubious grounds
theoretically.
Although recent years have seen some progress in the development of a theoreticallyinformed basis to assessment, there is still a significant leap of faith where treatment is
concerned. Classification of types of treatment have not generally been based upon sound
theoretical analyses or used to drive greater understanding of mechanisms of recovery. In
fact, the literature contains few examples of treatment studies that would meet established
criteria for evaluative research. Two kinds of research are reviewed: (1) reports of specific
rehabilitation techniques (case reports, group studies), and (2) evaluations of rehabilitation
outcome in programmes where there is a major focus upon executive dysfunction (eg.
TBI).
Studies in the first category are typically concerned with a narrow focus of clinical efficacy
and tend to be lacking in appropriate controls. Studies in the second category often take a
more social perspective which is critical to the amelioration of disability, but are loosely
constructed and frequently underspecified regarding therapeutic techniques. Many of the
established methods utilised in apparently successful interventions come from
behavioural psychology. In this sense cognitive neuropsychology is a latecomer on the
scene, but a very welcome one nonetheless if treatment choice is to be based on something
more scientific than trial and error. The challenge for cognitive rehabilitation is to predict
who will benefit from what techniques. What is important in this aim is that we
understand more about the process of treatment change and especially the role of
learning. Taxonomies of interventions are not necessarily helpful in this respect. On the
basis that nothing is as practical as a good theory, rehabilitation practitioners need to see
that insights from cognitive neuropsychology are relevant to the real world in which they
work and their patients live. Five steps are suggested to facilitate this process: (a) the
development of treatment-focussed rather than diagnostic assessments. (b) a move away
from simplistic taxonomies of types of treatment (c) the inclusion of post-hoc testing of a
priori assumptions about how an intervention might be expected to bring about an
expected change in behaviour (d) A more flexible and diverse approach to research
design. (e) Involvement of relevant and sensitive measures of disability as a factor in
treatment choice.
4. Memory Deficits
Professor Hans Markowitsch
The Neuroanatomy of Memory
Memory nowadays is divided according to time and content. Within the dimension of
time several different types of memory have been distinguished; short-term or on-line
memory (working memory) and long-term memory; short-term memory lasting from
seconds to minutes and long-term memory referring to everything of longer duration.
With respect to content, there are at least four principal long-term memory divisions
which may even be hierarchically arranged. The most complex memory system is the
episodic-autobiographical one which requires self-conscious reflection and is embedded in
the dimensions of time and locus. It frequently is affect-related. Semantic memory, on the
other hand, is context-free fact memory. On the more automatic, implicit level, procedural
memory and the priming system constitute the other two long-term memory systems with
procedural memory referring largely to motor-related skills and priming to a higher
likeliness of re-identifying stimuli which one had perceived at a previous time point
(Tulving & Markowitsch, 1998).
On the brain level, working memory recruits prefrontal and (left) parietal structures. For
information acquisition, episodic and "though to a lesser degree" semantic memory engage
limbic structures and portions of the prefrontal cortex, while priming is principally a
matter of unimodal neocortical regions and procedural memory one of the basal ganglia,
possibly of cortical motor regions and cerebellar structures. For the last two memory
systems, information storage and information retrieval engage the same structures
necessary for acquisition or encoding, while for the episodic and memory systems the
situation is more complex. Both of these are represented in neocortical nets, the episodic
memory system furthermore possibly recruits limbic structures. There seems to be a
preponderance of right-hemispheric nets for episodic and of left-hemispheric ones for
semantic memories. Similarly, episodic information retrieval is triggered via righthemispheric prefrontal and anterior structures, while semantic memory retrieval activates
the same net of the left hemisphere (Markowitsch, 2000).
These networks for information processing have been established on the basis of both
patient data and results from normal subjects using functional imaging methods. Finally,
recent research demonstrates that in part similar brain regions appear metabolically
suppressed in patients with so called non-organic, that is, psychiatric amnesias. For these,
an increased release of stress hormones is seen as basis for what can be termed a mnestic
block syndrome (Markowitsch et al., 1999).
Markowitsch, H.J. (2000). Memory and amnesia. In M.-M. Mesulam (Ed.), Principles of
cognitive and behavioral neurology (pp. 257-293). New York: Oxford University Press.
Markowitsch, H.J., Kessler, J., Russ, M.O., Frölich, L., Schneider, B., & Maurer, K. (1999).
Mnestic block syndrome. Cortex, 35, 219-230.
Tulving, E., & Markowitsch, H.J. (1998). Episodic and declarative memory: Role of the
hippocampus. Hippocampus, 8, 198-204.
Professor Narinder Kapur
Memory Assessment for Memory Rehabilitation
This talk will provide an overview of memory assessment as it relates to memory
rehabilitation. Memory functioning needs to be considered in the context of a patient's
emotional/motivational state and other aspects of his/her cognitive functioning. It is also
useful to have a conceptual framework for memory functions, such as one that recognises
a number of different memory systems, including episodic and semantic memory,
working memory and procedural memory. We suggest that memory assessment in
memory rehabilitation usually seeks to answer one or more of the following questions: (a)
What is going on? (Neuropsychological diagnosis, nature and extent of memory
impairment); (b) What is going to happen? (Long-term prognosis of memory functioning,
generality of memory deficits to everyday settings); (c)What is going to help? (Cognitive
or environmental interventions which will improve the patient's memory functioning); (d)
What improvement has occurred? (Whether recovery of function has taken place, whether
treatment has been effective). Memory assessment procedures that help the
neuropsychologist to address these questions will be reviewed, and possible future
developments in the field of memory assessment will be outlined.
Professor Elizabeth Glisky
Treating Memory Impairment
For the past 15-20 years, memory rehabilitation has focused primarily on finding ways to
alleviate the disability associated with memory impairment and thereby enhance the
likelihood that affected individuals will be able to function independently in everyday life.
In so doing, some notable successes have been achieved: Patients, even those with very
severe deficits, have been able to learn varying amounts of knowledge and skills that, in
many cases, have helped them attain some degree of independence. This achievement is in
stark contrast to the lack of success of memory remediation prior to the mid-80s when the
dominant approach to treatment focused on reducing or eliminating underlying memory
impairment by repetitive drills and practice. Intermediate to these two approaches has
been the attempt to train or retrain memory-impaired individuals in the use of mnemonic
strategies or other memory-enhancing techniques, derived from the normal memory
literature. These methods have had modest success, particularly for those individuals with
mild to moderate impairments. Of particular concern with respect to all of these
approaches is the lack of evidence for generalization of training gains beyond the training
context.
This presentation will review the evidence with respect to the latter two approaches,
documenting the very modest successes, and suggesting possible reasons for the failures.
In particular, I will suggest that a) there is some evidence that memory impairment can be
reduced and that some patients can learn to use memory strategies and processes more
efficiently through appropriate training; b) exercise and practice is essential for such
relearning but it needs to be directed towards functionally relevant tasks; c) generalization
to new contexts cannot be expected after a few hours or even a few weeks of training, but
may take months of experience or repeated practice, much like the course of original
learning; d) treatment of impairment depends critically on well-specified models of
normal memory function, which do not yet exist, although brain neuroimaging has added
considerably to our theories; e) the newly-emerging possibilities for neurogenesis,
enhanced plasticity in the adult brain, and neural transplantation encourage research into
ways of facilitating the neural changes important for memory; and f) our ability to monitor
the effects of our interventions at the level of the brain through functional neuroimaging
may provide further information as to whether and under what conditions rehabilitation
successes are being achieved primarily through reorganization of function in new neural
circuits, through restoration of function in damaged neural systems, or through some
combination of the two.
Professor Barbara Wilson
Can Memory Disabilities Be Effectively Treated?
Everyday problems (i.e. the disabilities) that arise from organic memory impairments are
among the most handicapping for memory impaired people and their families. It is these
problems that should be targeted in rehabilitation. Although there is little evidence that
rehabilitation can restore memory functioning, there is considerable evidence that
disabilities can be treated effectively. For example, a randomised control trial allocating
people to a paging system first or to a waiting list first, requested clients to identify
everday memory and/or planning difficulties. Baselines were taken on successful
achievement of target behaviours. No differences were found between the two groups at
this stage. People in group one were then given a pager and people in group two waited
for 7 weeks without a pager. At this point, group one showed a clinically and statistically
significant improvement in achieving their targets. Group two showed no change. Group
one then returned their pagers and group two received the pagers. After a further 7 weeks,
group two showed a significant improvement. Group one showed some decline but not to
baseline levels (Wilson et al 2001). This was convincing evidence that for the group as a
whole and for the majority of people in the study, the paging system reduced everyday
memory and planning problems. In addition too new technology, procedures for
enhancing learning have resulted in the reduction of disabilities for memory impaired
people (e.g. Clare et al., 2000). Both the Wilson et al.,and Clare et al., studies addressed real
life problems of concern to the people referred for help. They (with their families) selected
the problems to be treated. This is an important part of modern rehabilitation practice. As
well as cognitive disabilities, people with organic memory deficits face emotional
problems and these also need to be addressed in rehabilitation programmes. Evidence for
the effectiveness of psychological approaches for the treatment of anxiety and mood
disorders is considered. The success of memory rehabilitation for the treatment of
disabilities may well lie in the fact that it encompasses a range of theoretical approaches.
No one model, theory or framework is sufficient to address the many and complex
disabilities faced by people requiring cognitive rehabilitation. Models of cognitive
functioning are necessary but not sufficient. We need to also refer to models of assessment,
learning, behaviour, emotion, compensation, and recovery at the very least (Wilson, 2002).
A successful memory rehabilitation programme following these principles is presented.
The main messages of this paper are first that rehabilitation makes clinical and economic
sense and second, it is possible to combine theory, scientific methodology and clinical
relevance.
Wilson B.A, Emslie H.C, Quirk K and Evans J.J. (2001). Reducing everyday memory and
planning problems by means of a paging system: a randomised control crossover study.
Journal of Neurology, Neurosurgery and Psychiatry. 70, 477-482.
Clare L,Wilson B.A, Carter G, Breen K Gosses A and Hodges J (2000) Intervening with
everyday memory problems in dementia of the Alzheimer type: an errorless learning
approach. In Journal of Clinical and Experimental Neuropsychology 22, 132 - 146.
Wilson B.A (2002) Towards a comprehensive model of cognitive rehabilitation. In
Neuropsychological Rehabilitation 12, 97-110.
5. Attentional Deficits
Dr Elizabeth Styles
Attentional Behaviour: Varieties, Deficits and Theoretical Accounts
A review of experiments with normal participants in cognitive psychology reveals many
varieties of attention involved in cognitive tasks. Attention may be selectively focused to
facilitate preferential processing of some information whilst other information is ignored.
Attention can be shifted between stimuli and between tasks. It may be divided, within
limits, or it may he sustained over time. Attention may be viewed as exerting supervisory
control or being itself directed, endogenously by top down processes. In other tasks,
attention can be shown to he captured, bottom up or exogenously by environmental
events. In addition, attention appears necessary for the emergence of conscious awareness.
Early work investigated the auditory modality, more recent models and evidence concern
vision and lately cross-modal attention. The variety of tasks said to involve attention
means there is no single definition or unified theory of attention, although at a general
level, attention can be considered as the function or set of functions that enable effective
selection for action allowing for coherent behaviour in an informationally rich and
complex environment. Styles (1997) provides an overview of attention from the
perspective of cognitive psychology, together with some neuropsychological data.
Patterns of cognitive deficits and dissociations of attentional behaviours in patients with
brain damage demonstrate the involvement of cognitive systems that subserve different
attentional functions relatively independently. With respect to attentional deficits, much
work has centred on deficits involving problems of visual attention such as unilateral
neglect, extinction, and simultanagnosia. However, neglect can also apply to motoric
aspects of behaviour. Other deficits involve problems of the attentional control of goal
directed behaviour. A review of patient data reveals that different brain locations,
pathways and circuits underlie these different deficits. In general, the cortical areas are
involved with higher level attentional mechanisms. Frontal cortex subserves aspects of
executive control, monitoring of attention and the planning of goal directed behaviour.
Parietal cortex is involved in orienting and selection. Subcortical areas such as superior
colliculus and thalamus are involved in arousal, shifting and modulating attention.
However, we know from cognitive neuroscience that these areas do not work in isolation.
Evidence from cognitive neuroscience arises from studies of alert monkeys, a variety of
electrophysiological techniques and from in vivo imaging of both normal and damaged
human brains. Networks of connectivity reveal different brain circuits involved in aspects
of visual and motor behaviour and the voluntary control of actions. There appear to be a
number of separate attentional systems that involve different but interacting brain sites.
The challenge now is to link data from cognitive psychology with the deficits apparent in
neuropsychological patients and brain anatomy. Current models that attempt to do this
are discussed and their ability to predict attentional deficits in patients are evaluated.
Parasuraman (1998) and Gazzaniga (2000) both offer the reader important collections of
papers concerning evidence and theories of varieties of attention from a cognitive
neuroscience perspective.
Gazzaniga, M S. (Ed.), (2000). The New Cognitive Neurosciences. Cambridge, MA: MIT Press.
Parasuraman,R.(Ed.),(1998). The Attentive Brain. Cambridge, MA: MIT Press.
Styles, E. A. (1997). The Psychology Of Attention. Hove, UK: Psychology Press.
Professor Ed Van Zomeren
Assessment of Attentional Disorders
Attention has once more become a central theme in psychology - but a consensus
regarding definitions of concepts and the usefulness of theoretical models is still lacking.
Also, the assessment of attention in clinical neuropsychology and rehabilitation is quite
diverse, including traditional paper-and-pencil tests, rating scales and computerized
batteries. This presentation therefore focuses on three questions (1) Which concepts of
attention are useful in clinical neuropsychology? How should these aspects be assessed?
(2)Can cognitive rehabilitation be based on neuropsychological assessment? Focussed,
divided and sustained attention are often seen as the main aspects of attention. In the last
two decades interest has grown in the executive aspects of attention, that can be brought
under the label of supervisory attentional control. Unfortunately, these four aspects cannot
be assessed separately, as almost any test requires some focusing, dividing of attention
over subtasks within the test and sustaining attention for as long as the test lasts. Also, any
test will ask some supervisory attentional control, for example monitoring one's
performance for errors and finding the optimal speed/accuracy trade off. It will be argued,
that for each individual admitted to a rehabilitation setting assessment could limit itself to
three aspects of attention: hemi-inattention (unilateral spatial neglect), speed of processing
and attentional control. Hemi-inattention is a basic impairment in the patient's orientation
on the outside world; it is a highly relevant impairment and can be assessed reliably.
Speed of processing is decreased in almost all patients with brain injury of some
significance; this impairment too is relevant for rehabilitation and social reintegration and
can be assessed reliably.
Finally, attentional control determines how a patient with mental slowness will manage,
when facing daily life tasks or rehab exercises. Thus, this is an essential aspect with
implications for compensatory behaviour and reintegration. However, assessment of
attentional control is as yet underdeveloped. Just like the assessment of executive
functions, it faces the dilemma that attentional control should be assessed in an
unstructured situation where the subject has to find this own strategies and priorities while testing requires a standardized situation with a standardized instruction. In
particular, the clinician would like to assess, whether the patient is attending to the
essential cues in a task situation - be this driving a car or a social chat. Possibilities and
limitations of such assessments will be discussed.
Professor Norman Park
Treating Attention Impairments: A Review of the Evidence
My presentation will examine the efficacy of attention rehabilitation after an acquired
brain injury by reviewing studies that have evaluated the effectiveness of interventions for
attentional disorders. In my talk, attention refers to the voluntary control over more
automatic brain systems so as to be able to select and manipulate sensory and stored
information briefly or for prolonged periods of time (Posner & Petersen, 1990). A
particular focus of my presentation will be on studies that have attempted to restore or
retrain attention through treatment. The rationale for the restoration approach is that
practice on carefully designed exercises can promote the recovery of damaged neural
circuits and thereby restore function of the attentional processes themselves. The strong
version of the restoration hypothesis holds that for some patients and deficits it is possible
to regenerate specific damaged neural regions so that the tasks can be performed in away
that is similar to non-brain-damaged individuals (Robertson &Murre, 1999).
My talk will report findings from a recent meta-analysis of attention rehabilitation (Park &
Ingles, 2001). That study reviewed thirty studies involving 359 participants. Performance
improved significantly (using a d+ statistic) after training across studies when
performance before and after training was compared. However, performance did not
improve significantly in studies with a control condition as well. Further analyses showed
that compensatory treatments that focused on improving performance on specific skills
significantly improved performance on tasks requiring attention, but that restorationbased approaches included in the meta-analysis did not significantly affect outcomes.
I will build on this meta-analysis by reviewing individual studies that contribute to a
better understanding of these findings. In particular, I will consider whether the treatment
effects generalize to non-trained outcomes, particularly outcomes that measure
functionally relevant skills. In the concluding section, I will summarize advances that have
been made in our understanding of treating attention impairments and in evaluating their
effectiveness. I will also suggest fruitful directions in which the field of neurorehabilitation
might move forward.
Posner, M. I., & Petersen, S. E. (1990). The attention system of the human brain. Annual
Review of Neuroscience, 13, 25-42.
Robertson, I. H., & Murre, J. M. J. (1999). Rehabilitation of brain damage: Brain plasticity
and principles of guided recovery. Psychological Bulletin, 125, 544-575.
Professor McKay Moore Sohlberg
Can Disabilities Resulting from Attentional Impairments be Effectively Treated?
A review of the cognitive rehabilitation literature reveals a number of distinct approaches
for addressing attention difficulties that are associated with a reduction in disability. This
presentation will evaluate the "evidence for efficacy" associated with these interventions.
Unfortunately, analyzing intervention research is not a straightforward process. It requires
the reviewer to be conscious of the relevant underlying assumptions and biases, and to
navigate through a quagmire of complex definitional and measurement issues (Ylvisaker,
Coelho, Kennedy et al., 2002). We will begin with a brief overview of the theoretical
assumptions and definitional challenges encountered in the review process. This
discussion will be followed by a description of the different attention intervention
approaches and their associated outcomes. The talk will conclude by offering clinical
guidelines based on current research and suggestions for future investigations.
Therapies designed to address problems associated with attention impairments that have
been evaluated in the cognitive rehabilitation literature include: direct attention process
training, metacognitive strategy training, implementation of external aids, environmental
modifications/accommodation, and collaboration-focused treatments. As will be
described, these vary along several important dimensions. In addition to drawing from a
broad range of theoretical frameworks, each of the interventions has been subject to
varying levels of experimental scrutiny. The interventions also differ in the degree to
which they are "direct" interventions. For example, while the training of attention
processes and the implementation of external attention aids both consider contextual and
environmental variables, they rely on individualized therapy with the client as the
primary recipient of services. In contrast, collaborative interventions are "indirect" in that
the family and/or living context may be the chief target of intervention.
An overview of studies reporting successful and unsuccessful outcomes will be provided
with a focus on measurement issues. There are a wide variety of methods used to assess
changes in attention-related disability following intervention. For example, studies
evaluating the effect of direct process training and use of metacognitive strategies have
employed functional rating scales, self and care giver report of changes in attentionrelated activities and/or general activity/participation, informal surveys of changes in
vocational or living status to evaluate treatment effects, and changes in specific attention
related tasks (Sohlberg, Avery, Kennedy et al, in submission). Measurement tools for
studies investigating the effects of collaboration-based approaches include qualitative
analysis of field reports evaluating whether there is a reduction of difficulties instated
areas of concern (Sohlberg, McLaughlin, Todis et al., 2001).
While the measurement and methodological issues are prominent, current research
supports the clinical utility of a variety of approaches for reducing disability related to
attention impairments. Clearly a "one-size-fits all" solution does not work, and the
evolving research continues to improve our ability to respond to the diverse needs of the
rehabilitation patient. Future research aimed at improving disability-related markers for
attention will allow us to determine what types of interventions work best for which types
of clients.
Sohlberg, M.M., McLaughlin, K.A., Todis, B., Larsen, J., & Glang, A. (2001). What does it
take to collaborate with families affected by brain injury? A preliminary model. Journal of
Head Trauma Rehabilitation, 16, 498-511.
Sohlberg, M.M., Avery,J., Kennedy, M., Ylvisaker, M., Coehlho, C., Turkstra, L., &
Yorkston, K. (in submission). Establishing practice guidelines for attention process
training. Subcommittee of ANCDS writing evidence based practice standards.
Ylvisaker, M., Coehlho, C. Kennedy, M., Sohlberg, M.M., turkstra, L., Avery, J., &
Yorkston, K. (2002). Reflections on evidence-based practice and rational clinical decision
making. Journal of Medical Speech-Language Pathology. 10(2).
6. Pathology-specific outcomes
Professor Nadina Lincoln
Cognitive Rehabilitation for Stroke: Reviewing the Evidence
Cognitive problems are common consequences of stroke and have a significant impact on
outcome. Advice is given to rehabilitation teams to enable them to alter their interventions
with patients to compensate for specific impairment. Generally this has not been evaluated
but preliminary studies on dressing have identified specific strategies according to the
nature of the cognitive deficit. Cognitive rehabilitation programmes have also been
directed at specific cognitive impairments. The effectiveness of these will be reviewed
through consideration of meta-analysis of randomised controlled trials. Cochrane reviews
of attention, memory and spatial neglect have indicated that rehabilitation programmes
reduce the cognitive impairment but there is no evidence to support or refute their effect
on disability. Meta-analysis is currently hindered by the diversity of outcome measures
used in cognitive rehabilitation programmes and a case will be made for identifying
measures of cognitive disability following stroke which could provide common outcome
measures for future trials. Evidence from single case experimental evaluations will also be
considered which indicates potential treatments for spatial neglect and apraxia following
stroke, which warrant further evaluation.
Dr Linda Clare
Cognitive Rehabilitation in early-stage Dementia: Evidence and future directions
A social disability model of dementia offers a strong rationale for adopting rehabilitation
as a framework for intervention. Theoretical models and experimental evidence suggest
that, in the early stages, cognitive functioning should be an important focus of
rehabilitation. Within the tradition of interventions addressing cognitive functioning in
dementia, three main strands can be discerned. (1)Cognitive stimulation involves practice
on a range of standard, non-specific tasks intended to produce general enhancement in
cognitive functioning. (2)Cognitive training involves practice on standard tasks designed
to improve performance in specific aspects of cognitive functioning, such as memory.
(3)Cognitive rehabilitation involves collaboration on individually-designed interventions
targeting clinically-relevant outcomes, related to cognitive functioning, that have been
negotiated with the client and family. Evidence for the effectiveness of each of these three
approaches will be outlined, and factors that impact on the outcome will be considered.
Results from single cases, group comparisons and RCTs indicate that each of these
approaches can result in significant improvements in aspects of cognitive functioning.
However, cognitive functioning cannot be considered in isolation from the wider
psychological and social impact of early-stage dementia, and future development of
cognitive approaches requires not only a greater emphasis on individualised
interventions, but also an holistic approach that integrates cognitive rehabilitation within a
broader therapeutic context.
Professor Hugo Du Coudray
(with Professor Nancy Carney)
The Effectiveness of Cognitive Rehabilitation for Traumatic Brain Injury: A Systematic
Review
In 1998, the U.S. Agency for Healthcare Research and Quality (AHRQ) funded the
Evidence-Based Practice Center (EPC) of Oregon Health and Science University (OHSU) to
conduct a systematic review of the scientific literature about the effectiveness of
rehabilitation for the treatment of traumatic brain injury (TBI). The report included a
chapter about cognitive rehabilitation interventions for TBI. In the summer of 2002, we
updated the research about cognitive rehabilitation by conducting a further systematic
review of the literature published between 1996 and the present.
In this lecture the findings of the original report will be summarized, together with recent
findings from the update. In preparation for a discussion of the findings, various research
designs will first be defined, and the nature and usefulness of the information available
from each design identified. Flaws in studies that may limit the value of the information
reported will be discussed. We will review the purpose, process, and procedures for
conducting a systematic review, and will discuss the research designs that are optimal for
answering particular kinds of questions within the context of a systematic review.
7. Theory of Cognitive rehabilitation
Dr Argye Hillis
Cognitive Rehabilitation: What have we learned from the decade of the brain?
Cognitive rehabilitation following brain damage was undertaken for many years in the
absence of a well-founded model of the cognitive processes underlying tasks that were
being rehabilitated. This behavioral approach "worked" to varying degrees. However,
some advances were made in effectiveness when clinicians started considering models of
the mental representations and processes underlying specific cognitive tasks. These
cognitive architectures allowed clinicians to pinpoint which processes were impaired or
spared in individual patients, in order to rationally focus therapy. This "cognitive
neuropsychological" approach to rehabilitation was an important step in improving
cognitive therapy. However, because cognitive neuropsychology provided theories about
the functional architectures of various tasks, rather than theories about how these systems
might change in response to intervention, their usefulness had limitations. It was
subsequently proposed by Baddeley and others that connectionist models of cognitive
tasks, since they model learning as well as the architecture of cognitive tasks (e.g.,
reading), might provide more productive basis for designing rehabilitation strategies. In
fact, there have been examples of this sort of contribution of connectionist models to
constraining or revising rehabilitation of language. However, the actual examples in the
literature to date at best provide evidence regarding most effective stimulus selection,
rather than constraining actual rehabilitation strategies.
In this talk, I propose that the usefulness of connectionist models for cognitive
rehabilitation is quite limited, because they cannot account for the crucial biological factors
in learning and recovery. I argue that brain neurochemistry, which can be modified by
medications, mood, motivation, and reinforcement can powerfully influence cognitive
recovery. Additionally, the biology of the brain is such that the intensity of training is a
crucial factor in (re-)establishing synaptic connections that underlie learning and
relearning. That is, synaptic plasticity (long term potentiation and long term depression)
are modeled fairly well by connectionist networks. However, synaptic plasticity in the
brain depends on the frequency as well as amount and duration of stimulation, and
crucially depends on the availability of neuroepinephrine, acetylcholine, and other
neurotransmitters, which depends on reward, punishment, and other human responses
and states. Thus, I argue that adequate attention to these biological variables is essential to
further progress in improving cognitive rehabilitation.
Professor Ian Robertson
The Neural Basis for a Theory of Cognitive Rehabilitation
Rehabilitation of the damaged brain can foster reconnection of damaged neural circuits;
Hebbian Learning mechanisms play an important part in this. Following on from the work
of Robertson and Murre (1999), I propose a triage of post-lesion states, depending on the
loss of connectivity in particular circuits. A small loss of connectivity will tend to lead to
autonomous recovery, while a major loss of connectivity will lead to permanent loss of
function; for such individuals, a compensatory approach to recovery is required. The third
group, I argue, have potentially "rescuable" lesioned circuits, but guided recovery depends
on providing precisely targeted bottom-up and top-down inputs, maintaining adequate
levels of arousal and avoiding activation of competitor circuits which may suppress
activity in target circuits. Empirical data are implemented in a neural network model and
clinical recommendations for the practice of rehabilitation following brain damage are
made.
Robertson, I. H., & Murre, J. M. J. (1999) Rehabilitation of brain damage: Brain plasticity
and principles of guided recovery. Psychological Bulletin 125, 544-575.
Robertson IH, McMillan TM, MacLeod E, Edgeworth J, Brock D (in press) Rehabilitation
by Limb Activation Training (LAT) Reduces Left Sided Motor Impairment in Unilateral
Neglect Patients: A Single-Blind Randomised Controlled Trial. Neuropsychological
Rehabilitation.
Manly, T., Hawkins, K., Evans, J., Woldt, K., & Robertson, I. H. (2002). Rehabilitation of
Executive Function: Facilitation of effective goal management on complex tasks using
periodic auditory alerts. Neuropsychologia 40, 271-281.