Neuropsychological Studies of Nonfocal Brain Damage: Dementia and Trauma

323 Pages·1988·14.82 MB·English

by  Andrew A. Swihart, Francis J. Pirozzolo (auth.), Harry A. Whitaker (eds.)

SPRINGER SERIES IN NEUROPSYCHOLOGY
Harry A. Whitaker, Series Editor
Springer Series in Neuropsychology
Harry A. Whitaker, Series Editor
Phonological Processes and Brain Mechanisms
H.A. Whitaker (Ed.)
Contemporary Reviews in Neuropsychology
H.A. Whitaker (Ed.)
Neuropsychological Studies of Nonfocal Brain Damage: Dementia and Trauma
H.A. Whitaker (Ed.)
Harry A. Whitaker
Editor
Neuropsychological Studies of
Nonfocal Brain Damage
Dementia and Trauma
With 33 Illustrations
Springer-Verlag
New York Berlin Heidelberg
London Paris Tokyo
Harry A. Whitaker
Professor of Neurology
Department of Neuroscience
University of North Dakota School of Medicine
Fargo, North Dakota 58102, USA
and
Director, Cognitive Neuroscience Research Program
The Neuropsychiatric Institute
Fargo, North Dakota 58103, USA
Library of Congress Cataloging-in-Publication Data
Neuropsychological studies of non-focal brain damage.
(Springer series in neuropsychology)
Includes bibliographies and index.
1. Neuropsychological tests. 2. Dementia-Diagnosis.
3. Alzheimer's disease-Diagnosis. 4. Brain damage-
Diagnosis. I. Whitaker, Harry A. II. Series.
(DNLM: 1. Brain Injuries-psychology. 2. Dementia-
psychology. 3. Neuropsychology. WL 354 N4944]
RC386.6.N48N48 1988 617/.481 87-23509
© 1988 by Springer-Verlag New York Inc.
Sof tcover reprint of the hardcover 1s t edition 1988
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DOl: 10.1007/978-1-4613-8751-0
Preface: Clinical Research
in Neuropsychology
Two general research models in behavioral neurology and neuropsychology have
emerged since the latter part of the 19th century; both are so-called "medical
models:' In the first model, the relation between a focal lesion and a specific
functional impairment is observed. This relationship becomes the basis, in con-
temporary terms, for drawing an inference about the functional architecture of a
cognitive system. From virtually the beginning of contemporary behavioral
neurology and neuropsychology, this relationship has been challenged.
Hughlings-Jackson argued that there was no direct or simple connection between
the locus of a lesion and an element of functional architecture. Von Monakow's
concept of diaschisis has been for years a theoretical concept invoked to explain
away puzzling deficits associated with localized lesions. In recent research,
positron emission tomography (PET) scans have shown that areas of
hypometabolism occur distant from focal lesions. This fact suggests that the
specific functional impairments that we observe may arise from both the locally
damaged brain and the distant brain region, in spite of the fact that it is uncertain
to what degree hypometabolism results in impaired function.
In the other model, patients with lesions in a similar area, or of a similar type,
are assessed for a list of functional impairments. A group of patients with a simi-
lar type of lesion (e.g., stroke, tumor, closed head injury) or a similar disease
(e.g., multiple sclerosis, Parkinson's disease, senile dementia of the Alzheimer
type) are observed to see if they exhibit similar impairments or, in traditional
terms, a syndrome. The inference about the way in which disease or lesion type
affects behavior will be couched in terms of how the particular disease affects a
specific brain system (e.g., myelin), chemistry (e.g., dopamine system), or
region (e.g., frontal lobe).
The second model is the appropriate one for investigating nonfocal brain
damage. "Nonfocal" is being used here in the conventional sense to contrast with
"focal." In point of fact, both the notions of focal lesion and nonfocallesion are
misleading. As just noted above, focal lesions are typically associated with areas
of hypometabolism (and, inferentially, functional changes) in other parts of the
brain. Likewise, the notion of nonfocal lesion is misleading if one logically
means diffusely located in all brain structures or systems. Such is not the case.
vi Preface: Clinical Research in Neuropsychology
Although a particular structure, such as myelin, may be widely affected in the
brain, other structures and systems remain unaffected. The so-called nonfocal or
diffuse brain diseases, including closed head injury, do not result in lesions that
are spread uniformly throughout the brain.
This volume does not address the neuropsychology of all nonfocal diseases; for
example, multiple sclerosis is not discussed, and Parkinson's disease is not dis-
cussed in depth. However, the principles of assessment and modeling that are dis-
cussed in the following chapters also apply to other disease entities, mutatis
mutandis. The 10 chapters are equally divided between discussions of dementia
and discussions of closed head injury. A precis of each chapter follows.
Swihart and Pirozzolo compare the status of sensory, motor, cognitive, and
behavioral functions in the normal aged with those of several dementias. Vision,
audition, olfaction, gustation, and somesthesis all decline with age. The same is
true of motor functions: Simple and complex reaction time, fine motor coordina-
tion, and postural reflexes exhibit decreased performance with age. The so-called
classic aging pattern of intellectual function is marked by a relative preservation
of verbal skills accompanied by a decline in nonverbal or performance skills.
Some age-related language changes are actually improvements rather than decre-
ments, such as an increased quantity and complexity of narrative discourse style.
Age-declines in memory are generally acknowledged, but are problematic to
interpret within a cognitive model of memory. One view is that the ability to
spontaneously process to-be-remembered material-i.e., to use optimal encod-
ing processes at a deep level-declines with age. Some research has associated
this decline with age-related impaired cognitive and attentional reSOurces. Age-
related declines in visuospatial skills have been documented using standard
neuropsychological tests of parietal lobe functioning. Personality, emotionality,
and mood state do not decline systematically with age, but depression is a
common affective disturbance in the elderly. A variety of changes in the brain's
morphology, physiology, and chemistry have been associated with advancing
age; correlating these with neuropsychological changes has been problematic.
Swihart and Pirozzolo next review a number of disease processes that have
been associated with dementia: Alzheimer's disease (OAT), multi-infarct demen-
tia, Parkinson's disease (PO), Huntington's disease (HO) , progressive supra-
nuclear palsy, normal pressure hydrocephalus, Pick's disease, and pseudo-
dementia. Where the information is known, Swihart and Pirozzolo discuss the
clinical course, the neuropsychological functioning, and the problems in dif-
ferential diagnosis associated with these dementias, comparing and contrasting
normal age changes and various neuropathological changes associated with each
disease entity.
Bigler compares the findings on computed tomography (CT) scans with the
neuropsychological findings associated with OAT, specifically considering corti-
cal atrophy and ventricular enlargement, based on a study of 42 patients. The
neuropsychological data were taken from the Wechsler Adult Intelligence Scale
(WAIS) and the Wechsler Memory Scale (WMS). No significant correlations
were found between neuropsychological performance and ventricular enlarge-
Preface: Clinical Research in Neuropsychology vii
ment; however, correlations were found between some neuropsychological meas-
ures of the WAIS and WMS and with the measurements of cortical atrophy. The
second issue raised by Bigler is the correlation between neuropsychological per-
formance and dementia type. In a study of 138 patients with presumptive demen-
tia, a cluster analysis grouped them into five different types of dementia in terms
of verbal and visuospatial functioning. Neither ventricular enlargement nor cor-
tical atrophy correlated systematically with any of the dementia clusters. He con-
cludes that neuropsychological measures are better than CT analysis at
estimating as well as predicting the degree of deterioration in demented patients.
Cummings begins with an historical sketch of the issues in the clinical diagno-
sis of Alzheimer's disease, beginning with Alois Alzheimer's initial report in
1907. Of particular interest in this discussion is the alternating prominence of
neuropathological diagnoses and clinical-behavioral diagnoses. He goes on to
outline a set of clinical features that distinguish dementia of the Alzheimer type
(DAT) from the other dementias, considering memory, language, visuospatial,
cognitive, personality, affect, and motor systems. On clinical grounds, the most
difficult differential diagnosis is between DAT and either Pick's disease or vascu-
lar dementia.
As part of a general interest in the language impairments associated with
dementia of the Alzheimer type, Ulatowska, Allard, Donnell, Bristow, Haynes,
Flower, and North investigated discourse performance in 10 patients diagnosed
with DAT. The experimental narrative and procedural discourse tasks included a
self-generated story, a story elicited by pictures, the retelling of a story, the
providing of a summary and a moral for a story, and the providing of a written
version of a story presented in pictures. Five types of analysis were performed:
sentence structure, narrative content, discourse structure, reference, and a rating
of content and clarity. The DAT subjects were impaired on some tasks, but not on
others. Sentence-level and discourse-level linguistic structures were preserved,
but they showed substantial deficits in both content and reference and in their
ability to produce summaries and morals to stories. The most obvious disruption
of discourse performance by these DAT subjects was at the level of content; they
produced a greater amount of irrelevant and/or incorrect information. DAT sub-
jects also produced many more reference errors than normal controls; not only
did they use more pronouns, but they used them incorrectly more often. Meas-
ures of syntactic structure and discourse structure did not differ between the DAT
subjects and normal controls. One of the interesting conclusions reached by
Ulatowska et al. is that the language impairments in DAT are not best described
as a form of aphasia. These impairments do seem to be similar to certain charac-
teristics of the language of the elderly, albeit to a greater degree, which of course
raises the question of whether some of the impairments in DAT are in part the
effects of aging per se.
Long and Williams address some of the problems of the patient with mild to
moderate closed head injury. They begin with a brief review of the physical
aspects of closed head injury (CHI) and the general clinical characteristics for
estimating outcome. Their recovery model emphasizes six factors: preinjury
viii Preface: Clinical Research in Neuropsychology
status, extent of brain damage, impairments of cognitive function, emotional
adjustment, sociological-environmental factors, and vocational ability. Each of
these factors is discussed in detail in subsequent sections of the chapter. They
conclude with a discussion of neuropsychological rehabilitation of the CHI
patient that emphasizes planning, patient and family education, stress reactions,
and family support.
Goldstein and Levin correlate the distinction between automatic and volitional
cognitive operations to neurological conditions that affect attention. Sources of
capacity reduction-such as stress or depression, aging, or brain disease-will
affect volitional, effortful, and problem-solving processes more than automatic
processes. Some diseases, such as Parkinson's, produce a selective deficit of
effortfullvolitional but not automatic processing. Goldstein and Levin extend the
application of this theoretical framework to survivors of CHI. To study the possi-
ble effects of CHI on automatic processing, they gave a group of 15 nonaphasic,
long-term survivors of Severe CHI, using a taped word list in which some words
were repeated up to 7 times. To study the effects on effortful processing, they
gave the same subjects a free-recall test, with memory for words assessed after
each trial. A clear difference emerged between CHI subjects and controls on
effortful processing abilities, but not on automatic processing abilities. In a
second experiment to further explore the hypothesis that frequency of occur-
rence processing (an automatic process) is preserved after CHI, Goldstein and
Levin tested a new group of 16 chronic survivors of CHI on their ability to esti-
mate the number of times a given word had been presented. In this experiment,
a difference between the experimental and control groups in the area of auto-
matic processing was shown, although the groups did not differ in a cognitive
estimation task. Goldstein and Levin conclude by comparing the current theories
that amnesia represents in part a loss of automatic processing abilities to the data
showing an impaired sensitivity to frequency information in CHI patients.
Wiig, Alexander, and Secord evaluated the relationships between ratings of
levels of cognitive functioning (LOCF) and measures of linguistic and metalin-
guistic abilities in patients who had sustained closed head injury. Three groups
of patients were identified according to the criteria of the Rancho Level of Cogni-
tive Functioning Scales: VI, confused but appropriate; VII: automatic and
appropriate; and VIII; purposeful and appropriate. Measures of interpreting and
matching metaphors, interpreting sentence ambiguities, making inferences, and
recreating sentences differentiated reliably between the confused and the auto-
matic LOCF levels. The findings support the hypothesis that post-CHI language
and cognitive dysfunctions are related to each other and involve both linguistic
and metalinguistic abilities.
Mateer and Moore Sohlberg note that a reduction in memory capacity is a fre-
quent complaint of individuals who have suffered closed head injury. Traditional
approaches to memory rehabilitation have emphasized either the restoration of
memory or the development of compensatory strategies. Setting these aside,
Mateer and Moore Sohlberg address the question of an ecologically valid
memory rehabilitation approach that considers memory mechanisms as they
Preface: Clinical Research in Neuropsychology ix
operate in natural contexts. An example is prospective memory, or the ability to
remember to perform future acts. Prospective memory, along with five other
classes of memory (retrograde, anterograde, episodic, semantic, and working),
were used as the basis for a questionnaire that was sent to a randomly selected
group of 178 head-injured patients and 157 control SUbjects. Analysis of the sur-
vey data showed that 47% of the variance in responses to the questionnaire was
accounted for by items that loaded on the Attention/Prospective Memory factor,
suggesting that the ability to carry out planned actions in the future depends a
great deal on attention. Both brain-injured and control individuals ranked the
failures of prospective memory as occurring most often. In other words, most
people are concerned with their ability to remember to perform some action and
with attention-based memory processes, such as keeping a number in your head
while dialing; yet there are currently no established assessment or treatment tools
available with which to rehabilitate Prospective Memory. Mateer and Moore
Sohlberg outline three treatment programs for memory rehabilitation: attention
process training, prospective memory training, and memory notebook training.
Patient data providing some evidence for the efficacy of these training programs
are discussed.
Cytowic, Stump, and Larned address the problem of the head-injured patient
who, though not overtly impaired, nevertheless sustains a variety of symptoms
that affect work and personal activities. This is the patient who is often neglected
by primary care personnel, the patient who has sustained a shaking injury of the
brain. The authors evaluated 178 patients with closed head injury for the inci-
dence and follow-up prevalence of 20 different self-assessed symptoms and 7
different formal behavioral neurology tests. A number of the findings are of
interest. There were high incidences of neck pain, dizziness, nonvascular
headache, and memory and thought changes, as well as a wide range of subjective
visual symptoms, in spite of normal acuity and normal oculomotor function on
standard testing. Patient outcome-clinically defined as the point at which the
patient was discharged from active medical care-was assigned to one of three
groups: normal, symptomatic, or impaired. About half of the patients were dis-
charged as normal; they were able to return to work or the home without medica-
tion and with no evident need for follow-up medical care or medications,
although they were not all symptom-free on careful testing. About 30% remained
symptomatic; these subjects had identifiable complaints that they felt were toler-
able or acceptable and that were relieved by medication. About 20% remained
impaired with an unsatisfactory outcome. Subjective visual function impair-
ments were found in a majority of the patients in the study, including nearly a
third of the patients in the normal outcome group. These impairments do not
show up on routine ophthalmic examination, but must be tested for specifically.
Since one question raised by Cytowic, Stump, and Larned was the efficacy of
treatment, they conducted an alprazolan study on 40 patients in the group;
20 patients were given alprazolan, and 20 comprised the control group. The
alprazolan-treated group had a more rapid recovery in terms of the number of
treatment days from injury to discharge (a mean of 93 days compared to a mean
x Preface: Clinical Research in Neuropsychology
of 155 days), although injuries prevented all 40 patients in this study from
returning to work. A different study on a new group of CHI patients was under-
taken to assess how well magnetic resonance imaging (MRI) scans revealed struc-
turallesions in this patient population. Gross lesions usually were not seen, but
there was an increased prevalence of unidentified bright objects (UBOs) in white
matter. The location of UBOs did correspond to predicted location based on
neuropsychological examination. Based on a study of 25 patients, the MRI scan
showed abnormalities in less than half of those who had abnormal neuro-
psychological test results, but when the MRI did show abnormalities, it agreed
with the neuropsychological results over 80% of the time. The data suggest that
UBOs appear sometime after CHI, and they may ultimately disappear; this is
based on the observation that the patients in this study who had normal MRIs (no
UBOs) tended to have been scanned either very early or very late after their head
injury. Cytowic, Stump, and Larned conclude with discussions of the criterion of
returning to work as an indicator of persisting brain damage, as well as a discus-
sion of neck injuries associated with CHI. The overall message of this chapter is
quite clear: Shaking injuries to the brain produce real injuries and deficits, in
spite of the failure of superficial clinical examination or gross brain scanning to
reveal them.
Smith, Butters, and Granholm address the different nature of the semantic
memory disorder in two types of dementing illnesses - DAT, which has primarily
cortical involvement, and Huntington's disease (HD), which has primarily sub-
cortical involvement. Using the network model of semantic memory, they show
that DAT involves a disruption of spreading activation among nodes, leading to
a breakdown in the structure and usage of semantic knowledge. However, ortho-
graphic and phonological processing abilities remain largely intact from the early
to the middle stages of the disease. In contrast, HD spares language abilities for
the most part, although recent studies of HD patients suggest impairments in
tasks that require lexical access or that require specific knowledge about seman-
tic relations between lexical items. Focusing on their own research, Smith, But-
ters, and Granholm completed several studies on the organization of semantic
memory in DAT and HD. In the first study, control and HD patients were com-
pared on a word-pair priming task, where the word pairs were strong or moderate
associates. Control subjects and mild and moderate HD subjects all exhibited
positive priming effects, regardless of the strength of association or type of rela-
tionship between the word pairs. However, with progression of HD, there was a
trend of decreasing priming effects for strongly associated word pairs and
increasing priming effects for moderately associated word pairs, thus suggesting
an overall decline in the degree of associative strengths of word pairs. When con-
sidered in the light of other language tests, it is suggested that HD does in fact
break down some aspects of lexical-semantic organization. In a second study
comparing DAT and HD patients, a stem-completion priming task was
employed. Somewhat unexpectedly, DAT patients were severely impaired on this
priming task; HD patients were somewhat impaired. In a third study, semantic
priming of word pairs was compared between DAT and HD patients. DAT