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Biomedical subjects

A Kertesz

Publications and source records attributed to A Kertesz.

At least 19 recordsLinked to original sources

Neuropsychological deficits in vascular dementia vs Alzheimer's disease. Frontal lobe deficits prominent in vascular dementia.

OBJECTIVE: To detect neuropsychological differences between Alzheimer's disease (AD) and vascular dementia (VAD). DESIGN: Neuropsychological measures were compared in clinically defined AD and VAD patient groups. SETTING: Ambulatory and hospitalized patients were referred to a behavioral neurology clinic and to the neuropsychology department of a teaching hospital. PATIENTS: Consecutive, referred patients who fulfilled National Institute of Neurological Disorders and Stroke/Alzheimer's Disease and Related Disorders Association and Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition, criteria for AD and VAD were selected to participate in the study based on the history and clinical findings. A modified ischemic score of 3 or less was an independent selection criterion for AD (n = 103) and a score of 4 or more for VAD (n = 25). Computed tomography or magnetic resonance imaging was used to exclude other structural causes. Patients with cognitive changes related directly to a stroke were excluded. Patients were matched for age, education, age at onset, and severity of dementia. MEASURES: The variable measures were the subtests of the Wechsler Adult Intelligence Scale-Revised (WAIS-R), Wechsler Memory Scale-Revised, Mattis Dementia Rating Scale (MDRS), and Western Aphasia Battery (WAB). Patients were further stratified into mild and severe dementia categories, based on their performance on the MDRS. RESULTS: Variables that were significantly different were selected for discriminant function analysis. The Writing subtest of the WAB, the Picture Arrangement subtest of the WAIS-R, and the Motor Performance subtest of the MDRS were the best discriminators of AD and VAD in the overall and severely affected populations. Patients with VAD performed significantly worse on the MDRS Motor Performance subtest, the WAIS-R Picture Arrangement subtest, the WAB Writing subtest, the WAIS-R Object Assembly subtest, and the WAB Block Design subtest. The AD group performed significantly worse on the WAB Repetition subtest, and patients with severe AD performed significantly worse on the Story Recall test. CONCLUSIONS: Patients with VAD performed worse on tests that are influenced by frontal and subcortical mechanisms. Patients with AD performed worse on memory and some language subtests.

Aged

Human corpus callosum: a stable mathematical model of regional neuroanatomy.

The functional utility of regional parameters of the corpus callosum (CC) derived from factor analysis has been demonstrated in the rat and the human. In this study, we have utilized factor analysis to compare CC structure between two independent groups of human subjects. Tracings of the CC were taken from the midsagittal MRIs of two human samples consisting of 103 healthy volunteers and 146 neurological patients. CCs were digitized and factor analyses were performed on 99 widths, area, axis length, and perimeter. The factor structures of these two data sets were highly congruent except that one factor analysis yielded a seven-factor solution, whereas the factor analysis of the other subject population gave six factors. Further study determined that the six-factor structure could be attributed to the presence of non-consistent right-handed males whose wider CCs in the isthmus region biased the correlations. When CC parameters of consistent and non-consistent right-handed subjects were standardized, a seven-factor structure resulted. Reproducibility of the factor structure indicates that there are shared neuroanatomical characteristics of CC morphology among two disparate populations of humans in spite of variability in CC size due to sex, age, hand preference, and hand consistency.

Adolescent

Quantification of functional deficit in Alzheimer's disease using a computer-assisted mapping program for 99mTc-HMPAO SPECT.

A computer-assisted mapping program was developed to determine changes of cerebral perfusion in normal and pathological aging using single photon emission computer tomography (SPECT) and 99mTc-hexamethylpropyleneamine oxime (HMPAO). The software program outlined the cortex on 14 adjacent brain slices, and superimposed a ring of 12 regions of interest on each slice. Regional/global and regional/cerebellar relative flow values were calculated in 27 patients with clinically diagnosed Alzheimer's disease (AD) (mean age 71 years, SD 7.6) and in 10 normal controls (mean age 73.7 years, SD 7.3). The Dementia Rating Scale (DRS) was used to assess mental status in all subjects. Multiple regression analysis demonstrated a significant correlation between relative flow values and the DRS score. Regional/cerebellar (R = 0.88, p < 0.0001) relative flow values were a better indicator of cortical impairment than regional/global relative flow values (R = 0.68, p = 0.003). Of the brain regions of interest, the left parietal flow values correlated best with the DRS score (r = 0.83, p < 0.0001), a cutoff value of 77 accurately classifying 80% of the normals and 100% of the patients diagnosed as having Alzheimer's disease. The data show that computer-assisted mapping of SPECT can provide semiquantitative flow values with high diagnostic accuracy.

Aged

Predicting recovery from aphasia with connectionist networks: preliminary comparisons with multiple regression.

We trained a series of simulated neural networks with the raw scores on the Western Aphasia Battery from 91 aphasic patients. Patients were tested at 3 and at 12 months post onset. The most successful network we trained is able to predict AQ for an individual in 12 months from the raw scores at 3 months post-onset to a tolerance of + or -4.5. We then compared the relative success of a small range of trained networks to predict recovery with linear multiple regression. With the small groups of subjects involved in this preliminary study, the networks appeared to be more successful at predicting recovery.

Aged

Diagnosis of vascular dementia: Consortium of Canadian Centres for Clinical Cognitive Research concensus statement.

Interest in vascular causes for cognitive impairment is increasing, in recognition that such causes are common, and possibly preventable. This has led to attempts to better define vascular dementia and its natural history. Several sets of criteria for the diagnosis of vascular dementia have been proposed. We provide a brief overview of the background to the initiation of a Canadian consensus conference, established by the Consortium of Canadian Centres for Clinical Cognitive Research (C5R) and report the conclusions reached at that conference. To date, no one set of criteria is demonstrably superior to another; we have therefore not endorsed any of the competing sets, nor have we recommended our own. Instead we suggest that empiric studies are required to establish valid criteria. A diagnostic checklist, which combines existing criteria and additional data, is attached for clinicians wishing to participate in such studies.

Canada

Neuropsychological evaluation of language.

Neuropsychological evaluation of language may be based on the psychometric approach or on extensive exploration of modular functions according to cognitive or linguistic theory. Various approaches have several features in common, although some emphasize individual functions, and others explore syndromes in brain-damaged populations. Systematic assessment of language has been developed according to the goals of various clinicians and researchers. Beyond the diagnostic need, prognosis, and planning for therapy, there are important theoretical reasons to have standardized aphasia tests and complementary experimental explorations of language deficit. Objective quantitation of deficit allows the study of the anatomical and physiological organization of language-related structures. It also contributes to the relationship of language and other modalities of cognition, hemispheric lateralization, language development in children, and language dissolution in degenerative disease. The requirements, content, standardization, and application of aphasia tests are discussed.

Agraphia

The pathology and nosology of primary progressive aphasia.

We present three cases of primary progressive aphasia (PPA) with Pick-variant pathology to support a hypothesis of an underlying nosologic relatedness. Neuropathologic examination demonstrated focal brain atrophy with corresponding neuronal loss and gliosis, accompanied by superficial spongiosis. Specific histologic findings were ballooned neurons (Pick cells) in the atrophic areas, and in two of the cases, Pick bodies. They were immunoreactive for tau. In contrast to classic Pick's disease, there were no Pick bodies in the hippocampus. The intense neurofilament immunoreactivity of the perikarya of the ballooned neurons greatly facilitated their recognition. Based on our cases and a critical review of the literature, we hypothesize that the common underlying pathology of PPA is a variant of Pick's disease. Furthermore, we propose the concept of "Pick complex" to include other neurodegenerative diseases characterized by focal cortical degeneration, such as PPA, frontal lobe dementia, ALS with PPA, and corticonigral and corticobasal ganglionic degenerations.

Aged

Profiles of language impairment in primary progressive aphasia.

OBJECTIVE: The profile of language impairment in patients with primary progressive aphasia in comparison with the language impairment in patients with Alzheimer's disease and after stroke. DESIGN: The Western Aphasia Battery and the Mattis Dementia Rating Scale evaluated the language and cognitive impairment. Follow-up studies were done 1 to 5 years after the initial testing in seven of 10 patients with primary progressive aphasia, and a postmortem examination of the brain was done in two patients. SETTING: All 10 patients with primary progressive aphasia were previously healthy, community-dwelling persons when first tested. PATIENTS AND OTHER PARTICIPANTS: All patients with primary progressive aphasia reported at least a 2-year history of slowly progressive aphasia without other signs of global dementia. The initial Western Aphasia Battery results of the 10 patients with primary progressive aphasia were compared with those of a sample of 10 patients with probable Alzheimer's disease and with those of a sample of 10 patients with aphasia due to a left hemispheric stroke. Both reference samples were matched for age and sex; the sample with stroke-caused aphasia was additionally matched for the aphasia type. RESULTS: Expressive language disability with reduced speech fluency and anomia but preserved language comprehension and nonverbal cognition were typical features in early stages of primary progressive aphasia. Spontaneous speech was significantly more impaired in patients with primary progressive aphasia in comparison with those with aphasia after left hemisphere stroke and with language impairment in patients with Alzheimer's disease. Follow-up examinations revealed continuous, often rapid deterioration of language impairment. The neuropathological examination showed Alzheimer's disease in one patient and Pick's disease in the other. CONCLUSION: The profile of aphasia suggests that primary progressive aphasia tends to affect anterior parts of the language-dominant cortex first.

Aged

Subcortical contributions to drawing.

Constructional impairment is often considered a sign of cortical damage. However, aphasia, agraphia, and apraxia, disorders traditionally deemed cortical, have been well described following subcortical lesions, suggesting an important role for subcortical structures in cognition. Drawing impairment following subcortical lesions has not been systematically explored or compared with that following cortical damage. We examined relative incidence and severity of drawing impairment after cortical and subcortical strokes and whether there were qualitative differences between these two groups' drawings. Drawings by 125 patients with single hemispheric strokes of similar volume (42 left cortical, 36 left subcortical, 20 right cortical, 27 right subcortical) were compared using a standardized scoring system. Although previously noted right/left differences were confirmed, "subcortical drawings" did not differ from "cortical drawings" on any measures, including overall impairment. Compared with cortical patients, drawing impairment in those with subcortical lesions (especially left) was more strongly associated with impairment of other cognitive abilities. Thus, although a subcortical lesion does not cause more severe drawing impairment, subcortical lesions affecting drawing lead to more widespread cognitive dysfunction than do similarly sized cortical lesions. Drawing impairment often follows subcortical strokes and is by no means an indicator of cortical lesion localization.

Aged

Music and language in degenerative disease of the brain.

Music and language functions were studied in two musicians with degenerative disease. Both patients were tested on a standardized language battery and a series of music tasks. In the first case with left cortical atrophy and primary progressive aphasia, expressive music functions were spared with impaired reception of rhythm. The second case with posterior cortical atrophy, greater on the right, was nonaphasic, had spatial agraphia, a visuopractic deficit, and severe expressive music deficits, but intact rhythm repetition. The aphasic patient showed dissociations between music and language in fluency and content; continuous, organized, although reiterative music production was contrasted with nonfluent language. The nonaphasic patient showed the opposite pattern of deficits; unmusical production with impaired melody and rhythm organization that was contrasted with fluent, intelligible language. The double dissociation between language and music functions supports the existence of independent cognitive systems, one consistent with conventional left lateralization models of language, temporal sequence, and analytic music processing and another with a right lateralization model of implicit music cognition.

Agraphia

The structural determinants of recovery in Wernicke's aphasia.

Recovery of comprehension and total language in 22 Wernicke's aphasics was correlated with lesion size and extent of involvement of certain structures on CT. Recovery rates and outcomes were separately examined using 0-3 months and 0-12 months poststroke language data. Quantitative measures of structural damage were regressed on total aphasia and comprehension outcome measures. Supramarginal and angular gyri appeared to be the most significant structures in recovery in addition to initial severity and lesion size. This was confirmed by using ANOVA to compare the extent of involvement in each postcentral structure among the poor, moderate, and good recovery groups. The superior temporal and middle temporal gyri are less involved in the good recovery group. Structures posteriorly adjacent to Wernicke's area are important for compensation in Wernicke's aphasia and in the accompanying comprehension deficit. Persisting Wernicke's aphasia usually involves the supramarginal and angular gyri in addition to the superior temporal area.

Aged

Clinical forms of aphasia.

A survey is given on the history of knowledge of aphasia and on the necessity and possibilities of classification of aphasic disability. Also the association of clinical syndromes of aphasia with particular damage to the brain is outlined. For Wernicke's aphasia (fluent aphasia with comprehension deficit) a superior posterior temporal lesion is obligatory. The persistent jargon aphasia is associated with a lesion of the supramarginal gyrus. Broca's aphasia is seen with posterior inferior frontal lesions, but additional central and subcortical components are involved in persisting deficit. The lesions producing transcortical motor aphasia involve the supplementary speech area of Penfield. Transcortical sensory aphasia is related to lesions that overlap the watershed area between the middle cerebral and the posterior cerebral arteries.

Aphasia

Multiple dimensions of handedness and the human corpus callosum.

Consistency of right-hand preference correlates with callosal isthmus size. Anterior corpus callosum (CC) regions vary as a function of sex and right- versus left-hand preference. We analyzed regional CC anatomy in a sample of right- and left-handed men and women on the basis of both degree ("Consistency") and direction ("Hand") of hand preference scores. Significant Hand x Consistency effects indicated that both are important factors in CC organization. These data also suggested that a single continuum of hand preference and regional CC size may not be applicable across all subjects.

Adolescent

Arthritis in hemochromatosis.

We reviewed the clinical and radiographic features of arthropathy in 25 subjects with hemochromatosis, 16 probands and 9 discovered homozygous relatives. Clinical arthritis was present in 15/16 probands and 1/9 discovered homozygotes (p < 0.005). Radiologic evidence of arthropathy was seen additionally in 2 asymptomatic discovered homozygotes. The metacarpophalangeal joints and wrists were most commonly involved; severe hip disease occurred in 6. Patients with clinical or radiologic arthropathy were older than patients without. Arthropathy occurred in all 4 female probands, but in none of the 3 female discovered homozygotes. Chondrocalcinosis was seen in 9 subjects but was usually asymptomatic. The arthritis of hemochromatosis may be difficult to differentiate from several other joint diseases, especially calcium pyrophosphate dihydrate deposition disease.

Adult

Anatomical asymmetries and functional laterality.

Anatomical and functional asymmetries were measured using MRI and dichotic, visual field and hand performance laterality tasks in 104 normal right- and left-handed male and female adults. Comprehensive linear and area measures showed consistently larger brains when handedness and language laterality were in the same direction. Right-handers with left cerebral dominance for dichotic listening and left-handers with right cerebral dominance had larger structures. Hand performance was the strongest functional laterality related to anatomical asymmetries. Left hemisphere dominance on this task was associated with larger right frontal and left occipital widths. Dichotic listening or visual field laterality alone was not associated with contralaterally larger temporal, parietal or occipital measurements. Left visual field dominance for reading, interacting with right-handedness, was associated with wider left parietal width. The complex associations between anatomical and functional asymmetries contribute to individual differences in cerebral organization. The demonstrated association of coincident hand performance and language laterality measures with larger anatomical structures may confer biological advantage. Morphometric analysis in vivo may have increasing importance in interpreting behaviour.

Adult

A factor analysis of the human's corpus callosum.

We have recently developed a computer program for measuring midsagittal sections of the human corpus callosum, similar to one used for the rat. Callosal area, perimeter, axis length, and 99 widths for 104 subjects were entered into a factor analysis in order to define regional clusters. Seven width factors were obtained. Regional widths were found to be sensitive to Sex X Handedness interactions in the anterior body, with right-handed females and left-handed males being larger. In the posterior body males had wider callosa than females. A further analysis within the 'isthmus' region compared consistent and non-consistent right-handed males and females. Consistent right-handed males and both female groups had smaller callosa than non-consistent right-handed males. These findings confirmed the use of consistency of handedness as an important independent variable with respect to human callosal morphology.

Adult

On drawing impairment in Alzheimer's disease.

Spontaneous drawings of 38 patients, diagnosed by the National Institute of Neurological Disorders and Stroke-Alzheimer's Disease and Related Disorders Association criteria as "probable Alzheimer's disease," and of 39 normal control subjects were analyzed by two independent observers using a standardized scoring system. Drawings of patients with Alzheimer's disease displayed fewer angles, impaired perspective and spatial relations, simplification, and overall impairment compared with those of the control subjects. This represents a combination of the deficits seen following right- and left-hemisphere lesions. Neglect, tremor, and perseveration were not prominent. Drawing impairment was relatively independent of language or memory impairment, but drawing performance was related to perceptual and executive dysfunction in the visuospatial domain. Deterioration was followed up for up to 3 years.

Aged