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Biomedical subjects

R K Heaton

Publications and source records attributed to R K Heaton.

At least 109 records · Page 6Linked to original sources
PubMed1983

Neuropsychological functioning after prolonged high altitude exposure in mountaineering.

This prospective study examined the possibility of long lasting CNS sequelae of high altitude exposure in mountaineering. An extensive battery of neuropsychological and personality tests was given to 22 subjects before and after Himalayan climbs above 5334 m (17,500 ft). All subjects were at altitude for long periods without supplemental oxygen, but did not suffer other physical insults such as serious injury or food or water deprivation. Although several climbers experienced acute effects of mountain sickness while at altitude, their post-climb evaluations revealed no evidence of lasting cerebral dysfunction or psychological deficit. A few climbers' subjective ratings of mental functioning were worse after their expeditions, but these self-assessments were unsupported by their performances on the objective testing. It was concluded that in healthy people who do not suffer other physical insults as well, acute CNS effects of low oxygen tensions during high altitude climbs are reversible.

Adult↗
PubMed1982

A comparison of the Wisconsin Card Sorting Test and the Category Test.

An important clinical question is whether the Wisconsin Card Sorting Test and the Category Test, two tests of abstraction and concept formation, are interchangeable. This study attempted to answer this question by correlation results on the two tests and comparing their diagnostic accuracy in large groups of brain-damaged patients (N = 207) and normal controls (N = 150). It was concluded that these tests are not clinically interchangeable and that both can make important contributions to a comprehensive neuropsychological assessment.

Adult↗
PubMed1982

Diagnostic utility of the Thurstone Word Fluency Test in neuropsychological evaluations.

Previous research has found that verbal associative fluency tasks are sensitive to the presence of cerebral lesions and more sensitive to frontal lobe and left hemisphere lesions than to other focal lesions. The present study investigated the diagnostic utility of the Thurstone Word Fluency Test (TWFT), a test of written verbal fluency, in detecting and localizing cerebral lesions. Using results from 203 brain-damaged and 134 normal subjects, we found that TWFT performance is affected by cerebral damage generally. At the same time, it is more impaired by frontal than by nonfrontal, by left than by right hemisphere, and by left frontal than by right frontal lesions. This test does not discriminate focal frontal from diffuse lesions. Stepwise discriminant function analyses indicated that the TWFT adds to the Halstead-Reitan Battery in discriminating focal frontal from nonfrontal lesions, but not in discriminating left hemisphere from right hemisphere lesions. Only markedly impaired TWFT performances had lateralizing significance.

Adult↗
PubMed1982

Neuropsychological findings in myotonic dystrophy.

Although the literature contains several references to clinically apparent cognitive deficits in patients with myotonic dystrophy (MYD), efforts to support these observations with formal testing have been lacking. The current study compared 17 MYD patients with 25 normal controls on an expanded Halstead-Reitan Battery. The MYD group scored worse than the controls on nearly every neuropsychological measure. Significant neuropsychological impairment was present even when tests of motor skills were excluded. There was no relationship between general neuropsychological impairment and degree of weakness, myotonia, or muscle atrophy in the MYD patients. These findings suggest that cognitive impairment can be an important and relatively independent component of the disability in MYD, which should be considered in the clinical evaluation and counselling of persons with this disease.

Adult↗
PubMed1982

Life quality of patients with chronic obstructive pulmonary disease.

Two hundred three patients with hypoxemic chronic obstructive pulmonary disease (COPD) and 73 healthy control subjects matched for age, sex, race, and neighborhood of residence were administered three self-report inventories concerned with the following four dimensions of life quality: emotional functioning, social-role functioning, activities of daily living, and recreational pastimes. An additional inventory was administered to a spouse or another close relative of each patient. The life quality of patients with COPD was found to be impaired relative to healthy subjects on all dimensions. Depression was the preponderant emotional disturbance reported; difficulties with home management and reduction in social interaction were the primary social-role deficits. Ambulation, mobility, sleep and rest, and a variety of recreational pastimes were also severely affected. Life quality exhibited moderate but significant relationships to neuropsychological, pulmonary, and cardiac functioning and to exercise capability. Age and socioeconomic status were found to be possible moderators of the relationship of COPD to life quality. A model to integrate these findings is proposed. Implications for the management of COPD and for the evaluation of medical treatments of chronic disabling conditions are described.

Activities of Daily Living↗
PubMed1982

Neuropsychologic findings in hypoxemic chronic obstructive pulmonary disease.

As part of a six-center clinical trial of the effectiveness of continuous v nocturnal oxygen in the management of hypoxemic chronic obstructive pulmonary disease (COPD), we performed detailed neuropsychologic assessments of these patients prior to their beginning treatment. The 203 patients (age, 65 years; Pao2, 51 mm Hg; forced expiratory volume in 1 s, 0.74 L) performed significantly worse than controls on virtually all neuropsychologic tests. Moderate to severe test impairment suggestive of cerebral dysfunction was found in 42% of the patients, as compared with 14% of controls. Higher cognitive functions (abstracting ability, complex perceptual-motor integration) were most severely affected, although half the patients also showed decrements in motor speed, strength, and coordination. Low-order significant inverse correlations were found between neuropsychologic impairment and Pao2, resting arterial oxygen saturation and hemoglobin levels and maximum work. It is concluded that cerebral disturbance is common in hypoxemic COPD and may be related in part to decreased availability of oxygen to the brain.

Adult↗
PubMed1981

A comparison of clinical and automated interpretation of the Halstead-Reitan Battery.

The diagnostic accuracy of two clinicians was compared with that of the Russell, Neuringer, and Goldstein (1970) quasi-actuarial system for interpreting the Halstead-Reitan Battery (HRB). The clinicians' independent ratings of HRB data were highly reliable, and were more accurate than the automated system in predicting the presence and laterality of structural cerebral lesions. Comparisons of the subgroups correctly and incorrectly classified by the clinicians suggest some intrinsic limitations of the test data in predicting lesion presence, and especially laterality. Classification accuracy was related to etiology of lesions, and also to extent and location of focal lesions. Neither the clinicians nor the automated system exceeded base-rate predictions regarding chronicity, but this may have been due to sampling bias in the acute group. Although the clinicians' superiority in two of the three prediction tasks may be due to their greater flexibility in weighting complex and unique patterns of test data, it remains to be seen whether this potential advantage will hold up against more sophisticated actuarial methods.

Adult↗
PubMed1979

Neuropsychological impairment with schizophrenia vs. acute and chronic cerebral lesions.

Performed detailed neuropsychological evaluations with 25 recently hospitalized schizophrenics in whom systematic neurologic workups had failed to reveal CNS disease. Efforts were made to minimize possible effects of drug-induced extrapyramidal symptoms on test performance. Although the schizophrenics showed some neuropsychological impairment relative to 25 normals, their deficits were not as severe as those of patients known to have either acute or chronic brain disorders (N = 25). The diagnostic accuracy achieved by the tests supports their use in short-term treatment facilities when the differential diagnosis includes schizophrenia and brain disorder, especially acute brain disorder. Schizophrenics' neuropsychological impairment was more correlated with degree of EEG abnormality than with degree of psychosis, which suggests a possible organic basis for the deficits that they showed on testing.

Acute Disease↗
PubMed1979

Level and variability of performance on neuropsychological tests.

Compared non-specific variability across subtests and overall level of performance on the Wechsler Adult Intelligence Scale (WAIS) and the Halstead-Reitan Battery (HRB) for normal, schizophrenic, acute and chronic brain-damaged Ss. Both variability and level of performance measures for each of the two test batteries significantly distinguished normal from abnormal Ss, but the HRB measures were more sensitive. Intra-S variability across subtests had a significant negative correlation with level of performance on the HRB, but not on the WAIS. This correlation could not be accounted for fully by a ceiling effect and was thought to represent in part a characteristic feature of ts performance on the HRB. While WAIS variability appeared to be independent of level of performance, it was not much help in differentiating between the four S groups. It was concluded that non-specific variability across subtests is not a helpful independent measure of neuropsychological function on the two batteries studied.

Adult↗
PubMed1979

Cortical atrophy, ventricular enlargement and intellectual impairment in the aged.

Fifty-nine subjects over age 60 had a computerized tomography (CT) scan and completed four neuropsychological tests. Measurements of ventricular size and sulcal enlargement were compared to test performance. Performance of the elderly subjects was also compared to that of subjects aged 16 to 40 years. Subjects over 60 years of age had significantly more brain atrophy and more impaired test performance than younger subjects. Subjects aged 80 to 99 had more atrophy and impaired performance than those 60 to 79 years. Our results suggest that, with aging, the brain atrophies and loses its abilities as measured by neuropsychological testing. However, CT evidence of atrophy only weakly predicts impaired mental function independently of age.

Adolescent↗
PubMed1978

Dopamine excretion and vulnerability to drug-induced Parkinsonism. Schizophrenic patients.

Before and during a standardized course of trifluoperazine therapy, 18 schizophrenic patients underwent repeated examinations for extrapyramidal motor signs, clinical psychopathology, and urinary excretion of free and conjugated forms of dopamine and its metabolites. Patients excreting more free dopamine and metabolites, or showing less complete conjugation, before drug treatment, were much less likely than others to develop parkinsonian akinesia and rigidity during drug treatment. Neither catatonic rigidity nor akinesia before treatment was predictive of a parkinsonian response to trifluoperazine, but pretreatment tremor may have been. The severity of schizophrenic psychopathology was unrelated to dopamine excretion. This study of schizophrenic patients, and our previous research in Parkinson's disease, suggest that urinary dopamine excretion may reflect dopaminergic function of the extrapyramidal motor system in both conditions.

Adult↗