Milton E. Strauss

Olfactory Recognition: Differential Impairments in Early and Late Huntington's and Alzheimer's Diseases

Forty-two patients with senile dementia of the Alzheimer type (SDAT), 38 patients with Huntingtons disease (HD) and matched normal controls were administered tests of olfactory, verbal, and visual recognition after being screened for normal olfactory discrimination. Early-affected Huntingtons patients (EHD) with minimal chorea or cognitive deficit displayed marked deficits in olfactory recognition despite normal verbal and visual performance, even after correction for task difficulty, suggesting involvement of olfactory brain regions early in the disease process. In the early Alzheimers group (EAD), marked deficits were seen on all recognition modalities indicating more global impairment. Both overall (early plus late) patient groups were impaired relative to controls on all recognition tasks, with the olfactory paradigm being most affected.

Effects of anticholinergic medication on memory in schizophrenia.

Verbal memory and reaction time of ten schizophrenic patients were compared at two different serum anticholinergic levels. Verbal recall was worse at higher drug levels, while reaction time tended to be improved by anticholinergic treatment. Implications for studies of memory in schizophrenia are considered.

Neuropsychological and neuroradiological correlates in Huntington's disease.

Measurements of cortical and subcortical atrophy were made on CT scans of 34 patients with Huntingtons disease. Significant correlations were found between the bicaudate ratio (BCR) and an eye movement scale (r = 0.44, p less than 0.01), and activities of daily living scale (r = 0.57, p less than 0.001) and the Mini-Mental State Exam (r = 0.49, p less than 0.01). No correlations were found between BCR values and severity of chorea or voluntary motor impairment. A detailed neuropsychological evaluation of 18 Huntingtons disease patients showed significant correlations between the BCR and Symbol Digit Modalities test (r = 0.65, p less than 0.01), and parts A (r = 0.72, p less than 0.001) and B (r = 0.80, p less than 0.0001) of the Trail Making Test. These data support work in primates that demonstrates the role of the caudate nucleus in cognitive and oculomotor functions, but not in motor control (which is governed by putamino-subthalamic systems). The specific cognitive skills correlated with caudate atrophy in Huntingtons disease are those reported in primate work to be served by the frontal-caudate loop system: eye movements, conceptual tracking, set shifting and psychomotor speed.

Clinical Correlates of Dementia and Disability in Huntington's Disease*

The relationship of duration of illness and severity of neurological impairment to psychometric performance and activities of daily living was examined in 57 patients with Huntingtons Disease (HD). As earlier studies suggested, a distinct cognitive profile characterized patients early in the disease. Duration of symptoms, however, proved to be a weaker correlate of cognitive decline than was motor impairment at the time of testing. For predicting adaptive functioning, both duration of symptoms and neurological status were important variables. This study underscores the limitations of length of illness as a classificatory variable in studies of dementia in HD. We further suggest that future studies consider the contribution of defects in precise timing and sequential operations to the cognitive and adaptive deficits of these patients.

Computerized Wisconsin Card Sorting Test: Comparison with Manual Administration

Computer-based testing in neuropsychology potentially offers important advantages. These include improvement in reliability and more efficient use of resources. For tests such as the Wisconsin Card Sorting Test (WCST) in which examiners must provide on-going feedback to subjects, reliability may be decreased by variability and errors in test presentation, errors in response recording and feedback, and errors in scoring. In addition, an important aspects of neuropsychological assessment is qualitative, that is, observations of the processes by which the subject responds to the test situation. The mechanics of administering the WCST hinder the examiner from allocating attention for observing these processes. Accordingly, we have automated both the administration and the scoring of the WCST. Although potential benefits of computerizing the WCST seem likely, it is possible that factors which cannot at present be duplicated by a computer may effect performance. This study compared performance between the standard manual Heaton version of the WCST and the computerized version. In a group of 33 normal and psychiatric subjects, there were significant differences in the number of Errors and the number of Correct responses, but no significant differences in performance were found for Perseverative Responses, Perseverative Errors, and Set Breaks. The mean number of Categories achieved was 2.0 for the computer administered version and 2.4 for the manual version: this difference was only marginally significant (p = 0.065). The computerized form of the WCST appears to yield similar quantitative results on scores which are most specifically affected by brain injuries in testing with the manual form. Lower variance was seen in the computer scores. This result is consistent with more reliable administration and accuracy in data acquisition and scoring in the computer version. The results overall indicate that the computer version is not a substitute for a human examiner, rather, the computer can function as a reliable partner, carrying out the mechanics of test presentation and scoring, freeing the examiner to more fully support the subject in taking the test and to observe the non-quantitative aspects of test performance.

Disengagement of attention in schizophrenia

We compared covert shift of visual attention in patients with schizophrenia or bipolar disorder, both in states of remission, to normal controls to examine the persistence of lateralized attentional deficits into nonpsychotic states. Although patients were slower in all conditions than normals, there was no difference in pattern of attentional shift among the groups. This suggests that the left-hemisphere deficit in shift of covert attention in schizophrenia may be limited to periods of florid illness.

Perceptual span in schizophrenia and affective disorders.

Perceptual span was assessed in schizophrenic, bipolar affective disorder-manic, bipolar affective disorder-depressed, and nonpsychotic inpatients. Both schizophrenics and manics processed less information than depressives, and did not differ from each other. This suggests that reduced span may be a concomitant of psychoses characterized by distractibility and thought disorder, rather than a trait specific to schizophrenia.

Impaired Wisconsin Card Sort Performance in Schizophrenia May Reflect Motivational Deficits

To the Editor.— During the past several years important reports have appeared in theArchives 1-3 concerning relationships between regional cerebral blood flow and impaired Wisconsin Card Sort (WCS) performance in schizophrenia. One provocative finding has been that impairment on this task is not corrected by instruction. 4 The WCS task requires the respondent to match cards that vary simultaneously in a number of dimensions (color, form, and number of elements) to one of four models. The subject is told whether each placement is correct or incorrect and must discover the correct sorting rule from this feedback. The first rule is to sort by color. When this rule has been learned, the correct dimension is changed, first to form and then to number. The subject is not informed of this change; rather, he or she must discover the new rule. 5 Although many different scores can be derived from the

Expression of symptomatic distress by Puerto Rican and Euro-American patients with depression and schizophrenia.

Latinos, principally Puerto Rican, and Euro-American psychiatric outpatients diagnosed with schizophrenia or major depression were compared on their responses to the Brief Symptom Inventory (BSI). The internal consistency reliability of the BSI dimensions and factor structures were comparable in the two cultural groups. Puerto Rican respondents scored significantly higher than Euro-Americans on the Global Severity Index, an index of distress, as well as on several subscales of the instrument. Multiple regression analysis suggested differences in expression of symptoms between Latinos and Euro-Americans only for obsessive compulsive and anxiety symptoms once general severity of symptom expression was controlled. Differences in symptom expression on the BSI associated with ethnicity were greater than those associated with diagnosis.

Aspects of procedural memory are differentially impaired in huntington's disease

Procedural memory encompasses several phenomena, including motor and perceptual learning, cognitive rule learning and priming. These subclasses are differentially affected by differing neuropathologies, suggesting their functional independence and reliance upon different neural substrates. To test this hypothesis, performance on a maze learning task was compared in 15 Huntingtons disease (HD) patients and 15 normal controls (NC) to assess specific route learning, cognitive skill learning and the effects of route predictability on performance. Results revealed that the HD group: (1) showed normal learning curves for a specific maze route; (2) are deficient in generalizing the cognitive skills across mazes; and, (3) fail to improve performance on a maze with a predictable route relative to mazes with unpredictable routes. These results are interpreted as supporting the independence of procedural memory subclasses. The basal ganglia are suggested as important structures in mediating the ability to generalize skills and appreciate patterned organization in to-be-acted-upon stimuli.