Biomedical subjects

P Maruff

Publications and source records attributed to P Maruff.

77 records · Page 5Linked to original sources

PubMed1994

Computer-administered visual analogue mood scales: rapid and valid assessment of mood in HIV positive individuals.

Studies of cognition in patients with the human immunodeficiency virus must take into account the effects of mood. Standardised mood-rating questionnaires are oftentimes consuming and fatiguing for such patients and so may be omitted from experiments. Visual analogue rating scales for affective state are rapidly administered and are quite acceptable to subjects. In 64 HIV seropositive homosexual or bisexual males, measures of anxiety and depression derived from two computer-administered visual analogue scales were compared with anxiety and depression ratings from the Spielberger State-Trait Anxiety Inventory and the Center for Epidemiological Studies-Depression. Analogue ratings of anxiety correlated .80 with STAI State anxiety and .58 with STAI Trait anxiety measures and analogue ratings of depression correlated .78 with CES-Depression measures. Analogue ratings may differentiate situational anxiety and depression more effectively and so are valid tools in assessment of anxiety and depression in HIV seropositive subjects. These may be of particular value when limitations of time or patient illness require a rapid assessment of mood variables in neuropsychiatric research.

AIDS Dementia Complex↗

PubMed1993

Selective impairment of express saccade generation in patients with schizophrenia.

When a temporal gap is introduced between the offset of a central fixation point and the onset of a peripheral saccadic target, normal subjects generate an increased number of short latency (90-150 ms) saccades, termed express saccades, and the profile of express saccade frequency across different gap sizes for any individual subject, even if untrained in the task, shows a high test-retest reliability. In patients with schizophrenia, the generation of express saccades was also normal for gap sizes of 200-300 ms or in an overlap task (gap = 0 ms). However, for temporal gaps of 50-150 ms, the generation of express saccades was significantly impaired in the schizophrenic subjects. This selective deficit appeared to be independent of the patients' neuroleptic medication status and did not correlate with the severity of schizophrenic symptoms. It is postulated that the successful execution of an express saccade requires that the cognitive operations of disengagement of visual attention and selection of the appropriate motor command to generate a saccade both be commenced or completed during the temporal gap between fixation offset and peripheral target onset. Our results suggest that, in schizophrenia, there is an impairment in the cortical/subcortical neural network that generates express saccades and controls these cognitive operations. Potential sites for such dysfunction in schizophrenia include the parietal cortex and the GABA-ergic function of the superior colliculus.

Adult↗

PubMed1991

Validation of a clinical antisaccadic eye movement test in the assessment of dementia.

The ability to generate antisaccades (eye movements deliberately made in the direction opposite to that of a visual stimulus) may be used to assess central nervous system function in a variety of neurologic and psychiatric disorders. However, the usefulness of this paradigm in clinical practice is limited by the need for an oculographic laboratory. We describe a clinical version of such an antisaccadic task and present normative data from 332 subjects. We also examined clinical antisaccades and cognitive performance in 30 patients with Alzheimer's disease, five patients with Huntington's disease, and 12 patients with pseudodementia. In Alzheimer's disease, error rates in the clinical antisaccadic test correlated well with those from a laboratory-based antisaccadic task measured on the same day by infrared oculography, confirming that the clinical antisaccadic test is a valid analog of the more sophisticated laboratory paradigms. Clinical antisaccadic error rates correlated strongly with the severity of dementia in Alzheimer's disease, and correlations with cognitive performance suggested that the clinical antisaccadic test may have some specificity for frontal lobe dysfunction. Patients with pseudodementia had normal clinical antisaccadic error rates, and the test may therefore be of use in differentiating dementia from pseudodementia. This clinical antisaccadic test provides a simple, reliable, and inexpensive quantitative clinical tool that is of value in the assessment of disturbances of higher cortical function.

Adolescent↗

PubMed1989

[High-resolution eye movement recording in the assessment of neurologic complications in HIV-1 infection].

HIV-1 related brain disease gives rise to widespread eye movement abnormalities that include impairment of fixation, saccadic speed and accuracy, antisaccadic generation and smooth pursuit function. Quantitative high resolution recording of eye movements is a valuable, non-invasive technique both for measuring the severity and progression of the AIDS dementia complex and the early detection of neurologic dysfunction in asymptomatic HIV-seropositive subjects or in patients with AIDS. In particular, it may be of use in neurologically at-risk patients requiring antiviral therapy and in monitoring the neurologic responses to such treatment.

AIDS Dementia Complex↗

PubMed1983

Tizanidine--initial pharmacokinetic studies in patients with spasticity.

The time-course of plasma concentrations of the antispasticity agent tizanidine were measured by a specific radioimmune-assay in six adults who had severe spasticity due to multiple sclerosis. The drug was given as a single oral 4 mg dose to each subject. The drug had a mean absorption half-life of 0.30 +/- 0.155 h following a mean lagtime of 0.361 +/- 0.118 h, and a mean terminal elimination half-life of 4.16 +/- 2.06 h. Only 2.65 +/- 0.82% of the dose was excreted unchanged in urine in 2 h. Calculated values of clearance and apparent volume of distribution were almost certainly overestimates as it seems probable that the orally-administered drug undergoes significant presystemic elimination (its bioavailability was not determined in the investigation here reported). Relief of spasticity, from the dosage used, was relatively slight and appeared greatest at the time of peak plasma levels of the drug.

Adult↗