Biomedical subjects
N Hymas
Publications and source records attributed to N Hymas.
The neurology of obsessional slowness.
Seventeen of 59 patients admitted to hospital for treatment of Obsessive-Compulsive Disorder (OCD) were found to have significant slowness, mainly due to difficulty in initiating goal-directed action and suppressing intrusive and perseverative behaviour. In this subgroup subtle neurological abnormalities were found more frequently than in healthy controls and included loss of motor fluency, hesitancy of initiation of limb movements, speech and gait abnormalities, cogwheel rigidity, complex repetitive movements and tics. Difficulties in cognitive set-shifting and complex spatial-and-shifting abilities were found on neuropsychological testing, but no correlation was found between these disturbances and either the degree of obsessionality or the severity of motor dysfunction. These results suggest that patients with obsessional slowness may have a dysfunction in the frontal-basal-ganglia loop system.
Deficit in cognitive shifting ability in patients with obsessive-compulsive disorder.
Reports on cognitive test deficits in patients with obsessive-compulsive disorders and interpretations of the underlying dysfunction have been conflicting. In the present study, 15 obsessive-compulsive patients were compared with 15 matched normal controls on three types of test sensitive to: spatial ability, ability to shift cognitive set, and combinations of both. Performance deficits as compared with controls were shown in Block Design, the Short Wisconsin Card Sort, the Word Fluency Test, and on the Money Road Map Test. No deficits were present on a number of other measures. The pattern of results is interpreted partly as revealing deficits in ability to shift cognitive set, more particularly with nonverbal material.
Sporadic facial stereotypies in patients with schizophrenia and compulsive disorders.
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Platelet membrane properties in Alzheimer and multi-infarct dementias.
Recent investigations revealed that the physical properties of both central and peripheral cell membranes are changed in dementia of the Alzheimer Type (DAT). We attempted to ascertain whether this effect is specific for DAT by studying the polarization of diphenylhexatriene (DPH) fluorescence (an indicator of membrane "microviscosity") in the membranes of platelets isolated from DAT patients, patients with multi-infarct dementia and healthy controls. The 3 groups were matched as closely as possible for age and sex distributions. Platelet phospholipid composition was also examined in an attempt to identify the chemical basis of the membrane change(s). These studies revealed that DPH fluorescence polarization is significantly reduced in platelets from DAT patients, but not in patients with multi-infarct dementia, compared with controls. Analysis of the phospholipid composition of platelets from the 3 groups of subjects did not find any significant differences which might explain the change in membrane properties.