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Biomedical subjects

S Fleminger

Publications and source records attributed to S Fleminger.

7 recordsLinked to original sources
PubMed1992

Control of simultaneous movements distinguishes depressive motor retardation from Parkinson's disease and neuroleptic parkinsonism.

Patients with depressive motor retardation, neuroleptic induced parkinsonism or Parkinson's disease were tested on movement tasks requiring control of simultaneous movements. This was in order to determine whether these three groups of patients, who all show slowing of movements, also share the distinctive impairment of simultaneous movement control that is observed in Parkinson's disease. Though all three patient groups showed equivalent slowing on the motor tasks that were studied, the patterns of impairment were different. Only the patients with parkinsonism, either neuroleptic induced or from Parkinson's disease, showed additional slowing of a rapid ballistic elbow flexion movement when it was performed simultaneously with a rapid squeeze of the ipsilateral hand. Only patients with parkinsonism showed a significant increase in dual task interference on a bimanual bead and tapper task, compared with controls. The bead and tapper interference in patients with depressive motor retardation was between that of controls and parkinsonism. Having a bimanual skill had a large effect on the subjects' dual task interference on this task. The measures of dual task interference for the two tasks did not correlate with one another; difficulty running simultaneous motor programs does therefore not explain the interference that is observed when tapping is performed while the other hand simultaneously performs a dextrous motor task. Only patients with parkinsonism showed increased fatigue on the tapping task. The patients with depressive motor retardation did have elevated scores on a clinical rating of parkinsonism. Nevertheless there are clearly defined differences between the movement disorder observed in patients with depression, and that observed in in parkinsonism. The patterns of impairments in patients with neuroleptic parkinsonism were very similar to those of Parkinson's disease.

Adult↗
PubMed1992

Seeing is believing: the role of 'preconscious' perceptual processing in delusional misidentification.

We have no introspective knowledge of the effects of preconscious processing on our perceptions. We are, therefore, not aware that our expectancies may have prejudiced our perceptions. Expectancies tend to foster perceptions with which they are consonant. Therefore false expectations, driven by false beliefs, may result in misperceptions which reinforce those false beliefs. This morbid cycle is central to the delusional misidentification syndromes. This cycle, with positive feedback, is intrinsically unstable, which helps to explain brief episodes of delusional misidentification. Good sensory data, strong links between sense data and memory, and good judgement will all help to prevent misperceptions. The less these constraints are disrupted, the stronger will be the psychological forces needed to generate a delusional misidentification. It is likely that suspiciousness generates particularly assertive effects on preconscious processing of perceptions. Abnormalities of perceptual processing in patients with schizophrenia explain their proclivity to delusional misidentification.

Attention↗
PubMed1991

The relationship between the occupation of the D-1 dopamine receptor by [3H]piflutixol and the activity of dopamine-sensitive adenylate cyclase in rat striatal membranes.

The relationship between occupation of the D-1 dopamine receptor by [3H]piflutixol and inhibition of dopamine-sensitive adenylate cyclase has been studied. Experiments were performed in parallel; after the initial incubation to enable binding of [3H]piflutixol, half the tubes were assayed for [3H]piflutixol binding and the other half assayed for adenylate cyclase activity. The assay conditions for the two halves of the experiments were identical. (+/-)Sulpiride (3 x 10(-5)M) was present in all tubes to mask drug binding to the D-2 receptor. The inhibition of dopamine- (10(-3) and 10(-5)M) sensitive adenylate cyclase with increasing concentrations of [3H]piflutixol in the incubation mixture was compared to the saturation of specific [3H]piflutixol binding with those same concentrations of [3H]piflutixol. There was a linear relationship between receptor occupation by [3H]piflutixol and inhibition of dopamine sensitive adenylate cyclase. In a second experiment dopamine was present during the initial incubation with [3H]piflutixol. This resulted in a displacement of specific [3H]piflutixol binding and, as a consequence, a reduction of [3H]piflutixol's inhibition of dopamine-sensitive adenylate cyclase. In the absence of GTP in the initial incubation dopamine produced a greater reduction of [3H]piflutixol's inhibition of dopamine adenylate cyclase than displacement of specific [3H]piflutixol binding. In the presence of GTP in the initial incubation both displacement curves were shifted to the right, i.e. dopamine was less potent. However, under these conditions dopamine produced less inhibition of [3H]piflutixol's inhibition of dopamine adenylate cyclase than displacement of specific [3H]piflutixol binding. These results are interpreted as resulting from changes in D-1high and D-1low ratios as a result of incubation in the presence or absence of GTP.

Adenylyl Cyclase Inhibitors↗
PubMed1991

Left-sided Parkinson's disease is associated with greater anxiety and depression.

Seventeen patients with Parkinson's disease which was markedly asymmetric and worse on the right side of the body (RHP) were compared with 13 patients whose signs were worse on the left (LHP). The two groups of patients were well matched for age, duration of symptoms, disability, overall severity of signs, and medication. The mean scores on ratings of depression, using both a self-rating scale and semi-structured interview rating, were almost twice as great in the LHP group. The LHP group also had significantly more symptoms of anxiety. The prevalence of clinically significant psychopathology was increased about five fold in the LHP group compared with the RHP group. There was a close correlation between anxiety and depressive symptoms. The depression experienced by the patients was 'atypical', with relatively little anhedonia and evidence of a negative view of self, and prominent symptoms of anxiety. The best predictor of symptoms of depression and anxiety was a measure of social support and stress. They also correlated with the overall severity of Parkinson's disease.

Activities of Daily Living↗