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Biomedical subjects

C N Karson

Publications and source records attributed to C N Karson.

71 records · Page 4Linked to original sources
PubMed1983

A comparison of two iatrogenic dyskinesias.

The authors compared the regions of motor involvement in levodopa-induced dyskinesia and neuroleptic-induced tardive dyskinesia. Significantly more patients with tardive dyskinesia than parkinsonian patients with levodopa-induced dyskinesia had lip and tongue movements. Patients with tardive dyskinesia had significantly higher mean AIMS scores in the orofacial region than parkinsonian patients with levodopa-induced dyskinesia. More patients with levodopa-induced dyskinesia than those with tardive dyskinesia demonstrated hyperkinesia in the lower extremities. Limb and truncal movements in levodopa-induced dyskinesia were worse in patients with more severe parkinsonism and correlated positively with the length of Parkinson's disease. These findings suggest that these dyskinesias may involve different pathophysiological mechanisms.

Antipsychotic Agents↗
PubMed1983

An inverse correlation between spontaneous eye-blink rate and platelet monoamine oxidase activity.

An inverse correlation between platelet monoamine oxidase activity and spontaneous eye-blink rate, a putative measure of central dopaminergic activity, was found in medication-free chronic schizophrenic patients without tardive dyskinesia (n = 20, rs = -.47, P less than .025). A similar correlation was found when patients with tardive dyskinesia were included but was weaker (n = 27, rs = -.35, P less than .05). Normal controls and patients with tardive dyskinesia did not demonstrate this relationship. This report confirms a previous finding of a significant platelet monoamine oxidase-blink rate correlation in chronic schizophrenic patients. Insofar as this relationship is mediated by dopamine, it suggests that dopaminergic relations are more readily demonstrated in schizophrenic subjects than normals. Moreover, tardive dyskinesia appears to obscure this dopaminergic relationship.

Adult↗
PubMed1982

Haloperidol-induced changes in blink rates correlate with changes in BPRS score.

Spontaneous eye blink rates, psychiatric symptoms and response to neuroleptic medication may all be mediated by dopamine. Fixed doses of haloperidol, a dopamine blocking agent, were administered for six weeks to 17 chronic schizophrenic patients who had been previously withdrawn from all medications. The change in blink rates caused by haloperidol corresponded to a change in the thought disturbance syndrome which measures positive symptoms (r = .48, P less than .05). The relationship was particularly clear in patients with normal cerebral ventricles (r = .74, P less than .01).

Adult↗
PubMed1981

Speaking, thinking, and blinking.

The effect of several mental tasks on the spontaneous eye blink rate in 36 normals was examined. The blink rate during silence was 19.0 blinks/minute. This was significantly lower than the mean blink rate during speech (24.7 blinks/minute) and while listening to a paragraph to be memorized (27.6 blinks/minute). Reading reduced the blink rate to 12.3 blinks/minute. Men were more able to suppress and speed up blinking than women.

Adult↗
PubMed1981

Drug effect on blink rates in rhesus monkeys: preliminary studies.

Various drugs that alter central monoamine activity were given to monkeys to determine effects on blink rate. Chronic pargyline treatment raised the mean +/- SD blink rate slightly to 18.2 +/- 5.3 blinks/90 sec. When phenylethylamine was added to chronic pargyline treatment, blinks increased from a base line of 16.8 +/- 7.6 blinks/90 sec to 37 +/- 15 blinks/90 sec. Apomorphine (0.36 mg/kg) raised blinks from a base lone of 12.2 +/- 2.8 blinks/90 sec. to 41.9 +/- 10.3 blinks/90 sec. and reversed a decrease in blinking caused by haloperidol. The neurochemical basis of blinking and implications for tardive dyskinesia are discussed.

Animals↗
PubMed1979

Oculomotor signs in a psychiatric population: a preliminary report.

Oculomotor signs were evaluated in 172 psychiatric patients. Schizophrenic patients demonstrated a significantly higher incidence of staring, pursuit breaks, and lateral glances than did controls or other psychiatric patients. Oculomotor signs may help to differentiate schizophrenia from affective and nonpsychotic disorders. Patients with tardive dyskinesia and patients treated with tricyclic antidepressants demonstrated a significant elevation in mean blink rate. Elevated blink rates may be on early indicator of tardive dyskinesia.

Adult↗
PubMedDate not supplied

Decreased mesopontine choline acetyltransferase levels in schizophrenia. Correlations with cognitive functions.

The objective was to replicate a reported decrease of choline acetyltransferase (ChAT) in the mesopontine tegmentum of deceased schizophrenics and to see if such a decrease is related to their cognitive status as measured during life. Rigorous antemortem psychiatric evaluations were performed on our large population of schizophrenic patients. Mesopontine tissue was collected promptly following death from eight of these patients, from an additional five schizophrenics without systematic premortem psychiatric evaluation, and from control subjects. ChAT content of this brain tissue was determined using Western immunoblot analysis. There were 13 schizophrenic patients and 8 control subjects. The mean age of subjects in the two groups was similar (64 +/- 9 yr vs 63 +/- 10 yr). Even in the face of reduced post mortem intervals in the patients with schizophrenia, mesopontine tegmental ChAT concentrations were depressed by 70% in schizophrenic patients (1.28 +/- 1.74 vs 4.39 +/- 3.20 ng ChAT/micrograms tissue protein, P < 0.01), and correlated with orientation and reasoning (rs = 0.90 and 0.98, respectively) in those subjects assessed antemortem. Mesopontine ChAT concentrations are depressed in schizophrenia and correlate significantly with measures of cognitive performance in patients with this disorder.

Aged↗
PubMedDate not supplied

Intellectual impairment in adolescent psychosis. A controlled psychometric study.

The relationship of cognitive impairment to the course of schizophrenia remains uncertain. By studying psychotic adolescents, 90% of whom were hospitalized for the first time, we hoped to reduce the influence of such confounding variables as lengthy disease process, neuroleptic treatment, and institutionalization. 39 psychotic adolescent subjects who fulfilled DSM-III criteria for schizophrenia, schizophreniform psychosis, paranoid schizophrenia, or atypical psychosis were compared to 41 non-psychotic adolescent psychiatric controls. Subjects were administered the Wechsler Intelligence Scale for Children-Revised, Peabody Individual Achievement tests of reading, reading comprehension, and mathematics, Bender-Gestalt, and Purdue Pegboard test within 3 weeks of admission to a psychiatric hospital. Performance IQ was significantly lower in the psychotic group (72 versus 93, P = 0.03). Thus, the IQ pattern in adolescent psychotic patients at an early stage in their illness was similar to the pattern displayed by chronic adult schizophrenic patients. Results were not consistent with theories of left hemisphere involvement in schizophrenia. Academic achievement was similar in both groups despite marked differences in performance IQ. Psychotropic medication had no significant impact on the results. In summary, deficits in processing novel material seem at the very least to be present at the onset of the psychotic disorder, though they may be non-progressive thereafter.

Adolescent↗
PubMedDate not supplied

Preliminary studies of alpha rhythm and neuropsychological impairment in schizophrenia.

Patients with chronic schizophrenia had their EEGs recorded during medication withdrawal. Neuropsychological testing was done on the same patients during a period of 'optimum' functioning during neuroleptic treatment. Correlations between alpha activity, verbal IQ and Halsted-Reitan battery performance were evident over the entire scalp. This led us to examine whether these correlations were related to the inability of a substantial proportion of these patients to generate significant alpha activity. Patients unable to generate significant alpha activity tended to have neuropsychological impairment. These preliminary results suggest that this measure of brain physiology may relate to functional impairment in schizophrenia.

Adult↗