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Biomedical subjects

R Howard

Publications and source records attributed to R Howard.

At least 19 recordsLinked to original sources
PubMed1992

Brainstem auditory evoked responses (BAERs) during the menstrual cycle in women with and without premenstrual syndrome.

Brainstem auditory evoked responses (BAERs) were recorded at three menstrual cycle phases (menstrual, late follicular, and late luteal) in a sample of healthy control women (n = 21) and in a sample of women (n = 30) diagnosed as suffering from Late Luteal Phase Dysphoric Disorder (LLPDD). The latter were divided on the basis of retrospective and prospective self-ratings into moderate (PMS+) and severe (PMS++) symptom groups. Results showed (1) no change in BAER latencies at different phases of the menstrual cycle; (2) increased BAER latencies for wave III in women with moderate PMS symptoms compared with healthy controls; (3) increased BAER latencies for waves III and V in women with severe PMS symptoms compared with healthy controls. These results raise the possibility of brainstem dysfunction in PMS women, and support the idea of a neurobiological predisposition to this order.

Adult↗
PubMed1992

Smoking, nicotine dose and the lateralisation of electrocortical activity.

The effects of cigarette smoking on the balance of activity of the cerebral hemispheres were studied in two experiments. Experiment 1 examined the effects of smoking on lateralisation of EEG alpha and beta power in six male smokers, and revealed a dose-related biphasic action. Low doses of nicotine as measured by residual butt analysis increased left hemisphere activity in a dose related manner, while higher doses (greater than 1.1 mg) reversed this effect. Experiment 2 examined the time course of the changes in EEG alpha, beta, theta and delta lateralisation in 11 male smokers. During the initial period of smoking there was a reduction in EEG alpha, reflecting cortical activation, followed by an increased in alpha power towards the end of the cigarette. These changes were accompanied in smokers taking moderate nicotine doses, by an initial shift towards left hemisphere activation, followed by a reduction in left hemisphere activation relative to the right. Initial changes in delta and theta power were negatively correlated with nicotine dose. Higher nicotine doses were associated with greater shifts towards right hemisphere activation, as indicated by beta and delta lateralisation, and also with greater decreases in subjective arousal. These results were interpreted as supporting the hypothesis that the stimulant action of lower doses of nicotine involves the activation of a left hemisphere "Go" system, while the sedative effect of higher doses involves increased activation of the right hemisphere "NoGo" system.

Adult↗
PubMed1992

Contingent negative variation as an indicator of sexual object preference: revisited.

This study attempted to replicate the finding of Costell et al. (1972) that contingent negative variation (CNV) in anticipation of opposite sex nudes is of greater amplitude than CNV in anticipation of same sex nudes. In order to control for variation in level of attention, which may have accounted for the result of Costell et al., a 'match/mismatch' CNV paradigm was used in which S2 was either identical to S1 or differed from it. Subjects (n = 6 males) were required to indicate a same/different judgement by button pressing at S2 offset. CNV in anticipation of opposite sex nudes was of significantly greater amplitude than CNV in anticipation of same sex nudes, confirming the finding of Costell et al. This offers encouragement for the application of CNV to the assessment of sexual object preference in sex offenders.

Adult↗
PubMed1992

Relationship between CNV asymmetries and individual differences in cognitive performance, personality and gender.

This study used verbal and spatial variants of a cognitive 'match/mismatch' paradigm to explore relationships between functional brain asymmetries and individual differences in cognitive performance, personality and gender. Contingent negative variation (CNV) elicited in the 'match/mismatch' paradigm was recorded from central (Cz, C3 and C4) derivations in two male and one female samples. Results indicated gender differences in both the degree and direction of CNV asymmetries. Males showed a left hemisphere asymmetry in the verbal task and a right hemisphere asymmetry in the spatial task, with significant laterality (C3-C4) differences between tasks across the foreperiod. Females showed a left hemisphere asymmetry in both tasks with laterality differences between tasks confined to the early part of the foreperiod. CNV amplitude in the verbal task correlated with verbal memory performance and verbal I.Q. CNV amplitude in the spatial task correlated with visuospatial memory performance. Social extraversion was associated with greater left-hemisphere asymmetry in both tasks, while behavioural extraversion was associated with left-hemisphere asymmetry in the verbal task only, and with smaller verbal than spatial CNVs.

Adult↗
PubMed1992

From the jumping Frenchmen of Maine to post-traumatic stress disorder: the startle response in neuropsychiatry.

The startle response is a universal and phylogenetically ancient reflex. Pathological exaggerations and modifications of startle underlie the symptomatology of a surprisingly diverse range of neuropsychiatric disorders, a fact that seems to have gone largely unappreciated. We review the available literature on the physiology of the normal human startle response and examine the neuropsychiatric conditions characterized by pathological startle. Startle epilepsy and primary hyperekplexia are considered as neurological disorders involving abnormal startle. Patients with hyperstartle and exotic culture-bound syndromes characterized by excessive startle are considered by the authors to represent extreme variants of the normal startle response. Post-traumatic stress disorder, drug and alcohol withdrawal states and schizophrenia all have abnormal startle as a clinical feature secondary to increased arousal and presumed disturbance of central neurotransmitter systems. The neurophysiological mechanisms by which abnormalities of the startle response may occur are discussed and a system of classification of neuropsychiatric hyperstartles is suggested.

Humans↗
PubMed1992

The use of a low phenylalanine diet with amino acid supplement in the treatment of behavioural problems in a severely mentally retarded adult female with phenylketonuria.

If phenylketonuria is untreated in infancy, it causes irreversible brain damage. No dietary treatment can alter this brain damage. However, it has been shown that dietary treatment can reduce behaviour disturbances often associated with the condition. In this study, a subject's behaviour was monitored over 18 weeks while on a low phenylalanine diet. Results demonstrate a significant reduction in the level of her disturbed behaviour.

Adult↗
PubMed1991

Direct observation in vitro of how neuroblasts migrate: medulla and cochleovestibular ganglion of the chick embryo.

The hypothesis that neuroblasts migrate in the nervous system by a locomotory process was tested experimentally. An in vitro preparation permitted direct observation of postmitotic cells migrating from the rhombic lip of the medulla and the anlage of the cochleovestibular ganglion. Cell locomotion was not seen. Instead migration was produced by elongation of a leading process, followed by translocation of the nucleus (perikaryal translocation). On the basis of comparisons with previous observations in situ, we propose that this represents a common mode of migration in the developing nervous system. Cell clusters were explanted from the rhombic lip at the developmental stage when they migrate from the ventricular zone to the acoustico-vestibular anlage in the medulla. Cells from the cochleovestibular ganglion were explanted after migration from the otocyst, but before ganglionic differentiation. Each neuroblast's migration route was formed by an elongating leading process ending in a growth cone. The growth cone attached to other cells and processes or ended freely on an acellular substrate. Nonneuronal cells usually migrated as has been described for fibroblasts, yet with some of the features of perikaryal translocation, but some nonneuronal precursor cells may migrate the way neuroblasts do. Neuroblasts did not migrate preferentially on the processes of nonneuronal cells, although the reverse could be observed. In fact a variety of interactions between migratory cells, neuronal and nonneuronal, were observed. The advantage of the experimental system described here is that one can observe cells migrating spontaneously at the times in development when they normally do so, while preserving the cellular populations present in situ.

Animals↗
PubMed1991

Karl Philipp Moritz' Journal of Empirical Psychology (1783-1793): an analysis of 124 case reports.

Karl Philipp Moritz edited Gnothi Sauton, the Journal of Empirical Psychology (1783-1793), which stands as the first of numerous psychological and psychiatric periodicals. We evaluated 124 psychiatric or neurological case reports from the journal according to modern diagnostic criteria and present a brief outline of the contributors' and patients' sociodemographic characteristics, selected case reports and the surmised risk factors. A reliable diagnostic reassignment of the well-described cases was feasible; this may indicate that patients retain similar psychiatric disturbances over the centuries. As in the popular literature of the period, examples of 'sentimental students' and 'desperate soldiers' represented the most frequently discussed, prototypical high-risk personalities in the Journal, which marked the step from literature to empirical science. The influences of this case material upon contemporary psychiatric writing and thought are reviewed.

Germany↗
PubMed1991

Psychiatric, neurological and medical aspects of misidentification syndromes: a review of 260 cases.

Two hundred and sixty case reports of misidentification syndromes were evaluated. One hundred and seventy-four patients had a Capgras syndrome misidentifying other persons, 18 a Fregoli syndrome, 11 intermetamorphosis, 17 reduplicative paramnesia and the rest had other forms or combinations of mistaken identification. Schizophrenia (127 cases), mostly of paranoid type, affective disorder (29), and organic mental syndromes including dementia (46) were the most common diagnoses in patients who misidentified others or themselves. The patients with reduplicative paramnesia more frequently suffered from head trauma or cerebral infarction and showed more features of right hemisphere lesions on neuropsychological testing or CT scan than the patients with other misidentification syndromes. Forty-one case-reports implicated underlying medical conditions. Forty-six of the patients were reported to show violent behaviour. The misidentification of persons can be a manifestation of any organic or functional psychosis, but the misidentification of place is frequently associated with neurological diseases, predominantly of the right hemisphere. Misidentification syndromes show a great degree of overlap and do not represent distinctive syndromes nor can they be regarded as an expression of a particular disorder. These patients deserve special diagnostic and therapeutic attention because of the possible underlying disorders and their potentially dangerous behaviour.

Adult↗
PubMed1991

Recent studies on dementia senilis and brain disorders caused by atheromatous vascular disease: by A. Alzheimer, 1898.

In 1898, Alzheimer wrote an exhaustive update on psychogeriatric issues. He discussed paralytic dementia, involutional melancholia, senile dementia, presenile dementia, arteriosclerotic dementia, Binswanger disease, stroke-induced dementia, and other dementias of vascular origin. In this paper, he appeared to describe his very first case of Alzheimer disease, he anticipated the ischemic score, and outlined his opinion about numerous issues of dementia research that are of current interest.

Alzheimer Disease↗