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Biomedical subjects

G W Fenton

Publications and source records attributed to G W Fenton.

At least 19 recordsLinked to original sources
PubMed1992

Anticholinergic drug effects on quantitative electroencephalogram, visual evoked potential, and verbal memory.

Electroencephalographic (EEG) power and coherence spectrum and visual evoked potential (VEP) recordings were made in a group of control subjects on two occasions, a week apart, before and after the subcutaneous administration of either 0.6 mg scopolamine (hyoscine-hydrobromide), a centrally acting anticholinergic drug, or 0.5 mg methscopolamine nitrate, a peripherally acting anticholinergic drug. After scopolamine administration, the EEG power spectrum significantly slowed and EEG coherence at the alpha and beta frequencies decreased. Left interhemispheric coherence increased at 1 Hz and 3-7 Hz. Methscopolamine had no significant effect on the quantitative EEG. The latency of the major positive components of the VEPs, to both flash and pattern stimuli, were not significantly affected by either drug. Verbal memory was significantly reduced after scopolamine. The results suggest that previous reports of scopolamine-induced changes in the EEG power spectrum and in verbal memory can be attributed to the central action of the drug rather than to peripheral side effects.

Adult↗
PubMed1991

The psychobiology of minor head injury.

Twenty-six consecutive admissions to an accident and emergency unit with minor head injury were examined. This was defined as a head injury warranting brief in-patient overnight stay but with a post-traumatic amnesia of less than 12 hours. Each patient had a neurological examination, a post-traumatic symptom check list completed, EEG power spectra analysis and auditory brain stem-evoked potential recordings, and a four-choice reaction-time measurement. These assessments were repeated six weeks later. Six months after the head injury a symptom check list was completed and four-choice reaction time measured again. Post-traumatic symptoms are persistent in half of all patients at six weeks and six months follow-up. The EEG power spectra showed a significant change in theta power between the first recording and the second one at six weeks, with relative reduction being noted. Approximately half of all patients had significant delays in brain stem conduction time at day 0. There was a trend towards a decrease in brain stem conduction time at six weeks, though in almost half the brain stem conduction time still remained abnormal at six weeks. Head-injured patients had prolonged choice reaction times at day 0 with serial improvement between then and six months, though the values at six weeks were still significantly longer than healthy controls. It is suggested that these findings reflect both cortical and brain stem damage following minor head injury, the brain stem damage being more persistent. There appear to be three patterns of recovery, half recovering within six weeks, a minority persisting over six months with persisting brain stem dysfunction and less than a third showing an exacerbation of symptoms with no evidence of brain stem dysfunction, the exacerbation being possibly a consequence of psychological and social factors.

Adolescent↗
PubMed1990

Assisted natural recovery from alcohol problems: effects of a self-help manual with and without supplementary telephone contact.

One hundred and seven problem drinkers responding to a newspaper advertisement were randomly assigned to groups receiving: (1) a general advice and information booklet; (2) a behaviourally-based self-help manual; (3) in addition to the manual, an opportunity to make progress reports to a telephone answering service; and (4) in addition to the manual, an opportunity to make telephoned progress reports to an interviewer. Eighty-seven (81.3%) respondents were successfully followed-up and collateral information was available for 54 (61.1%) of these. Results showed a higher proportion drinking above recommended limits at six months follow-up in the control group (78%) than in the groups receiving the manual (53%). There were no significant differences due to presence or type of telephone contact and poor use was made of the opportunity for telephone contact. Findings justify the widespread promotion of self-help materials as a means of assisting the natural recovery process among problem drinkers.

Adolescent↗
PubMed1990

A quantitative histological study of early clinical and preclinical Alzheimer's disease.

Brains from 70 unselected general hospital necropsy cases aged 60-95 years were surveyed histologically for changes of Alzheimer's disease using Congo Red-Gallocyanin preparations. Counts were made of neurofibrillary tangles in two areas of the neocortex, the hippocampal formation and the substantia innominata. Neurons were counted in the subiculum of the hippocampus, the substantia innominata and the locus coeruleus. In addition, a retrospective enquiry was made concerning the mental health of the patients in the study; cognitive performance was graded on the Global Deterioration Scale (GDS 1-7). Four cases (5.7%) had clinical and pathological changes amounting to early Alzheimer's disease. Tangles were very numerous in all areas and there was a 30% deficit or more of neurons in at least two of the structures counted. Although the diagnosis of Alzheimer's disease was not recorded during life, all had shown signs of early cognitive decline (GDS grades 3-6). A further six cases (8.6%) showed excessive tangle accumulation which may represent preclinical Alzheimer's disease. Tangles were present in the temporal neocortex (Brodmann area 22), whereas they were absent in the remainder of the survey. Tangle density in the hippocampal formation (greater than 50 tangles in a 10 microns section) was also above the baseline level of the majority of cases. However, neuron loss was not widespread in these cases and none had shown evidence of cognitive impairment. The findings confirm that the early stages of Alzheimer's disease commonly occur amongst general hospital necropsies. The emergence of clinical signs of dementia appears to be related to the loss of a critical volume of neurons and not to tangle accumulation alone.

Aged↗
PubMed1989

Musical hallucinations in a deaf elderly woman.

Musical hallucinations had caused an 86-year-old deaf woman to become anxious and depressed. She was admitted, and tranquilizing and hypnotic drugs afforded some slight improvement. The use of her hearing aid to increase ambient noise levels reduced the intensity of the hallucinations, and the patient improved.

Aged↗
PubMed1987

Anticonvulsant medication in a mental handicap hospital: 1972-1982.

The prescription sheets for all patients in a mental handicap hospital on one day in 1972 and on the same date in 1982 were examined to identify trends in anticonvulsant medication over a 10-year period. There was a reduction in size of the hospital population associated with fewer very young and milder handicapped persons. Prescription of anticonvulsants fell slightly during the decade under study with a dramatic fall in the use of phenobarbitone, and a parallel increase in the prescription of carbamazepine. Other changes included the use of sodium valproate in a significant minority of patients and the occasional use of clonazepam in 1982, while phenytoin remained a first-rank anticonvulsant throughout the period under review. The proportions of patients on polytherapy did not change over the 10-year period, though the contribution of phenobarbitone to the combined drug regimes was significantly reduced.

Anticonvulsants↗
PubMed1986

The contingent negative variation (CNV) to fear-related stimuli in acquisition and extinction.

Contingent Negative Variation (CNV) in anticipation of phobic and neutral slide material was recorded in Acquisition of a learned association between tone pitch and slide type, and in Extinction (following removal of slide presentation). In phobic volunteers, no clear CNV differentiation between 'phobic' and control condition was apparent in either Acquisition or Extinction. For Control subjects, a different pattern entirely has been demonstrated, with anticipation of the neutral condition giving rise to a larger CNV than anticipation of the 'phobic' condition (in Acquisition). In addition, Extinction led to a reversal of this CNV amplitude relationship, with the tone previously associated with the phobic slide producing a DC-shift which was larger than that following the tone previously paired with the neutral slide. The results are compatible with a dynamic model of CNV generation according to which CNV amplitude is positively related to an expectancy for reward or non-punishment but inversely related to an expectancy for punishment or non-reward.

Adult↗
PubMed1978

The contingent negative variation in antisocial behaviour: a pilot study of Broadmoor patients.

Using a classical click/flash paradigm, the CNV was recorded from the following three groups of subjects at Broadmoor Hospital: (1) 14 'psychopathic' patients selected by use of the 4/9 MMPI profile and confirmed by independent clinical diagnosis; (2) 15 'non psychopathic' patients, all psychotic and mainly schizophrenic; (3) 14 healthy staff control subjects. All three groups were matched for age and sex; the two patients groups were also matched for length of stay. Two series of 32 paired stimuli were used, separated by an interval of 30 minutes. The mean CNV voltage was significantly lower in the 'non-psychopathic' patients. The amplitude of the 'psychopath's' CNV response did not differ significantly from that of the staff controls, but the response variability between the first and second series of trials was much greater in the 'psychopathic' patients than in the other two subject groups. The 'psychopathic' subjects tended to show more rapid initial development of the CNV.

Adult↗
PubMed1977

Metabolic and EEG changes during transcendental meditation: an explanation.

Two experiments were conducted to measure the oxygen uptake (Experiment II) and the carbon dioxide production (Experiment I) during transcendental meditation. A control group of non-meditators and a few meditators listening to music was used for both experiments. In Experiment I, a controlled group of fasting meditators was also included. A drop in oxygen consumption and carbon dioxide production, found by previous authors during transcendental meditation, was confirmed. It was, however, possible to show that these drops were physiologically of small significance, and were of the magnitude to be expected from muscle relaxation. EEG recordings were taken during Experiment II in the meditating group. The EEG results showed transcendental meditation to be a method of holding the mediator's level of consciousness at stage 'onset' sleep. No evidence could be found to suggest that meditation produced a hypometabolic state beyond that produced by muscle relaxation and there was no evidence that the EEG changes were different from those observed in stage 'onset' sleep. No support was found for the idea that transcendental meditation is a fourth stage of consciousness.

Analysis of Variance↗
PubMed1977

Epileptic seizures induced by psychotropic drugs.

On the basis of information abstracted from case histories, 41 patients who had experienced epileptic seizures thought to be due either to treatment with psychiatric drugs or to withdrawal from sedative drugs were compared with a control group of patients. Those who had experienced seizures were more commonly first born and had a history of post-natal brain damage. During the week preceding the seizure there had been a marked increase in drug prescribing. The implications for drug management are discussed.

Adolescent↗
PubMed1975

Psychiatric symptom profiles of patients with epilepsy: a controlled investigation.

A comparison was made of the mental state of patients with chronic epilepsy and matched controls with locomotor disorders, using a reliable psychiatric interview technique. The symptom profiles of the two groups were similar. The profiles of temporal lobe and other epileptics were also similar. Epileptic patients with a high current psychiatric morbidity were characterized by a raised incidence of previous neurotic illness and raised neuroticism scores on the Eysenck Personality Inventory.

Adult↗