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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
PubMed1995

Electroencephalography and single photon emission computed tomography in dementia: a comparative study.

A series of elderly patients with dementia of Alzheimer type (AD), multi-infarct dementia (MID) and functional (non-organic) psychiatric illness (major depressive disorder) were selected according to DSM-III-R criteria and received: a battery of cognitive tests, EEG and Single Photon Emission Computed Tomography (SPECT) using 99mTc HMPAO. The EEG and SPECT scans were examined independently of the clinical data. The former were divided into two abnormal categories, those showing AD type change and vascular change respectively, and a normal group. The SPECT scans were classified as follows: a SPECT rCBF pattern showing bilateral temporoparietal perfusion deficits (AD type); those showing single focal perfusion deficits or multiple areas of low perfusion in the cerebral cortex suggestive of ischaemic change (vascular type SPECT picture); a mixed AD/MID pattern; and those with normal scan findings. There were significant associations between clinical diagnosis, EEG rating and SPECT rCBF pattern, approximately three-quarters of AD and MID patients having the predicted EEG and scan changes. Normal EEG recordings were more common in the MID patients. The two tests agreed in about two-thirds of cases, with no consistent pattern apparent in the cases with divergent findings. Each test misclassified a minority of dementia patients, but in only one patient were both investigations normal. Almost half of the so called 'functionally ill' patients had abnormal rCBF changes, showing mainly vascular changes while one-fifth had abnormal EEGs.

Aged↗
PubMed1994

Neurophysiology and SPECT cerebral blood flow patterns in dementia.

A series of elderly patients with dementia of Alzheimer type (AD), multi-infarct dementia (MID) and functional (non-organic) psychiatric illness (major depressive disorder) were selected by DSM III-R criteria and had the following investigations: a battery of cognitive tests, EEG with power and coherence spectral analyses of T4-T6, T3-T5, P4-O2, P3-O1 channels, visual evoked potential (flash and pattern reversal) and P300 recordings as well as single photon emission tomography (SPECT) using 99mTc HMPAO. Three subsets of patients were chosen on clinical and SPECT criteria. These were as follows: patients with a clinical diagnosis of AD and a SPECT rCBF pattern showing bilateral temporo-parietal perfusion deficits (AD type), patients with a clinical diagnosis of MID and a SPECT rCBF pattern showing single focal perfusion deficits or multiple areas of low perfusion in the cerebral cortex suggestive of ischaemic change (MID type SPECT picture) and functionally ill patients with normal rCBF (controls). The AD type group differed from the MID rCBF group in having significantly less alpha and more delta 2 (2- < 4 Hz) power. The latter had significantly lower alpha power than the controls. The 2 dementia groups with abnormal rCBF patterns did not differ in terms of coherence spectra or P300 latencies, but both had lower within and between hemisphere alpha coherence values and longer P300 latencies than the "controls" with normal rCBF. There were no group differences in the flash VEP P2-pattern reversal P100 latency difference values.

Aged↗
PubMed1994

Activation sequence of discrete brain areas during cognitive processes: results from magnetic field tomography.

Magnetic field tomography is a technique for extracting 3-dimensional estimates of current density in the brain, from non-contact, non-invasive measurements of the magnetic field generated by the brain. It allows visualisation of both cortical and subcortical focal activation patterns at millisecond intervals, and the relative time difference between active cortical areas. We have used this technique to study the activation history of discrete brain regions associated with the preparation for, initiation and inhibition of movement, and movement itself in a CNV paradigm. The strongest focal activities are found within well defined cortical regions, namely the auditory (A1), sensorimotor (SM1), medial parietal area (MPA) and anterior supplementary motor area (SMA). For the movement condition, activation history differs for the warning stimulus and the stimulus initiating movement.

Acoustic Stimulation↗
PubMed1994

Petechial haemorrhage following a partial seizure with secondary generalization: atypical presentation and differential diagnosis.

A case is reported of a patient who had a respiratory arrest on a high dependency ward in a High Security Hospital with an unusual presentation. The patient had head and upper abdominal petechial haemorrhages with extensive conjunctival haemorrhaging. A considered antecedent for this potentially life-threatening presentation was strangulation. Analysis of all the available clinical information supports the hypothesis that he had a single tonic-clonic seizure with a focal-motor onset. This constitutes an unusual consequence of a partial seizure with secondary generalization.

Adult↗
PubMed1994

Electroencephalography, computed tomography and violence ratings of male patients in a maximum-security mental hospital.

A retrospective study of brain investigations of 372 male patients in a maximum-security mental hospital patients is described. All computed tomography (CT) scan and electroencephalography (EEG) reports were collected and rated blind; patients were subsequently divided into 3 groups according to the violence rating of their pre-admission offending behaviour. The 3 groups were similar in their mean age, psychiatric diagnosis, Wechsler Adult Intelligence Scale score and proportions of patients investigated with EEG and CT. In the most violent group, 20% had focal temporal electrical abnormalities on EEG (slowing and/or sharp waves) and 41% had structural abnormalities localised to temporal lobe on CT (dilated temporal horn and/or reduced size of temporal lobe). The corresponding figures for the least violent group are 2.4% and 6.7% respectively. These results suggest that high violence rating scores are associated with temporal lobe abnormalities on CT and abnormal temporal electrical discharges on EEG.

Adult↗
PubMed1994

Cognitive therapy, analytic psychotherapy and anxiety management training for generalised anxiety disorder.

BACKGROUND: We test the hypotheses that (a) cognitive therapy is of comparable efficacy to psychodynamic psychotherapy, (b) 8-10 sessions of therapy is as effective as 16-20 sessions, and (c) brief therapist training is as effective as intensive training. METHOD: Of 178 out-patients referred to a clinical trial of psychological treatment for generalised anxiety, 110 patients met DSM-III-R criteria for generalised anxiety disorder and were randomly assigned to three different forms of psychotherapy. The main comparison was between cognitive therapy and analytic psychotherapy, delivered by experienced therapists at weekly or fortnightly intervals over six months. A third treatment, anxiety management training, was delivered at fortnightly intervals by registrars in psychiatry after a brief period of training. Eighty patients completed treatment and were assessed before treatment, after treatment, and at six-month follow-up. RESULTS: Cognitive therapy was significantly more effective than analytic psychotherapy, with about 50% of patients considerably better at follow-up. Analytic psychotherapy gave significant improvement but to a lesser degree than cognitive therapy. There was no significant effect for level of contact. Patients receiving anxiety management training showed similar improvements to cognitive therapy after treatment, with rather lower proportions showing clinically significant change. CONCLUSIONS: Cognitive therapy is likely to be more effective than psychodynamic psychotherapy with chronically anxious patients. Significant improvements in symptoms can be achieved by trainee psychiatrists after only brief instruction in behaviourally based anxiety management. However, the superiority of cognitive therapy at follow-up suggests that the greater investment of resources required for this approach is likely to pay off in terms of more sustained improvement. There is no evidence that 16-20 sessions of treatment is more effective, on average, than 8-10 sessions.

Adolescent↗
PubMed1994

Neuroleptic medication for dystonia. Reciprocal relationship between effects on motor function and mood.

BACKGROUND: The presence of dysphoric symptoms associated with neuroleptic medication is commonly reported. METHOD: Neuroleptic treatment of a segmental dystonia resulted in a disabling depressive illness, which when treated with antidepressants led to the return of the involuntary movements. RESULTS: The use of several different antidepressants and neuroleptics confirmed the association between drugs and symptoms. Genetic studies excluded "poor metaboliser status" as a reason for the patient's sensitivity to these drugs. CONCLUSIONS: The case illustrates a delicate imbalance between dose of neuroleptic medication and depressive symptoms. We should be aware of the possibility of mood changes in patients treated with neuroleptics for a variety of conditions.

Adult↗
PubMed1993

EEG power spectra and cognitive change in geriatric psychiatry: a longitudinal study.

Elderly patients with senile dementia of the Alzheimer type (SDAT), multi-infarct dementia (MID) and functional psychiatric illness, along with elderly control subjects, were studied longitudinally at 6 monthly intervals over a 2 year period, with cognitive testing and EEG power spectral analyses being carried out on each occasion. There was no significant change in the EEG power over time although a significant regression effect was noted for cognitive performance in the SDAT group. A number of between-group differences were apparent. The SDAT patients had more delta and theta power and less alpha power than those with MID and the latter group had a higher percentage of delta and theta power than the functional patients. The functional patients and normal subjects were differentiated from each other by a number of EEG power variables. The implications of these findings with respect to differential diagnosis in geriatric psychiatry are discussed.

Aged↗
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↗