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Biomedical subjects

C E Polkey

Publications and source records attributed to C E Polkey.

At least 127 records · Page 7Linked to original sources
PubMed1989

Cognitive mapping after unilateral temporal lobectomy.

An investigation of the extension of O'KEEFE and NADEL's [The Hippocampus as a Cognitive Map. Oxford University Press, Oxford 1978] theory of hippocampal functioning is described in patients who have undergone unilateral temporal lobectomy for the relief of epilepsy. A new spatial task, incorporating a recall-for-designs test but based on studies of spatial memory and cognitive mapping in animals was devised. Results supported the prediction of temporal lobe structure involvement in the mediation of non-egocentric but not egocentric space, and of the role of right temporal lobe structures in conditions designed to encourage "place" but not "cue" learning strategies. The role of verbal mediation in task performance is also discussed.

Adolescent↗
PubMed1989

Reading with one hemisphere.

The subjects of this study were 2 originally right-handed teen-aged girls who had undergone complete hemispherectomy (1 left, 1 right) for intractable epilepsy. Both subjects had developed normal language and reading capacities before the onset of their illness. The reading performance of H.P. (whose right hemisphere had been removed), while not as advanced in level as that of a normal 17-yr-old, showed no abnormality in any subcomponent of reading skill. The reading performance of N.I. (whose left hemisphere had been removed) was poor, but with a pattern of retained and impaired subskills strikingly similar to adult deep dyslexic patients and to split-brain patients given reading tasks lateralized to the left visual field (right hemisphere). The results are discussed with regard to implications for the reading capacity of the nondominant right hemisphere and also its putative contribution to normal reading.

Adolescent↗
PubMed1989

Implant infections and antibiotic-impregnated silicone rubber coating.

A method is described for coating silicone rubber-encapsulated implant devices with an outer layer of silicone rubber impregnated with a mixture of gentamicin sulphate and diethanolamine fusidate. A coating of this sort provides bactericidal activity lasting for a few days in the film of fluid surrounding such an implant. When used for coating our implants, the retrospective rate of implant infections believed to have been introduced at the time of surgery was reduced to 0.7% (coated), compared with 10.0% (uncoated), a highly significant difference (p less than 0.001). Systemic perioperative antibiotic prophylaxis was not shown to confer any such benefit.

Escherichia coli Infections↗
PubMed1989

Acute hippocampal recording and pathology at temporal lobe resection and amygdalo-hippocampectomy for epilepsy.

An electrocorticographic (ECoG) study is reported of patients undergoing surgery for epilepsy of temporal lobe origin. During 22 en bloc resections and six out of a total of 18 amygdalo-hippocampectomies, the activity of the hippocampus was also recorded by a multipolar strip electrode placed along its axis on the ventricular surface. Patients with mesial temporal pathology, chiefly mesial temporal sclerosis, made up the majority of those selected for amygdalo-hippocampectomy. They showed a characteristic ECoG pattern, with spikes localised to the mid part of the second and third convolutions and inferior aspect of the temporal lobe. Typically, this was associated with hippocampal discharges showing an anterior maximum. Pathology involving lateral temporal neocortex and non-specific findings were associated with more widespread temporal spikes and a maximum discharge amplitude over the mid and posterior parts of the hippocampus. It is suggested that intraoperative recording of the ECoG and hippocampal activity may provide a guide to the choice between en bloc resection and amygdalo-hippocampectomy.

Action Potentials↗
PubMed1988

Verbal and abstract designs paired associate learning after unilateral temporal lobectomy.

The combined use of a new abstract designs Paired Associates test with the Verbal Paired Associates test of Form 1 of the Wechsler Memory Scale was investigated with respect to eliciting material specific memory deficits after unilateral temporal lobectomy. Although the verbal test differentiated between the memory ability of these two groups more clearly than the abstract designs test, the effectiveness of looking at the difference between total scores on the two tests was demonstrated. The two tests produced similar levels of performance in control subjects.

Analysis of Variance↗
PubMed1987

Relationships between neuropathology and cognitive functioning in temporal lobectomy patients.

Cognitive functions were examined before operation and 4 weeks after operation with respect to pathology in 40 patients who underwent temporal lobectomy for epilepsy. Hippocampal sclerosis was associated with febrile convulsions, an earlier onset of regular seizures, poorer preoperative intelligence and with a tendency towards greater cognitive improvement across the operation than found in patients with tumour-like malformations or non-specific pathology. Damage to the amygdala was associated with a poorer outcome for the retention in memory of verbal and non-verbal material. The absence of any specific abnormality in the resected tissue was not associated with a poorer cognitive outcome 4 weeks after the operation.

Adult↗
PubMed1987

Lateralisation of memory functions in epileptic patients by use of the sodium amytal (Wada) technique.

Lateralisation of speech and memory functions was determined in 27 patients, being assessed for surgical treatment of unilateral temporal lobe epilepsy, using the sodium amytal procedure. The most common outcome with regard to language was the retention of normal left hemisphere dominance, regardless of handedness or side of lesion. In contrast, memory functions were most often to be found only in the unaffected hemisphere, also regardless of handedness or side of lesion. A lesion of either hemisphere appeared capable of interfering with language and verbal memory functions in an unexpectedly high proportion of patients.

Adolescent↗
PubMed1986

Sacral anterior root stimulators for bladder control in paraplegia: the first 50 cases.

The first 50 patients who have received sacral anterior root stimulator implants are presented, with follow-up of from 1 to 9 years. Forty-nine are alive and 43 are regularly using their implants for micturition. Of the 49 living, 39 are "very pleased, without significant reservations", six are pleased on balance but have reservations, and four are dissatisfied. Residual urine volumes are substantially reduced in all patients who are using their implants. Ten of the 12 female patients and the majority of male patients have become continent. The voiding pressure in implant-driven micturition can be regulated by adjusting the stimulus parameters, and is always kept below 90 cm H2O. Of seven patients with ureteric reflux before operation, four have ceased to reflux and the other three are unchanged. Changes in the radiographic appearances of the bladder have been favourable or zero, but there have been two cases of deterioration in the upper urinary tracts. Significant harmful effects have been CSF leaks, urinary infections following post-operative urodynamic study, and accidental damage to roots. Anterior roots nearly always recover from accidental damage, and posterior roots do not.

Adult↗
PubMed1985

The new Maudsley series of temporal lobectomy. I: Short-term cognitive effects.

Cognitive effects of temporal lobectomy for the relief of focal seizures were examined in 59 adult cases (29 left and 30 right). Verbal and non-verbal intelligence and memory were tested pre-operatively and four weeks post-operatively. Slight, non-significant differences between left and right cases pre-operatively were added to by slight, non-significant differences in change across the operation, to produce some significant post-operative differences--right cases being significantly higher on verbal IQ and lower on non-verbal IQ, for example. Variation in cognitive outcome was related to certain subject variables. Those who showed no deterioration or more improvement across the operation tended to be younger, less intellectually able pre-operatively, had an earlier first seizure and an earlier onset of regular seizures. The implications of these results for a model of the effects of temporal lobectomy are discussed.

Adolescent↗
PubMed1985

The relationship of transient hemiparesis following febrile convulsions in infancy to subsequent temporal lobectomy for intractable seizures.

Nine patients with transient hemiparesis following a febrile convulsion were part of a group of 71 patients undergoing temporal lobectomy with mesial temporal sclerosis or non-specific changes in the specimen. There was no gross evidence of additional brain damage in tests before surgery and their response to surgery was as good as the 62 patients without this history.

Adolescent↗
PubMed1984

Urodynamic observations on patients with sacral anterior root stimulators.

The urodynamic changes produced by sacral anterior root stimulators have been assessed in 13 patients with spinal injuries. Before surgery all of the eleven men and two women had poor or absent bladder control with large residual volumes. Videocysto-urethrography with pressure and flow studies was performed pre-operatively and repeated once post-operatively, at intervals of 6 months to 5 years. In all cases the residual volume was reduced to less than 50 ml and the functional bladder capacity increased to within the normal range. All the patients were able to void voluntarily by activating their implants in bursts. This produced an interrupted stream at normal voiding pressures and acceptable flow rates. There was definite improvement in vesico-ureteric reflux and decrease in bladder trabeculation following implantation of the stimulator. Use of the stimulator has enabled nine of the patients to be continent at night. Eight of them are also dry during the day.

Adult↗
PubMed1981

Selection of patients with chronic drug-resistant epilepsy for resective surgery: 5 years' experience.

Selection criteria are the key to success in resective surgery for intractable epilepsy. Using such criteria about 50% of patients admitted for assessment are considered unsuitable, half of these for neurophysiological reasons or because there is evidence of more than one area of structural abnormality. Selection for a good result from temporal lobectomy can be judged, both on the proportion of positive pathological lesions in the resected temporal lobes and on a high degree of seizure relief together with a low incidence of side effects. The same holds for other resections. The relationship between these factors is reviewed.

Chronic Disease↗