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Biomedical subjects

J A Jarratt

Publications and source records attributed to J A Jarratt.

25 records · Page 2Linked to original sources

The cutaneo-anal reflex: a useful index of neuropathy?

Recent studies have suggested that the latency of the cutaneo-anal reflex is prolonged in idiopathic faecal incontinence, suggesting neuropathic damage to the external anal sphincter. Electrical responses were recorded from the external anal sphincter following stimulation of the ipsilateral and contralateral perianal skin in normal subjects and patients with idiopathic faecal incontinence. Ipsilateral stimulation gave rise to shorter latencies of the earliest responses to stimulation compared with contralateral stimulation (P less than 0.001). When care was taken to compare results obtained by stimulating the skin on corresponding sides of the sphincter, the latency of both the early and late components of the cutaneo-anal reflex in incontinent patients was not significantly different from that in control subjects. The durations of the motor unit potentials, obtained by conventional electromyography, were prolonged in incontinent patients, indicating that they have external sphincter neuropathy. The data support the suggestion that external sphincter neuropathy in idiopathic faecal incontinence is due to a stretch injury to the pudendal nerve, and indicate that measurement of the latency of the cutaneo-anal reflex may be an inadequate means of demonstrating nerve damage in patients with idiopathic faecal incontinence.

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The role of partial denervation of the puborectalis in idiopathic faecal incontinence.

Recent studies have suggested that patients with idiopathic faecal incontinence have neuropathic damage to the external and sphincter and pelvic floor musculature, though no direct assessment of puborectalis function has been made in intact man. Obstetric trauma and chronic straining at stool are thought to be possible causes for damage to the puborectalis nerve supply. In this study the motor unit potential duration in the external sphincter and puborectalis was measured by conventional electromyography in incontinent patients and two groups of continent patients who strained at stool. Our results confirm that incontinent patients had significant neuropathic damage to the puborectalis and the external sphincter compared with controls. Patients with the descending perineum syndrome, who were continent, showed partial denervation of the external sphincter and puborectalis, though the degree of abnormality in puborectalis was less than that in incontinent patients. Finally, patients with constipation showed neurogenic abnormalities in the external anal sphincter but not in the puborectalis. The findings suggest that partial denervation of the external sphincter can occur independently of partial denervation of the puborectalis in patients who strain at stool but if severe changes are present in both muscles, the patient is likely to be incontinent.

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The use of conventional electromyography to assess external sphincter neuropathy in man.

Conventional electromyography was used to measure motor unit potential duration in the external anal sphincter in normal subjects and patients with idiopathic faecal incontinence. The results revealed a direct correlation between age and mean motor unit potential duration in control subjects, but no differences between age-matched male and female subjects. Patients with faecal incontinence exhibited prolongation of mean motor unit potential duration compared with matched controls. This technique provided useful quantitative data on reinnervation within the anal sphincter, complementing the results of single fibre electromyography.

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Differences in anal sphincter function and clinical presentation in patients with pelvic floor descent.

Perineal descent is found in patients with idiopathic fecal incontinence and patients with the descending perineum syndrome, who have little or no incontinence but present with a symptom pattern that suggests obstructed defecation. To investigate why patients with perineal descent present in different ways, manometric, radiologic, and neurophysiologic studies were performed in 53 patients with radiologically proven perineal descent and 34 control subjects. Thirty-two patients exhibited incontinence to rectally infused saline, while 21 patients presented with obstructed defecation but exhibited no incontinence. Both patient groups exhibited similar degrees of perineal descent on straining and increases in the motor unit potential duration of the external anal sphincter, indicative of neuropathic damage. Both groups had an abnormal rectoanal inhibitory reflex and an abnormal anorectal angle, though the latter was more obtuse in idiopathic fecal incontinence. However, although patients with incontinence had lower maximum basal and maximum squeeze sphincter pressures than normal, these values were normal in patients with obstructed defecation. Our findings suggest that perineal descent and neuropathy are not necessarily associated with incontinence as long as sphincter pressures remain normal.

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Nerve fibre refractory period in patients treated with rubidium and lithium.

Nerve fibre refractory period distributions have been measured on the median nerves of six manic-depressive patients controlled with lithium carbonate, three chronic patients (two manic-depressives and one catatonic schizophrenic) controlled with rubidium chloride, and eight normal volunteers. Rubidium prolonged the refractory periods of all nerve fibres while lithium increased only the longer refractory periods.

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