Anorectal dysfunction and constipation are well recognized in Parkinson's disease and may reflect the direct involvement of the gastrointestinal tract by the primary Parkinson's disease process. We hypothesized, therefore, that anorectal function would alter in parallel with fluctuations in motor function related to on- and off-periods in Parkinson's disease, and employed combined anorectal manometry and electromyography to investigate anorectal function during both on- and off-periods in patients with Parkinson's disease. Manometric recordings revealed a deterioration in voluntary sphincter squeeze during off-periods (squeeze index, on versus off, mean +/- SEM: 46.4 +/- 11.1 versus 29.6 +/- 7.9 mm Hg, p < 0.05); correspondingly, simultaneous electromyographic (EMG) recordings showed poor recruitment of external anal sphincter and puborectalis muscles during off-periods. A hypercontractile ("paradoxical") rectosphincteric reflex response occurred during both on- and off-periods, and was associated with an increase in EMG activity in the external sphincter and/or the puborectalis muscle. These changes in manometric and EMG parameters paralleled changes in overall motor function. These findings provide further support for the involvement of the pelvic floor musculature in the Parkinson's disease process and also provide EMG correlates for some of the manometric abnormalities described in Parkinson's disease.

Of 45 patients with acoustic neuromas (0.3-5.0 cm), 73% had facial nerve impairment on electrophysiologic testing, but only 16% had facial weakness. Cranial nerve conduction was the most sensitive measurement, especially prolongation of the ipsilateral R1 latency of the blink reflex compared with that of the contralateral reflex. The severity of nerve conduction abnormality was highly correlated with tumor size. Our results confirm and quantitate the sensitivity of nerve action potential latency in response to chronic nerve compression.

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Edwards LL, Wszolek ZK, Normand MM. Neurophysiologic evaluation of cyclosporine toxicity associated with bone marrow transplantation.

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