Movement Disorders zyxwvutsrqpon Vol. 10, zyxwvutsrqpo No. zyxwvutsrqp 5, zyxwvutsrqponmlk 1995,. pp. 650-657 zyxwvutsrqponm 0 1995 Movement Disorder Society zyxwvutsrqpo Anorectal Function in Fluctuating (On-Off) Parkinson’s Disease: Evaluation by Combined Anorectal Manometry and Electromyography Waseem Ashraf, *Zbigniew K. Wszolek, *Ronald F. F‘feiffer, *Marlene Normand, *Kenneth Maurer, Faye Srb, *Loraine L. Edwards, and Eamonn M. M. Quigley Sections of Gastroenterology and Hepatology and *Section of Neurology, University of Nebraska Medical Center, Omaha, Nebraska, U.S.A. Summary: Anorectal dysfunction and constipation are well recognized in Par- kinson’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 func- tion related to on- and off-periods in Parkinson’s disease, and employed com- bined 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 zyxwv & SEM: 46.4 5 11.1 versus 29.6 zyxwvut f 7.9 mm Hg, p < 0.05); correspondingly, simultaneous electro- myographic (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 exter- nal sphincter and/or the puborectalis muscle. These changes in manometric and EMG parameters paralleled changes in overall motor function. These find- ings provide further support for the involvement of the pelvic floor muscula- ture in the Parkinson’s disease process and also provide EMG correlates for some of the manometric abnormalities described in Parkinson’s disease. Key Words: Anorectal manometry-Anal sphincter electromyography-Anorectal function-Parkinson’s disease-‘ ‘On-off ’ fluctuations. In some patients with Parkinson’s disease, ther- apy may be complicated by a variable response to oral L-Dopa, which features a striking fluctuation between relative mobility and immobility. The tim- ing of these fluctuations usually corresponds with the onset and termination of the therapeutic effects of L-Dopa (1,2), thus giving rise to this phenomenon commonly referred to as on-off periods or fluctua- Accepted March 27, 1995. Address correspondence to Dr. E. M. M. Quigley at Depart- ment of Internal Medicine, Section of Gastroenterology and Hepatology, University of Nebraska Medical Center, 600 South 42nd Street, Box 982000, Omaha, NE 68198-2000, U.S.A. tions. These fluctuations have also been associated with variable bladder (3,4) and esophageal motor function (5). Gut dysfunction, which is common in Parkin- son’s disease, is often debilitating and occasionally even life threatening (6,7). Increasing neuropatho- logical and neurophysiological evidence suggests that such gastrointestinal symptoms as dysphagia, constipation, and defecatory dysfunction in Parkin- son’s disease may be an integral component of the primary disease process (6,&11). Thus, in clinical studies an improvement in defecation and anorectal function has been demonstrated in Parkinson’s dis- ease patients in response to the subcutaneous ad- 650