Gastric myoelectrical activity in patients with Parkinson's disease - Evidence of a primary gastric abnormality

Parkinson's disease patients may experience various gastrointestinal sympto ms; however, the exact pathophysiology of these symptoms is not fully under stood. Therefore, the aim of this study was to investigate the pattern of g astric myoelectrical activity in patients with Parkinson's disease. Eleven patients with Parkinson's disease and 10 healthy subjects participated in t he study. Patients were stratified as "receiving dopaminergic therapy" (N = 5) and "off therapy" (N = 6). Gastric myoelectrical activity was measured by means of surface electrogastrography (EGG) for 30 min before and for 90 min after a standardized meal. The dominant frequency, postprandial EGG pow er change, and the percentage of normal 2-4 cycles/min (cpm) slow-wave acti vity in the three groups were calculated and compared. The mean postprandia l EGG power increase in the untreated patients was smaller than in the trea ted patients (-3.11 +/- 1.01 and 1.17 +/- 1.96 dB; P = 0.072). Moreover, bo th of these values were significantly decreased when compared to the contro l group (untreated vs control: -3.11 +/- 1.01 vs 8.01 +/- 1.86 dB; P = 0.04 and treated vs control: 1.17 +/- 1.96 vs 8.01 +/- 1.86 dB; P = 0.02). The percentage of normal 2-4 cpm slow waves in untreated patients was not diffe rent from the treated patients (82.6 +/- 6.6% vs 75.8 +/- 13.6%, P = NS) or from the control group (88.2 +/- 5.4%, P = NS). The dominant frequency aft er the meal was similar to that in the fasting state both in the untreated (3.3 +/- 0.1 vs 3.2 +/- 0.2 cpm; P = NS) and treated patients (3.2 +/- 0.1 vs 5.1 +/- 0.1 cpm, P = NS), whereas the dominant frequency significantly i ncreased postprandially in the control group (2.88 +/- 0.12 vs 3.05 +/- 0.1 6; P < 0.05). Abnormalities in gastric myoelectrical activity in untreated Parkinson's disease patients reflect direct involvement of the gastrointest inal tract by the primary disease process. EGG can be regarded as a useful diagnostic tool in evaluating gastrointestinal involvement in neurodegenera tive diseases.