Gastric Myoelectrical Activity in Patients with Parkinson's Disease (Evidence of a Primary Gastric Abnormality)

Parkinson's disease patients may experiencevarious gastrointestinal symptoms; however, the exactpathophysiology of these symptoms is not fullyunderstood. Therefore, the aim of this study was toinvestigate the pattern of gastric myoelectrical activityin patients with Parkinson's disease. Eleven patientswith Parkinson's disease and 10 healthy subjectsparticipated in the study. Patients were stratified as “receiving dopaminergic therapy” (N= 5) and “off therapy” (N = 6). Gastricmyoelectrical activity was measured by means of surfaceelectrogastrography (EGG) for 30 min before and for 90 min after a standardized meal. The dominantfrequency, postprandial EGG power change, and thepercentage of normal 2-4 cycles/min (cpm) slow-waveactivity in the three groups were calculated andcompared. The mean postprandial EGG power increase in theuntreated patients was smaller than in the treatedpatients (–3.11 ± 1.01 and 1.17 ±1.96 dB; P = 0.072). Moreover, both of these values weresignificantly decreased when compared to the control group(untreated vs control: d–3.11 ± 1.01 vs8.01 ± 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 wasnot different from the treated patients (82.6 ±6.6% vs 75.8 ± 13.6%, P = NS) or from the controlgroup (88.2 ± 5.4%, P = NS). The dominantfrequency after the meal was similar to that in thefasting state both in the untreated (3.3 ± 0.1 vs3.2 ± 0.2 cpm; P = NS) and treated patients (3.2± 0.1 vs 3.1 ± 0.1 cpm, P = NS), whereasthe dominant frequency significantly increasedpostprandially in the control group (2.88 ± 0.12vs 3.05 ± 0.16; P < 0.05). Abnormalities ingastric myoelectrical activity in untreated Parkinson'sdisease patients reflect direct involvement of thegastrointestinal tract by the primary disease process.EGG can be regarded as a useful diagnostic tool inevaluating gastrointestinal involvement inneurodegenerative diseases.