Impaired gastric myoelectrical activity in patients with Parkinson's disease and effect of levodopa treatment.

The aim of this study was to evaluate gastric myoelectrical activity in patients with Parkinson's disease during and after levodopa treatment. Thirteen Parkinson's patients and 13 age-matched Parkinson's-free controls were enrolled. Electrogastrography was used to record gastric myoelectrical activity in all subjects for 30 min before and 30 min after a standard meal. In the group with Parkinson's disease, gastric myoelectrical activity was recorded during both the "on" (with levodopa treatment) and the "wearing-off" (without levodopa for at least 12 hr) periods. Results were as follows. (1) The patients without treatment showed a significantly lower percentage of regular slow waves and a significantly higher instability coefficient of the dominant frequency; (2) the patients showed an absence of the normal postprandial increase in gastric slow wave frequency which was seen in the controls: and (3) treatment with levodopa resulted in an improvement in the fed state, including a marginal increase in the percentage of regular slow waves (P = 0.1), a significant decrease in the instability coefficient, and an enhanced postprandial power increase. In conclusion, patients with Parkinson's disease have reduced slow wave rhythmicity and an impaired postprandial response in gastric myoelectrical activity. These abnormalities may be partially corrected with levodopa treatment in the fed state.