[Relation between autonomic dysfunction and progression of Parkinson's disease]

It has been claimed that cardiovascular dysfunction in patients with Parkinson's disease is less severe than multiple system atrophy. Autonomic dysfunction, however, increases with progression of Parkinson's disease. We studied the relation between autonomic dysfunction and disease severity by cardiovascular function testing with the Valsalva maneuver. The study group comprised 20 healthy controls (age, 52.7 +/- 13.6 years) and 31 patients with Parkinson's disease (59.0 +/- 7.2 years), including 13 who were previously untreated (55.0 +/- 6.2 years) and 18 who were receiving levodopa (61.8 +/- 7.1 years). The Valsalva maneuver was done having the subject exhale into a mouthpiece with an expiratory pressure of 40 mmHg for 15 seconds. Blood pressure and RR interval were measured during the Valsalva maneuver by tonometry, using a non-invasive blood pressure monitoring system (ANS 508, Nihon Colin Co., Ltd). Baroreceptor reflex sensitivities (BRS) of the second phase (BRS II) and fourth phase (BRS IV) of the Valsalva maneuver were calculated, and blood pressure elevations during the late second phase (IIp) and fourth phase (IVp) were measured. BRS II, BRS IV, and IVp in the patients of Parkinson's disease were significantly lower than those of healthy controls. BRS II, BRS IV, and IIp, however, did not significantly differ between the previously untreated patients and healthy controls. IVp of the previously untreated patients was significant lower than that of healthy controls. BRS II and BRS IV of patients with Parkinson's disease who were receiving levodopa for less than 5 years were significantly lower than those of the healthy controls. BRS II, BRS IV, and IIp decreased as disease duration increased, while IVp was unrelated to disease duration. These results suggest that patients with early Parkinson's disease have cardiac sympathetic autonomic dysfunction with maintained baroreceptor reflex sensitivity. Reduced baroreceptor reflex sensitivity was associated with levodopa treatment in patients with Parkinson's disease. Baroreceptor reflex sensitivity decreased and vasomotor sympathetic autonomic dysfunction developed as duration of disease increased.