Acute effects of whole-body vibration at 3, 6, and 9 hz on balance and gait in patients with Parkinson's disease.

Vibration as a stimulus to treat Parkinson’s disease (PD) patients was first recommended by Charcot in 1892, and although this approach was subsequently abandoned, recently, whole-body vibration (WBV) protocols have been suggested as a modern substitute.– A small number of studies have assessed the effects of WBV on motor symptoms in PD, with apparently positive results, obtained in open-trial designs. In each case, however, only a fixed frequency of stimulation was used, and no placebo group was included. It is therefore of fundamental interest to examine a range of “doses” (in this case, frequencies) in order to optimize potential therapeutic effects. Using an appropriate placebo-controlled experimental design, we have explored the use of different vibration frequencies, some of which had already been reported to have an effect after 1 session. Forty-eight patients with PD diagnosed as idiopathic participated in this study. Possible participants were excluded if any other disease or impairment potentially affected the validity of the results, and selected PD were naive to WBV protocols. Patients were randomly allocated to each of 4 groups: placebo, vibration at 3 Hz, vibration at 6 Hz, and vibration at 9 Hz (n = 12 each). The protocol followed previous work reporting excellent results of single-session WBV by means of a vibrating platform comprising 5 vibration sets of 1’ each (interset rest period, 1’). The stepped platform (amplitude of 13 mm) thrusts the right and left legs upward alternately. During stimulation, patients stood on the platform with their feet separated at a stable and comfortable position and with the knees slightly flexed. In the placebo group, patients adopted the same posture without vibration. Instead, they were required to stay still, trying to minimize hip oscillation; this controlled for a placebo effect. Stimulation and evaluation were done during ON periods. The protocol conformed to the Declaration of Helsinki. The effect of vibration on gait and balance was evaluated by the timed-up-and-go (TUG) and functional reach (FR) tests. Patients were evaluated just before (PRE), after (POST), and 48 hours after (POST-2) stimulation. Examiners were blind to protocol and group assignment.