The effects of the vibratory stimulation of the neck muscles for the evaluation of stepping performance in Parkinson's Disease

The equilibrium system needs the coordination of three subsystems: sensory, skeletal and central nervous system. The central nervous system (CNS) counteracts equilibrium perturbations by means of compensatory and anticipatory postural adjustments (APA). While compensatory adjustments deal with actual perturbations of balance, the APA precede perturbations. The APA consist of preprogrammed activation of the muscles, according to task parameters [6] and are important to minimize the effects of planned postural perturbations. APA are specific to the movement, adapt to changes in external postural support by changing APA timing and magnitude. These APA are altered in Parkinson disease (PD) where have characterized by a reduced amplitude, an increased duration and a delayed onset of APA in tasks such as gait initiation. This study investigates the effects of a vibratory stimulus applied to the neck muscle groups in subjects with PD.