The Effects of Posteroventral Pallidotomy on Balance Function in Patients with Parkinson’s Disease

Parkinson’s disease is a chronic, progressive neurodegenerative disorder resulting from dopaminergic cell loss in the pars compacta of the substantia nigra. Conventional treatment of Parkinson’s disease consists of pharmacological replacement of dopamine. A treatment alternative, posteroventral pallidotomy (PVP), has been used for medically intractable stages of the disease. The purpose of this study was to evaluate the effects of PVP on balance function, as measured by dynamic posturography, in patients with medically intractable Parkinson’s disease. Five subjects were studied within 2 days prior to and within 6 months following PVP. Pretreatment abnormalities were found in vestibular, visual, and somatosensory processing in balance function. Posteroventral pallidotomy resulted in improvement in vestibular compensation of posture in some patients, which may be at least partially due to an improvement in latencies to respond to changes in stance. Dynamic posturography is an effective tool in the evaluation of balance and posture in patients with advanced Parkinson’s disease.