What Is Wrong with Balance in Parkinson's Disease?

Postural instability and resulting falls are major factors determining quality of life, morbidity, and mortality in individuals with Parkinson's disease (PD). A better understanding of balance impairments would improve management of balance dysfunction and prevent falls in patients with PD. The effects of bradykinesia, rigidity, impaired proprioception, freezing of gait and attention on postural stability in patients with idiopathic PD have been well characterized in laboratory studies. The purpose of this review is to systematically summarize the types of balance impairments contributing to postural instability in people with PD.