Movement Disorders

Movement disorders are a group of neurological conditions that cause abnormal or involuntary movements, or impair the ability to move normally. The category encompasses a wide spectrum of conditions — most notably Parkinson's disease, essential tremor, restless legs syndrome (RLS), dystonia, Huntington's disease, and ataxia — each with distinct causes, presentations, and progression patterns. Parkinson's disease, the most recognized movement disorder, affects an estimated 0.572% of North Americans aged 45 and older, with annual direct medical expenditures estimated between $7.4 and $8.6 billion. Essential tremor is even more common — a 2025 U.S. claims-based study found a diagnosed prevalence of 0.42% after age standardization, rising to 1.61% among adults 75 and older, with an estimated annual direct medical cost of approximately $9.4 billion. Restless legs syndrome affects millions more, with a global prevalence estimated at over 7%. Movement disorders are strongly age-associated, and projections suggest the number of Americans affected will nearly double between 2010 and 2050 as the population ages. Treatment varies widely by condition and may include medications (particularly dopaminergic therapies), physical therapy, deep brain stimulation, and emerging gene therapies, but most movement disorders remain progressive and without a cure.