Functional Movement Disorders

Abstract

Functional movement disorders (FMDs) are a diagnostic and treatment challenge and can be particularly debilitating conditions, even more so than their “organic” movement disorder counterparts. FMDs may represent the most common movement disorders emergency encountered by neurologists, as these patients frequently present acutely, with an unclear diagnosis that includes dramatic, debilitating, and uncontrolled movements, often with associated painful spasms or pain crises. In this chapter, we review the literature on FMDs, focusing on both those with a loss of motor function (i.e., weakness) and those with a “gain” of abnormal motor function (i.e., functional tremor, dystonia, gait, myoclonus, parkinsonism, tics). We discuss the diagnostic criteria for functional motor disorders. Assessment in these disorders should no longer be considered as a diagnosis of exclusion, and particular emphasis should be given to the positive and negative findings and “rule in” clinical signs, which can help to make the diagnosis. We review the growing evidence of the underlying neurobiological basis of these disorders. We also discuss management recommendations for FMD in the emergency and inpatient setting, which should be multidisciplinary (encompassing neurology and psychiatry input, physical therapy, occupational therapy, speech therapy, and psychotherapy) and tailored to the patient’s symptoms.