Psychogenic movement disorders

This review summarizes the progress made in the area of psychogenic movement disorders (PMDs) over the past 2 years, and a simplified classification of diagnostic certainty is proposed that incorporates electrophysiological assessment.

Functional magnetic resonance imaging studies have demonstrated altered blood flow in conversion disorders that may reflect changes in synaptic activity. Electrophysiological testing shows limitations in distinguishing between psychogenic and organic propriospinal myoclonus and dystonia. Recent evidence cautions against the uncritical acceptance of all cases of posttraumatic myoclonus and 'jumpy stump' as being organic in nature. 'Essential palatal tremor' is recognized as a rather heterogeneous group of tremors that includes psychogenic tremor. Two recent studies evaluating the long-term prognosis of psychogenic tremor differ in the degree of unfavorable outcome. Different groups of PMDs might have distinctive gait characteristics with prognostic, diagnostic, or therapeutic value. Two recent reviews provide comprehensive information on the understudied area of PMDs in children.

The diagnosis of PMDs should not be regarded as a diagnosis of exclusion. Careful clinical assessment is critical, and imaging or electrophysiological studies may provide important insights and confirmation of the diagnosis though some cases remain challenging and current assessments fail to provide needed clarification. Treatment is often delayed, contributing to a largely unfavorable long-term outcome. Well designed randomized control trials that validate and compare therapeutic options are urgently required.