Functional movement disorders in dopa-responsive dystonia

Functional neurological movement disorders are common and disabling. Little is known about their coexistence with other non-functional movement disorders and their impact on the general disease burden.

Investigating frequency and characteristics of functional movement disorders in GCH1-positive dopa-responsive dystonia patients.

Twenty-one patients underwent a detailed clinical motor examination and completed self-questionnaires evaluating non-motor characteristics.

Seven patients (33 %) had comorbid functional movement symptoms, including functional gait disorders (n = 7), balance disturbances (n = 7), and weakness (n = 5), dominating the clinical phenotype and resulting in disability with immobilization. None of them was previously diagnosed with or treated for the functional symptoms. Functional movement symptoms appeared suddenly (on average 18 years after the first dopa-responsive dystonia symptoms) and were unresponsive to L-Dopa. These patients showed significantly higher disability and received unnecessary treatments.

Functional neurological movement disorders are common in patients with dopa-responsive dystonia and impact the clinical picture and the degree of disability. Diagnosing both disorders in an individual patient has substantial therapeutical implications because increases in L-Dopa dosages to treat functional symptoms should be avoided, and physiotherapy should relocate attention away from the affected body region so that movements in the affected body part can be executed without external control to facilitates automatic movements. Physiotherapy should be complemented by psychoeducation and psychotherapeutic approaches.