[Psychogenic tremor: clinical, electrophysiologic and psychopathologic assessment].
There are few studies analyzing the incidence, clinical characteristics and diagnostic work-up of psychogenic tremor. We studied the clinical and electrophysiological characteristics and the associated psychopathology in a series of patients with psychogenic tremor. All patients (n = 8) diagnosed with documented or clinically established psychogenic tremor in the movement disorders section of our Department of Neurology in a two-years period were analysed. Psychogenic tremor was diagnosed in 9.5% of the patients that consulted for postural or action tremor of the upper limbs. In all cases tremor had a variable frequency and amplitude and improvement with distraction. Electrophysiological studies revealed asynchronic muscle activity and considerable variation of the dominant frequency when weight was added to the patient hands. Six patients were initially misdiagnosed of essential tremor (n = 3); Parkinson's disease (n = 1); and cerebrovascular disease (n = 2). Final psychiatric diagnoses were depression (n = 4); conversive disorder (n = 2); and malignering (n = 2). Psychogenic tremor is a relatively frequent cause of tremor in a Movement Disorders Clinic and has a characteristic clinical and electrophysiological pattern.