Typically, patients present in the third to fifth decades, and women usually present earlier than men. The hand assumes a semiflexed position of the fingers with possible hyperextension of the fingers and hyperflexion or extension of the wrist with supination or pronation. The symptoms become exaggerated with attempts to perform a specific task, such as writing. In some cases the hand may dart across the page with a sudden jerk. A related condition is primary writing tremor.
Affected individuals exhibit a prominent large-amplitude tremor only with writing.
Subtle findings include mild dystonic postures developing either spontaneously or with movement and reduced arm swing. One third of patients have a tremor in the affected arm or hand while writing or when the extremity is outstretched. Patients affected with primary writing tremor, a variant of writer s cramp, may exhibit a large-amplitude tremor only during writing. In contrast to essential tremor, action or sustentation tremors are not seen with other tasks such as holding a full cup of liquid or coordination testing. Dystonic posturing is usually not seen with this condition.