Tremor magnitude: a single index to assess writing and drawing in essential tremor.

Hand tremor often causes disability in patients with essential tremor (ET). Aim of the study was to investigate whether tremor magnitude, a new single quantitative score obtained from digital tablet recordings of writing and drawing, is able to adequately reflect disability in ET patients. Mean tremor magnitude values showed significant difference between 14 ET patients and 14 healthy age matched controls (p<0.0001). The tremor magnitude values showed significant correlation with standard methods of clinical assessment (p<0.01). We present tremor magnitude as an index that reflects disability resulting from tremor and can help to evaluate ET.