Digitizing Tablet and Fahn–Tolosa–Marín Ratings of Archimedes Spirals have Comparable Minimum Detectable Change in Essential Tremor

Drawing Archimedes spirals is a popular and valid method of assessing action tremor in the upper limbs. We performed the first blinded comparison of Fahn–Tolosa–Marín (FTM) ratings and tablet measures of essential tremor to determine if a digitizing tablet is better than 0–4 ratings in detecting changes in essential tremor that exceed random variability in tremor amplitude