Tourette syndrome. Clinical rating and quantitative assessment of tics.

An adequate rating scale for the measurement of tic severity must account for the multiple motor and phonic tics that increase and decrease over time. Available rating scales for Tourette syndrome have used historical information, direct observation, or both. Videotapes provide an objective means to quantify tics over time in a controlled environment. Videotapes also can be viewed multiple times for careful review of tic frequency and distribution. A unified rating scale, which integrates all elements of tic assessment is being developed, but is not currently available.