Diurnal and weekly variation of tardive dyskinesia measured by digital image processing.

The diurnal and weekly variability of tardive dyskinesia (TD) was assessed instrumentally by digital image processing. Weekly assessments were obtained in ten patients over a 6-week period. In six of the ten patients, assessments were obtained four times over a single 12-h period. Results indicate that TD movements measured by instrumental assessment vary from week to week and throughout the day. Factors that appear to have affected the variability were changes in medications and the time of day when the assessments were conducted.