Fig. 2.

COURSE study flow chart. Tele telephone interview, YGTSS Yale Global Tic Severity Scale. If no tic exacerbation was detected and confirmed then the original 16 month assessment schedule (left side) was retained. The maximum study period was 18 months if a tic exacerbation was detected at the final visit. A maximum of two pairs of expedited and post-exacerbation visits was possible. Expedited visits shortened the study period accordingly