Inclusion Criteria:  Completed participation in the study called "Peripheral induction of inhibitory brain circuits to treat Tourette's: pilot" Informed consent by adult participant, or assent by child and informed consent by guardian  Exclusion Criteria:  Has an implanted device that could be affected by electrical current Pregnancy known to participant or (for children) to the parent Severe or unstable systemic illness Factors (such as exaggerated symptom report) that in the judgment of the principal investigator may make the outcome measures inaccurate Judged by investigator to be unlikely to complete study procedures