Dystonias By Hector A Gonzalez-Usigli, MD, HE UMAE Centro Médico Nacional de Occidente Reviewed / Revised Feb 2022 | Modified Sep 2022 View Patient Education Classification Diagnosis Treatment Key Points Dystonias are sustained involuntary muscle contractions of antagonistic muscle groups in the same body part, leading to sustained abnormal posturing or jerky, twisting, intermittent spasms that can resemble tremors, athetosis, or choreoathetosis.