The primary aim of this study is to identify the prevalence of four previously identified non-motor markers - (1) spatial discrimination threshold, (2) temporal discrimination threshold, (3) vibration-induced illusion of movement, and (4) kinesthesia - in a population of cervical dystonia patients, unaffected family members, and healthy volunteers (control group). Consenting participants will receive a neurological examination performed by a movement disorders neurologist, followed by an assessment of the four non-motor symptoms.~The investigators hypothesize that a distinct combination of non-motor symptoms will be more prevalent in the CD group, and therefore this set of symptoms may be indicative of disease development. This combination will be identified through analysis of the concurrence of the non-motor features across the three groups of participants. This study will fill an important unmet need, as to the investigators' knowledge there are no published studies assessing the comorbid presentation of these four non-motor symptoms in a single cervical dystonia population. The exploration of a distinct combination of concurrent non-motor symptoms as a marker for the development of cervical dystonia will improve the ability of movement disorders neurologists to diagnose the condition.~The results of this study will facilitate the investigators' longstanding aim of improving rates of cervical dystonia diagnosis. Cervical dystonia is currently diagnosed based upon the exclusion of other movement disorders; therefore, characterization of non-motor features in cervical dystonia patients will help to refine the diagnostic criteria for this condition. This investigation will also improve understanding of the factors associated with CD. Future studies can examine the source of these associated factors in order to help understand the cause of CD, since the etiology is currently unknown.
This study will examine the prevalence of four previously identified non-motor markers in a population of cervical dystonia patients, unaffected family members, and healthy volunteers in an attempt to identify a distinct combination of non-motor symptoms that may be indicative of disease development.