The Influence of Family History of Tremor on Cervical Dystonia

D.D. Duane, M. Clark, L. Gottlob, J.L. Case, L.L. LaPointe

Arizona Dystonia Institute/Arizona State University

Scottsdale/Tempe, Arizona

Family history of tremor is common in cervical dystonia (CD), although specifics regarding the relatives' tremor seldom are known. Tremor is a common accompaniment to focal dystonia, at times preceding it's clinical appearance. Although tremor manifestations in CD are not uniform in character, distribution or rate, they commonly share characteristics with 'essential tremor.' The relationship between CD, a family history of tremor, the occurrence of tremor in CD and the characteristics of the dystania in the presence of either is unknown. This study investigates the occurrence of family history of movement disorder (Mov Dis) including tremor (FT) in 231 consecutive CD patients evaluated per protocol between 1188 and 1193. Tremor was documented by simultaneous accelerometer monitor of head and hands, videotape and high resolution voice recordings. Compared were gender, age of CD onset, duration of CD symptoms, distribution of dystonia, distribution of tremor, tremor rate and family history of: non-parkinsonian tremor (FT), dystonia (Dys), Parkinson disease (PD) and scoliosis (scol).

127 patients (100 female, mean age CD onset 46 yr, mean duration 10.5 yr) demonstrated non-dystonic tremor (CD/T): 81 head, 27 head and hands, 12 hands, five head and voice, two head, hands and voice. Modal tremor rate was 6 hertz. 83 (65%) had isolated CD (CD only) while 44 included at least one other dystonic site (CD+). 104 patients (74 female, mean age CD onset 44.5 yr, mean duration 8.5 yr), had no recorded tremor (CD no T). 84 (81%) had CD only (P= <.l versus CDIT).

Overall, 119 patients (52%) had family history of one or more of the movement disorders investigated. 70 (55%) of CD/T had relatives with Mov Dis versus 49 (47%) CD no T (P-NS). 58% of 70 CD/T with family history Mov Dis had CD only versus 74% of 49 CD/T without family history Mov Dis (P=<.l). CD only occurred in 82% of the 49 CD no T with family history Mov Dis and 80% of the 55 CD no T without family history Mov Dis. Presence or absence of family history Mov Dis did not influence tremor distribution, rate.

Of CDIT, 41 (32%) had family history of only FT, mean CD duration 13.5 yr, 51% CD only versus 20 (19%) CD no T (P= <.0l) with family history of only FT, mean CD duration 9 yr, 95% CD only (P= <.001 versus CDIT). With or without manifest tremor, rates of family history of non-tremor movement disorders were similar 13% versus 14%; Dys +I- others 9% each; Scol +/- other 10% versus 13%; PD +I- other 6% versus 7%.

The presence of non-dystonic tremor increases the probability of extranuchal dystonia in CD. That effect is increased by the presence of family history of tremor. CD patients with tremor have an increased probability of family history of tremor versus those without tremor. The extent to which longer duration of symptoms contributes to CD+ is not clear, but a familial tremor effect on the occurrence of tremor in dystonia and more widespread dystonia is likely.

Platform presentation, Movement Disorder Society Symposium on hyperkinetic Movement Disorders, Boston, MA, October 17, 1993.

Duane DD, Clark M, Gottlob L, Case JL, LaPointe LL: The influence of family history of tremor on cervical dystonia. Movement Disorders, VIll-313-314, 1993.

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