A new screening tool for cervical dystonia.
BACKGROUND
Family studies of dystonia may be limited in part by small family size and incomplete ascertainment of dystonia in geographically dispersed families. Further, prevalence estimates of dystonia are believed to be underestimates, as most studies are clinic-based and many individuals do not present to a physician or are misdiagnosed. As a low-cost highly sensitive screening tool is needed to improve case detection for genetic and epidemiologic studies, the authors developed the Beth Israel Dystonia Screen (BIDS), a computer-assisted telephone interview.


OBJECTIVE
To evaluate the validity and utility of a computer-assisted telephone interview in screening for cervical dystonia.


METHODS
The BIDS was administered and videotaped neurologic examinations performed on 193 individuals from 16 families with cervical and cranial dystonia. With use of a final rating of definite dystonia, as determined by video review of a systematic neurologic evaluation, as the gold standard, the predictive value of a subset of questions from the BIDS was assessed.


RESULTS
A positive response to at least two of five screening questions had a sensitivity for cervical dystonia of 100% and a specificity of 92%. With use of a positive response to three or more questions, definite dystonia was determined with 81% sensitivity and 97% specificity.


CONCLUSIONS
The Beth Israel Dystonia Screen (BIDS) identifies cervical dystonia with excellent sensitivity and specificity in a family-based sample. The authors recommend the BIDS for family studies, but cross-validation in a population sample is advisable before applying this method to epidemiologic studies.
Department of Neurology, Beth Israel Medical Center, 10 Union Square E., Suite 5J, PACC, New York, NY 10003, USA. rsaunder@bethisraelny.org
R
R
Saunders-Pullman
J
J
Soto-Valencia
C
C
Costan-Toth
J
J
Shriberg
D
D
Raymond
C A
CA
Derby
R B
RB
Lipton
S B
SB
Bressman
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005192:Family Health; D005260:Female; D006306:Health Surveys; D006801:Humans; D007407:Interviews as Topic / Q000379:methods*; D008297:Male; D008403:Mass Screening / Q000379:methods*; D008875:Middle Aged; D011237:Predictive Value of Tests; D015995:Prevalence; D012372:ROC Curve; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D011795:Surveys and Questionnaires / Q000592:standards*; D014103:Torticollis / Q000175:diagnosis* / Q000453:epidemiology