Validity of family history data on primary adult-onset dystonia.
BACKGROUND
To our knowledge, no study has assessed the validity of family history data provided by probands with adult-onset dystonia.


OBJECTIVE
To measure the sensitivity and specificity of interviewing patients with primary adult-onset dystonia as a method for obtaining information on dystonia in first-degree relatives.


METHODS
Seventy probands with primary adult-onset dystonia were asked to identify first-degree relatives who had dystonia. Available relatives were then directly examined by a trained neurologist. The validity of the probands' reports was tested against the neurologists' diagnoses.


RESULTS
Among 300 first-degree relatives who were examined, 26 received a diagnosis of dystonia. Only 7 of the 26 were identified by the probands' reports. Among the 274 relatives free of dystonia, the probands reported 5 as having dystonia. The probands' reports therefore yielded a sensitivity of 27.0% and a specificity of 98.2%.


CONCLUSIONS
Because the family history method yields low sensitivity and incurs a risk of misclassification, it is of limited use in family studies of adult-onset dystonia. The only valid means of ascertaining dystonia among relatives remains neurological examination of at-risk subjects.
Department of Neurological and Psychiatric Sciences, University of Bari, 1-70124 Bari, Italy.
Davide
D
Martino
Maria S
MS
Aniello
Gianluca
G
Masi
Paolo
P
Lamberti
Valeria
V
Lucchese
Simona
S
Lamberti
Paolo
P
Livrea
Alfredo
A
Berardelli
Giovanni
G
Defazio
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016009:Chi-Square Distribution; D003710:Demography; D020821:Dystonic Disorders / Q000175:diagnosis / Q000235:genetics*; D005192:Family Health; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009460:Neurologic Examination; D011569:Psychiatric Status Rating Scales; D012680:Sensitivity and Specificity