Diagnostic criteria for blepharospasm: A multicenter international study

Defazio G.

First

;Jinnah H. A.;Berardelli A.;Perlmutter J. S.;Berkmen G. K.;Berman B. D.;Jankovic J.;Baumer T.;Comella C.;Cotton A. C.;Ercoli T.;Ferrazzano G.;Fox S.;Kim H. -J.;Moukheiber E. S.;Richardson S. P.;Weissbach A.;Wrigth L. J.;Hallett M.

2021-01-01

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Abstract

Background: There are no widely accepted criteria to aid the physician in diagnosing BSP. Objective: To validate recently proposed diagnostic criteria for blepharospasm in a larger and geographically diverse population and to develop a screening system for blepharospasm. Methods: Video-recordings from 211 blepharospasm patients and 166 healthy/disease controls were examined by 8 raters. Agreement for presence of orbicularis oculi spasms, sensory trick, and increased blinking was measured by k statistics. Inability to voluntarily suppress the spasms was asked by the examiner but not captured in the video. Patients/controls were also requested to fill a self-administered questionnaire addressing relevant blepharospasm clinical aspects. The diagnosis at each site was the gold standard for sensitivity/specificity. Results: All the study items yielded satisfactory inter/intra-observer agreement. Combination of items rather than each item alone reached satisfactory sensitivity/specificity. The combined algorithm started with recognition of spasms followed by sensory trick. In the absence of a sensory trick, including “increased blinking” or “inability to voluntarily suppress the spasms” or both items yielded 88–92% sensitivity and 79–83% specificity. No single question of the questionnaire yielded high sensitivity/specificity. Serial application of the questionnaire to our blepharospasm and control subjects and subsequent clinical examination of subjects screening positive by the validated diagnostic algorithms yielded 78–81% sensitivity and 83–91% specificity. Conclusion: These results support the use of proposed diagnostic criteria in multi-ethnic, multi-center cohorts. We also propose a case-finding procedure to screen blepharospasm in a given population with less effort than would be required by examination of all subjects.