Oromandibular dystonia screening questionnaire for differential diagnosis

ObjectivesOromandibular dystonia, which is characterized by stereotypic, task-specific, or sustained contractions of masticatory and/or lingual muscles, is frequently misdiagnosed as temporomandibular disorders or psychogenic disease. Diagnostic delay in oromandibular dystonia is not acceptable; thus, a screening tool that can distinguish this condition from a temporomandibular disorder may be helpful for medical professionals unfamiliar with involuntary movements or temporomandibular disorders.Materials and methodsA questionnaire that included questions on the clinical features of oromandibular dystonia, such as stereotypy, task-specificity, sensory tricks, and morning benefit, and included questions to rule out temporomandibular disorders (total point range 0-40) was administered to 553 patients suspected to have involuntary movements.ResultsBased on a careful examination and the differential diagnosis, the patients were divided into four groups: oromandibular dystonia (n=385), oral dyskinesia (n=84), psychogenic (functional) movement disorder (n=50), and temporomandibular disorders (n=34). The questionnaire had a high level of internal consistency as measured by the Cronbach's (0.91), and item-total correlation was significant (p<0.001). The test-retest reliability on two separate occasions showed a significant correlation (p<0.001). Mean total scores of the questionnaire significantly differed among oromandibular dystonia (32.0), temporomandibular disorders (10.4; one-way analysis of variance, p<0.001), oral dyskinesia (21.0; p<0.001), and psychogenic (functional) movement disorder (13.7; p<0.001).ConclusionsFindings of this study suggest that the present questionnaire is a simple diagnostic tool that is useful for tentative differentiation of oromandibular dystonia from temporomandibular disorders.Clinical relevanceThis screening tool can be used to distinguish oromandibular dystonia from temporomandibular disorders.