Prevalence of spontaneous oral dyskinesia in the elderly: a reappraisal

The prevalence and status of spontaneous oral dyskinesia (SOD), clinically defined as the presence of oral stereotypies of no apparent cause, remain controversial in the elderly. The reported high prevalence of SOD in institutionalized demented cases, the apparent similarity between SOD and tardive dyskinesia (TD), and the role of aging in both conditions, are used as arguments to minimise the prevalence of TD and causal role of antipsychotics. We observed 1,018 (69.3% women) noninstitutionalized, frail elderly subjects attending day care centers to document the prevalence and phenomenology of SOD. A total of 38 subjects, including 29 women, were suspected of having SOD, for a prevalence rate of 3.7% (95% confidence interval, 2.6-4.9%), 4.1% for women and 2.9% for men. A survey covering medical and dental issues was filled out by 508 volunteers. Subjects with suspected SOD reported more frequent ill-fitting dental devices (P = 0.002; odds ratio [OR] = 3.5), oral pain (P = 0.01; OR = 3.0), and a lower rate of perception of good oral health (P = 0.04; OR = 0.4) compared to nondyskinetics. Individuals with suspected SOD typically presented with mild stereotyped masticatory or labial movements compared to the more complex phenomenology of probable TD cases. Thus, SOD is comparatively infrequent in the elderly. The relation between its distinct orodental health profile and stereotyped manifestations warrants further attention.