Validation of self-reported articulatory oral motor skill against objectively measured repetitive articulatory rate in community-dwelling older Japanese adults: The Otassha Study

Aim To assess the validity of self-reported articulatory oral motor skill against objectively measured repetitive articulatory rate (oral diadochokinesis [oral-DDK]) as a gold standard index for articulatory oral motor skill in community-dwelling older Japanese adults.Methods This cross-sectional study included 607 Japanese adults (mean age = 73.9 years). A single-item self-report questionnaire for articulatory oral motor skill was developed. Study participants completed a 1-month-interval test-retest protocol to assess reliability of the questionnaire, and the protocol was tested by the kappa statistic. Oral-DDK with /ta/ (i.e., the number of repetitions of the monosyllable /ta/ per second) was measured during the on-site examination. Low oral-DDK performance was defined as <5.2 times/s in men and <5.4 times/s in women. Oral-DDK performance, oral functions other than articulatory oral motor skill, and physical frailty were compared in the groups with and without self-reported low articulatory oral motor skill as determined by the response to the questionnaire.Results Self-reported low articulatory oral motor skill was identified in 18.5% of the study population. The self-report questionnaire had good test-retest reliability, with a kappa statistic of 0.71. Self-reported low articulatory oral motor skill was significantly associated with a lower value of oral-DDK with /ta/ and a higher proportion of low oral-DDK performance, difficulties in chewing and swallowing, dry mouth, and physical frailty. Self-report had high specificity (83.1%) but low sensitivity (42.1%) for detecting low oral-DDK performance.Conclusions A single-item self-report questionnaire for articulatory oral motor skill had acceptable test-retest reliability and was associated with objectively measured articulatory oral motor skill.