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. Geriatr Gerontol Int 2023; 23: 729–735 .