Comparison of the Rate of Verbal Oral Movements in Healthy Younger and Older Native Speakers of Persians

Background: Normal aging is associated with many changes in speechproducing elements that can influence the articulators’ ability to produce sounds quickly and precisely. To diagnose any motor problems in the oral area, obtaining numerical oral motor performance rates in normal individuals is necessary. According to previous studies, quantitative measures of Oral diadochokinesis (DDK) vary across different cultures, languages, and ages. However, little research was conducted in native Persian speakers to evaluate normal DDK in different age groups. Therefore, this study aimed to determine and compare DDK indicators in healthy young and older native Persian speakers. Methods: In this cross-sectional study, the participants were 105 healthy young and older individuals (56 women and 49 men) with age range from18-40, 60-80, and >80 years. Each subject was asked to repetitively express the syllables 15 times, and the sequence /pataka/ 10 times. Mann–Whitney and independentsample t-tests were applied to show the differences, respectively between and within age groups. Results: The significant difference was revealed between young and older groups in performance in all tasks (P=0.00). In younger participants, increasing age correlated significantly with increasing time needed to produce /ta/ (P=0.04) and /ka/ (P=0.01) syllables. Moreover, the rate variation decreased as the point of articulation moved backward in the vocal tract for /ta/ and /ka/ production in both the older (P=0.6) and younger group (P=0.4). Conclusion: This study’s results can also help clinicians document the differences in the articulation rate between older and younger people and diagnose abnormal oral motor rates.