Comparison of Oral Diadochokinesis in Two- and Three-Syllable Structures Consisting of Consonants and Vowel /a/ with Two- and Three-Syllable Structures Consisting of Consonants and Vowel /u/ in 7-9-Year-Old Children of Kermanshah, Iran

Diadochokinesis tasks, as a traditional component of speech-motor assessment, are an indicator of the evaluation of oral motor skills. This study aimed to help determine a criterion for the evaluation of the speed of consecutive movements by determination of diadochokinesis in normal children aged 7 to 9 years. Moreover, by creating syllabic assignments, consisting of closed and open vowels, it was possible to compare the speed of production in reciprocal movement conditions.

The current descriptive-analytical study used a cross-sectional design. It was conducted on 210 primary school students in three age groups of 7, 8, and 9 years old in Kermanshah City, Iran, who were randomly selected. Students had to repeat two-syllable structures 15 times and three-syllable structures 10 times. The structures consisted of consonants and vowels/a/ and /u/ to determine their durations.

The production speed of the two-syllable structures /pata/ and /paka/ was significantly higher, compared to that of /putu/ and /puku/, respectively (P=0.002). However, in the two-syllable structures /taka/ and /tuku/ (P=0.09) and trisyllable structures /pataka/ and /putuku/ (P=0.11), the difference of the mean diadocokinesis was not significant. Therefore, the vowel /a/ increased the ability of diadochokinesis in some syllabic combinations but had no effect on some other combinations.

With the increase of age, the ability to produce two- and three-syllable structures quickly and accurately increases. Usage of the vowel /a/, compared to the vowel /u/ in some syllabic combinations increased the speed of diadochokinesis but had no effect in some syllabic combinations