Diadochokinetic rate (DDK) quantifies the laryngeal and oral muscle coordination,
but there are insufficient baseline evidence exist, that limits the effectiveness
of computerized DDK evaluation in assessing motor speech control. In the end, this
study will give normative data on age and gender effects on both oral and laryngeal
DDK in Tamil speakers.
Cross sectional Study.
A total of 150 participants in the age range of 17-25;11 years were divided into three
groups- Group I (17-19;11 years), Group II (20-22;11 years) and Group III (23-25;11
years) with equal number of male and female. The participants were asked to produce
/pʌ/, /tʌ/, /kʌ/, /pʌtʌkʌ/, /a/& /i/ for 5 seconds in Motor Speech Profile (MSP),
at Computerized Speech Lab (CSL). The parameters such as Average DDK period (DDKavp),
average DDK rate (DDKavr), Standard deviation(SD) of DDK period (DDKsdp), Coefficient
of Variation of DDK period (DDKcdp), Perturbations of DDK period (DDKJit) and Coefficient
of variation of the DDK peak intensity (DDKcvi) were selected for analysis.
The effect of age was noted for Laryngeal DDK, the DDKavr of /a/ (P = 0.008) and /i/ (P = 0.04) and DDKcdp for /a/ (P = 0.01), the mean values of those parameters are higher for the individuals within the age
of 23-25;11 years but no difference was observed across the age for Oral DDK. The
effect of gender was noted for Laryngeal DDK, DDKsdp (P = 0.007) and DDKJit (P = 0.04) for /i/, the mean values are higher for females. For Oral DDK, DDKJit (P = 0.006) for /kʌ/ the mean values are higher for females.
The normative data has been established for the Tamil speakers. Age specific normative
should be used during the DDK evaluation of speech disorders in MSP, CSL.