Oral diadochokinetic rates for normal Thai children

The diadochokinetic (DDK) rate represents an index for assessing motor skills. It is commonly used in routine clinical evaluation of diseases of the central nervous system, disturbances of the peripheral sensory motor formations and immaturity of the speech mechanism. Oral DDK rates are a popular guideline for the assessment, diagnosis and treatment of patients with a neurological deficit of the speech mechanism. Baseline DDK rates have been published for English-speaking children, but not for Thai-speaking children. Thailand is situated in South East Asia, and the language belongs to the monosyllabic, tonal, Sino-Tibetan group with extensive multisyllabic borrowings from the non-tonal, Pali-Sanskrit group.

To assess the oral DDK rates for normal Thai children aged between 6 and 13 attending primary schools in order to establish a baseline for assessing, diagnosing and treating patients.

Subjects included 197 students who repeated, in rapid succession, specified sounds representing different levels of physiologic complexity, as indicated by differences in the developmental schedule, articulatory placement and syllabic content. Twenty syllable repetitions were required for monosyllabic utterances, 15 for bisyllablics and 10 for trisyllablics. Visi Pitch Analysis was used to calculate the average time that subjects took to produce the sounds.

The time taken for the lip functions /pe,Cyrillic/, /a:-u:/, /u:-i/ and /i:-a:/ averaged 4.55, 6.67, 7.53 and 7.27 seconds, respectively. The tongue functions /te,Cyrillic/, /le,Cyrillic/, /ke,Cyrillic/ and click averaged 4.58, 4.82, 4.85 and 5.87 seconds, respectively. Tongue movement side-to-side between the corners of the mouth averaged 8.73 seconds, while the lip-tongue functions /pe,Cyrillic-te,Cyrillic/, /pe,Cyrillic-ke,Cyrillic/ and /pe,Cyrillic-te,Cyrillic-ke,Cyrillic/ were 6.97, 7.52 and 6.85 seconds, respectively. Sex and age influenced oral DDK time. The findings differ from those reported for English-speaking children.

A basis for assessment of children with neuromotor deficits or oral structure impairment is provided for both Thai and South East Asian children with similar physiological development and languages with similar sounds.