Diadochokinesis and Articulation Impairment

The relationship between diadochokinetic rates and the degree of articulation impairment, measured as number of articulation errors on a test, was investigated. Sixand eight-year old children with articulation impairment demonstrated reduced diadochokinetic rates which appeared to improve with age. The larger the number of articulation errors, the slower the rates on both verbal and non-verbal tasks of diadochokinesis. INTRODUCTION Many speech pathologists seem to feel that poor motor coordination is associated with an individual's failure to develop articulate speech. Studies have investigated the relationship between both gross and fine motor skills and articulatory defectiveness. Generally, investigations of gross motor skills have shown inconclusive and conflicting results. Mase (1946), and Carrell (1936) found no differences in motor abilities between articulatory defective and control groups. Other researchers (Albright, 1948; Clarke, 1969; lenkinsand Lohr, 1964; and Dickson, 1962) have found that children with normal speech are superior to those with speech defects on tests of gross physical abilities. Overall investigations of gross motor skills in normal and articulatory defective subjects seem to favour the normal group, but "sufficient evidence is lacking to support the hypothesis that articulatory defectiveness demonstrates a general retardation in motor skills" (Winitz, 1969; p. 155). A considerable amount of research has been dedicated to the study of diadochokinesis. This may be defined as the maximum speed of movement with which a given reciprocating act (such as syllable repetition, tongue protrusion, or jaw movement) can be performed without confusion in the movement. Verbal diadochokinesis refers to the production of rapidly alternating sequences of syllables (Lundeen, 1950; Fletcher, 1972). Non-speech diadochokinesis includes movements of the tongue, jaw, lips, teeth, etc. repeated in a given period of time (Mase, 1946; Reid, 1947; Fairbanks and Spriestersbach, 1950). Typically, measurement of verbal diadochokinesis involves counting the number of syllables spoken in a five second period of time (Albright, 1946; Prins, 1962). Mechanical measures such as placing a stylus to the jaw (Seth, 1934), a bulb against the lips (Blackburn, 1931) or covering the subject's face with a mask (Strother and Kriegman, 1943) have been used. Although these methods were accurate, they introduced psychological and physiological abnormalities into the situation. Fletcher (1972) found that counting repetitions over a period of time produced as accurate estimates of diadochokinetic syllable rate as did mechanical measures. A limited amount of research has dealt with diadochokinesis and its relationship to articulation. Mase (1946) found that normal children were significantly better at rapid