By means of pellet tracking technique using an x-ray microbeam system, observations of articulatory movements were made on clinical cases of cerebellar degeneration. In some selected cases, electromyographic study was also performed. The data were specifically examined with reference to the range, velocity and consistency (reproducibility) of the movements of the articulators as well as to the pattern of coordination of the different articulators involved. It was found in the case of ataxic dysarthria of cerebellar origin, that the dynamic patterns were best repesented by difficulty in initiation of purposive movements and inconsistency of artieulatory movements, particularly in repetitive production of monosyllable. On electromyography, breakdown of the rhythmical patterns in the articulatory muscles was quite obvious in the repetition of monosyllables. It was suggested that analysis of dynamic aspects of the dysarthrias shoulc he a promising approach for elucidating the nature of central problems of speech productior and for differential diagnosis of various types of dysarthrias.
