Correlation analysis of the temporal patterns of articulatory movement and EMG

Abstract

The movements of pellets on the velum, jaw, etc., were recorded by an X-ray microbeam system simultaneously with the EMG activity of the pertinent muscles, and the relationship between the temporal patterns of motor control signals and articulatory movements were analyzed. The magnitude of EMG activity at a given time instant was assumed to be related to the displacement, velocity, and acceleration of the movement of the articulator, and a functional formula which approximated the relationship between these variables and the EMG signal was estimated. For the velar movement and the EMG activity of the levator palatini muscle, the velocity dependent component in the EMG signal had nearly the same amplitude of variation as that of the displacement dependent component. Quantitative analysis revealed that the patterns of EMG activity did not reflect the difference in the velocity of velum lowering between /m/ and /N/ (the syllable-final nasal segment in Japanese). It is concluded that the movement of the tongue dorsum in the production of /N/ results in an enhancement of the velum lowering. [Work supported by Ministry of Education Grant-in-Aid for Scientific Research No. 310707.]