Frequency analysis of human jaw tremor at rest

• Published in: Archives of oral biology Vol. 24; no. 10; pp. 709 - 718
• Main Authors: Palla, S., Ash, M.M.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 1979
• Subjects: Adult; Computers; Dentistry; Electrocardiography; Electromyography; Female; Humans; Jaw - physiology; Male; Masticatory Muscles - physiology; Movement; Oscillometry; Posture
• ISSN: 0003-9969; 1879-1506
• DOI: 10.1016/0003-9969(79)90029-3

It is not known whether rest position is controlled actively by a low degree of muscular activity or passively by muscular and tissue visco-elasticity. The frequency analysis of the jaw tremor at rest was studied to determine if it could be useful for the study of rest position. Jaw tremor was recorded in three different head positions of normal subjects by two accelerometers fixed to the upper and lower premolars. The acceleration signals were low-pass filtered, digitized and analysed by computer. A Fast Fourier Transform algorithm was used to determine spectral density. Electromyograms of the right and left anterior temporal and masseter muscles and an electrocardiogram were recorded with surface electrodes, and the data correlated with jaw tremor. The lower jaw oscillated at the same frequency as the head, and the tremor was a low-frequency narrow-band process. Head deflection produced changes in the power spectral density of the tremor. A time correlation between the shape of the acceleration raw data and the heart beat was present in every subject. However, frequency content and power spectral density of the jaw tremor at rest may be determined also by the degree of muscular activity.