2022 Volume 81 Issue 6 Pages 491-501
There are differences in the recording methods for cVEMP used across institutions. However, the impact of head and body positions on the results of cVEMP testing is yet to be determined in patients with dysequilibrium. We assessed the effects of three body positions used for cVEMP recordings on the results, and demonstrated the advantages and disadvantages of each position. Three body positions were used for the cVEMP recordings; A. supine/head rotated; B. semi-recumbent/head rotated and elevated; and C. supine/head elevated. The subjects of the present study were 139 patients (9-91 years old) with dysequilibrium of various causation, 41 patients underwent the recordings in two positions, and a total of 360 ears were included. The results of the cVEMP testing were classified as normal, abnormal, and indeterminate. The rates of normal, abnormal, and indeterminate results were 50.6%, 35.0%, and 14.4%, respectively. The rate of abnormal results of the test increased with increasing age. The rate of indeterminate results was 13.2%, 11.3%, and 16.7% for positions A, B, and C, respectively. The mean background sternocleidomastoid muscle (SCM) electrical activity (SCM activity) was smaller in the recordings obtained in position A than in those obtained in the other positions. A positive correlation was identified between the age and SCM activity and the raw p13-n23 complex amplitude (amplitude) was larger in the recordings obtained in position B than in other positions. A negative correlation was identified between the age and amplitude of the potentials recorded in position C. These results suggest that positions A and C might be less burdensome to the patients, but the amplitudes of the potentials were a smaller, and there appeared to be a higher likelihood of the p13-n23 complexes being overlooked. On the other hand, while position B was more burdensome for the patients, the detection rate of the p13-n23 complexes was higher. As each body position has different characteristics, selection of the measurement position appropriate for individual patients is recommended. VEMP recordings may be useful to detect bilateral otolith dysfunction that may cause chronic dizziness in the elderly.
