[Characteristics of cervical vestibular evoked myogenic potential in different test positions]

Objective: To investigate the characteristics of cervical vestibular evoked myogenic potential (cVEMP) of normal youth with different test positions, to study the relationship between test positions and test parameters, and to explore the suitable test position for clinical practice. Methods: Fifty healthy young volunteers (25 males, 25 females, 100 ears) were enrolled in this study. Two test positions were used, including sitting with the head turned away from the test (SIT) and supine with the head held straight up (SUP). The derivation rate, latency and amplitude were analyzed. Results: The derivation rates of both SIT and SUP were 100%. The VEMP threshold in SIT was (93.5±4.3)dBnHL. The latency of P1 and N2 in SIT was longer than that in SUP, with significant different (P< 0.05), the amplitude of P1-N2 in SIT was less than that in SUP, with significant different (P< 0.05). Regarding to the latency of P1 and N2 in SIT, the left was longer that right, with (P=0.013) and (P=0.015) respectively. The latency in SUP between sides was not significant (P>0.05). The amplitude ratio and asymmetry in SIT were more obvious than in supine position (P=0.009 and 0.016). In SIT position the P1-N2 amplitude in males was larger than in females, with significant difference (P=0.031); In SUP position the P1-N2 amplitude in males was less than in females, with significant difference (P=0.043). Conclusion: The cVEMP can be affected by the different test positions, it is recommended to select a more suitable test position according to the condition of the subject and the purpose of the test.