[Effects of aging on air-conducted sound elicited ocular vestibular- evoked myogenic potential and cervical vestibular-evoked myogenic potential].

OBJECTIVE: To identify the aging effects on air-conducted sound (ACS) elicited ocular vestibular-evoked myogenic potential (oVEMP) and cervical vestibular-evoked myogenic potential (cVEMP) in normal Chinese population.

METHODS: Nighty-seven normal subjects (194 ears) were recruited for conventional ACS-oVEMP and ACS-cVEMP examinations. The candidates'age were 4-83 years old (Ave. ± SD, 45.7 ± 19.3), 41 male and 56 female, divided into 5 groups according to age. 500 Hz short tone burst was employed for examinations. Thresholds were identified and the parameters of the responses to 100dB nHL were calculated and compared among groups. SPSS 13.0 software was used to analyze the date.

RESULTS: As the age growing, the response rate for oVEMP decreased. It was recorded 100% in both ≤ 10-year-old and 11-30-year-old groups, 84.00% in the 31-50-year-old group, 48.15% in the 51-70-year-old group and 15.00% in the > 70-year-old group; while that for cVEMP were 100% in both ≤ 10-year-old group and 11-30-year-old group, 82.00% in the 31-50-year-old group, 77.78% in the 51-70-year-old group and 45.00% in the > 70-year-old group. The thresholds elevated and the amplitudes decreased in both examinations with the age growing. However, latencies and latency-intervals of both oVEMP and cVEMP examinations displayed minor difference among groups except that nI latency of oVEMP prolonged with age growing.

CONCLUSIONS: With the age growing, the otolithic end organ input pathways degenerate in normal subjects, as shown that ACS elicited oVEMP and cVEMP responsed less with higher threshold and smaller amplitude. The extremely low response rates of both VEMPs in the > 70-year-old group in this study indicates that VEMPs can only provide limited diagnostic information among very old people in clinical practice.