Olfactory and gustatory function in healthy adult Chinese subjects

Objective: To investigate the effect of age and gender on olfactory and gustatory function and to establish test methodology and normative values in Chinese subjects.

Study design: Cross-sectional study.

Setting: The center laboratory and the Department of Otolaryngology-Head & Neck Surgery, Beijing Tongren Hospital.

Subjects and methods: The T&T olfactometer, the Sniffin' Sticks olfactory test, olfactory event-related potentials (oERPs), trigeminal event-related potentials (tERPs), and the triple drop method for gustatory testing were used to examine the chemosensation in 90 healthy adults (45 men and 45 women).

Results: Older subjects (age 51-65 years) showed worse olfaction compared with younger subjects (age 18-35 years) when both T&T (younger -1.71 ± 0.41, older -0.92 ± 0.95; P < 0.01) and Sniffin' Sticks (threshold, discrimination, identification score: younger 33.17 ± 2.83, older 30.89 ± 3.35; P < 0.05) testing were performed. Measurement of oERPs revealed that older patients (N1 471 ± 85 ms, P2 676 ± 93 ms) had longer latencies compared with younger ones (N1 368 ± 57 ms, P2 561 ± 74 ms, P < 0.05) of N1/P2 wave. The results of trigeminal nerve-related potential examination showed that N1/P2 latencies were longer and amplitudes were lower in older people (N1 384 ± 98 ms/-5.01 ± 4.00 uv, P2 568 ± 95 ms/6.53 ± 3.62 uv) compared with younger patients (N1 316 ± 31 ms/-7.20 ± 3.43 uv, P2 472 ± 66 ms/8.72 ± 3.09 uv; P < 0.05). Gustation was normal in all subjects, and there was no significant difference between younger and older groups.

Conclusion: Age and gender affect olfaction in Chinese adults as measured by standard testing methods used in other human populations. In healthy Chinese subjects, gustation was normal and did not vary with age. Our data provide preliminary normative values for future investigation of chemosensation in the Chinese population.