Abstract
Background/Objectives Accurate normative data is essential for interpretation of nerve conduction studies (NCS), though the impact of patient ethnicity is unclear. Anecdotal experience suggests nerve conduction is faster in East Asians (EA) than in Caucasians. The present study tested this hypothesis.
Methods This is a retrospective audit of patients presenting to Westmead Hospital Neurophysiology between March 2020 and December 2022. Patients were included if amplitudes were within lab normative values; the median, ulnar, tibial, and sural nerves were assessed. Ethnic data was collected from recorded demographic information.
Results 200 patients were included: 84 East Asian and 116 Caucasian. There was no difference in median age (EA 55 [47–64], Caucasian 54 [43–64] years, P=0.135), male to female ratio was 2:3. The F wave latencies were significantly faster in East Asians after controlling for height (Ulnar: EA 23.0±7.9ms, Caucasian 27.5±2.0ms, P=0.005; Median: EA 22.2±7.6ms, Caucasian 26.3±1.8ms, P=0.013; Tibial: EA 47.4±4.8ms, Caucasian 51.7±5.4ms, P=0.041). Distal motor latencies were faster for ulnar nerves only (EA 2.5±0.4ms, Caucasian 2.7±0.4ms, P=0.009). Upper limb sensory latencies were faster in East Asians (Ulnar: EA 2.0±0.2ms, Caucasian 2.1±0.3ms, P=0.018; Median: EA 2.4±0.2ms, Caucasian 2.6±0.3, P=0.020), while only the sural nerve demonstrated significantly faster conduction velocities (EA 51.5±6.1m/s, Caucasian 48.0±4.8m/s, P=0.003). Motor velocities were not significantly different.
Conclusion The present study supports the hypothesis that nerve conduction is faster in East Asians, as measured by F waves and distal latencies. This has potential implications for normal values in neurophysiology laboratories. Prospective studies are planned to further explore these potential differences.
