Sural nerve conduction study: Reference values in the Algerian population

Objectives: The sural nerve is the most tested sensory nerve in the lower extremities in the electrodiagnostic assessment of peripheral neuropathies. This study presents the reference values of the sural nerve conduction study (NCS) from a significant sample of the Algerian population. Methods: This is a prospective study of right sural NCS in healthy subjects based on the later recommendations of AANEM-NDTF. The nature of the distribution of each electrophysiological parameter was therefore determined. The lower and upper limits were calculated by using the 5th and 95th percentiles respectively and a logarithmic transformation was performed for Sensory Nerve Action Potential (SNAP) amplitude distribution. Results: 115 subjects aged between 20 and 60 years were selected, including 58 women and 57 men. Unlike Sensory Nerve Conduction Velocity (SNCV), the distribution of SNAP amplitude is not Gaussian. The lower limit of SNAP amplitude was 7.70 µV when using the 5th percentile and 6.80 µV by using the Standard Deviation (SD) method after log transformation. Similarly, the lower limit of SNCV was 43 m/s. The SNAP amplitude was greater in women and decreased with age, height and BMI. Conclusion: The values found in this study are comparable to those published in the literature. It may be more appropriate to determine the reference values using percentiles as recently recommended by several authors.