Peripheral nerves and nerve function in highland Ethiopians

In Ethiopia, where leprosy has been one of the commonest causes of peripheral nerve enlargement and dysfunction, nerve functions are assessed by a battery of "physical" tests. Voluntary Muscle Test (VMT) and Graded Sensory Skin Test (STG) are standard tests used for persons with leprosy. Normal values for nerve function tests (NFT) in Highland Ethiopians have not previously been determined, but have been taken from standard textbooks. In this study, normal values for NFT were determined by VMT, STG, 2-Point Discrimination Tests both static and moving, and Thermal Threshold Test. Physiological enlargement of right ulnar and radial-cutaneous nerves has been recognised by some leprologists, but we were unable to find written records in the available medical literature.

We assessed 236 students and adults aged 10-75 years from Chencha Woreda, an area with low endemicity of leprosy for 25-30 years. Two affected by leprosy were excluded from the analysis.

NFT thresholds were affected variously by age, exercise and skin factors, domicile and exposure to organo-phosphates. Nerve size was affected by age, gender, exercise, skin fold thickness, body mass index. Exercise related physiological nerve enlargement has been documented.

These data provide a usefull baseline for investigation of peripheral nerve function in highland Ethiopians.