Systemic lupus erythematosus may have an early effect on peripheral nerve function in patients without clinical or electrophysiological neuropathy: comparison with age- and gender-matched controls.

Asymptomatic electrophysiological peripheral neuropathy is described in systemic lupus erythematosus (SLE) patients. To determine if SLE could have an even earlier effect on peripheral nerve function even before the development of electrophysiological abnormalities, we compared nerve conduction studies (NCS) of SLE patients without electrophysiological or clinical peripheral neuropathy with healthy controls. Consecutive SLE patients without clinical neuropathy (or other known causes of neuropathy) underwent sensory and motor NCS of all four limbs. Results of 61 patients without electrophysiological criteria of neuropathy were compared with age- and gender-matched controls. Although still within the laboratory's range of normal values, significant differences were found in several NCS parameters between patients and controls. SLE patients had lower amplitudes for ulnar, fibular, and tibial compound muscle action potentials (CMAP) and sural sensory nerve action potentials (SNAP); slower conduction velocities for median, ulnar, and fibular motor nerves, and median, ulnar and sural sensory nerves. SLE patients also had longer minimum F-wave latencies for median, ulnar, fibular, and tibial nerves. H reflexes were more often absent in patients. Correlations were found between the number of disease relapses and motor conduction velocities of the fibular and tibial nerves. SLE may have early effect on peripheral nerve function in patients even before they develop electrophysiological or clinical neuropathy.

Effects of demographic and physical factors on nerve conduction study values of healthy subjects in a multi-ethnic Asian population.

INTRODUCTION: We investigated the effects of demographic and physical factors on nerve conduction studies (NCS) in a multi-ethnic Asian population. METHODS: One hundred sixty-six healthy Malaysians of different ethnicities (51.2% women, aged 21-77 years) underwent NCS using a standard protocol. Correlations of various factors to NCS were determined, and multiple linear regression analysis was used to develop predictive equations for each parameter. RESULTS: Age and ethnicity were the commonest independent factors influencing NCS followed by gender, height, weight, and body mass index. Increasing age predicted a reduction in lower limb motor and all sensory nerve action potential amplitudes and decrease in motor and sensory (except sural) conduction velocities. Ethnic Indians had slower motor and sensory conduction velocities in several nerves and also had differences in action potential amplitudes. CONCLUSIONS: NCS parameters in multi-ethnic Malaysians were influenced independently by various demographic and physical factors, including ethnicity. Muscle Nerve 54: 244-248, 2016.