Motor nerve conduction, auditory evoked potential, and visual evoked potentials in severely malnourished children vs healthy controls: An electrophysiological study

Background: Severe acute malnourishment (SAM) is a significant public health problem in India and many developing countries. The World Health Organization (WHO) defines – Severe acute malnutrition (SAM) as very low weight-for-height or a mid-upper arm circumference (MUAC) of less than 115 mm or the presence of nutritional edema. According to the most recent NFHS-5 survey (2019- 2021) covering 36 states and union territories (UTs), the prevalence remains at an alarming 7.7%. Malnutrition slows down the myelination process, thus preventing the increase in the calibre of myelinated nerve fibres. Motor nerve conduction, auditory evoked potential and visual evoked potential changes caused by severe acute malnutrition can be evaluated clinically and electrophysiologically. These changes are produced mainly due to a deficiency of micro and macronutrients like vitamins, minerals, protein, fat & Carbohydrates.
Aim: Severe acute malnutrition affects the myelination and growth of the central and peripheral nervous systems. This study aimed to assess the effects of severe acute malnutrition on peripheral motor median and ulnar nerve conduction, auditory evoked potential and visual evoked potential in children.
Materials & Methods: The study group included 50 severely acute malnourished children (SAM) of 6 – 59 months of age, recruited from SMTU, J.A. Group of the Hospital, G.R.M.C. Gwalior (M.P.), based on WHO classification for severe acute malnutrition. The Control group consisted of 50 normally nourished healthy children of the same age group. The case-control study period was extended from January 2021 to December 2021. Ethical clearance from the Institutes and written informed consent were taken from the parents/guardians of SAM patients. The family, immunization, birth, metabolic, endocrinal disorder, and history of neuromuscular disease were taken in detail. The study was performed using the four-channel RMS – EMG EP MARK- II. The electrophysiological parameters were evaluated for velocity, distal latency, and amplitudes. Results were analyzed statistically using the unpaired student’s t-test.
Results: This study showed decreased motor nerve conduction velocity ( p < 0.05 ) and delayed distal latencies in the median and ulnar motor nerves of both upper limbs in children with severe acute (SAM) malnutrition. There were significant differences in the mean latencies of the waves I to V and the mean interpeak latencies (IPLs) of the waves I-III and I-V on the right and left ears between the study and control groups (P < 0.05). We observed significant alteration in mean latencies of wave p 100 in VEP.
Conclusion: The present study shows a statistically significant alteration in electrophysiological parameters in children with severe acute malnutrition. This may be due to nutritional deficiency affecting the myelination of peripheral nd central nerves depending on the duration and severity of malnutrition.