Contingent negative variation for assessment of neurological deficits in children with hypothyroidism

Abstract

Objectives: Hypothyroidism is one of the most common endocrine disorders. Its effect on the central nervous system is more pronounced, especially in the pediatric age group. Despite receiving adequate thyroid hormone replacement therapy, several patients continue to suffer from neurological impairments including cognitive dysfunction. Contingent negative variation (CNV) is an event-related potential (ERP) that is considered as an indicator of cognitive function. In this study, CNV was recorded in children with hypothyroidism. To the best of our knowledge to date, there have been no studies of CNV in hypothyroidism. Materials and Methods: This prospective study included 52 children between 8 and 15 years of age who were newly diagnosed with hypothyroidism. Diagnosis of hypothyroidism was based on laboratory thyroid function tests. CNV ERP was recorded in the enrolled children at the time of diagnosis, 1-month, and 6-month follow-up. Initial CNV (iCNV) and late CNV (lCNV) amplitudes and latencies were recorded each time. Results: Although the amplitudes of iCNV and lCNV appeared to increase during follow-ups, the changes were not statistically significant (P > 0.05). Similarly, there appeared to be a modest reduction in latencies of iCNV or lCNV during follow-up; however, these changes were not statistically significant either. Conclusion: Our study did not show any significant changes in neurophysiological parameters. This may be attributed to a shorter time period of follow-up of six months and a smaller sample size. There is a possibility that CNV parameters may show more pronounced changes after a prolonged duration of treatment.