Prolongation of VEP p 100 latency in hypothyroidism

Hypothyroidism is a syndrome characterized by the clinical and biochemical manifestation of thyroid hormone deficiency. The present study was undertaken to examine the functional integrity of visual pathway. Visual evoked potential is a non invasive tool to assess the integrity of visual pathway. Forty patients (17- 64yearsold, mean 37.7) with biochemical evidence of hypothyroidism, with thyroxine less than 4µg/dl and thyrotropin above 4.5 m IU/L including both gender were taken as a study group and compared with control group who were normal subjects and age and sex matched. Informed consent was obtained. Experimental protocol was approved by ethical committee. Both study and control groups were subjected to physical examination and laboratory investigations including triiodothyronine, thyroxine, and thyrotropin. VEP recording was done by using four channel digital polygraph. The results were statistically analyzed using student‘t’ test. P < 0.05 was accepted as significant. P 100 latency of VEP was prolonged in study group compared to control group and the differences was statistically significant. The result of present study shows significant prolongation of P100 latency of VEP suggestive of central nervous involvement in hypothyroidism.