Effect on Reaction Time in Primary Hypothyroid Patients Before and After Thyroxin Treatment

Introduction Thyroid hormones play a crucial role in the proper functioning of the nervous system. Both T3 and T4 hormones have many significant actions on the neuromuscular system and brain. In hypothyroid patients, various neurological signs and symptoms such as weakness, fatigue, paresthesias, arthralgias, etc. may be seen. Reaction time is a good indicator of the processing of the central nervous system. So, our study aims to observe the change in reaction time in hypothyroid patients as compared to the control group. And to understand, if some difference is observed, how does it change after treatment with thyroxin in a hypothyroid group. Materials and methods This study was conducted at the tertiary care teaching hospital in the Vidarbha region. In this study, 40 newly diagnosed primary hypothyroid patients (including males and females), in the age group of 20 to 45 years, and whose thyroid-stimulating hormone (TSH) levels were between 10 and 50 mIU/L and free T4 levels below the normal level were included. A suitable comparable control group of the same demographic parameter was selected. Reaction time was taken before the start of thyroxin treatment in both groups, and results were analyzed by using an unpaired t-test. The reaction time of the hypothyroid group was again measured after eight weeks of the start of thyroxin treatment, it was compared with the initial reaction time, and data were compared by using the paired t-test. Result In the hypothyroid group as compared to the control group both auditory and visual reaction times were significantly on the higher side (p<0.05). Also, there was a significant improvement in reaction time after the start of thyroxin treatment (p<0.05), which suggests improvement in CNS activity in hypothyroid patients after initiation of therapy. Conclusion Thyroid hormones play a crucial role in the proper functioning and processing of the central nervous system. Due to this reason, reaction time in hypothyroid patients was on the longer side, showing a slowing of the nervous system when reacting to a specific stimulus. After thyroxin treatment for a sufficient period, reaction times were of shorter duration as compared to before the start of thyroxin, which shows well-recovered nervous activity. Therefore, reaction time is not only used as a handy tool to identify early central nervous system manifestations of hypothyroidism but also used to monitor response to treatment.