Changes in cognitive functions caused by acute hypothyroidism during withdrawal of l-thyroxine in patients with differentiated thyroid carcinoma

Abstract

Objective: Chronic hypothyroidism is associated with significant neurocognitive deficits. However, present data about the effect of acute hypothyroidism on cognitive functions are limited. This study aimed to investigate the cognitive functions of patients with differentiated thyroid carcinoma (DTC) in acute hypothyroidism caused by l-thyroxine withdrawal (THW) using auditory event-related potentials (AERPs). Methods: Twenty-three patients with DTC and fifteen healthy subjects (group 1) were involved in the study. AERPs were recorded using the standard auditory “Oddball” paradigm from the Fz, Cz, Pz, and Oz regions. P300 waves were analyzed. The first records were obtained from group 1 and DTC patients under thyroxine treatment (group 2a). In the patient group, AERP recordings of the patients were repeated approximately 1 month after the withdrawal of thyroid hormone (THW) when the patients became hypothyroid (Group 2b). Results: P300 latencies were found to be significantly longer in group 2a in the Cz (P < .01), Pz (P < .001), and Oz (P < .001) regions compared to group 1, except for Fz. Group 2b P300 latencies were also longer than group 1 Cz (P < .009), Pz (P < .001), and Oz (P < .001) regions, except Fz. When comparing group 2a and group 2b, the P300 latency of group 2b was longer in the Pz region (P < .05). Conclusion: In this study, it was shown that cognitive functions in patients with DTC had a slower cognitive function in the state of acute hypothyroidism induced by 1-month THW than in both healthy individuals and during l-thyroxine treatment.