Lateralization of Memory and Cognitive Functions with Regard to Thyroid Functioning

Abstract

Clinical hypothyroidism has had a long, but conflicted, history as being recognized as a potentially reversible cause of cognitive impairment. One piece of information that recurs throughout the literature concerning the control of thyroid functions data suggests a left-sided dominance. This research aimed to discover which hemisphere controls thyroid functions specific to memory and cognitive functioning. We hypothesized that the left hemisphere controlled thyroid functioning and would show a bias in neuropsychological testing in a clinical population, resulting in individuals with higher TSH levels performing worse on verbal tasks than their lower TSH level counterparts. Twenty-six female participants with either hypothyroidism or Hashimoto’s disease were grouped into one of two groups (Low TSH/High TSH) based on their TSH serum levels at the time of neuropsychological testing. The results provided no support, finding no significant differences between the Low TSH and High TSH groups in performance on verbal tasks.