Are neuropsychological changes relevant in subclinical hypothyroidism?

Introduction: Neuropsychological changes are still controversial in patients with subclinical hypothyroidism (SH). The objective of this study is to assess these changes. Method: Cross-sectional study comparing the results of the neurocognitive evaluation of 65 SH patients and 31 individuals without thyroid disease. Subclinical hypothyroidism was defined as at least two elevated serum TSH levels (> 4 mu UI/ml) with normal serum free T-4 levels (0.9-1.8 ng/dl). The participants underwent the following neuropsychological assessment: Buschke's Selective Reminding Procedure, Rey-Osterrieth Complex Figure Test, Warrington's Recognition Memory Test for Words and Faces, and the Vocabulary subtest of the WAIS-R. Results: The groups were similar in regard to mean age, sex and educational level. No neuropsychological change was found in patients with SH when compared with euthyroid individuals. Conclusion: No difference was observed in the performance of the neuropsychological tests between both groups in regard to the functions studied.