Is cognitive impairment related to hypothyroidism improved by hormone-replacement therapy?

Purpose. - Although cognitive impairment related to hypothyroidism has been investigated, issues regarding treatment have been less extensively studie d. The aim of this study was to assess cognitive function in patients with hypothyroidism just before treatment and after hypothyroidism had resolved. Methods. - Standardized psychometric assessment (including ten tests) was d one in 30 outpatients with biochemical evidence of hypothyroidism (TSH = 92 ,1 mU/L, range: 11,4-400) and in 30 control subjects matched for age and ge nder with normal thyroid function. These tests were repeated twice before t reatment and after hypothyroidism had been cured. Statistical analysis was done using the Mann-Whitney U test Results. - The baseline characteristic of patients with hypothyroidism show ed that attention, motor speed, memory and visual-spatial organization were significantly impaired. Cognitive decline was significantly greater with i ncreasing age. Cognitive impairment significantly decreased after hypothyro idism had been cured, reaching values obtained in age-matched control subje cts. Conclusion. - Attention, motor speed, memory and visual-spatial organizatio n are significantly impaired in hypothyroidism, particularly in the elderly , suggesting that ageing could have potential effects on cognitive function s. Hormone-replacement therapy leads to normalization of the cognitive func tions. (C) 2000 Editions scientifiques et medicales Elsevier SAS.