Effect of thyroid stimulating hormone on adaptive behaviour in Down's syndrome.

Patients with Down's syndrome are particularly vulnerable to the development of both hypothyroidism and Alzheimer's disease. Both hypothyroidism and Alzheimer's disease may be associated with elevated serum concentrations of thyroid stimulating hormone. In a group of institutionalized Down's syndrome patients with normal thyroid function, global scores of ability were higher than in a group of patients with elevated thyroid stimulating hormone levels in the presence of normal T3 and T4. The actual concentrations of thyroid stimulating hormone were shown to be significantly and inversely correlated with scores of global abilities. If these findings are reproducible, the authors believe that thyroid stimulating hormone estimation may provide confirmatory evidence of clinical dementia in this group of mentally handicapped individuals.