Neurological abnormalities in patients treated for hypothyroidism from early life.

Neurological and psycholocial assessment was carried out on 30 patients aged 2.7 to 21 years (mean 9.4) who were being treated for hypothyroidism starting before the age of 2 years. Their IQ scores lay in the normal range (71--122; mean 92.4) but 77% showed at least one sign of impaired brain function. Clumsiness was found in 33%, behaviour disorders in 23%, speech disorders in 20%, learning disorders in 26%, squint in 53%, nystagmus in 10%, and minor motor disorders in 50%. Many showed several of these features and hypothyroidism in early life appears to lead to widespeard impairment of brain function. These neurological findings were equally common in patients in whom treatment started between 4 and 10 weeks of age and patients treated after 10 weeks, suggesting that early detection of hypothyroidism by neonatal screening may be of limited benefit. Children who have been hypothyroid in early infancy require careful assessment to prevent further visual, emotional, scholastic, or vocational difficulties.