Neuropsychological study in treated thyroid dysgenesis

Abstract

60 patients aged 3-14 yrs, with hypothyroidism (HY) and athyreosis or ectopic thyroid gland, were examined for neuropsychological defects. They were selected on the basis of the following criteria: definite diagnosis of HY, absence of neonatal anoxia and of any factor predisposing to mental retardation, assessment of bone age (BA) at diagnosis, adequate therapy, normal subsequent physical development and hormonal control. The duration of HY was estimated as the time elapsed between BA at diagnosis and initiation of therapy. Psychoneurological defects were related to early HY according to the following schedule: Prenatal: hyperkinesis, short attention span, fine motor coordination disability; perinatal: impaired spatial orientation; 1-3 mo: slow ideation, enuresis; 2-4 mo: strabismus, articulatory speech defects; 2-12 mo: slow motor activity. In HY of prenatal onset, children treated before age 1 mo present some MBD symptoms which they compensate favourably with age; treatment after age 3 mo results in mental retardation, and after age 6 mo in cerebellar ataxy. HY starting at birth or later does not result in mental retardation.