EVOKED POTENTIALS TN NEWBORNS WITH CONGENITAL HYPO-THYROIDISM

Abstract

To evaluate the effect of congenital hypothyroidism (CH) on nervous systen development, we performed evoked potential studies on 6 infants at 3-8 weeks of age with CH before any therapy was given. All infants were screened at the time of hospital discharge and again at about 2 weeks by filter paper determination of T4 and TSH. A serum specimen confirmed the abnormal filter paper values at the time of study. The infants participating in this study all had serum TSH concentrations > 100 μU/ml (normal 2.5 S.D. above lab mean for age). Visual evoked potentials (VEP) were abnormal in 3 of 6 subjects and all showed a pattern of immaturity. Somatosensory evoked potentials (SSEP) were normal. These BAEP results indicate selective caudal brainstem dysfunction in these infants with CH that is not consistent with immaturity alone and differs from BAEP abnormalitites in older children who had been treated for CH for many years (Pediatr Res 20:570, 1986). We conclude that infants with relatively mild CH (serum T4 values > 4 μg/dl at 3-8 weeks of age) have evidence of abnormal caudal brainstem development, and that normal T4 production is necessary to assure normal brain development at a time before diagnosis of CH can be made by neonatal screening.