Median Nerve Conduction Velocity and Central Conduction Time Measured With Somatosensory Evoked Potentials in Thyroxine-Treated Infants With Down Syndrome

Abstract

Postnatal thyroxine treatment of infants with Down syndrome did not alter somatosensory evoked potential-measured peripheral or central nerve conduction significantly. The absence of favorable effects suggests that pathologic mechanisms other than mild postnatal hypothyroidism underlie the impaired nerve conduction. The absence of adverse effects suggests that longstanding plasma free thyroxine concentrations in the high-normal range are not harmful to nerve maturation.

Increased neonatal thyrotropin in Down syndrome

“…There is usually a liberal attitude towards thyroxine treatment of DS children with evidence of subclinical hypothyroidism. Thyroxine therapy is easy to carry out and no adverse effects have been reported in this group of children (15,29). Recently, beneficial effects of thyroxine on growth and mental development in DS were observed during the first two years of life (14), but no information on differences between genders was given in that report.…”

The effectiveness and safety of thyroxine replacement therapy for children with down syndrome and subclinical or congenital hypothyroidism—A systematic review

“…There was one study comparing Thyroxine with placebo in 196 DS neonates which found modest reduction of TSH levels and development and growth improvement [13]; the other study that compared Thyroxine to placebo showed similar declines in TSH levels, but did not alter somatosensory evoked poten al-measured peripheral or ti Table 1. Results of the identified studies.…”

“…To ensure blinding, only the endocrinologist had access to the laboratory data. However, blinding of participants and observers was done, and the blinding was assessed by telephone interview 3 -6 months after the last study visit, in which parents were asked whether during the study they had knowledge of the kind of study medication their child received [13,14].…”

“…Withdrawals were clearly assessed by the two studies which had drop outs, the number and the reasons of participants withdrawal was stated and intention to treat analysis was used [13,14]. In the first study 8% (9/69) of the experimental group withdrew from the trial due to nonadherence to treatment and loss to follow up and were considered at the analysis of the data [12].…”

“…In the first study 8% (9/69) of the experimental group withdrew from the trial due to nonadherence to treatment and loss to follow up and were considered at the analysis of the data [12]. There were balanced withdrawal of participants from the experimental and the control groups of the two studies [13,14].…”