PERIPHERAL NERVE CONDUCTION STUDIES IN PASSIVELY ADDICTED NEONATES

Abstract

The contribution of the peripheral nervous system to the neonatal abstinence syndrome was evaluated. Nerve conduction velocities were determined in 25 passively addicted(PA)infants born to mothers receiving methadone maintenance; 12 of the mothers abused other drugs concomitantly. Nerve conduction velocities in PA infants, both at 3-7 days and 3-4 weeks of age, did not differ from those of 11 control infants. Within the PA group, no conduction velocity differences(p > 0.1) were noted when comparing (a)maternal methadone use versus polydrug abuse, (b) mild versus severe neonatal abstinence, and (c)neonatal treatment with either paregoric or phenobarbital. Nerve conduction velocities were also normal in 3 PA infants who developed abstinence-related seizures. No relationship could be demonstrated between nerve conduction velocities and severity of abstinence on day of study(p> 0.4). Electromyographic studies were normal in 23 PA infants; the remaining two infants displayed minimal denervation abnormalities. Since 2-5 year follow-ups in PA infants have shown motor dysfunction and since this study fails to document a peripheral nervous system component to this dysfunction, the role of the central nervous system should be the prime focus of future research in the neonatal abstinence syndrome.