Neuromuscular responses to disturbance of balance in children with prenatal exposure to alcohol

Alcohol-exposed children display delayed motor development and impaired fin e- and gross-motor skills, including deficits in the maintenance of balance . In a recent study, we assessed the contribution of visual, somatosensory, and vestibular information to the ability to maintain balance. Our finding s suggested that alcohol-exposed children were overly reliant on somatosens ory information and were unable to compensate by using the visual and/or ve stibular systems. To understand the nature of these observed balance defici ts, corrective postural reactions were examined by exposing standing subjec ts to rapid toe-up movements of the support surface. Subjects for this stud y were alcohol-exposed (ALC) and normal control (PIC) children matched for age and sex. Postural reactions were quantified by measuring electromyograp hic activity of the triceps surae and anterior tibialis muscles. Analyses r evealed no differences between the ALC and NC groups on short- and medium-l atency electromyographic responses, which are thought to be involuntary mon o- and polysynaptic spinal reflexes, respectively. However, when compared w ith the NC group, the ALC group displayed increased long-latency responses, which are thought to involve a transcortical pathway. Although we are not able to rule out the possibility of additional peripheral (e.g,, vestibular ) disturbance as a contributing factor to postural instability, our finding s suggest that the balance deficits seen in alcohol-exposed children are, a t least in part, central in nature.