Control of precision grip in children with heavy prenatal alcohol exposure

Abstract

Background: Fine motor skill deficits have been reported for children with histories of prenatal alcohol exposure, but little is known whether impaired motor skill extends to the regulation of precision grip control. Methods: Children with (n = 15) and without (n = 17) histories of heavy prenatal alcohol exposure used their dominant hand to grasp, lift, and hold in space a small-instrumented object with a mass of 19 g. Object mass was also experimentally increased by separately adding two aluminum cubes with mass of 200 and 400 g. Participants completed a block of eight trials for each object mass with the last six trials in each trial block being statistically analyzed. Selected temporal and kinetic parameters of grip force (GF) and load force (LF) were examined to quantitatively index precision grip performance of the two groups. Results: Compared to typically developing peers, children with prenatal alcohol exposure used excessive and more variable LF and greater GF to lift each object mass, with more finger GF than thumb GF being applied to the apparatus. The GF/LF ratio for the clinical group was greater when lifting the smallest mass load. When holding the object in space, children with prenatal alcohol exposure produced greater GF for the smallest mass load, again with more GF being applied via the finger compared to the thumb. Conclusions: Children with heavy prenatal alcohol exposure demonstrate force deficits when using precision grip to manipulate an object with three different masses. Chronic irregular precision grip could manifest as a fine motor skill developmental delay that may negatively impact completion of functional activities of daily living requiring grasping an object with the index finger and thumb.