Auditory motor adaptation in children with and without developmental coordination disorder (DCD)

Abstract

Tasks, such as dancing, require coordination between the various body segments and synchronization of the movement to auditory stimuli. Children with developmental coordination disorder (DCD), who have significant motor deficits, demonstrate impairments in bimanual self-paced tapping and tapping in synchrony to different frequencies of auditory cues. The purpose of this dissertation was to examine the ability of children with and without DCD to adapt to changing rhythms with constant frequency, under conditions where they could and could not perceive the change in the rhythm. First, we examined differences in the auditory phasing threshold, coordination and its stability in non-disabled children between 4 and 10 years. All children detected changes in rhythm however, the ability to detect more subtle changes increased with age. Children adapted to both perceptible and subliminal changes in rhythm and the developmental trajectories in both conditions were similar. However, variability in performance decreased across age. We, then, investigated the ability of children with DCD to adapt to perceptible and subliminal change and compared their performance to age- and gender- matched typically developing children (TDC). Children with DCD perceived changes in rhythm similar to TDC, and adapted to both perceptible and subliminal changes in rhythm but were more variable under all phasing conditions. The impairments in tapping may be a result of motor "noise" rather than a perceptual-motor coupling process. Finally, we investigated variability using linear measures to assess the amount and a non-linear measure to assess the structure of temporal/spatial variability. Children with DCD were more variable in their linear temporal variability compared to TDC and adults. Adults and TDC but not children with DCD had higher spatial variability in their non-dominant than their dominant finger, suggesting that children with DCD are delayed in lateralization. Children with and without DCD had lower non-linear structural variability than adults. This suggests that children with DCD freeze degrees of freedom to produce movements; however, they are not as effective as TDC. Our results can be interpreted within a neuro-anatomical computational model of motor control that may delineate potential areas of future investigation in children with DCD.