Effect of Short-Term Training on Reaching Behavior in Infants: A Randomized Controlled Clinical Trial

Abstract

The purpose of this study was to test the effect of short-term training on reaching behavior in infants at the onset of reaching. The study was a single-blind, parallel group design, randomized controlled clinical trial. Thirty healthy infants were randomly assigned to a social control group (n = 15) or a reaching training group (n = 15). Infants began the study up to 3 days after the onset of reaching and were assessed three times across 2 days: pretraining (before training), posttraining 1 (after 1 session of training), and posttraining 2 (after 3 sessions of training). The reaching training group received 3 sessions of training by a physical therapist while the control group received a similar amount of time sitting in the therapist's lap. The data were analyzed using repeated-measures analyses of variance, and independent-samples tests with Bonferroni adjustments. Short-term training resulted in increased frequency of object contacts, shorter and smoother reaches, and improved hand positioning. The few short training sessions likely provided opportunities for infants to explore and learn to select movements from their existing movement repertoire. These results demonstrate that adaptive changes in infants' novel behaviors can emerge rapidly, and highlight the need for increased understanding of how to most effectively time early interventions.

Influence of Short-Term Training on the Distal Adjustments of Reaching in Preterm Infants

“…In the study by Heathcock et al 10 , preterm infants who received daily training of approximately 20 minutes after 8 weeks showed an increased frequency of reaching with an open hand and with the ventral surface, while the group born preterm who received only social interaction showed greater frequency in reaches with a closed hand and dorsal surface. Also, Cunha et al 39 have shown that full term infants presented more reaches with ventral hand after a short-term and goal-directed training. We can infer that although the preterm infants in our study increased their frequency of reaching, they were unable to perform reaches with the ventral hand after only one training session, which would be a more functional strategy for touching and grasping objects.…”

Evidence of training influence on infant manual behavior: a systematic review

“…As to assessments, only few studies included at least one retention test or follow-up assessments after the first post-training assessment 8,10,24,26 . This hampers the conclusions that could be drawn on the duration of observed effects of training, since it is not possible to evidence whether initial changes in motor behavior were only immediate or more long lasting.…”

“…During taskspecific trainings, pre-reaching infants were induced to repeat toy-oriented arm movements organized in steps of activities. Activities included haptic contact with the toy and assisted and active toy-oriented hand movements [8][9][10] . In the contingent reinforcement approach, 3-month-old infants were exposed to moving/sounding toys or a mobile which could be activated contingently upon infants' upper limb actions 11 .…”

“…These movement experiences have been used as induced trainings to advance or enhance the amount and duration of object-directed manual behaviors in typically developing infants and at-risk infants over 1-2 brief-term sessions or daily sessions. In general, authors have suggested these trainings provide infants with opportunities to improve upper limb control 8,9,11 , select more efficient movement patterns 6,8,9,11 , become motivated and engaged 10,12 , and learn to couple object perception and movement action 6,10 . These trainings, therefore, can be considered interesting tools to potentiate early manual development in typical infants and to prevent or minimize manual impairment in infants at risk for developmental disorders during early intervention practice.…”

“…All 21 studies presented at least one assessment after training (post-training). However, only 5 studies 8,10,[24][25][26] presented at least one retention measure (after the posttraining) or weekly follow-up assessments during or after the training weeks. Most of the studies analyzed the infants' behaviors using video recording (Table 3).…”