Brain lateralization in children with upper-limb reduction deficiency

Background: The purpose of the current study was to determine the influence of upper-limb prostheses on brain activity and gross dexterity in children with congenital unilateral upper-limb reduction deficiencies (ULD) compared to typically developing children (TD). Methods: Five children with ULD (3 boys, 2 girls, 8.76 +/- 3.37 years of age) and five age- and sex-matched TD children (3 boys, 2 girls, 8.96 +/- 3.23 years of age) performed a gross manual dexterity task (Box and Block Test) while measuring brain activity (functional near-infrared spectroscopy; fNIRS). Results: There were no significant differences (p = 0.948) in gross dexterity performance between the ULD group with prosthesis (7.23 +/- 3.37 blocks per minute) and TD group with the prosthetic simulator (7.63 +/- 5.61 blocks per minute). However, there was a significant (p = 0.001) difference in Laterality Index (LI) between the ULD group with prosthesis (LI = - 0.2888 +/- 0.0205) and TD group with simulator (LI = 0.0504 +/- 0.0296) showing in a significant ipsilateral control for the ULD group. Thus, the major finding of the present investigation was that children with ULD, unlike the control group, showed significant activation in the ipsilateral motor cortex on the non-preferred side using a prosthesis during a gross manual dexterity task. Conclusions: This ipsilateral response may be a compensation strategy in which the existing cortical representations of the non-affected (preferred) side are been used by the affected (non-preferred) side to operate the prosthesis. This study is the first to report altered lateralization in children with ULD while using a prosthesis.

Automated summary

The study found that children with congenital unilateral upper-limb reduction deficiencies (ULD) showed significant activation in the ipsilateral motor cortex on the non-preferred side when using a prosthesis, unlike typically developing children. This ipsilateral response may be a compensation strategy used by the affected side to operate the prosthesis. This study is the first to report altered lateralization in children with ULD while using a prosthesis.