Adaptation of reaching movements in children and young adults with myelomeningocele.
OBJECTIVE
To investigate the ability to adapt reaching movements to new visuomotor gain conditions in subjects with myelomeningocele (MMC) and subjects without disabilities. In addition, differences in movement error within the MMC group were investigated.


METHODS
Thirty subjects with myelomeningocele, 9-19 y, and 30 subjects without disabilities were included in the study. Data were collected with a digitizing tablet linked to a computer. The subjects made reaching movements towards three targets at different distances displayed on the computer screen, and movements were carried out under two different gain conditions-a base condition and an altered condition. Adaptation was quantified from the extent error and expressed in percentage of the target distances. For statistical analysis, ANOVA and t-tests were used.


RESULTS
Under the base condition, no statistically significant difference between the groups was found, but after the first gain change, the MMC group evinced larger percentage error compared to the control group (p = 0.005). Analysis showed that the subjects in the MMC group did not fully adapt their movements under the altered condition after several trials of practice, but in the control group movements were rapidly adapted to the new gain. Subjects with early and severe symptoms of brainstem dysfunction showed a dramatic increase in error variability under the altered condition, while subjects who had shunt-treated hydrocephalus did not have larger percentage error compared to the others.


CONCLUSIONS
Motor adaptation of reaching movements was impaired in subjects with MMC, but short-term motor learning did also occur in the MMC group.
Department of Women's and Children's Health, Section for Paediatrics, Folke Bernadottehemmet, Children's Hospital, Uppsala University, Uppsala, Sweden. simone.norrlin@akademiska.se
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Norrlin
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Rösblad
D000222:Adaptation, Physiological; D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003936:Diagnosis, Computer-Assisted; D006801:Humans; D008591:Meningomyelocele / Q000503:physiopathology*; D009068:Movement / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology