Article

Extensive neuromotor development occurs early in human life, but the
time that a brain injury occurs during development has not been rigorously
studied when quantifying motor impairments. This study investigated
the impact of timing of brain injury on the magnitude and distribution of
weakness in the paretic arm of individuals with childhood-onset hemiparesis.
METHODS: A total of 24 individuals with hemiparesis were divided into time
periods of injury before birth (PRE-natal, n = 8), around the time of birth
(PERI-natal, n = 8), or after 6 months of age (POST-natal, n = 8). They, along
with 8 typically developing peers, participated in maximal isometric shoulder,
elbow, wrist, and finger torque generation tasks using a
multiple-degree-of-freedom load cell to quantify torques in 10 directions. A
mixed-model ANOVA was used to determine the effect of group and task on a
calculated relative weakness ratio between arms. RESULTS: There was a significant
effect of both time of injury group (P < .001) and joint torque direction (P <
.001) on the relative weakness of the paretic arm. Distal joints were more
affected compared with proximal joints, especially in the POST-natal group.
CONCLUSIONS: The distribution of weakness provides evidence for the relative
preservation of ipsilateral corticospinal motor pathways to the paretic limb in
those individuals injured earlier, whereas those who sustained later injury may
rely more on indirect ipsilateral corticobulbospinal projections during the
generation of torques with the paretic arm.

Langue : ANGLAIS