2 Associations Between Motor Functioning and Intellectual Abilities in Pediatric Arterial Ischemic Stroke

Objective:Motor impairments are one of the most common adverse outcomes after pediatric arterial ischemic stroke (AIS), affecting approximately half of survivors. The development of motor and cognitive skills is closely interrelated, and they share common neural substrates. The objective of this study was to examine whether motor functioning after the acute phase of stroke is associated with school-age intellectual abilities. We also examined associations between concurrent motor functioning and intellectual abilities. Finally, we explored clinical features associated with motor impairments.Participants and Methods:Participants were 64 children, 34 childhood AIS (Meanage= 11.90[2.38]); 30 perinatal AIS (Meanage= 8.75[2.22]), from the Children’s Stroke Program at SickKids Hospital. Motor functioning was assessed with the Pediatric Stroke Outcome Measure sensorimotor subscale at two timepoints, Time 1 or early recovery (childhood group between 30 days post-stroke to 1 year; perinatal group between 2-5 years of age) and Time 2, closest to neuropsychological testing. Intellectual abilities were measured using the Wechsler Intelligence Scale for Children 4th or 5th edition. Associations between motor and intellectual functioning were examined separately in childhood and perinatal AIS groups. Clinical features associated with motor impairment were examined across the full sample.Results:Motor functioning during early recovery was significantly associated with processing speed (r= -.391, p= .036) in the perinatal group and with overall intellectual functioning (r= -.414, p= .018) verbal intellectual abilities (r= -.444, p= .011), working memory (r= .393, p= .026), and processing speed (r= -.351, p= .042) in the childhood group. There were no associations between concurrent motor and intellectual functioning in the perinatal group, and only with processing speed (r= -.525, p= .002) in the childhood group. When motor functioning was dichotomized as no/mild motor deficit and moderate/severe motor deficit at Time 1, children in the perinatal group with moderate/severe motor deficit had significantly lower perceptual reasoning scores (f[28]= 2.15, p= .040) and participants in the childhood group with moderate/severe motor deficit had significantly lower perceptual reasoning (f[32]= 2.35, p= .025) and processing speed (f[32]= 2.14, p= 0.41) scores. There were no differences between no/mild and moderate/severe motor deficit groups for either perinatal or childhood AIS at Time 2. Clinical features associated with moderate/severe motor deficit at Time 1 were cortical+subcortical infarcts, large lesions, presenting with hemiparesis and seizures at time of neuropsychological assessment, and accessing occupational therapy and physical therapy.Conclusions:Results suggest that motor functioning during early stroke recovery is associated with intellectual outcome, whereas motor functioning at time closest to neuropsychological assessment is not. This may be related neuroplastic changes post-injury, likely in frontal-subcortical connections, that result in observable motor deficits after stroke and affect subsequent hierarchal brain maturational processes thereby impacting later cognitive outcome. Different patterns of associations between motor functioning and specific intellectual abilities in perinatal and childhood groups suggest possible age-mediated effects on this relationship.