Cerebral blood flow imbalance is associated with motor outcome after pediatric arterial ischemic stroke

Participation after childhood stroke: Is there a relationship with lesion size, motor function and manual ability?

BACKGROUND

Childhood arterial ischemic stroke (AIS) is associated with significant morbidity with up to 50% of affected children developing hemiparesis. Hemiparesis is assumed to influence participation within the peer group, but it is unclear to what extent its severity affects participation in different areas of social life.

METHODS

Thirteen children (mean age 9y6m) with AIS (6 without hemiparesis, 7 with hemiparesis) and 21 controls (mean age 9y8m) participated. We scored hemiparesis severity with hand strength asymmetry (pinch and grip strength), measured with a dynamometer. We assessed manual ability (ABILHAND-Kids), socioeconomic status (Family Affluence Scale) and participation (Participation and Environment Measure - Children and Youth). From structural MRI, we measured lesion size. We investigated differences in participation and its relationship with hemiparesis severity using non-parametric partial correlations (controlling for lesion size, manual ability, and socioeconomic status), interpreted as absent (r < 0.25), weak (r = 0.25-0.50), moderate (r = 0.50-0.75) or strong (r > 0.75). Analyses were performed in jamovi 1.6.3.

RESULTS

Children with AIS (with or without hemiparesis) showed reduced participation frequency at school (p < 0.001), whilst participation at home and in the community resembled that of their peers. Severity of hemiparesis was moderately related to frequency and involvement at home and to involvement and desire for change in the community, although unrelated to school participation.

CONCLUSION

Reduced participation in school life requires close attention in the follow-up of children with AIS - regardless of the severity of hemiparesis. Participation at home and in the community is related to hemiparesis severity and may be improved with participation-focused motor intervention strategies.

Cerebral blood flow and cognitive outcome after pediatric stroke in the middle cerebral artery

Adaptive recovery of cerebral perfusion after pediatric arterial ischemic stroke (AIS) is sought to be crucial for sustainable rehabilitation of cognitive functions. We therefore examined cerebral blood flow (CBF) in the chronic stage after stroke and its association with cognitive outcome in patients after pediatric AIS. This cross-sectional study investigated CBF and cognitive functions in 14 patients (age 13.5 ± 4.4 years) after pediatric AIS in the middle cerebral artery (time since AIS was at least 2 years prior to assessment) when compared with 36 healthy controls (aged 13.8 ± 4.3 years). Cognitive functions were assessed with neuropsychological tests, CBF was measured with arterial spin labeled imaging in the anterior, middle, and posterior cerebral artery (ACA, MCA, PCA). Patients had significantly lower IQ scores and poorer cognitive functions compared to healthy controls (p < 0.026) but mean performance was within the normal range in all cognitive domains. Arterial spin labeled imaging revealed significantly lower CBF in the ipsilesional MCA and PCA in patients compared to healthy controls. Further, we found significantly higher interhemispheric perfusion imbalance in the MCA in patients compared to controls. Higher interhemispheric perfusion imbalance in the MCA was significantly associated with lower working memory performance. Our findings revealed that even years after a pediatric stroke in the MCA, reduced ipsilesional cerebral blood flow occurs in the MCA and PCA and that interhemispheric imbalance is associated with cognitive performance. Thus, our data suggest that cerebral hypoperfusion might underlie some of the variability observed in long-term outcome after pediatric stroke.

Relationship between motor abilities and executive functions in patients after pediatric stroke

Patients after pediatric stroke typically experience varying extent of motor and cognitive impairments. During rehabilitation, these impairments are often treated as separate entities. While there is a notion claiming that motor and cognitive functions are interrelated to some degree in healthy children, a minimal amount of evidence exists regarding this issue in patients after pediatric stroke. The purpose of this study was to investigate the association between motor abilities and executive functions in patients after pediatric arterial ischemic stroke. Twenty-seven patients (6 - 23 years) diagnosed with pediatric arterial ischemic stroke in the chronic phase (≥ 2 years after diagnosis, diagnosed < 16 years) and 49 healthy controls (6 - 26 years) were included in this study. Participants completed six tasks from standardized neuropsychological tests assessing the dimensions of executive functions, namely working memory, inhibition, and shifting. Additionally, we assessed hand strength and upper limb performance with two tasks each. In the patient group, the association between upper limb performance and executive functions was stronger than between hand strength and executive functions. Our results point toward the idea of a close interrelation between upper limb performance and executive functions. Training more complex and cognitively engaging motor abilities involving upper limb performance rather than basic motor abilities such as hand strength during a rehabilitation program may have the power to foster executive function development and vice versa in patients after stroke.

Functional connectivity and upper limb function in patients after pediatric arterial ischemic stroke with contralateral corticospinal tract wiring

To develop individualized motor rehabilitation, knowledge of the relationship between neuroplastic reorganization and motor recovery after pediatric arterial ischemic stroke (AIS) is crucial. Thus, we investigated functional connectivity in patients after AIS with good motor outcome and in patients with hemiparesis compared with typically developing peers. We included 18 patients (n = 9 with hemiparesis, n = 9 with good motor outcome) with pediatric AIS in the chronic phase (≥ 2 years after diagnosis, diagnosed > 16 years) and 18 peers matched by age and gender. Participants underwent a standardized motor assessment, single-pulse transcranial magnetic stimulation to determine the type of corticospinal tract wiring, and resting-state functional magnetic resonance imaging to examine motor network connectivity. Corticospinal tract wiring was contralateral in all participants. Patients with hemiparesis had lower interhemispheric connectivity strength compared with patients with good clinical outcome and peers. Patients with good clinical outcome had higher intrahemispheric connectivity strength compared with peers. Further, higher intrahemispheric connectivity was related to better motor outcome in patients. Our findings suggest that better motor outcome after pediatric AIS is related to higher motor network connectivity strength. Thus, resting-state functional connectivity might be predictive for motor recovery after pediatric AIS.