Improved Hand Function in Children With Cerebral Palsy With Repeat Doses of Augmented Pediatric Constraint-Induced Movement Therapy

Date Presented 04/13/21 Children with unilateral cerebral palsy participating in repeat doses of pediatric constraint-induced movement therapy camp augmented with the Hocoma Armeo®Spring demonstrated significant improvements in hand function and bimanual performance for both doses and showed a generalized upward trend in hand function over time. Primary Author and Speaker: Heather Roberts Additional Authors and Speakers: Sara P. Johnston, David Plutschack

Corpus callosal microstructure predicts bimanual motor performance in chronic stroke survivors

Much of the research using diffusion tensor imaging (DTI) in stroke focuses on characterizing the microstructural status of corticospinal tracts and its utility as a prognostic biomarker. However, the ischemic event in the lesioned cortex also triggers structural and functional alterations in its contralateral homolog through the corpus callosum (CC), known as transcallosal diaschisis. The few studies that have characterized the microstructural status of the CC using DTI only examine its relationship with paretic limb performance. Given the well-established role of the CC for bimanual coordination, especially fibers connecting the larger sensorimotor networks such as prefrontal, premotor and supplementary motor regions, we examine the relationship between the microstructural status of the CC and bimanual performance in chronic stroke survivors (n = 41). We used movement times for two self-initiated and self-paced bimanual tasks to capture bimanual performance. Using publicly available control datasets (n = 52), matched closely for acquisition parameters, including sequence, diffusion gradient strength and number of directions, we also explored the effect of age and stroke on callosal microstructure. We found that callosal microstructure was significantly associated with bimanual performance in chronic stroke survivors such that those with lower callosal FA were slower at completing the bimanual task. Notably, while the primary sensorimotor regions (CC3) showed the strongest relationship with bimanual performance, this was closely followed by the premotor/supplementary motor (CC2) and the prefrontal (CC1) regions. We used multiple mixed regression to systematically account for loss of callosal axons (i.e., normalized callosal volume) as well as differences in lesion size and other metrics of structural damage. Chronic stroke survivors presented with significantly greater loss of callosal fiber orientation (lower mean FA) compared to neurologically intact, age-similar controls, who in turn presented with lower callosal FA compared to younger controls. The effect of age and stroke were observed for all regions of the CC except the splenium. These preliminary findings suggest that in chronic stroke survivors with relatively localized lesions, callosal microstructure can be expected to change beyond the primary sensorimotor regions and might impact coordinated performance of self-initiated and cooperative bimanual tasks.

Corpus Callosum Integrity Relates to Improvement of Upper-Extremity Function Following Intensive Rehabilitation in Children With Unilateral Spastic Cerebral Palsy

Background The corpus callosum (CC) plays an important role in upper extremity (UE) function. The impact on UE function in children with unilateral spastic cerebral palsy (USCP) and improvements following intensive interventions remain unknown. Objectives To examine the (1) relationship between UE function and CC integrity and (2) relationship between CC integrity and changes in UE function following intensive interventions. Methods We retrospectively analyzed clinical and neuroimaging data from a sample of convenience of 44 participants (age 9.40 ± 3.10 years) from 2 larger trials. Participants received 90 hours of Hand-Arm Bimanual Intensive Therapy (HABIT) or Constraint-Induced Movement Therapy (CIMT). Unimanual dexterity (Jebsen-Taylor Test of Hand Function [JTTHF]) and bimanual performance (Assisting Hand Assessment [AHA]) were assessed preintervention and postintervention. CC tractography was reconstructed with diffusion tensor imaging (DTI) and segmented into 3 regions (genu, midbody, splenium). Pearson correlations and regression were used to assess the relationship between outcomes and DTI parameters (ie, fractional anisotropy [FA], number of streamlines, and mean, radial, and axial diffusivity). Results Both groups improved in bimanual performance ( P < .01). The CIMT group improved in unimanual dexterity ( P < .01). Baseline unimanual dexterity and bimanual performance correlated with FA and number of streamlines for most CC regions ( P < .05). Following CIMT, pre-post changes in JTTHF were negatively correlated with axial and radial diffusivity of the CC, and AHA with splenium and number of streamlines for the CC, midbody, and splenium (all P < .05). Following HABIT, midbody FA was positively correlated with pre-post AHA changes ( r = 0.417; P = .042). Conclusions CC integrity is important for UE function in children with USCP.

Reduced Modulation of Task-Related Connectivity Mediates Age-Related Declines in Bimanual Performance

Aging is accompanied by marked changes in motor behavior and its neural correlates. At the behavioral level, age-related declines in motor performance manifest, for example, as a reduced capacity to inhibit interference between hands during bimanual movements, particularly when task complexity increases. At the neural level, aging is associated with reduced differentiation between distinct functional systems. Functional connectivity (FC) dedifferentiation is characterized by more homogeneous connectivity patterns across various tasks or task conditions, reflecting a reduced ability of the aging adult to modulate brain activity according to changing task demands. It is currently unknown, however, how whole-brain dedifferentiation interacts with increasing task complexity. In the present study, we investigated age- and task-related FC in a group of 96 human adults across a wide age range (19.9–74.5 years of age) during the performance of a bimanual coordination task of varying complexity. Our findings indicated stronger task complexity-related differentiation between visuomotor- and nonvisuomotor-related networks, though modulation capability decreased with increasing age. Decreased FC modulation mediated larger complexity-related increases in between-hand interference, reflective of worse bimanual coordination. Thus, the ability to maintain high motor performance levels in older adults is related to the capability to properly segregate and modulate functional networks.

Randomized controlled trial combining constraint-induced movement therapy and action-observation training in unilateral cerebral palsy: clinical effects and influencing factors of treatment response

Introduction: Constraint-induced movement therapy (CIMT) improves upper limb (UL) motor execution in unilateral cerebral palsy (uCP). As these children also show motor planning deficits, action-observation training (AOT) might be of additional value. Here, we investigated the combined effect of AOT to CIMT and identified factors influencing treatment response. Methods: A total of 44 children with uCP (mean 9 years 6 months, SD 1 year 10 months) participated in a 9-day camp wearing a splint for 6 h/day and were allocated to the CIMT + AOT ( n = 22) and the CIMT + placebo group ( n = 22). The CIMT + AOT group received 15 h of AOT (i.e. video-observation) and executed the observed tasks, whilst the CIMT + AOT group watched videos free of biological motion and executed the same tasks. The primary outcome measure was bimanual performance. Secondary outcomes included measures of body function and activity level assessed before (T1), after the intervention (T2), and at 6 months follow-up (T3). Influencing factors included behavioural and neurological characteristics. Results: Although no between-groups differences were found ( p > 0.05; η2 = 0–16), the addition of AOT led to higher gains in children with initially poorer bimanual performance ( p = 0.02; η2 = 0.14). Both groups improved in all outcome measures after the intervention and retained the gains at follow up ( p < 0.01; η2 = 0.02–0.71). Poor sensory function resulted in larger improvements in the total group ( p = 0.03; η2 = 0.25) and high amounts of mirror movements tended to result in a better response to the additional AOT training ( p = 0.06; η2 = 0.18). Improvements were similar irrespective of the type of brain lesion or corticospinal tract wiring pattern. Conclusions: Adding AOT to CIMT, resulted in a better outcome for children with poor motor function and high amounts of mirror movements. CIMT with or without AOT seems to be more beneficial for children with poor sensory function. Trial registration: Registered at ClinicalTrials.gov on 22nd August 2017 (ClinicalTrials.gov identifier: NCT03256357).