# The Loss of Independent Joint Control of the Upper Limb in Spastic Hemiparetic CP

> **NIH NIH R01** · NORTHWESTERN UNIVERSITY · 2022 · $327,845

## Abstract

PROJECT SUMMARY
Pediatric-onset hemiplegia (PH) causes movement impairments on one side of the body and accounts for
more than a third of all cases of cerebral palsy, the most common motor disability in childhood. Motor
impairments in this population include weakness, movement synergies, and coupling movements between
limbs (between arms and between paretic arm and legs), all of which limit independence with functional
mobility throughout the lifespan. Crucial tasks, such as reaching and grasping, required for countless daily
activities including participating in the classroom, become limited or impossible. In the previous cycle of this
R01, we discovered that the timing of brain injury during neurodevelopment impacted the expression of
weakness, involuntary coupling of shoulder abduction with elbow, wrist, and finger flexion (flexion synergy),
and involuntary coupling between upper limbs during isometric tasks. Our previous work uncovered the
importance of the timing of the injury on the preservation of neural structures, expressed in the integrity of
white matter, as they may be affected differently based on the stage of neurodevelopment when the injury
occurs. During early injuries (PRE-natal), there may be preservation of direct ipsilateral corticospinal
projections that are present as part of typical neural development. We hypothesize that this explains the
reduced presence of the flexion synergy and the greater movement coupling between upper limbs. Conversely,
in later injuries (PERI- and POST-natal) we hypothesize that the developmental pruning of these ipsilateral
corticospinal projections is in process (PERI-natal) or has already occurred (POST-natal) leading to increased
reliance in indirect ipsilateral corticoreticulospinal pathways to control movement of the paretic limbs. These
indirect pathways branch significantly at the spinal cord, explaining the presence of the flexion synergy and
abnormal involuntary coupling between the paretic leg and arm. In an effort to determine the effects of time of
injury and limb loading on motor impairments during functional reaching-grasping tasks in PH and the link to
neural microstructural morphology, we propose to: 1) quantify upper extremity reaching distance and hand
opening/closing ability; 2) determine the expression of between-limb movement coupling; and 3) identify the
changes in white and gray matter complexity of motor pathways in ipsilesional and contralesional hemispheres
as well as the brainstem. As such, the proposed research will, for the first time, investigate the effect of time of
brain injury on motor pathway complexity in individuals with pediatric-onset hemiplegic who express within-limb
and between-limb coupling dysfunction. This will provide the foundation for the development of more effective
targeted, time-of-injury specific interventions for the treatment of abnormal within- and between-limb coupling
to improve functional capabilities in this population.

## Key facts

- **NIH application ID:** 10377977
- **Project number:** 5R01NS058667-09
- **Recipient organization:** NORTHWESTERN UNIVERSITY
- **Principal Investigator:** JULIUS P DEWALD
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $327,845
- **Award type:** 5
- **Project period:** 2008-06-01 → 2024-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10377977

## Citation

> US National Institutes of Health, RePORTER application 10377977, The Loss of Independent Joint Control of the Upper Limb in Spastic Hemiparetic CP (5R01NS058667-09). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10377977. Licensed CC0.

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