Impact of Upper Extremity Impairment and Trunk Control on Self-Care Independence in Children With Upper Motor Neuron Lesions

OBJECTIVE: The purpose of this study was to evaluate the relative importance of different approaches to measure upper extremity selective voluntary motor control (SVMC), spasticity, strength, and trunk control for explaining self-care independence in children affected by upper motor neuron lesions. METHODS: Thirty-one patients (mean [SD] age = 12.5 [3.2] years) with mild to moderate arm function impairments participated in this observational study. Self-care independence was evaluated with the Functional Independence Measure for children (WeeFIM). Upper extremity SVMC was quantified with the Selective Control of the Upper Extremity Scale (SCUES), a similarity index (SI(SCUES)) calculated from simultaneously recorded surface electromyography muscle activity patterns, and an accuracy and involuntary movement score derived from an inertial-measurement-unit–based assessgame. The Trunk Control Measurement Scale was applied and upper extremity spasticity (Modified Ashworth Scale) and strength (dynamometry) were assessed. To determine the relative importance of these factors for self-care independence, 3 regression models were created: 1 included only upper extremity SVMC measures, 1 included upper extremity and trunk SVMC measures (overall SVMC model), and 1 included all measures (final self-care model). RESULTS: In the upper extremity SVMC model (total variance explained 52.5%), the assessgame (30.7%) and SCUES (16.5%) were more important than the SI(SCUES) (4.5%). In the overall SVMC model (75.0%), trunk SVMC (39.0%) was followed by the assessgame (21.1%), SCUES (11.0%), and SI(SCUES) (4.5%). In the final self-care model (82.1%), trunk control explained 43.2%, upper extremity SVMC explained 23.1%, spasticity explained 12.3%, and strength explained 2.3%. CONCLUSION: Although upper extremity SVMC explains a substantial portion of self-care independence, overall trunk control was even more important. Whether training trunk control and SVMC can translate to improved self-care independence should be the subject of future research. IMPACT: This study highlights the importance of trunk control and selective voluntary motor control for self-care independence in children with upper motor neuron lesions.