Upper Extremity Muscle Strength in Children With Unilateral Spastic Cerebral Palsy: A Bilateral Problem?

OBJECTIVE: The objective was to investigate whether muscle strength in the nonaffected and affected upper extremities (UEs) in children (7-12 years) with unilateral spastic cerebral palsy (USCP) differs from that in children with typical development (TD). METHODS: A cross-sectional study design was used. Isometric arm strength (wrist flexion, wrist extension with flexed and extended fingers, elbow flexion/extension) was assessed in 72 children (mean age = 9.3 [SD = 1.9] years) with USCP, and isometric grip/pinch strength was assessed in 86 children (mean age = 9.3 [SD = 1.8] years) with USCP. Arm/grip/pinch strength was assessed in 120 children (mean age = 9.5 [SD = 1.7] years) with TD. Arm strength was measured with a hand-held dynamometer, and grip/pinch strength was measured with a calibrated, modified (digitized) grip dynamometer and a pinch meter. The nonaffected UE of children with USCP was compared with the preferred UE of children with TD because both sides represent the preferred UE. The affected UE was compared with the nonpreferred UE of children with TD, as both sides represent the nonpreferred UE. RESULTS: In all measurements except for grip strength of the preferred UE, children with USCP were weaker than children with TD. CONCLUSIONS: In children with USCP, muscle strength weakness exists in both UEs. IMPACT: When unimanual or bimanual ability limitations are present in children with unilateral cerebral palsy, investigation of the muscle strength of the nonaffected UE should be part of the assessment.

Psychometric Evaluation of 2 New Upper Extremity Functional Strength Tests in Children With Cerebral Palsy.

BACKGROUND: For children with unilateral spastic cerebral palsy (USCP), reduced muscle strength can lead to activity limitations. However, none of the existing measures of upper extremity strength measure strength in the context of functional activities in which strength must be maintained for several seconds. OBJECTIVE: The objective of this study was to evaluate the psychometric properties of 2 newly developed functional hand and upper extremity muscle-strength tests (Cup-Task and Box-Task) in children aged 7 to 12 years with USCP. DESIGN: A longitudinal study design was used. METHODS: A standardized protocol with detailed descriptions of all procedures and measurements was used to determine test-retest reliability, interrater reliability, and criterion validity. RESULTS: A total of 86 children (53 males, 33 females, mean age = 9.3 years) with USCP participated in this study, with a subset performing each measurement. Only the results of children who were able to perform the measurement were included for analysis. Excellent test-retest reliability (intraclass correlation coefficients = 0.887-0.944; 95% confidence intervals = 0.713-0.969) and interrater reliability (intraclass correlation coefficients = 0.896-0.960; 95% confidence intervals = 0.813-0.980) were observed. The Cup-Task Affected-Hand and Box-Task were moderately correlated with maximum isometric grip strength. The Cup-Task Nonaffected-Hand had a low correlation with maximum isometric grip strength. LIMITATIONS: Age, sex, and manual ability were not normally distributed, which could have influenced the results. CONCLUSIONS: For children with USCP who can perform the tasks, the Cup-Task and Box-Task are reliable and valid instruments for measuring functional upper extremity muscle strength.

Upper extremity strength measurement for children with cerebral palsy: a systematic review of available instruments.

BACKGROUND: In order to make inferences about strength related to development or treatment interventions, it is important to use measurement instruments that have sound clinimetric properties. PURPOSE: The objective of this review is to systematically evaluate the level of evidence of the clinimetric properties of instruments for measuring upper extremity muscle strength at the "body functions & structures" level of the International Classification of Functioning, Disability and Health for Children and Youth (ICF-CY) for children with cerebral palsy (CP). DATA SOURCES: A systematic search of the PubMed, EMBASE, OTseeker, CINAHL, PEDro, and MEDLINE databases up to November 2012 was performed. STUDY SELECTION: Two independent raters identified and examined studies that reported the use of upper extremity strength measurement instruments and methods for children and adolescents with CP aged 0 to 18 years. DATA EXTRACTION: The COSMIN (COnsensus-based Standards for the selection of health status Measurement INstruments) checklist with 4-point rating scale was used by 2 independent raters to evaluate the methodological quality of the included studies. Best evidence synthesis was performed using COSMIN outcomes and the quality of the clinimetric properties. DATA SYNTHESIS: Six different measurement instruments or methods were identified. Test-retest, interrater, and intrarater reliability were investigated. Two test-retest reliability studies were rated as "fair" for the level of evidence. All other studies were rated as "unknown" for the level of evidence. LIMITATIONS: The paucity of literature describing clinimetric properties, especially other than reliability, of upper limb strength measurement instruments for children with CP was a limitation of the study. CONCLUSIONS: For measuring grip strength, the Jamar dynamometer is recommended. For other muscle groups, handheld dynamometry is recommended. Manual muscle testing (MMT) can be used in case of limited (below MMT grade 4) wrist strength or for total upper limb muscle strength. Based on lacking information regarding other clinimetric properties, caution is advised regarding interpretation of the results.