Upper Extremity Strength in Cerebral Palsy

Rationale:

Children with Cerebral Palsy (CP) experience limitations in motor activities and participation in the community, predominantly caused by impairments in muscle function. Aside from abnormal posturing due to spasticity, muscle weakness can significantly contribute to impaired muscle function and there is increasing evidence that muscle weakness significantly impairs upper limb motor function and ability to perform manual tasks in children with CP. Studies in the last decade have shown that muscle weakness, not spasticity, is the greatest limiting factor of motor function in children with CP. Furthermore, there is increasing evidence that the strength in the upper extremities of children with CP is less compared to their typically developing peers (TDP). A systematic review focused on the psychometric properties of strength measurement instruments has shown that the number of studies investigating psychometric properties of strength measurement instruments is limited and that the methodological quality of these studies is low.

Aim:

The present study aims to investigate the reproducibility of the following three isometric strength measurements in the upper extremity of children and adolescents with unilateral CP as well as in TDP: Hand Held Dynamometry (HHD), pinch and grip strength using the E-link system and functional strength. To study to which extent upper extremity strength, both in the affected side and the non-affected side, differs from the strength in the upper extremities of TDP, these measurements will also be performed by children without neurological problems.

Study Design:

A cross-sectional study in which the reproducibility of three strength measurement instruments, i.e. HHD, E-link and Functional strength, will be investigated in children and adolescents with unilateral CP and TDP.

Population:

Children with unilateral spastic CP (with perinatal acquired hypoxic ischemic incidents), aged 7 to 18 years, Manual Ability Classification System (MACS) levels I-III, who are mentally able to perform the measurements will be included and TDP.

Outcome measures:

The most important psychometric property in strength measurement instruments is reproducibility. Reproducibility will be investigated using the following factors: Intraclass Correlation Coefficient (ICC), Limits of Agreement (LOA), Standard Error of Measurement (SEM) and the Smallest Detectable Difference (SDD). Reference values will be determined using the Generalised Additive Models for Location, Scale, and Shape (GAMLSS) method.


Eligibility Criteria:
Inclusion Criteria CP:

* Children with unilateral spastic CP (with perinatal acquired hypoxic ischemic incidents),
* aged 7 to 18 years,
* MACS levels I-III,
* mentally able to perform the measurements

Inclusion criteria Healthy Controls:

* children attending primary or secondary school
* agd 7 to 18 years

Exclusion Criteria CP:

* Surgical intervention \<6 months
* Botulinum Toxin A treatment in the upper extremity \< 6 months
* contractures in the upper extremity that might interfere with task performance

Exclusion criteria Healthy Controls:

* muscle disease
* lesion, fracture or cast \< 6 months