Upper Extremity Strength in Cerebral Palsy
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.
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