Lower Extremity Strength Profile in Ambulatory Adults with Cerebral Palsy and Spastic Diplegia: Norm Values and Reliability for Hand‐Held Dynamometry

• Published in: PM & R 2020-06, Vol.12 (6), p.573-580
• Main Authors: Eken, Maaike M., Lamberts, Robert P., Koschnick, Susanne, Du Toit, Jacques, Veerbeek, Berendina E., Langerak, Nelleke G.
• Format: Article
• Language: English
• ISSN: 1934-1482; 1934-1563
• DOI: 10.1002/pmrj.12257

Background The handheld dynamometer (HHD) is a well‐accepted tool to assess muscle strength in children with cerebral palsy (CP), though reliability is not tested for adults with CP and no normative data are available. Objectives To present strength levels of lower extremity muscle groups and test‐retest reliability of HHD measurements in ambulatory adults with CP and typically developed (TD) adults. Design Case‐control study. Setting Human motion laboratory. Participants Fifty‐four adults with CP (28 men; Gross Motor Function Classification System [GMFCS] level I/II/III: n = 25/20/9; mean age (SD) = 38 (7) year) and 62 TD adults (31 men; mean age (SD) = 37 (5) year). Interventions Not applicable. Main Outcome Measure(S) Maximum strength levels were obtained during voluntary isometric contraction of eight lower extremity muscle groups in adults with CP and spastic diplegia and TD adults using HHD. Three trials were performed per muscle group per leg. Test‐retest reliability was investigated by calculating intraclass correlation coefficient (ICC), coefficient of variation (CV), and typical error of measurement (TEM). Results Force and torque levels were significantly lower in all eight lower extremity muscle groups. Excellent ICC levels were observed in TD, GMFCS I and II (>0.90), and moderate to excellent (0.82‐0.97) in GMFCS III. CV and TEM were higher in adults with CP compared to TD adults, especially in GMFCS III. Limitations No subtypes other than adults with CP and spastic diplegia were included. Conclusions Lower extremity strength profiles demonstrate substantial muscle weakness in ambulatory adults with CP compared to TD adults, which highlights the importance to address muscle weakness in this population group. These strength profiles may serve as norm values for clinicians and researchers. In addition, HHD showed to be reliable to assess lower extremity strength in adults with CP.