How much trunk control is affected in adults with moderate-to-severe cerebral palsy?

Trunk control (TC) impairment is a typical feature in individuals with cerebral palsy (CP), but there are lack of methods that allow to quantify the extent to which static and dynamic TC is impaired in adults with moderate-to-severe CP. Thus, the aims of this study were to analyze the reliability of a posturography protocol to assess TC in adults with CP, and quantify their degree of TC impairment compared to a control sample of adults without CP. Forty-seven adults with moderate-to-severe CP and nineteen control participants were assessed via a protocol of static and dynamic seated trunk tasks, performed on a stable and an unstable surface placed on a force-plate. The mean radial error was the primary variable measured. A large percentage of CP participants successfully completed the static and dynamic conditions on the stable surface (static: 93.6%; dynamic: 91.5-72.3%); however, this percentage decreased considerably on the unstable surface (51.1-34.0%). The posturography protocol displayed good reliability in adults with CP (0.89 ≤ ICC ≤ 0.95; 15.2% ≤ SEM ≤ 20.7%). Adults with CP displayed significantly decreased TC in 4/5 tasks on the stable seat, particularly in dynamic conditions (1.71 ≤ d_g ≤ 1.91). Our results confirmed that TC is significantly affected in CP adults compared with controls without CP of similar age, but they present more difficulties to perform dynamic tasks. Thus, it would be recommend including dynamic in addition to static conditions to obtain a comprehensive assessment of TC impairment in adults with moderate-to-severe CP. Additional, these results encourage practitioners to design dynamic activities that challenge trunk control for rehabilitations/training programs.