DEVELOPMENTAL MEDICINE & CHILD NEUROLOGY

COMMENTARY

Trunk control in children with cerebral palsy: where are we now? KAAT DESLOOVERE

| LIEVE HEYRMAN

Department of Rehabilitation Sciences, KU Leuven, Leuven, Belgium.

doi: 10.1111/dmcn.12650 This commentary is on the original article by Curtis et al. To view this paper visit http:/dx.doi.org/10.1111/dmcn.12641.

Children with cerebral palsy (CP) often have impaired trunk control, which plays a crucial role in the achievement of functional abilities such as sitting and walking. Despite its major impact on function, assessment still remains a rarely studied topic. To improve our understanding of abnormal trunk control and to develop optimal treatment interventions, there is a need for standardized measurement tools that provide a more comprehensive trunk assessment. The paper by Curtis et al.1 addresses an important addition to this research field by studying trunk control in a substantial number of children with CP. The authors especially draw our attention to the importance of the decomposition of the trunk by promoting the assessment at separate trunk levels, thereby identifying the regions of interest which may support therapeutic goal-setting. In their study, Curtis et al. defined specific trunk control mechanisms which underlie the participants’ sitting abilities. This is in line with recent research on assessment of trunk motion during gait and its relation to underlying trunk deficits defined during sitting, highlighting that trunk pathology at least partially reflects a true underlying trunk deficit. The compensatory role of trunk movements with respect to lower limb impairments may be quite limited.2 One of the advantages of the segmental assessment of trunk control (SATCo) applied by Curtis et al. is that it allows trunk evaluation in children who have not (yet) achieved independent sitting. It may therefore be not surprising that the scientific reports on the use of the SATCo have so far mainly focused on more severely disabled children. Also in the current study by Curtis et al., the majority of the children were classified as Gross Motor Function Classification System level IV and V (representing 58% of the study group). The severity of the involvement was

further confirmed by the low-averaged Gross Motor Function Measure (GMFM) score of 40.6. While aspects of reliability and validity of the SATCo have previously been established,3 the psychometric properties of this clinical trunk scale may still need further exploration in children with a higher functional level, and caution is thus warranted to generalize the conclusions by Curtis et al. to the full population of children with CP. The authors related the SATCo to the total GMFM-66 score. However, Russell et al. reported that the GMFM-66 may be less descriptive for children functioning at low ability levels compared to the 88-item version of the GMFM.4 In future research, especially in more severely disabled children, it would be interesting to explore whether scores on the GMFM-88 show stronger relations to trunk control. Curtis et al. highlight a clinically relevant relationship between control of individual trunk segments during sitting and global control as well as functional mobility. However, one cannot assume that this necessarily reflects what happens during functional movements, such as walking. While the development of adequate trunk control is found to play a fundamental role in the acquisition of gait5 and the head and trunk were identified as the main contributors to decreased gait efficiency in children with CP,6 only a few studies have addressed trunk motion during gait so far.2 Curtis et al., illustrate the importance of separate assessment of the static, active, and reactive balance at different segmental trunk levels to allow individualized interventions. However, intervention studies targeting impaired trunk control in children with CP are still limited. Further research is required to increase the scientific evidence for implementation of recent findings into therapeutic interventions targeting impaired trunk control. In conclusion, the study by Curtis et al. provides an important contribution to the existing literature on the assessment of trunk control. Recent trunk studies herald the onset of a new, innovative research area in children with CP, which is still largely unexplored despite its clinical relevance. Therefore, further investigation of impaired trunk control is essential to enlarge the understanding of trunk impairments in these children and to provide substantial foundation for well-targeted treatment planning.

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2 Developmental Medicine & Child Neurology 2014