Sensory Function and Chronic Pain in Cerebral Palsy

点击翻译按钮获取中文摘要

Scientific advances from pain research in basic models and chronic pain populations are rarely translated and applied to improve our clinical understanding of pain and disability among individuals with significant intellectual, motor, and communicative impairments associated with neurodevelopmental disorders. Despite the well document burden of chronic pain in cerebral palsy (CP), the most common cause of pediatric-onset lifelong motor and developmental disability, there is relatively little known about sensory function in relation to chronic pain. The heterogeneity in CP etiology, pathophysiology, and clinical appearance suggests new approaches may be warranted to identify measureable phenotypic patient characteristics predictive of individual variation in chronic pain outcomes. Current pain assessment approaches used in CP are limited in their ability to subgroup CP patients in relation to sensory function that may be relevant for understanding pathophysiological pain mechanisms. Most of the sensory testing research conducted with CP, while important and not in question, has relied on sensory stimuli designed to assess impaired discriminative tactile abilities such as two-point discrimination, texture and shape perception reflecting large sensory fiber afferent function. There has been little work incorporating sensory testing approaches that simultaneously evaluate loss and gain of sensory function reflecting both large and small fiber afferent integrity. The specific purpose of this application is to address the limited scientific understanding of sensory function in CP to ultimately reduce the burden of chronic pain. As a first step to close the gap between the well documented pain burden in CP and the relatively unexplored pain mechanisms in CP we are proposing to investigate an objective standardized (protocol-based) measurement approach by extending the application of a modified quantitative sensory testing (QST) protocol to characterize and compare sensory function in children with CP with and without chronic pain. Our reasoning is as follows. First, comparing sensory function between chronic pain and no chronic pain groups has the potential to reveal differences in underlying tactile/nociceptive sensory function with high relevance for improving our understanding of chronic pain in CP and other severe IDD populations. Second, applying QST to a large sample of children and adolescents with CP will provide the basis for investigating sensory function in relation to individual and clinical characteristics, and health outcomes to identify novel tailoring variables that could guide pain treatment target selection (no such guidelines exist right now). Third, using a protocol-based approach affords an important standardized context in which to investigate nociceptive and inflammatory relevant biomarkers. Finally, the logic of QST provides the basis for exploratory but highly novel tests of sensory subtype constructs (gain, loss of function) informed by the chronic/neuropathic pain research literature as a first step toward creating sensory-function based grouping of chronic pain in CP.