The feasibility of a subgroup approach to create sensory-motor behavioral response profiles from a modified quantitative sensory test in cerebral palsy

Cerebral palsy is the most common motor disorder of childhood, leading to lifelong disability and associated comorbidities, including a high incidence of chronic pain. This hypothesis-generating study aimed to (1) investigate a modeling approach to subgrouping based on behavioral reactivity (BR) to a modified quantitative sensory test (mQST), and (2) explore potential relations between BR subgroups, pain status, and clinical features. For this cross-sectional study, recruitment was conducted through a systematic proportional stratified sampling approach in relation to cerebral palsy type (eg, spastic, mixed type). Caregivers completed the Dalhousie Pain Interview; health history was collected from the medical record. The mQST included 6 tactile stimuli applied to the back of the right and left calves (eg, light touch, pressure, heat), and the BR associated with each application was scored using a modified Face Legs, Activity, Cry, Consolability scale. Of the 188 participants enrolled, 12 (6.4%) did not tolerate the full mQST. Latent class analysis was conducted with 172 participants, and the model with 6 classes had the best fit, with no classes having fewer than 5% of the sample. The 6-class solution revealed subgroups with relatively flat to relatively reactive patterns specific to different stimulus application modalities, providing sufficient evidence that reactivity subgroups can be reliably modeled. Descriptively, there were no apparent differences in the BR profile by sex; however, potentially by age and pain experience. Our results in this study indicate that sensory response profiles may be a promising approach to better understand the nature of chronic pain in cerebral palsy.