New definitions of 6 clinical signs of perceptual disorder in children with cerebral palsy: an observational study through reliability measures

BACKGROUND: Recently authors have begun to emphasize the non-motor aspects of Cerebral Palsy and their influence on motor control and recovery prognosis. Much has been written about single clinical signs (i.e., startle reaction) but so far no definitions of the six perceptual signs presented in this study have appeared in literature. AIM: This study defines 6 signs (startle reaction, upper limbs in startle position, frequent eye blinking, posture freezing, averted eye gaze, grimacing) suggestive of perceptual disorders in children with cerebral palsy and measures agreement on sign recognition among independent observers and consistency of opinions over time. DESIGN: Observational study with both cross-sectional and prospective components. SETTING: Fifty-six videos presented to observers in random order. Videos were taken from 19 children with a bilateral form of cerebral palsy referred to the Children Rehabilitation Unit in Reggio Emilia. PARTICIPANTS: Thirty-five rehabilitation professionals from all over Italy: 9 doctors and 26 physiotherapists. METHODS: Measure of agreement among 35 independent observers was compiled from a sample of 56 videos. Interobserver reliability was determined using the K index of Fleiss and reliability intra-observer was calculated by the Spearman correlation index between ranks (rho - ρ). Percentage of agreement between observers and Gold Standard was used as criterion validity. RESULTS: Interobserver reliability was moderate for startle reaction, upper limb in startle position, adverted eye gaze and eye-blinking and fair for posture freezing and grimacing. Intraobserver reliability remained consistent over time. Criterion validity revealed very high agreement between independent observer evaluation and gold standard. CONCLUSIONS: Semiotics of perceptual disorders can be used as a specific and sensitive instrument in order to identify a new class of patients within existing heterogeneous clinical types of bilateral cerebral palsy forms and could help clinicians in identifying functional prognosis. CLINICAL REHABILITATION IMPACT: To provide clinicians with a definition of 6 clinical signs found in children with cerebral palsy in routine rehabilitation settings. Future research should explore the link between these signs and motor prognosis (i.e., time to independent walking).