Salivary alpha amylase and cortisol levels as stress biomarkers in children with cerebral palsy and their association with a physical therapy program

Introduction: Cerebral palsy (CP) is one of the main causes of physical disabilities in childhood. There is evidence that CP children display high levels of stress, which could interfere with learning processes and interpretation of relevant sensory information during motor skills acquisition and socialization.Objective: This study aims to compare basal levels of stress biomarkers (cortisol and alphaamylase) of healthy children (HC) and children with CP, and to investigate whether a physical therapy session using the neurodevelopmental technique (NDT) interferes with these levels.Methods: A cross-sectional design was used. A total of 86 children (HC: n = 45 and CP: n = 41) with matching age, sex, socioeconomic status, and sampling time. Salivary cortisol and alphaamylase levels were measured by means of electrochemiluminescence and spectrophotometry methods. A single saliva sample was collected in the HC group to determine basal levels. For CP group three samples were collected: a first sample was taken 20-30 min prior to the intervention, while two post-intervention samples were collected (5 and 20 min) to evaluate individual changes in salivary stress biomarkers.Results: Higher basal cortisol concentration was found in CP children when compared to HC group. Moreover, CP children showed a significant reduction in cortisol levels 20 min after NDT intervention. No significant differences were observed in alpha-amylase values.Conclusion: Present results show that CP causes alteration in basal cortisol values at childhood and suggest that CP children respond to environmental regulatory factors such as NDT, in attempt to reduce stress.