Snake: the development and validation of a questionnaire on sleep disturbances in children with severe psychomotor impairment.

Objective: Sleep disturbance and daytime restlessness are present in 50% to 80% of children with severe psychomotor impairment due to neurologic or other complex diseases. Although these issues severely impair the quality of life of the children and their families, they are not well addressed or managed by professionals. The lack of validated assessment tools prevents further research and the development of adequate therapies. Our aim is to develop and validate a sleep questionnaire for these children that could be used both for clinical management and systematic research.

Methods: The sleep questionnaire for children with severe psychomotor impairment (Schlaffragebogen für Kinder mit Neurologischen und Anderen Komplexen Erkrankungen, SNAKE) is based on expert opinion and consultation with parents. The psychometric quality of the questionnaire was assessed in a sample of 224 children with severe psychomotor impairment.

Results: Confirmative factor analysis showed that SNAKE comprises of five factors (based on ICSD-2). Fit indices, analysis of item characteristics and convergent validity (coherence with measures of sleep [i.e., sleep efficiency]) and correlation with selected subscales of the Sleep Disturbance Scale for Children (SDSC) were good. Re-test analysis (n=62) depicted high stability and good replication of validity.

Conclusions: SNAKE is a reliable and valid tool for the diagnosis of sleep disturbances in children with severe psychomotor impairment. The SNAKE questionnaire is the first tool that addresses the specific relationship between sleep disturbance and severe disability in children.