The sleep disturbance scale for children (SDSC) construction and validation of an instrument to evaluate sleep disturbances in childhood and adolescence

To attempt a categorization of sleep disorders in children, we developed a 27 item Likert-type rating scale (Sleep Disturbance Scale for Children: SDSC) and assessed the psychometric properties was developed. The scale was distributed to the mothers of 1304 children (1157 controls, mean age 9.8 y; 147 sleep disorder subjects, mean age 9.2y, composed of four clinical groups: Insomnia 39 subjects, Hypersomnia 12 subjects, Respiratory disturbances during sleep 25 subjects and Parasomnias 71 subjects). The internal consistency was high in controls (0.79) and remained at a satisfactory level in sleep disorder subjects (0.71); the test/retest reliability was adequate for the total (r=0.71) and single item scores. The factor analysis (variance explained 44.21%) yielded six factors which represented the most common areas of sleep disorders in childhood and adolescence. Enuresis was the only item with a factor loading lower than 0.40 and with a low inter-item correlation and was therefore eliminated, resulting in a final scale of 26 items. The re-evaluation of the sample, using the factor scores, supported the validity and the discriminating capacity of the scales between controls and the four clinical groups. The correlation between factor scores corroborated the hypothesis that childhood sleep disturbances are not independent entities nor do they cluster into different groupings related to each other. The SDSC appears to be a useful tool in evaluating the sleep disturbances of school-age children in clinical and non-clinical populations.