Modification of a parent-report sleep scale for individuals with CDKL5 deficiency disorder: a psychometric study

Study objectives: Sleep difficulties are common in CDKL5 deficiency disorder, a developmental and epileptic encephalopathy. This study evaluated the factor structure of the Disorders of Initiating and Maintaining Sleep (DIMS), Disorders of Excessive Somnolence (DOES), and Sleep Breathing Disorders domains of the Sleep Disturbance Scale for Children for CDKL5 deficiency disorder.

Methods: A cross-sectional psychometric study design was used. Data were collected for 125 individuals aged 3 years or older who attended a United States Centers of Excellence clinic or registered with the International CDKL5 Disorder Database.

Results: The median age was 10.3 years (range 3.2-40.7 years) and 105 (84%) were female. Two of the 3 Sleep Breathing Disorders items were not observed by most respondents and analysis was restricted to the DIMS and DOES domains. Using all items in the initial confirmatory factor analysis, 2 items in the DIMS domain and 1 item in the DOES domain loaded poorly. After deleting these items and repeating the analysis, item loading (.524-.814) and internal consistency (DIMS: .78, DOES: .76) statistics were good. The square of the interdomain correlation coefficient was .17, less than average variance extracted values for both domains and indicating good discriminant validity. The Tucker-Lewis and Comparative Fit indices were slightly lower than the threshold of > .9 for establishing goodness of fit.

Conclusions: The modified DIMS and DOES domains from the Sleep Disturbance Scale for Children could be suitable clinical outcome assessments of insomnia and related impairments in CDKL5 deficiency disorder and potentially other developmental and epileptic encephalopathy conditions.

Citation: Saldaris JM, Demarest S, Jacoby P, et al. Modification of a parent-report sleep scale for individuals with CDKL5 deficiency disorder: a psychometric study. J Clin Sleep Med. 2024;20 (12):1887-1893.