Validity Data for the Developmental Profile-4 in Individuals With Profound Intellectual and Multiple Disabilities and Developmental Epileptic Encephalopathies.

Valid neurodevelopmental assessments for individuals with profound intellectual and multiple disabilities (PIMD) and/or developmental and epileptic encephalopathy (DEE) are critical for clinical trials and clinical care as families report functional abilities are a priority for improvement. However, most extant tools have limited ability to measure relevant skills and meaningful change for individuals with severe to profound impairment. We evaluated the psychometric properties of the Developmental Profile, Fourth Edition (DP-4), a measure of neurodevelopmental functioning, in individuals with DEE and/or PIMD (Mdn = 8.4 years, range 1-50, 54% female). Two hundred and nineteen caregivers completed the DP-4 during a larger online survey, DEE Parents Speak. In this etiologically diverse sample, neurodevelopmental functioning was very low, with norm-referenced scores at the floor for greater than 50% of individuals on all subscales (age equivalencies 6-10 months). Rasch analysis of DP-4 scores, comparison by known groups, and comparison with other measures of functional abilities suggest initial evidence of construct and convergent validity. During focus groups and interviews, caregivers reported DP-4 components that were relevant for their child and threats to content validity. The DP-4 may be a valid measure of neurodevelopment for individuals with PIMD and/or DEE in clinical care and trials, although additional study is necessary, especially to evaluate responsiveness to change.