Psychometric properties of the Infantile Neuroaxonal Dystrophy Rating Scale

Area of Science:

• Neurology
• Pediatric Neurology
• Clinical Assessment Tools

Background:

• Infantile Neuroaxonal Dystrophy (INAD) is a rare, progressive neurodegenerative disorder affecting young children.
• Standardized outcome measures are crucial for evaluating disease progression and treatment efficacy in INAD.

Purpose of the Study:

• To evaluate the psychometric properties of the Infantile Neuroaxonal Dystrophy Rating Scale (INAD-RS).
• To determine the reliability and validity of the INAD-RS for assessing patients with INAD.

Main Methods:

• Retrospective analysis of interim data from the INAD Natural History Study.
• Involved clinician ratings of 39 patients with INAD.
• Assessed internal consistency, test-retest reliability, known-group validity, and longitudinal changes.

Main Results:

• The INAD-RS demonstrated good internal consistency, convergent validity, and test-retest reliability for gross motor, fine motor, bulbar, ocular, and temporo-frontal functions.
• The autonomic nervous system domain showed weaker contribution.
• Preliminary evidence indicated the scale could differentiate clinical phenotypes and detect changes over time.

Conclusions:

• The INAD-RS exhibits construct validity and reliability across five of six domains, excluding autonomic nervous system function.
• The scale is a promising tool for INAD research and clinical practice.
• Further validation is required to support its use in clinical trials and practice for disease progression assessment.