Needs management in families affected by childhood-onset dystrophinopathies

Characterizing Enrollment in Observational Studies of Duchenne Muscular Dystrophy by Race and Ethnicity

Observational research benefits from inclusion of diverse cohorts. To characterize racial and ethnic diversity in observational and natural history research studies of Duchenne muscular dystrophy (DMD), highly cited and influential observational studies were identified. Fourteen United States-based articles were included. All studies cited >70% White participants with the majority having few racial minority participants. Enrollment of Black/African American individuals was particularly limited (<5% in all but one study), and Hispanic/Latino participants ranged from 3.3- 26.5% of cohorts. These results suggest a need for effective strategies to recruit, enroll, and retain racially and ethnically diverse populations into observational research in DMD.

The NIH Toolbox for cognitive surveillance in Duchenne muscular dystrophy

OBJECTIVE

We performed a prospective, cross-sectional cognitive assessment in subjects with Duchenne Muscular Dystrophy (DMD) and their biological mothers.

METHODS

Thirty subjects with out-of-frame mutations in the dystrophin (DMD) gene, and 25 biological mothers were evaluated using the National Institutes of Health Toolbox Cognition Battery (NIHTB-CB). A parent completed the Behavior Rating Inventory of Executive Functioning (BRIEF), a standardized rating scale of executive functioning, for their child. Mothers completed self-reports of BRIEF and Neuro Quality-of-Life (NeuroQoL) Cognitive Function.

RESULTS

Overall, the subjects with DMD scored approximately one standard deviation (SD) below age-corrected norms on the NIHTB-CB Total Cognition score. They scored 1.5 SD below age-corrected norms in Fluid Cognition, which evaluates the cognitive domains of executive function, working memory, episodic memory, attention, and processing speed. Their performance was consistent with age expectations (i.e., within 1 SD below age-corrected norms) in Crystalized Cognition, which evaluates vocabulary and reading. Subjects with DMD had higher T-scores in several domains of BRIEF, demonstrating greater difficulty in executive functioning. The biological mothers had overall average or above average T-scores on NIHTB-CB. Mothers who were carriers of DMD mutation performed lower overall compared to mothers who were not carriers of DMD mutation (Cohen's d = -1.1). Carrier mothers performed lower than average (1.5 SD) in Executive Function, measured by Flanker Inhibitory Control and Attention. Biological mothers scored within expected score ranges for adults in BRIEF and NeuroQoL.

INTERPRETATION

The NIHTB-CB, combined with standardized self-reported measures, can be a sensitive screening tool for cognitive surveillance in DMD.