Neurobehavioral Profiles in Young Steroid-Naive Boys With Duchenne Muscular Dystrophy: A Baseline Data Analysis From the FOR-DMD Trial.

BACKGROUND AND

OBJECTIVES

Duchenne muscular dystrophy (DMD) is the most common pediatric hereditary neuromuscular disorder. While interest in brain involvement in DMD is increasing, neurobehavioral data in steroid-naive children remain limited, often nonstandardized, and derived from small cohorts. The primary objective was to characterize the baseline neurobehavioral profile of young steroid-naive boys with DMD enrolled in a multinational clinical trial. Secondary objectives were to examine associations with developmental features (speech and learning difficulties), motor function, parent respondent type, brain dystrophin isoform, age, and country.

METHODS

We performed a baseline cross-sectional neurobehavioral analysis of steroid-naive boys recruited in the "Finding the Optimum Regimen for Duchenne Muscular Dystrophy" trial. Eligible participants were glucocorticoid-naive boys aged 4 to <8 years with genetically confirmed DMD; boys with severe behavioral problems affecting participation were excluded. Four parent-reported scales were analyzed: Strengths and Difficulties Questionnaire (SDQ), Personal Adjustment and Role Skills Scale (PARS-III), IOWA Conners-Parent Scale, and Revised Rutter Scale. Associations with age, respondent (i.e., the parent who completed the questionnaire), brain dystrophin isoforms, speech-learning difficulties, country, and motor function were explored.

RESULTS

The cohort included 196 boys aged 4 to <8 years (mean 5.9 ± 1.0). Speech and learning difficulties were reported in approximately 40% and 25% of participants, respectively, with 20% presenting both. Scores across neurobehavioral scales were strongly correlated, with only 5%-10% of boys exceeding screening cutoffs. Speech and learning difficulties were associated with worse scores across all scales. Among boys with an above-threshold SDQ Impact score, the most frequently reported difficulty was classroom learning. No significant associations were observed with age, brain dystrophin isoforms, or country of origin. Weak correlations were identified between motor function and PARS-III scales, in particular between North Star Ambulatory Assessment total score and PARS-III Total, Peer Relations, and Productivity scores. Mothers more frequently reported inattentive-overactive behaviors than fathers.

DISCUSSION: Although this was a selected cohort, young boys with DMD may experience social, emotional, and learning difficulties that can interfere with everyday life, including schoolwork, despite the absence of a formal neurobehavioral diagnosis. These findings stress the importance of routine early psychosocial screening and targeted interventions.

TRIAL REGISTRATION INFORMATION: ClinicalTrials.gov: NCT01603407. First submitted: April 3, 2012. First participant enrolled: January 30, 2013. clinicaltrials.gov/study/NCT01603407.