Executive Skills and Academic Achievement in the Dystrophinopathies

Neurocognitive functioning among children and young people with Duchenne Muscular Dystrophy: A systematic review and meta-analysis

Objective: The neurocognitive aspects of DMD have received less attention than the physiological sequalae. This study conducted a systematic review and meta-analysis of available literature on the neurocognitive profile of children and young people with DMD. Method: Five databases (EMBASE, Medline, PsycInfo, Scopus and Web of Science) and the grey literature was searched on 27th January 2023. Eligible articles were available in English and reported neurocognitive outcomes. Neurocognitive domains reported in a comparable way across a minimum of three studies were included. The neurocognitive domains of Full-Scale IQ (FSIQ), Verbal IQ (VIQ), Performance IQ (PIQ) and Working memory (WMI) derived from Wechsler scales and receptive vocabulary ability derived from the Peabody Picture Verbal Test (PPVT) were included. A single mean meta-analysis was completed. Results: Relevant data was extracted and presented for 38 eligible studies; 2 of which are from grey literature. Results suggest children with DMD perform around 1SD below non-clinical norms for FSIQ, PIQ, VIQ and WMI. Unlike VIQ, scores derived from the PPVT were within the non-clinical norms. Studies were of moderate - high quality, there was significant heterogeneity and no publication bias. Conclusion: A systematic review of working memory has not previously been completed, it appears that children with DMD perform around 1SD below the mean, like FSIQ, PIQVIQ and WMI. The PPVT is a measure of receptive verbal ability and caution is recommended around the interchangeability of PPVT scores and the wider construct of verbal intelligence.

The Hidden Disease: Delayed Diagnosis in Duchenne Muscular Dystrophy and Co-Occurring Conditions

OBJECTIVE

Early diagnosis of Duchenne muscular dystrophy (DMD) is important for timely intervention to prolong function and preserve quality of life. The prevalence of various neurocognitive disorders is known to be higher in patients with DMD than the general population. In this study, we highlight cases of delayed DMD diagnosis that resulted from misattribution of early motor symptoms to co-occurring neurocognitive conditions. We also investigate the difference in age at DMD diagnosis in the setting of specific co-occurring neurocognitive conditions.

METHOD

In this study, we reviewed 40 consecutive patients seen at a Certified Duchenne Care Center, excluding siblings of already-diagnosed patients. We highlight cases of significant delay in DMD diagnosis in the setting of co-occurring neurocognitive diagnoses. We also investigate the association of autism spectrum disorder (ASD), attention-deficit/hyperactivity disorder (ADHD), intellectual disability, and speech/language delay on age of DMD diagnosis.

RESULTS

The prevalence of co-occurring neurocognitive diagnoses was 73.1% in patients diagnosed at or after age 5 years vs. 35.7% in those diagnosed before age 5 years. The average age of DMD diagnosis was 6.6 years in patients with any co-occurring neurocognitive diagnoses and 4.9 years in patients without ( p = 0.09). Individual analysis of ASD and ADHD showed significant differences. A greater number of co-occurring conditions were associated with an increased age at DMD diagnosis ( R2 = 0.87, p < 0.001).

CONCLUSION

The data suggest an association between the presence of co-occurring neurocognitive conditions and a later age of DMD diagnosis. One cost-effective diagnostic step that can be implemented by all pediatric practitioners is testing serum creatinine kinase (CK) in any child with motor delays or hypotonia, even in the context of other behavioral or cognitive disabilities.

Health-Related Quality of Life and Emotional Distress Among Mothers of Sons With Muscular Dystrophy as Compared to Sex- and Age Group-Matched Controls

The health-related quality of life and emotional distress among mothers of sons with Duchenne or Becker muscular dystrophies (n = 82) were compared to sex- and age group-matched controls (n = 26). Participants self-reported health-related quality of life for themselves and their son(s), emotional distress, and mood/anxiety-related medication. Mothers reported poorer health-related quality of life across all domains of their health-related quality of life, as well as higher levels of emotional distress. Clinically elevated symptoms of anxiety were reported by 39% of mothers. Mothers' report of poorer health-related quality of life for their son(s) was a significant predictor of worse health-related quality of life and emotional distress for themselves across most domains. Additionally, older age of mothers predicted greater energy/less fatigue and lower levels of anxiety. Results highlight the need for screening emotional distress among mothers, as well as consideration for accessible interventions to improve the psychosocial functioning among these families.