Investigation of Poor Academic Achievement in Children with Duchenne Muscular Dystrophy

Abstract

Duchenne Muscular Dystrophy (DMD) is a neurogenetic developmental disorder that presents with progressive muscular weakness. It is caused by a mutation in a gene that results in the absence of specific products that normally localize to muscle cells and the central nervous system (CNS). The majority of affected individuals have IQs within the normal range, generally with lower verbal than performance IQ scores. Prior work has demonstrated selective deficits on tests of verbal span and immediate memory. For the current study, 26 boys with DMD (and normal intellectual function) and their unaffected siblings were evaluated. Paired comparisons demonstrated that the children with DMD had significantly poorer academic achievement scores than their siblings, even though their vocabulary levels and home and educational environments were comparable. Children with DMD also had more behavioral concerns, physical disabilities, and poorer verbal memory spans. Linear regression indicated that behavioral concerns, executive function, and physical disability did not contribute substantially to academic performance, whereas performance on verbal span did. DMD presents with a selective developmental aberration in verbal span that has wide-ranging consequences on learning skills.Duchenne Muscular Dystrophy (DMD) is a neurogenetic developmental disability. DMD is known mainly as a genetic disease of muscle, although it also has developmental consequences on the central nervous system. DMD is caused by a mutation of a gene on the X chromosome (Koenig et al., 1987). It occurs in about 1/3,200 boys and results in progressive muscular weakness. DMD is the most common fatal childhood inherited disorder, and affected individuals rarely live past their late -20s. NIH-PA Author ManuscriptNIH-PA Author Manuscript NIH-PA Author ManuscriptEver since its original characterization by Duchenne (1872), boys with DMD have been known to be at increased risk of mental retardation, although the majority of boys with DMD are not mentally retarded. Whether impaired cognitive function in individuals with DMD resulted from the stresses of living with a chronic, progressive, physically disabling disorder or from the underlying etiology affecting the development of the nervous system was uncertain. Yet, well before discovery of the gene that causes the disorder, decreased academic achievement scores were documented, prompting investigators to write that "an investigation of intelligence and academic achievement should be a routine part" of care for all children with DMD (Worden & Vignos, 1962).The discovery that the mutated gene in DMD codes for multiple protein products that localize to separate tissue types, including muscle and brain, offers a potential explanation for the cognitive manifestation of the DMD phenotype (for reviews see J. L. Anderson, Head, Rae, & Morley, 2002;Mehler, 2000). In the brain, dystrophin isoforms normally localize to circumscribed cerebral and cerebellar cortical regions and are absent in autopsied brains of individu...

Diffusion tensor imaging study in Duchenne muscular dystrophy

“…The core cognitive deficit in DMD is "limited verbal span" (6). Some researchers have noted that children with DMD have greater difficulty on tests requiring attention to and repetition of verbal material (6)(7)(8)(9)(10). This finding remains consistent regardless of whether children with DMD are compared to normal controls, their siblings, or children with other degenerative muscle diseases.…”

“…This study recruited 12 patients [age 9.14±2.52 years (range, 6-13)] with a diagnosis of DMD (confirmed by genetic testing or muscle biopsy) from the DMD Multidisciplinary Outpatient Clinic of CAPF General Hospital, and 14 healthy volunteers [age 9.39±2.99 years (range, [6][7][8][9][10][11][12][13][14]]. Those who had a medical or surgical history of potential impact on neurocognitive functioning (e.g., head injury), were not contactable, or whose parents refused to consent were excluded.…”

“…The average IQ of a boy with DMD is 85, and consequently 30% of boys with DMD have an IQ of <70. The core cognitive deficit in DMD is "limited verbal span" (6). Some researchers have noted that children with DMD have greater difficulty on tests requiring attention to and repetition of verbal material (6)(7)(8)(9)(10).…”

Cognitive and adaptive deficits in young children with Duchenne muscular dystrophy (DMD)

“…We have further hypothesized that limited verbal span may be the core deficit in DMD. As deficits in verbal span have been linked to impairments in the acquisition of phonological knowledge and single-word vocabulary (Adams & Gathercole, 2000;Gathercole et al, 1997), this core deficit may also help to explain impairments seen in phonological awareness, reading, and writing found in children with DMD (Billard et al, 1992;Dorman et al, 1988;Hendriksen & Vles, 2006;Hinton et al, 2001Hinton et al, , 2004Leibowitz & Dubowitz, 1981;Worden & Vignos, 1962).…”

“There are not enough hours in a day to do everything”: Parents’ descriptions of everyday life with a child with severe physical disability

“…Many of them need wheelchairs to move around (Moat et al, 2013;Nereo & Hinton, 2003). In addition to orthopedic challenges (Miller & Bachrach, 2006), physical disabilities may involve additional problems that may occur, for example, as difficulties in linguistic skills (Hinton et al, 2004), movement control (Pirilä et al, 2011), sleeping (Mol et al, 2012), and oral-motor functioning (Bell et al, 2010).…”