Anna-Karin Kroksmark

A randomized comparative study of two methods for controlling Tendo Achilles contracture in Duchenne muscular dystrophy.

A 30-month prospective randomized study of 27 Scandinavian boys with confirmed diagnosis of Duchenne muscular dystrophy was done to compare the effect of passive stretching combined with the use of night splints (group A) or passive stretching (group B) on the evolution of Tendo Achilles contractures. Assessments were based on the methodology of Scott et al. (Muscle Nerve 1982;5:291-301)Analysis of the pattern and mechanism of dropout was done to eliminate bias between the two groups. Logistic regression showed that Tendo Achilles contracture was the most important variable (P=0.0020) for dropout. Methods of statistical analysis for longitudinal data avoiding induced serial correlations were used in the analysis. The expected annual change in Tendo Achilles contracture was found to be 23% less in group A than in group B after equalization for total muscle strength (%MRC).

A mutation in the fast skeletal muscle troponin I gene causes myopathy and distal arthrogryposis

Objective: To describe a three-generation family with distal arthrogryposis associated with myopathy and caused by a mutation in the gene encoding for sarcomeric thin filament protein troponin I, TNNI2. Methods: The authors performed clinical investigations and reviewed medical records. Muscle biopsy specimens were obtained for morphologic analysis. Genomic DNA was extracted from blood and analyzed for mutations in TNNI2. Results: The five affected individuals had predominantly distal congenital joint contractures, mild facial involvement (mild micrognathia, narrow palpebral fissures), and no detectable muscle weakness. The four affected adults had slightly increased levels of creatine kinase in blood, and muscle biopsy specimens showed findings of myopathy with changes restricted to type 2 fibers. These included variability of muscle fiber size, internalized nuclei, and increased interstitial connective tissue. Analysis of TNNI2 encoding the troponin I isoform expressed in type 2 muscle fibers disclosed a heterozygous three-base in-frame deletion, 2,918–2,920del, skipping the highly conserved lysine at position 176. The mutation was present in all 5 affected individuals but was not identified in any of the 11 unaffected family members. Conclusion: Distal arthrogryposis type 1 is genetically heterogeneous, and myopathy due to sarcomeric protein dysfunction may be one underlying cause of the disease.

A population-based study of genotypic and phenotypic variability in children with spinal muscular atrophy

Aims: To describe the occurrence of spinal muscular atrophy (SMA) in childhood; to evaluate if any of the genes in the SMA region on chromosome 5q13 correlates with disease severity; to make genotype–phenotype correlations; to evaluate the variability of different disease alleles in carriers and the sensitivity of multiplex ligation‐dependent probe amplification (MLPA) for detecting carriers.

Longitudinal data analysis: an application to construction of a natural history profile of Duchenne muscular dystrophy.

A 30-month prospective study of 27 Scandinavian boys with confirmed diagnosis of Duchenne muscular dystrophy was carried out to construct profiles of the natural history of the disease. Assessments which included measures of voluntary muscle strength and function were done at 3 monthly intervals except for the first and second which were separated by 1 month. Recently developed statistical methods for analysis of longitudinal data with repeated observations on the same individual were used avoiding the problem of induced serial correlations. This allowed for the construction of both reference and prediction profiles for the variables %MRC, motor ability, walking time for 10 m and the sum of myometry of seven muscle groups.

Evaluation of hand orthoses in Duchenne muscular dystrophy

Abstract Purpose: The purpose of this study was to evaluate whether treatment of boys with Duchenne muscular dystrophy using hand orthoses could benefit joint mobility, grip strength, or fine motor function. Method: Eight boys with Duchenne muscular dystrophy were provided with individually customised rest orthoses. The results were analysed using single-subject design. The study included a baseline and an intervention phase. A follow-up examination was also performed. Results: Boys with less than 50° passive wrist extension mobility were included. Wrist extension of the dominant hand increased in four and was maintained in four. Wrist extension in the non-dominant hand increased in five, was maintained in two and decreased in one. Thumb abduction in the dominant hand increased in six and two remained stable. In the non-dominant hand five increased and three remained stable. Grip strength and fine motor function showed also positive results. Conclusions: This study indicates that the use of hand orthoses in Duchenne muscular dystrophy can delay development of contractures and improve passive wrist extension and thumb abduction. Hand orthoses can therefore be recommended for boys who start to develop contractures in the long finger flexors. Due to small sample size further studies are needed to confirm this result. Implications for rehabilitation Evaluation of hand orthoses in Duchenne muscular dystrophy. Preserved hand function is of uttermost importance for performance of activities in the late stages of Duchenne muscular dystrophy. Contractures of long finger flexors affect hand function and limit performance of daily activities. Hand orthoses can delay development of contractures and preserve hand function and give prerequisites for independence. The occupational therapists should measure wrist joint mobility regularly to be able to find the right time for intervention with hand orthoses in this progressive disorder.