Axial muscle involvement in patients with limb girdle muscular dystrophy type R9.

INTRODUCTION/AIMS: Limb girdle muscular dystrophy type R9 (LGMDR9) is characterized by progressive weakness of the shoulder and hip girdles. Involvement of proximal extremity muscles is well-described whereas information about axial muscle involvement is lacking. It is important to recognize the involvement of axial muscles to understand functional challenges for the patients. The aim of this study was to investigate the involvement of axial and leg muscles in patients with LGMDR9. METHODS: This observational, cross-sectional study investigated fat replacement of axial and leg muscles in 14 patients with LGMDR9 and 13 matched, healthy controls using quantitative MRI (Dixon technique). We investigated paraspinal muscles at three levels, psoas major at the lumbar level, and leg muscles in the thigh and calf. Trunk strength was assessed with stationary dynamometry and manual muscle tests. RESULTS: Patients with LGMDR9 had significantly increased fat replacement of all investigated axial muscles compared with healthy controls (P < .05). Trunk extension and flexion strength were significantly reduced in patients. Extension strength correlated negatively with mean fat fraction of paraspinal muscles. Fat fractions of all investigated leg muscles were significantly increased versus controls, with the posterior thigh muscles being the most severely affected. DISCUSSION: Patients with LGMDR9 have severe involvement of their axial muscles and correspondingly have reduced trunk extension and flexion strength. Our findings define the axial muscles as some of the most severely involved muscle groups in LGMDR9, which should be considered in the clinical management of the disorder and monitoring of disease progression.

Patients With Becker Muscular Dystrophy Have Severe Paraspinal Muscle Involvement.

Introduction: Paraspinal muscles are important for gross motor functions. Impairment of these muscles can lead to poor postural control and ambulation difficulty. Little knowledge exists about the involvement of paraspinal muscles in Becker muscular dystrophy. Objective: In this cross-sectional study, we investigated the involvement of paraspinal muscles with quantitative trunk strength measure and quantitative muscle MRI. Methods and Materials: Eighteen patients with Becker muscular dystrophy underwent trunk, hip, and thigh strength assessment using a Biodex dynamometer and an MRI Dixon scan. Fourteen age- and body mass index-matched healthy men were included for comparison. Results: Muscle fat fraction (FF) of the paraspinal muscles (multifidus and erector spinae) was higher in participants with Becker muscular dystrophy vs. healthy controls at all three examined spinal levels (C6, Th12, and L4/L5) (p < 0.05). There was a strong and inverse correlation between paraspinal muscle FF and trunk extension strength (ρ = -0.829, p < 0.001), gluteus maximus FF and hip extension strength (ρ = -0.701, p = 0.005), FF of the knee extensor muscles (quadriceps and sartorius) and knee extension strength (ρ = -0.842, p < 0.001), and FF of the knee flexor muscles (hamstring muscles) and knee flexion strength (ρ = -0.864, p < 0.001). Fat fraction of the paraspinal muscles also correlated with muscle FF of the thigh muscles and lower leg muscles. Conclusion: In conclusion, patients with Becker muscular dystrophy demonstrate severe paraspinal muscular involvement indicated by low back extension strength and high levels of fat replacement, which parallel involvement of lower limb muscles. Assessment of paraspinal muscle strength and fat replacement may serve as a possible biomarker for both the clinical management and further study of the disease.

Muscle involvement assessed by quantitative magnetic resonance imaging in patients with anoctamin 5 deficiency.

OBJECTIVE: Using magnetic resonance imaging (MRI) and stationary dynamometry, the aim was to investigate the muscle affection in paraspinal muscles and lower extremities and compare the muscle affection in men and women with anoctamin 5 (ANO5) deficiency. METHODS: Seventeen patients (seven women) with pathogenic ANO5-mutations were included. Quantitative muscle fat fraction of back and leg muscles were assessed by Dixon MRI. Muscle strength was assessed by stationary dynamometer. Results were compared with 11 matched, healthy controls. RESULTS: Muscle involvement pattern in men with ANO5-deficiency is characterized by a severe fat replacement of hamstrings, adductor and gastrocnemius muscles, while paraspinal muscles are only mildly affected, while preserved gracilis and sartorius muscles were hypertrophied. Women with ANO5-myopathy, of the same age as male patients, were very mildly affected, showing muscle affection and strength resembling that found in healthy persons, with the exception of the gluteus minimus and medius and gastrocnemii muscles that were significantly replaced by fat. Although individual muscles showed clear asymmetric involvement in a few muscle groups, the overall muscle involvement was symmetric. CONCLUSIONS: Patients with ANO5-deficiency have relatively preserved paraspinal muscles on imaging and only mild reduction of trunk extension strength in men only. Our study quantifies the large difference in muscle affection in lower extremity between women and men with ANO5-deficiency. The clinical notion is that affection may be very asymmetric in ANO5-deficiency, but the present study shows that while this may be true for a few muscles, the general impression is that muscle affection is very symmetric.

Quantitative Muscle MRI as Outcome Measure in Patients With Becker Muscular Dystrophy-A 1-Year Follow-Up Study.

Introduction: With the advent of emerging molecular therapies for muscular dystrophies, the need for knowledge about natural history course of such diseases is of utmost importance in the preparation for future trials. However, for Becker muscular dystrophy such knowledge is scarce. Objective: In this 1-year follow-up study, we examined disease progression in Becker muscular dystrophy by monitoring changes in MRI-assessed muscle fat fraction (FF) in axial and lower limb muscles and quantitative muscle strength of axial muscles. Methods and Materials: Sixteen patients with Becker muscular dystrophy were investigated by (1) muscle strength of the trunk using a Biodex dynamometer and (2) Dixon muscle MRI of paraspinal and lower limb muscles. Quantitative MRI data was analyzed in two parts: The first part consisted of all participants (N = 16). The second analysis assessed two separate groups comprising lesser affected participants (N = 5) and more severely affected patients (n = 11). Results: Trunk extension and flexion strength remained stable from baseline to follow-up. MRI did not show any significant increase in muscle FF % from baseline to follow-up in all patients, except for multifidus at the spinal level T12 (p = 0.01). However, when we analyzed the two subgroups, according to disease severity, FF% increased in the lesser severely affected group at L4/L5 erector spinae (p = 0.047), sartorius (p = 0.028), gracilis (p = 0.009), tibialis anterior (p = 0.047), peroneals (p = 0.028), and gastrocnemius medialis (p = 0.009), while the severely affected group only increased significantly at T12 multifidus (p = 0.028) and T12 erector spinae (p = 0.011). No difference in muscle strength was observed in the two subgroups. Conclusion: Our results add to the existing knowledge about the natural rate of disease progression in BMD. As quantitative MRI was able to identify changes where strength assessment was not, MRI could be a strong biomarker for change in BMD. However, our findings show that it is important to stratify patients with BMD according to phenotype for future clinical trials.

Does progressive resistance strength training as additional training have any measured effect on functional outcomes in older hospitalized patients? A single-blinded randomized controlled trial.

OBJECTIVE: To evaluate the effect of progressive resistance strength training as additional training measured on functional outcomes in older hospitalized patients. DESIGN: A single-blinded randomized controlled trial. SETTING: Department of Geriatric Rehabilitation in university hospital. PARTICIPANTS: A sample of 71 patients were successively included and randomized either to the treatment group (TG) (n = 36) or the control group (CG) (n = 35). Fifteen participants dropped out (TG n = 7; CG n = 8), leaving 56 participants with a mean age of 79 (SD 7). INTERVENTION: Participants in the treatment group were treated in groups with progressive resistance strength training in addition to standard care. Progressive resistance strength training of the lower extremities was performed in three sets of 12-15 repetitions, intensity 60-70% of one repetition maximum, in four 50-minute sessions per week. MAIN MEASURES: The effect was evaluated by timed up & go test, 30-second chair-stand test, 10-m walk test, three tasks (transfer, walking, stairs) of the Barthel Index, and use of walking aids. RESULTS: Significant improvements in the 10-m walk test (P < 0.01) and Barthel Index (walking) (P = 0.01) were demonstrated within the treatment group but not in the control group. Both groups had significant improvements in timed up & go, 30-second chair-stand (modified) and Barthel Index (transfer and walking). No significant difference was found between groups except for the Barthel Index (stairs) (P = 0.05). Analysis by the mixed-effects model showed that the treatment group improved more than the control group in all outcome variables. CONCLUSION: The results indicate that for older hospitalized patients progressive resistance strength training as additional training may have an effect compared to standard care, but no statistically significant effects were demonstrated when measured by functional outcomes.