Gait patterns of patients with inclusion body myositis

Blood-flow restricted resistance training in patients with sporadic inclusion body myositis: a randomized controlled trial

OBJECTIVES

To investigate the effect of 12 weeks of low-load blood-flow restricted resistance (BFR) training on self-reported and objective physical function, and maximal muscle strength in patients with sporadic inclusion body myositis (sIBM).

METHOD

Twenty-two patients with sIBM were randomized into a training group (BFR group) or a non-exercising control group, according to CONsolidated Standards Of Reporting Trials (CONSORT) guidelines. The BFR group performed 12 weeks of BFR training twice per week. The primary outcome was the physical function domain of the 36-item Short Form Health Survey (pf-SF-36), which was used to measure self-reported physical function. All patients performed physical function tests (2-Minute Walk Test, Timed Up and Go, and 30-Second Chair Stand), completed the Inclusion Body Myositis Functional Rating Scale (IBMFRS), and were tested for isolated knee extensor muscle strength.

RESULTS

No effects of the training intervention were observed for pf-SF-36 or the objective physical function tests. Leg muscle strength decreased in controls (-9.2%, p = 0.02), but was unaltered in the BFR group (+0.9%, p = 0.87), resulting in a between-group difference in the per-protocol analysis (p = 0.026). Between-group differences in baseline to follow-up changes emerged for IBMFRS, in favour of the BFR group (p = 0.018).

CONCLUSION

Twelve weeks of BFR training did not improve self-reported or objective physical function in these sIBM patients. However, the training protocol had a preventive (retaining) effect on the disease-related decline in leg muscle strength, which may aid the long-term preservation of physical function and postpone the need for healthcare assistance.

A Biologically Inspired Knee Actuator for a KAFO

Knee–ankle–foot orthoses (KAFOs) are prescribed to improve abnormal ambulation caused by quadriceps weakness. There are three major types of KAFOs: passive KAFOs, semidynamic KAFOs, and dynamic KAFOs. Dynamic KAFOs are the only type that enables to control knee motions throughout the entire walking gait cycle. However, those available in the market are heavy, bulky, and have limited functionality. The UT dynamic KAFO is developed to allow knee flexion and assist knee extension over the gait cycle by using a superelastic nitinol actuator, which has the potential to reduce volume and weight and reproduce normal knee behavior. In order to match the normal knee stiffness profile, the dynamic actuator consists of two actuating parts that work in the stance and swing phases, respectively. Each actuating part combines a superelastic torsional rod and a torsional spring in parallel. Geometries of the two superelastic rods were determined by matlab-based numerical simulations. The simulation response of the dynamic actuator was compared with the normal knee stiffness, verifying that the proposed design is able to mimic the normal knee performance. The surrounding parts of the dynamic knee joint have then been designed and modeled to house the two actuating parts. The dynamic knee joint was fabricated and mounted on a conventional passive KAFO, replacing its original knee joint on the lateral side. Motion analysis tests were conducted on a healthy subject to evaluate the feasibility of the UT dynamic KAFO. The results indicate that the UT dynamic KAFO allows knee flexion during the swing phase of gait and provides knee motion close to normal.

Sporadic inclusion body myositis: A review of recent clinical advances and current approaches to diagnosis and treatment

Sporadic inclusion body myositis is the most frequent acquired myopathy of middle and later life and is distinguished from other inflammatory myopathies by its selective pattern of muscle involvement and slowly progressive course, and by the combination of inflammatory and degenerative muscle pathology and multi-protein deposits in muscle tissue. This review summarises the findings of recent studies that provide a more complete picture of the clinical phenotype and natural history of the disease and its global prevalence and genetic predisposition. Current diagnostic criteria, including the role of electrophysiological and muscle imaging studies and the recently identified anti-5'-nucleotidase (anti-cN1A) antibody in diagnosis are also discussed as well as current trends in the treatment of the disease.

Effects of blood-flow-restricted resistance training on muscle function in a 74-year-old male with sporadic inclusion body myositis: a case report

Sporadic inclusion body myositis (sIBM) is a systemic disease that is characterized by substantial skeletal muscle weakness and muscle inflammation, leading to impaired physical function. The objective was to investigate the effect of low-load resistance exercise with concurrent partial blood flow restriction to the working muscles (blood-flow-restricted (BFR) training) in a patient with sIBM. The training consisted of 12 weeks of lower extremity BFR training with low training loads (~25-RM). The patient was tested for mechanical muscle function and functional capacity before and after 6 and 12 weeks of training. Maximal horizontal gait speed increased by 19%, which was accompanied by 38-92% improvements in mechanical muscle function (maximal isometric strength, rate of force development and muscle power). In conclusion, BFR training was well tolerated by the patient with sIBM and led to substantial improvements in mechanical muscle function and gait speed.

Lower extremity peak force and gait kinematics in individuals with inclusion body myositis

OBJECTIVE

To determine the relationship between peak isometric muscle force and temporal characteristics of gait in individuals with sporadic inclusion body myositis (s-IBM).

METHODS

An observational study of 42 individuals with s-IBM (12 women; mean ± SD age 61.8 ± 7.3 years and mean ± SD disease duration 8.9 ± 4.3 years) was conducted at a federal hospital. Peak isometric force measurements for lower extremity (LE) muscle groups were obtained using quantitative muscle testing. Temporal characteristics of gait during habitual and fast walking conditions were measured using a portable gait analysis system.

RESULTS

All observed muscle force values were significantly lower than predicted values (P ≤ 0.001). During habitual walking, the subjects' gait speed and cadence were ≤83% of normative literature values. During fast walking, total gait cycle time was 133% of normal, while gait speed and cadence were 58% and 78% of normative literature values, respectively. Scaled LE peak muscle forces showed significant moderate correlations with temporal gait variables. Weaker subjects had greater limitations in gait speed and cadence compared with stronger subjects (P < 0.05). Peak isometric force of the knee flexors and ankle plantar flexors was significantly correlated with most temporal features of habitual gait.

CONCLUSION

Muscle weakness associated with s-IBM disease activity may contribute to diminished gait kinematics. Temporal features of gait were not substantially influenced by knee extensor weakness alone, considering the knee flexors and ankle plantar flexors played a compensatory role in maintaining the walking ability of individuals with s-IBM.

Functional impairment in patients with sporadic Inclusion Body Myositis

INTRODUCTION

We conducted a retrospective chart review of 53 patients diagnosed with sporadic Inclusion Body Myositis (sIBM) who have been followed at the McMaster Neuromuscular Clinic since 1996.

OBJECTIVES

We reviewed patient medical histories in order to compare our findings with similar cohorts, and analyzed quantitative strength data to determine functionality in guiding decisions related to gait assistive devices.

METHODS

Patient information was acquired through retrospective clinic chart review.

RESULTS

Our study found knee extension strength decreased significantly as patients transitioned to using more supportive gait assistive devices (P < 0.05). A decline to below 30 Nm was particularly indicative of the need for a preliminary device (i.e. cane)(P < 0.05). Falls and fear of falling poses a significant threat to patient physical well-being. The prevalence of dysphagia increased as patients required more supportive gait devices, and finally a significant negative correlation was found between time after onset and creatine kinase (CK) levels (P < 0.01).

CONCLUSION

This study supports that knee extension strength may be a useful tool in advising patients concerning ambulatory assistance. Further investigations concerning gait assistive device use and patient history of falling would be beneficial in preventing future falls and improving long-term patient outcomes.