Rhythmic Auditory Stimulation and Walking Speed in the 6-minute Walk Test

Study Overview
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Brief Summary
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The aim of this study is to investigate if rhythmic auditory stimulation can influence walking speed, during a 6MWT in patients with myasthenia gravis (MG).

Detailed Description
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Background The 6-minute walk test (6MWT) is widely used in the clinic to measure treatment efficacy and disease progression in patients with neuromuscular diseases and is found valid and reliable to measure decrease in walking speed. Rhythmic auditory stimulation has repeatedly been shown to improve gait parameters in individuals with neurologic impairment. The aim of this study is to investigate if rhythmic auditory stimulation can influence walking speed, during a 6MWT in patients with myasthenia gravis. Patients with MG are asked to complete two 6MWTs separated by minimum 30 minutes of rest. Before the 6MWTs patient is instructed to walk 60 m as fast as possible, and their steps per minute (SPM) is recorded. When completing the 6MWTs, one of the tests is accompanied by music (m6MWT) with a beat per minute (BPM) corresponding to patients' SPM. The order of the 6MWTs is randomly decided by pre-ordered sealed envelopes.

Official Title
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Does Rhythmic Auditory Stimulation Influence Walking Speed in the 6-minute Walk Test in Patients With Myasthenia Gravis?

Conditions
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Myasthenia Gravis

Intervention / Treatment
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* Other: 6-minute walk test


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Able to provide signed informed consent. Able to read and understand Danish or English. Diagnosis of mild to moderate MG (Able to provide signed informed consent. Able to read and understand Danish or English. Diagnosed with generalized mild to moderate myasthenia gravis (I-IV on the Myasthenia Gravis Foundation of American Clinical Classification, MGFA). Documented history of acetylcholine receptor (AChR) or Muscle Specific Kinase (MuSK) antibody positive, or abnormal repetitive nerve stimulation testing (decrement > 10%) on electromyography (EMG) or abnormal single fiber EMG (conduction block or jitter) or based on their clinical history and symptom improvement with acetylcholinesterase inhibitors. Ability to walk > 60 meters in a 6MWT. Exclusion Criteria: MGFA grade V disease Other disorders that are not related to MG, or drugs, that interfere with muscle strength, walking ability, balance and fatigue (e.g. heart failure). Serious medical illness (e.g. uncontrolled insulin dependent diabetes mellitus, symptomatic coronary artery disease, and cancer). Dementia or pregnancy. Unspecified reasons judged by the investigator

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Myasthenia patients<br>Danish patients with myasthenia gravis seen at the Department of Neurology, Rigshospitalet | Other: 6-minute walk test<br>* The 6-minute walk test (6MWT) is widely used in the clinic to measure treatment efficacy and disease progression in patients with neuromuscular diseases and is found valid and reliable to measure decrease in walking speed for neuromuscular patients.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 6-minute walk test (6MWT) | The distance (meter) and walking speed (meter per seconds) in a 6-minute walk test. | 6 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Heart rate | Monitoring of heart rate by a pulse-watch prior, during (average heart rate for 6 minutes) and after the 6MWT. All three measurements are in the same units (beats per minute), and are registered directly from the pulse-watch, which the patient wear during the walk test. | 5 minutes | 
| The Borg Rating of Perceived Exertion (RPE) scale. | Just after the completed 6MWT patients are asked to score the perceived exertion during walking. The scale is from 6 (no effort at all) to 20 (absolute maximal effort). | 2 minutes | 
| Myasthenia gravis composite score (MGC) | The Myasthenia Gravis composite score (MGC) covers 10 important functional domains most frequently involved in patients with MG. This scoring system is based on quantitative testing of muscle groups, or symptom history told by the patient, by means of a 4 point scale ranging from 0 (no symptoms) to 9 (severe symptoms). The scale measures ocular, bulbar, respiratory and limb function, grading each finding, and the total score ranges from 0(no myasthenic findings) to 50 (maximal myasthenic deficits). | 30 minutes | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Fatigue, 6-minute walk test, Rhythmic Auditory Stimulation