Effect of Functional Exercise in Patients With Spinal Bulbar Muscular Atrophy

Objective: Spinal and bulbar muscular atrophy (SBMA), or Kennedy s disease, is a slowly progressive, X-linked motor neuron disease for which there is currently no treatment. It is caused by a mutation in the androgen receptor that results in a polyglutamine repeat expansion. The role of exercise in motor neuron disease research is debated. Although SBMA is believed to be primarily a neuronopathy, the potential effect of aberrant androgen receptor activity on muscle leads exercise to be of uncertain utility in this population. Our objective is to examine the safety and efficacy of exercise regimens in Kennedy s disease.

Study Population: We aim to enroll 80 men with genetically confirmed Kennedy s disease.

Design: This will be a randomized, evaluator blinded, trial with 25 subjects in each exercise arm. Following informed consent, the subjects will undergo an initial medical and physical evaluations followed by a series of neurological tests and blood work over a two-day outpatient visit at the NIH. The subjects will provide blood work for analysis of hormonal levels and assessment of any potential muscle damage. On the second day of their visit, the subjects will be randomized and taught a series of either functional or stretching exercises that they will engage in as part of the study and control arms, respectively. Following the baseline visit to NIH, the subjects will be monitored throughout the study with telephone contacts and other measures including video recording to monitor their progress and compliance. The subjects will return to the NIH at the end of a 12 week period at which time the physical and laboratory testing will be repeated. After the 12 week exercise period there will be a four week period where we will follow-up with the participants by telephone and e-mail. At the end of the trial all of the subjects will be informed of the study results and given the opportunity to learn the exercises if they are found to be beneficial.

Outcome Measures: The primary outcome measure used will be the Adult Myopathy Assessment Tool (AMAT). Secondary outcome measures will involve quantitative muscle analysis (QMA), the Timed Up and Go (TUG) test, a quality of life measure (SF-36v2TM), adverse event questionnaires, a Computerized Dynamic Posturography (CDP) assessment of balance, accelerometer measurements of exercise effort, and progressive height sit-to-stand testing. Several exploratory biomarkers that may be affected by exercise will be evaluated, including insulin-like growth factor-1 (IGF-1), insulin-like growth factor binding protein 3, testosterone, growth hormone, and creatine kinase. Beck Depression Inventory (BDI) testing will also be used to determine if the subjects mood is affected by exercise. Qualitative sub-study questions, international index of erectile function, Block brief food questionnaire, Aggression Questionnaire, Activities-specific Balance Confidence (ABC) scale, Fatigue Symptom Inventory, and physical activity survey measures will also be employed.

• INCLUSION CRITERIA:

• Genetically confirmed SBMA.
• Ambulatory and walk a distance of at least 50 feet with or without a walker.
• Able to stand for 10 minutes without the use of any assistive devices.
• Willing to travel to the NIH at the beginning and end of the study.
• Willing to participate in telephone monitoring.
• AMAT score of less than 41, but greater than 14.
• Male.
• Willing to participate in all aspects of trial design and follow-up.
• Access to a computer with an internet connection
• Able to do all of the exercises according to the standards of the study examiners at the beginning and end of the study
• Willing to forgo starting an additional exercise plan for the 12 week duration of the study
• Age greater than 18 years

Exclusion criteria

• Medical condition which would preclude exercise such as COPD, congestive heart failure, and cardiac arrhythmias.
• Presence of an additional comorbid condition such as stroke, myopathy, or radiculopathy which also results in weakness.
• Beginning a separate exercise program involving at least two weekly sessions of 20 minutes of exercise each within two months of the start of the trial.