Breathing Muscle Training in Parkinson's Disease

Inspiratory Muscle Training (IMT) Inspiratory muscle training is achieved by using a POWERbreathe RMT/IMT Class 1 Medical Device (www.powerbreathe.com). They are advanced pressure threshold loading devices that strengthen inspiratory muscles by creating a resistance against the in-breath and are clinically proven to be beneficial for COPD, asthma and heart failure. They are hand held devices that can be used at home after initial training. Interval-Based Training All participants will undergo an 8 week home based H-IMT or S-IMT program after initial training by a senior physiotherapist with expertise in the use of the IMT devise. The home IMT resistive exercise intervention is based on the previously published protocols of Hill et al. (2010). IMT adherence will be recorded by the participants in their exercise logs. At week 2 participants will be reviewed in the clinic to ensure that they are performing the IMT optimally and to increase training loads. Subsequently, there will be weekly phone contact and the training load increased according to patient feedback. The IMT program is based on a protocol previously demonstrated to be feasible and effective (Hill et al. 2010). Initial training will be one on one, face to face and demonstrated and guided by a trained physiotherapist. It will take about 1 hour. Training takes place with the patient seated, wearing a nose clip. Patients are permitted to lean forward and fix their upper limbs on the arms of chair or table if desired. Training commences with a 1-minute warm-up at 50% of the target inspiratory training load (see “Training loads”). Thereafter, an interval based training approach is used, characterized by a work to rest ratio of 2 minutes (work) to 1 minute (rest). This 3-minute cycle is repeated 7 times, resulting in a 21-minute training session (ie, 14 minutes of loaded breathing). Patients are permitted to select their own breathing pattern, and expiration is unloaded. Subsequent training is undertaken at home 3 times a week for 8 weeks, and patients are encouraged to record their training sessions in an exercise diary. At week 2 there is a second one on one, face to face training session with the physiotherapist to ensure that the correct techniques are used, and to demonstrate how to increase training loads. Once weekly phone calls will be made on weeks 3-8 to answer any questions regarding the home training. Training Loads For the initial 2-minute interval, a training load is selected equivalent to 30% of a patient’s PImax. Loads less than 30% of PImax are insufficient to induce improvement in inspiratory muscle strength. Consistent with the current recommendations for whole-body exercise training, we will use a symptom limited approach to guide the progression of training loads. We select loads that patients describe as somewhat hard—that is, between 12 and 14 on the Rating of Perceived Exertion (RPE) scale. Training loads are increased during the designated rest intervals to achieve these RPE targets. Patients train at loads corresponding to a higher RPE if tolerated and there are no abnormal symptoms (eg, prolonged delayed onset muscle soreness). On completion of the first training session, patients are often training at loads equal to approximately 40% of PImax. The inspiratory load can usually be increased rapidly during the first 4 weeks of training, mainly due to neurosensory adaptation reflecting desensitization to the inspiratory loads and improved recruitment of motor units. Thereafter, the rate of increase often slows, and further increases in muscle function are likely to result from muscular hypertrophy. Sham inspiratory muscle training (S-IMT) will be performed at 10% of PImax with a 2-3 % increase in training load every week (Hill et al. 2006, 2010). Reassessment and maintenance Reassessment of all outcome measures is performed at completion of the training and 6 months after the initiation of training. Training-related gains are lost within 12 months if regular IMT is ceased. In order to optimize the maintenance of benefits, we encourage the completion of at least 2 IMT sessions each week at the load achieved during the final session of the 8-week program. At 6 months, those patients in the sham group will be offered H-IMT for 8 weeks, followed by reassessment after completion of training and at 6 months.