Fatigue in Patients With Amyotrophic Lateral Sclerosis

This research proposal will determine the immediate impact of expiratory muscle strength training (EMST) on fatigue of the respiratory and swallowing musculature, whether objective decompensation translates to subjective dyspnea and fatigue, and whether high resolution cervical auscultation (HRCA) signal features can noninvasively capture and characterize physiologic decompensation that relates to fatigue in patients with amyotrophic lateral sclerosis (PALS) via three Specific Aims.

Aim 1) Determine the impact of one EMST session on objective respiratory and swallow function.

Hypothesis 1) One EMST session will result in reduced pulmonary function tests (PFTs) (maximum expiratory pressure, forced vital capacity, peak cough flow) and declines in swallow function (Videofluoroscopy (VF), HRCA). PALS will have greater reductions in PFTs, and objective declines in swallow function after the experimental condition compared to the control condition.

Aim 2) Determine if objective decompensation translates to subjective ratings of dyspnea and fatigue after one EMST session.

Hypothesis 2) Subjective ratings of dyspnea and fatigue (Situational Fatigue Scale; Dyspnea ALS-15) will be associated with objective decompensation in respiratory and swallow function (PFTs, VF, HRCA) after one EMST session.

Aim 3) Investigate whether HRCA signal features analyses can non-invasively characterize immediate post-exercise physiologic changes in swallowing function that are related to fatigue.

Hypothesis 3) Pre- to post-EMST changes in HRCA signal features will be associated with physiologic changes in swallowing as measured by VF analyses.

This study will be a prospective study with randomized experimental and control conditions; and is directly related to the NIH funded research studies currently conducted in the Computational Deglutition (CD) Lab under the leadership of Dr. James Coyle and Dr. Ervin Sejdic.

Participants: 20 PALS will be recruited to undergo VF before and after undergoing the randomly ordered experimental and control conditions on two separate nonconsecutive days within a two-week time frame.

Baseline Procedures:

PALS will be instructed not to eat a meal or engage in exercise within two hours of their visit. Following consent, baseline assessment procedures be obtained. All baseline measurements of swallowing and pulmonary function will be performed before any potentially fatigue-inducing procedures are performed (i.e. exercise training).

1. The ALS functional rating scale revised (ALSFRS-R) (an instrument used to assess changes in functional status over time in PALS), will be completed.

2. Prior to completing swallowing and pulmonary measurements, PALS will complete the situational fatigue scale (SFS), which measures fatigue that results from completing functional daily activities.

3. Before undergoing swallowing and pulmonary measurements, PALS will also complete the Dyspnea ALS-15 (DALS-15), which is a measure of dyspnea that is known to be related to fatigue in PALS.

4. PALS will undergo an assessment of swallow function with concurrent recordings of videofluoroscopy (VF) and high-resolution cervical auscultation (HRCA) signals prior to undergoing PFTs to mitigate fatigue from the PFTs as a confound. VF procedures will be conducted first, because ten swallows of thin liquid are unlikely to cause fatigue of the respiratory and swallow musculature that would impact PFTs.

5. PALS will be seated upright in a chair and viewed in the lateral plane. HRCA signals will be simultaneously recorded from neck sensors (a contact microphone and accelerometer) that are attached to the anterior laryngeal framework with tape. VF and HRCA signals will be recorded onto a Labview Workstation. During each stage (pre-, post EMST) of VF, PALS will swallow ten thin liquid boluses of barium. Five liquid swallows will be a self-selected comfortable sip from a cup and five will be 3mL by spoon administered with a command to swallow. Presentation order for the liquid swallows will be randomized using a random number generator. If more than one aspiration event is observed during VF, the exam will be terminated immediately in order to ensure patient safety.

6. PFTs following VF will include maximum expiratory pressure (MEP) (measured with the MicroRPM handheld MEP device (Micro Direct Inc., Lewiston, ME)), peak cough flow (PCF) (measured with a handheld peak flow meter (BV Medical, Barrington, IL)), and FVC (measured with the Spirodoc spirometer and WinspiroPRO computer software (Medical International Research, New Berlin, WI)). All PFTs will be completed three times with PALS sitting in an upright seated position with a nose clip in line with standard PFT protocols. The highest of three measurements will be used for analyses.

EMST Training: PALS will use the EMST-150 device (Aspire Products, Gainesville, Florida) or the Philips Threshold PEP trainer (Philips Respironics, Cedar Grove, New Jersey). During the experimental condition, EMST devices will be set to 50% of PALS' highest MEP from their baseline PFT assessment. During the control condition, no resistance will be added, and the loaded spring will be removed from the device. For both experimental conditions, PALS will undergo the following standard treatment protocol:

1. PALS will complete five sets of five repetitions using an EMST device.

2. For each repetition, PALS will be instructed to take a deep breath in and blow until the valve releases.

3. Between repetitions, PALs will have 10-15 seconds of rest before the next repetition.

4. After each set, PALS will rest for one minute before completing the next set.

Post-treatment procedures: Following the EMST session with either the device set to 50% load or the sham device, PALS will undergo the same procedures (VF, HRCA, PFTs) as described above in steps 1-6 of the baseline procedures