The Manifestation of Surface EMG of Swallowing Muscles in Stroke Patients With Respiratory Muscle Training
Condition: Cerebrovascular Disorders
MeSH terms: Cerebrovascular Disorders
Study type: Interventional

Summary: 
      Purpose: To investigate of the respiratory function and swallowing function after respiratory
      muscle training, and the manifestation of surface EMG of swallowing muscles, and the
      lateralization of placement of electrodes in stroke patients. Methods: A prospective study.
      Consecutive patients with diagnosis of stroke will be proved by magnetic resonance image or
      computerized tomography. Stroke patients, aged 35-80 years old, with inspiratory muscle
      weakness or swallowing disturbance will be enrolled and randomly divided into control group
      (usual rehabilitation alone) and experimental group (inspiratory muscle strengthening
      training (IMST) group for patients with inspiratory muscle weakness and expiratory muscle
      strengthening training (EMST) for patients with swallowing disturbance, respectively. Each
      patients will receive usual rehabilitation. In the meanwhile we will recruit 23 healthy
      subjects for the control group.

      Each patient will receive baseline characteristics, duration of stroke, Brunnstrom's stage,
      muscle power, spirometry, peak cough flow, maximal inspiratory pressure (MIP),maximal
      expiratory pressure (MEP), resting heart rate, perception of dyspnea, resting oxyhemoglobin
      saturation (SpO2), hand grip strength of unaffected upper limb. And patients with swallowing
      disturbance will receive swallowing screen test, Functional Oral Intake Scale to evaluate the
      functional level of oral intake of food and liquid, and voice quality analysis for voice
      quality and bilateral surface electromyography for measurement of masseter, oris orbicularis,
      submental muscle and infraspinatus muscles. All of patients will be assessed again at 6 weeks
      and 12 weeks later.

      Patient with respiratory muscle weakness will receive IMT from 30% to 60 % of MIP through a
      respiratory trainer for two sets of 30 breaths or 6 sets of 10 repetitions. For patients with
      swallowing disturbance, EMST will commence from 15% to 75% of threshold load of an
      individual's MEP, 5 sets, 5 repetition with one minute of rest between sets.. The training
      resistance will be adjusted accordingly, with one or two minute of rest between sets. Both
      group will receive respiratory training, twice per day, 5 days per week. For checking the
      compliance of RMT at home, patients will be monitored by making a phone call to them once a
      week.
    

Detailed description: 
      Stroke patients commonly to have respiratory muscle weakness and swallowing disturbance.
      Their cardiorespiratory function could be markedly impaired within 7 weeks after a stroke,
      and maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) reduced.
      Dysphagic patients usually had reduced hyolaryngeal excursion. The contraction of
      submandibular hyolaryngeal muscles (geniohyoid, mylohyoid, anterior digastric) and thyohyoid
      muscles can influence on the hyoid bone and largynx . The decreased excursion and elevation
      of hyolaryngeal complex has been considered as one of cause of penetration and aspiration in
      patients with dysphagia.

      Respiratory muscle training (RMT) could improve cough effectiveness and reduce the incidence
      of pneumonia in acute stroke. RMT could significantly increase in MIP and MEP with training
      intensity of inspiratory muscle training (IMT) varied from 30% to 60% of MIP, duration of 3
      to 7 times per week and duration of each session from 10-30 minutes for a period of training
      from 6 to12 weeks in subacute stroke patients.

      Expiratory muscle strength training (EMST) had potential benefit for respiratory muscle
      strength, swallowing and cough function. EMST could significantly increase duration of
      activation with higher peak amplitudes of EMG signal of the submental muscles as compared to
      dry and wet swallowing in stroke patients(Wheeler, et al. 2007) and it also had promising
      outcomes for airway protection in persons with dysphagia second to neuromuscular impairment.

      Swallowing phase including oral phase, pharyngeal phase, pharyngeal and initial esophageal
      pahased. Surface EMG (sEMG), a simple, noninvasive, radiation-free and reliable method, can
      be used to screen and differentiate the swallowing disturbance by recording activity of
      surface EMG over the swallowing muscles, including orbicularis oris, masseters, submental
      muscles and infrahyoid muscles. The electric activity of sEMG can be filtered and rectified
      as EkG-looking line. It can provide complementary information to assess the dysphagia.

      Correlation of sEMG signals during swallowing in healthy adults has been reported And stroke
      patients with middle cerebral artery infarction had delayed swallowing onset, pretrigger
      duration of hyoid bone. The sEMG showed shorter duration of sEMG activity, latency between
      the start of EMG activity and actual movement, shortened submental muscle activity, and
      prolonged pretrigger duration during swallowing.

      Hypothesis Respiratory muscle training can activate the respiratory muscles, stimulate motor
      cortex of central nervous system of speech, swallowing and respiratory function through the
      certain process of neuroplasticity in brain and spinal cord. EMST could facilitate submental
      muscle contraction, increase submental muscle force and elevate the hyolaryngeal complex
      during swallowing.

      However, rare reports regarding the relationship between the respiratory muscle training and
      swallowing dysfunction in stroke patients. And stroke patients with different lesions may
      have specific sEMG patterns; the differentiation of sEMG pattern of swallowing muscles in
      different stroke disease with dysphagia is not explored yet, and also short of standards to
      study the sEMG of swallowing muscles.

      In this study, we will use a simple respiratory muscle training device(Threshold type) to
      train respiratory muscles and follow up its effect on swallowing, cough, voice quality in
      stroke patients with respiratory muscle weakness and/or swallowing disturbance.

      Forty-six stroke patients with respiratory muscle weakness, age between 35 to 80 years, will
      be enrolled. The participants will be randomly assigned by a computer random number generator
      into two groups, including the experimental group (RMT group plus usual rehabilitation) and
      the control group (usual rehabilitation alone). All allocations will be concealed in the
      opaque envelopes. The research assistant will enroll the participants, generate the
      allocation sequence, and assign participants to their groups after obtaining the informed
      consent.

      The patient will be randomized into 3 groups:

      Group I: IMST only: inspiratory muscle training for patients with inspiratory muscle weakness
      (MIP less than 70% of normal range).

      Group II: EMST: for patients with swallowing disturbance.

      Group III: Control group will receive regular rehabilitation.

      Each subject with respiratory muscle weakness or swallowing disturbance, baseline
      characteristics, including height, weight, body mass index, duration of the disease,
      neurological level (Brunnstrom's stage), spirometry, peak cough flow, resting heart rate,
      systolic and diastolic blood pressure, resting oxyhemoglobin saturation (SpO2), MIP, MEP,
      Borg's scale (0.5 to 10), 6-minute walking test, cough function, fatigue assessment scale and
      caregiver stress scale. Pulmonary function and respiratory muscle strength will be assessed
      by an experienced technician in our pulmonary functional room as a baseline at the begin of
      training program, and at end of program(6 weeks).

      Training protocol:

      Group I: IMST only:

      IMT will commence from 30% to 60 % of MIP and then adjust one level of training loading
      according to the tolerance of continuously breathing through a respiratory trainer for two
      sets of 30 breaths or 6 sets of 10 repetitions with one or two minute of rest between sets,
      once per day, 5 days per week. Training resistance will be adjusted as tolerated. The loading
      will be performed with the previous resistance setting or even lower if training load is not
      tolerated or not completed.

      During IMT, patients will be instructed to place their lips around breathing trainer in a
      sitting position with a nose-clip, inhale with enough force to open the valve (inhale deeply
      and forcefully), exhale through the mouthpiece (exhale slowly and gently), and then continue
      inhaling and exhaling without removing the device from their mouths. The training load and
      training program will be instructed by an experienced respiratory technician.

      Group II: EMST: for patients with only swallowing disturbance EMST will commence from 15% to
      75% of threshold load of an individual's MEP, 5 sets, 5 repetition with one or two minute of
      rest between sets, twice per day, 5 days per week. And training resistance will be adjusted
      accordingly. The loading will be performed with the previous resistance setting or even lower
      if training load is not tolerated or not completed. Each patients with swallowing disturbance
      will receive swallowing screen test, Functional Oral Intake Scale, voice quality analysis and
      surface electromyography by an experience physician and experienced speech therapist to
      evaluate the functional level of oral intake of food and liquid, voice quality and
      measurement of submental muscle strength respectively. And swallowing training program will
      be conducted by an experienced speech therapist.

      GroupIII：Control group will receive regular rehabilitation.

      Outcome measurements:

      Each subject's baseline characteristics, including height, weight, body mass index, and
      duration of the disease, neurological level (Brunnstrom's stage), spirometry, resting heart
      rate, rest respiratory rate, blood pressure, resting oxyhemoglobin saturation (SpO2), MIP,
      MEP, or the lowest resting SpO2, Borg's scale, six-minute walk work value and distance,
      six-minute upper extremity ergometry, peak cough flow, non-affected upper limb strength,
      fatigue assessment scale etc.

      For rectified and filtered sEMG, swallowing duration (the time lapse between the start and
      the end of swallowing. In second), mean peak amplitude (inμsec), and shape of contraction
      patterns of different stage of swallowing will be analyzed.

      The timing of serial evaluation including the assessment at baseline, 6 weeks and 3 month
      later.
    

Intervention name(s): Respiratory muscle training for IMST; Regular Rehabilitation; Respiratory muscle training for EMST
Intervention type(s): Other; Other; Other
Intervention description(s): 2 sets of 30 breaths or 6 sets of 10 repetitions with one or two minute of rest between sets, once per day, 5 days per week, training with breathing trainer.; Regular Rehabilitation: 2-3 times a week, 6 weeks.; 5 sets, 5 repetition with one or two minute of rest between sets, twice per day, 5 days per week, training with breathing trainer.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary purpose: Treatment
Keywords: Respiratory muscle training; Spirometry; Maximal Inspiratory Pressure; Maximal Expiratory pressure; Surface electromyography