Long Term Effects of Inspiratory Muscle Training in Cerebral Palsy
Condition: Aging; Cerebral Palsy; Muscle Weakness; Older People--Abuse of; Physical Inactivity; Respiratory Tract Problem
MeSH terms: Muscle Weakness; Cerebral Palsy
Study type: Interventional

Summary: 
      Background: Respiratory disease is one of the main causes of morbidity and mortality in
      adults with cerebral palsy (CP). Adequate pulmonary function is essential to prevent these
      health problems, however respiratory muscle training has not yet been studied in CP patients.
      The main objective of the study was to investigate the maintenance over time of improvements
      in respiratory parameters achieved with inspiratory muscle training (IMT).

      Methods: This was a controlled, randomised, double-blind trial and with allocation
      concealment performed on 27 institutionalized CP patients randomly distributed in 2 groups,
      "high intensity training group" (HIT) and "low intensity training group" (LIT). Participants
      followed a specific IMT program for 8 weeks, HIT workload was 40% of maximum inspiratory
      pressure (MIP) and LIT workload was 20% MIP. Once finished 8-week training period, CP
      patients continued their daily activities. Respiratory muscle strength and pulmonary function
      were measured pre-IMT, post-IMT, 4, 12 and 24 weeks after finishing IMT.
    

Detailed description: 
      Study design The study was a controlled, randomised, double-blind trial and with allocation
      concealment. The Bioethics Committee of the University of Salamanca affirms that the study
      meets ethical requirements for its execution (registry number 678)

      Participants Institutionalized adults with CP aged between 35 and 64 years were included in
      the study, they were all members of ASPACE Salamanca. 38 patients with CP were selected to
      participate in the study. 27 participants were voluntarily recruited to participate in
      respiratory training and randomly distributed in the High Intensity Training Group (HIT) or
      Low Intensity Training Group (LIT).

      Exclusion criteria: the presence of a respiratory disease in the previous month, inability to
      understand assessment tests or intervention or hemodynamic alterations (heart rate > 150
      beats per minute (bpm), systolic blood pressure > 140 millimeters mercury (mmHg) or diastolic
      blood pressure > 90 mmHg).

      The sample size was established by sampling calculation done from collected during a pilot
      study with 10 volunteers, which determined a minimum of 10 patients for each group to
      perceive differences of 12 cmH2O for MIP, power of 80%, security of 95%.

      Procedures and Measures of Outcomes Elderly people with cerebral palsy were randomly
      allocated, via computerized random assignment, to either a high intensity intervention group
      or a low intensity intervention group. The professional that collected the data and the
      participants were unaware of group assignment. Before (pre-intervention) and after
      (post-intervention) inspiratory muscle training, respiratory muscle strength and pulmonary
      function were evaluated. Once the intervention period phase ended, 3 more evaluations of the
      same parameters were mare, the first at 4 weeks, the second at 12 weeks and the third at 24
      weeks after finishing IMT.

      Primary outcome The primary outcome was respiratory muscle strength, measured pre-IMT,
      post-IMT and 4, 12 and 24 weeks after finishing IMT intervention. It was evaluated through
      maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP) using a pressure
      measurer (Elka PM-15, Laboliser, S.A., Barcelona, Spain), from residual volume and total lung
      capacity, severally. Each measure was expressed in millibars and turned into centimeter of
      water, reference unit, (cm H2O) (1 mbar = 1.01973 cm H2O), according to recommendations of
      the American Thoracic Society/European Respiratory Society (ATS / ERS) [24]. Each test was
      repeated 3 times or until 2 valid results were obtained (difference less than 5%). A rest
      time of 1 minute was respected between efforts to prevent short-term respiratory muscle
      fatigue. The highest value was selected. MIP was evaluated every 2 weeks to graduate the load
      of the device training.

      Secondary outcome The secondary outcome was pulmonary function, measured pre-IMT, post-IMT
      and 4, 12 and 24 weeks after finishing IMT intervention. The data collected were forced
      expiratory volume in 1 second (FEV1) and peak expiratory flow (PEF). It was measured using
      the peak flow device (Asma-1, Vitalograph Ltd, Buckingham, England) that expresses the
      results of FEV1 in liters (L) and PEF in liters per minute (L/min), according to the
      guidelines of the ATS/ERS.

      Experimental Protocol Inspiratory muscle training was carried out with a pressure threshold
      device (Treshold IMT, Philips-Respironics, Pittsburg, PA, USA). Threshold IMT provides
      consistent and specific pressure for inspiratory muscle strength and endurance training,
      regardless of how quickly or slowly patients breathe. This device incorporates a
      flow-independent one-way valve to ensure consistent resistance and features an adjustable
      specific pressure setting (in cm H2O) to be set by a healthcare professional. When patients
      inhale through Threshold IMT, a spring-loaded valve provides resistance. Before training
      began, the participants and primary caregivers completed one-session familiarization with a
      specialist to learn how to operate the device.

      Adult people with cerebral palsy carried out the training program for 8 weeks, 1 session
      every day, 5 days a week. The participants performed 10 series of 1 minute with 1-minute rest
      between them.

      The High Intensity Training Group (HIT) received IMT at 40% of MIP, the training load was set
      each 2 weeks to keep 40% of MIP. The Low Intensity Training Group (LIT) received IMT at 20%
      of MIP, following the same rules as HIT.

      The training protocols of the two groups were developed by a specialist in respiratory
      therapy and all sessions with IMT were supervised by their main caregiver, therefore
      adherence to the program was controlled, as well as possible unwanted effects (increased
      fatigue, breathing problems, dizziness or sickness).

      During the intervention period, both groups continued with their usual activity, receiving
      physiotherapy treatment for 45 minutes per day, 2 days per week. No participants received any
      other treatments.

      After finishing the 8-week intervention period with IMT, CP patients stopped training with
      IMT and continued with their daily normal activities. During the following 24 weeks (without
      IMT), three evaluations of the respiratory parameters analyzed in the trial were made (MIP,
      MEP, FEV1, PEF). The first evaluation was made 4 weeks after the intervention was completed,
      the second 12 weeks and the third 24 weeks after finishing IMT.
    

Intervention name(s): INSPIRATORY MUSCLE TRAINING
Intervention type(s): Device
Intervention description(s): After finishing the 8-week intervention period with IMT, CP patients stopped training with IMT and continued with their daily normal activities. During the following 24 weeks (without IMT), three evaluations of the respiratory parameters analyzed in the trial were made (MIP, MEP, FEV1, PEF). The first evaluation was made 4 weeks after the intervention was completed, the second 12 weeks and the third 24 weeks after finishing IMT.
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary purpose: Treatment