Using Cranial Nerve Non-invasive Neuromodulation to Improve Pain and Upper Extremity Function After a Stroke
Condition: Stroke
MeSH terms: Stroke
Study type: Interventional

Summary: 
      Following a stroke, individuals experience pain in the affected upper limb (UL) and residual
      weakness in the UL, which impacts their quality of life and performance of activities of
      daily living. To overcome these deficits, exercises are a key element to any rehabilitation
      program and are based on the reorganization capacity of the central nervous system (called
      neuroplasticity). To optimize the beneficial effects of exercises and potentiate
      neuroplasticity, non-invasive brain stimulation devices (NIBS) are increasingly used as a
      complementary therapy post stroke. Among NIBS, a new technique, called cranial nerve
      non-invasive neuromodulation (CN-NINM), is making its way into stroke rehabilitation since,
      unlike other NIBS such as tDCS, it allows the generation of a direct flow of neuronal
      impulses via the stimulation of the tongue. The goal of this project is therefore to
      investigate CN-NINM to document its feasibility and explore its efficacy at improving motor
      recovery and reduce pain at the affected UL in chronic stroke patients (> 6 months). CN-NINM
      will be applied for 20 minutes during each exercise session of the UL (3X/week, 4 weeks).
      Feasibility data will comprise adherence to CN-NINM, drop out rate and adverse events and UL
      motor recovery and pain will be assessed before and after the exercise program. At the end of
      this study, it is expected that it will be feasible to use CN-NINM as an intervention in
      combination with the exercise program and that it will result in improved motor function and
      reduced pain in affected UL.
    

Detailed description: 
      Following a stroke, survivors experience pain in the affected upper limb (UL) and residual
      weakness in the UL, which impacts their quality of life and performance of activities of
      daily living. Exercises is a key element of any rehabilitation program and is based on the
      capacity of reorganization of the central nervous system (called neuroplasticity) to allow
      overcoming stroke deficits. In addition, it is now recognized that in the chronic phase of a
      stroke, motor and functional gains are still possible following various training programs,
      such as a strength training program. To optimize the beneficial effects of exercise and
      potentiate neuroplasticity, non-invasive brain stimulation (NIBS) devices are increasingly
      used as a complementary therapy. Among NIBS, the most widely used technique is transcranial
      direct current stimulation (tDCS) that modulates cortical excitability and allows for
      clinical and functional gains, including recovering in UL motor function and pain. However,
      over 50% of individuals do not respond as expected to the combination of tDCS and
      rehabilitation exercises. This can be due to anatomical variability between individuals and
      electrical current shunting. Thus, to bypass these constraints, a new technique, called
      cranial nerve non-invasive neuromodulation (CN-NINM), is entering stroke rehabilitation.
      Unlike other NIBS such as tDCS, it generates a direct flow of neural impulses via tongue
      stimulation. Studies have shown that priming the motor cortex with CN-NINM during a training
      program can promote improved balance and gait and increased activation of the motor cortex.
      Until now, no studies have examined the use of CN-NINM for improving UL function and pain.

      Goals: 1) To assess the feasibility of using CN-NINM in chronic stroke survivors; 2) To
      explore the effectiveness of CN-NINM in improving motor function and reducing pain of the
      affected upper limb in chronic stroke survivors.

      Methods: In this feasibility pilot pre/post intervention study, 12 adults at the chronic
      phase of a stroke (>6 months) will be recruited. Sociodemographic and stroke-related
      variables (e.g., age, time since stroke) will be collected to confirm participant
      eligibility. Prior to training, participants will undergo a clinical evaluation of their
      affected UL as well as an evaluation of simulated pain at the affected UL. For the latter,
      the effect of CN-NINM on pain will be evaluated using a tonic thermal experimental pain
      paradigm. For this, a thermode (hot plate) will be applied to the forearm of the participants
      before and after a single 20-minute application of CN-NINM. On each occasion, thermal
      nociceptive stimuli will be induced for 2 minutes on the participants' forearm using the
      thermode. Although the temperature remains constant for the entire 2 minutes, the participant
      will be informed that the temperature may increase, decrease, or remain stable during the
      procedure. The participant will then, at all times, evaluate the intensity of the pain with a
      visual analogue scale connected to a computer (CoVAS: visual analogue scale from 0 to 100).
      Afterwards, the participants will take part in a 4-week training program of their affected UL
      (3X/week, 60-minute duration). During each training session, the CN-NINM will be applied for
      20 minutes at an intensity tailored to each participant comfort.
    

Intervention name(s): Strength training intervention; Cranial nerve non-invasive neuromodulation (CN-NINM)
Intervention type(s): Procedure; Procedure
Intervention description(s): The strength training program will last 4 weeks (3 X/week, 60 minutes). Using dead weights, the 1RM (i.e. the maximal load that an individual can lift once) will be estimated by the 10RM in order to avoid tendino-muscular injuries and fatigue. The 10RM will be determined for the muscles playing a key role in the functional performance of the upper limb (the wrist extensors and the elbow and shoulder flexors). In addition, the grip muscles of the affected hand will be trained with a JAMAR® dynamometer. Training will start at 50% of 1RM and progress by 10% each week to reach 80% of 1RM by week 4. The same gradation of intensity will be applied to the grip muscles. The training will begin and end by a 5-minute warm-up and relaxation period comprising of active movements of the trained muscles.; During each strength training session, the CN-NINM will be applied, with the help of a portable stimulator comprising a network of 18 electrodes, directly on the tongue of the participants for 20 minutes. The participants will hold the CN-NINM in place by pressing their tongue upwards. The CN-NINM will generate high-frequency pulses (50 μsec to 150 Hz), and the intensity of the stimulus will be set by each participant to a comfortable level of sensation, similar to the sensation in the mouth of a soft drink.
Allocation: Non-Randomized
Intervention model: Single Group Assignment
Intervention model description: The study model is a pre/post intervention pilot study.
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: Exercise; Upper limb; Motor recovery; Pain; Cranial nerve non-invasive neuromodulation