None listed
Conditions
Brief summary
The use of non-invasive brain stimulation offers promising opportunities to enhance motor function and motor learning in numerous rehabilitation areas. Transcranial direct current stimulation (tDCS) is a form of non-invasive brain stimulation. This technique uses a low direct current to evoke changes in brain excitability. Brain function can either be enhanced with anodal stimulation (positive polarity) or inhibited with cathodal stimulation (negative polarity) with current delivered through sponge electrodes on the person’s head over the targeted brain region. One possible placement for stimulation is the cerebellum which has a primary role in the coordination of movements and error correction. Applying tDCS over the cerebellum has been shown to enhance motor skill-learning in limb rehabilitation. However it is not known whether these effects also occur for corticobulbar-related motor functions, such as swallowing. The proposed research will investigate the effects of cerebellar tDCS on motor learning in swallowing in 36 healthy individuals. Each participant will be asked to complete two sessions of swallowing skill-training on two consecutive days. There will be one follow-up on day three and a second follow-up after one week. A behavioural training protocol, Biofeedback in Strength and Skill Training (BiSSkiT), will be used to increase precision and timing of swallowing as indicated by floor-of-mouth muscle contraction during swallowing using surface electromyography (sEMG) biofeedback. The feedback for the participant will be displayed as a real time waveform on a computer screen. The amplitude of the waveform will alter depending on the strength of floor-of-mouth muscle contraction during swallowing. For the swallowing training, the participant will be asked to hit a small target on the screen with the peak of the waveform. The target will move in position on each screen (every 30 seconds) to increase volitional control of swallowing by changing timing and amplitude of swallowing in each trial. Swallowing performance will be measured by calculating the peak-target error out of the distances between the highest peak of the waveform and the centre of the target. This measure will also be the baseline measure before and assessment swallows after the training and for the follow-ups. However, to assess learning, for the assessment swallows no feedback in form of a waveform will be provided. The swallowing task will be performed with and without cerebellar tDCS. Comparison between tasks will provide information about stimulation effects on motor learning. These findings will then be used to investigate parameters of cerebellar stimulation, such as dose, retention of skill, and electrode placement. This information may be used to determine the benefits of cerebellar tDCS on patients with swallowing disorders (dysphagia) to guide the development of effective dysphagia rehabilitation protocols.
Interventions
The study has three arms
Arm 1: anodal tDCS
Arm 2: cathodal tDCS
Arm 3: sham.
The cerebellar tDCS set up will be made for each participant in the three groups. This involves the attachment of three rectangular saline-soaked sponge electrodes (5×5 cm, surface area 25 cm^2) to the participants head. One will be placed on each cheek and the third one will be placed over the cerebellum (back of the head). The sponge electrodes will be connected to an electrically tested, registered stimulation devi
The study has three arms Arm 1: anodal tDCS Arm 2: cathodal tDCS Arm 3: sham. The cerebellar tDCS set up will be made for each participant in the three groups. This involves the attachment of three rectangular saline-soaked sponge electrodes (5×5 cm, surface area 25 cm^2) to the participants head. One will be placed on each cheek and the third one will be placed over the cerebellum (back of the head). The sponge electrodes will be connected to an electrically tested, registered stimulation device, tDCS Transcranial Stimulation Kit (TCT Research Limited), that applies a standard level of current (2mA) for 20 min while participants perform the swallowing tasks. Stimulation via these parameters induces a current at a density of 0.08 mA/cm^2. Using this set up the participant will be asked to perform two training sessions on consecutive days. During the training, muscle activity during swallowing will be measured via sEMG electrodes placed under the chin (submental muscles). The measured activity will be displayed on a computer screen, thereby providing feedback to the participant about the accuracy of their swallowing movements in real time. Participants will be asked to swallow every 30 seconds and manipulate their muscle activity so that the waveform on the screen touches a target box displayed on the same screen. The accuracy of each swallow will be displayed to the participants immediately on completion of that swallow. All participants will be asked to perform this swallowing task (the same for each participant) and will receive one of three types of tDCS (anodal, cathodal or sham). A certified clinician (speech and language therapist and PhD student) closely supervised by a research team that has a history in evaluating neurorehabilitation techniques and the use of non-invasive brain stimulation techniques, will administer the intervention.
Sponsors
The University of Canterbury Rose Centre for Stroke Recovery and Research
Study design
Allocation
Non-randomised trial
Intervention model
Parallel
Primary purpose
Treatment
Masking
Blinded (masking used) (Subject, Caregiver)
Eligibility
Sex/Gender
All
Age
50 Years to 80 No limit
Healthy volunteers
Yes
Inclusion criteria
Healthy individuals aged between 50 – 80 years of age with no history of neurological impairment, current symptoms of dysphagia, drug use that would affect neural or swallowing function or vision.
Exclusion criteria
Individuals who have metallic implants in their brain, had undergone recent brain neurosurgery, or anatomical changes that may modify current flow will be excluded.
Outcome results
None listed