Repetitive Transcranial Magnetic Stimulation Paired with Augmented Reality to Alter Concussion Symptoms

Repetitive transcranial magnetic stimulation (intermittent theta burst stimulation) will be delivered using a Magstim Rapid 2 stimulator (Magstim, Whitland, UK) guided using neuronavigation (Brainsight, Rogue Research, Montreal, QC, Canada) to target primary motor cortex. Participants will receive 14 days of stimulation over a 3-week period. Stimulation will use a protocol called accelerated iTBS (Duprat et al., 2016) whereby iTBS will be delivered three times during the same study session. Each iTBS session will deliver 600 pulses in 50 Hz bursts of 3 pulses for a total of 1800 pulses delivered each day. iTBS sessions will each be separated by 15 minutes (Duprat et al., 2016; Wu et al., 2013). Stimulation will be delivered at 70% of the participant's resting motor threshold. Immediately following each 600-pulse period of iTBS, individuals will participate in 5 to 10 minutes of AR vestibular rehabilitation therapy.

Participants will complete the vestibular training through Nreal Air AR Glasses (Nreal, China). The vestibular training task was custom-made in Unity V2021.3.14fI software using C+ script language. Participants will be standing upright for the AR training, with a safety bar positioned directly in front of them should they need to hold onto something. A large cross-shaped target will be positioned approximately 3 feet in front of the participant's head with its vertical center aligned with the participant's midline. This will act as a visual starting point. The training is adapted from clinical vestibular rehabilitation training methods used in PCD. The vestibular training task consists of locating and tracking a series of moving 3-dimensional balls presented at random within the participant's field of view.

Sham repetitive transcranial magnetic stimulation will be delivered using a Magstim Rapid 2 sham stimulator (Magstim, Whitland, UK) guided using neuronavigation (Brainsight, Rogue Research, Montreal, QC, Canada) to target primary motor cortex. Participants will receive 14 days of sham stimulation over a 3-week period. Stimulation will use a protocol called accelerated iTBS (Duprat et al., 2016) whereby sham iTBS will be delivered three times during the same study session. Each sham iTBS session will sound and feel identical to real iTBS delivery, but will not deliver a stimulating current. Sham iTBS sessions will each be separated by 15 minutes (Duprat et al., 2016; Wu et al., 2013). Sham stimulation will be delivered at 70% of the participant's resting motor threshold. Immediately following each 600-pulse period of sham iTBS, individuals will participate in 5 to 10 minutes of AR vestibular rehabilitation therapy.