DEVELOPMENT OF ADJUNCT THERAPIES COMBINED WITH REPETITIVE TRANSCRANIAL MAGNETIC STIMULATION FOR THE TREATMENT OF CHRONIC PAIN

Abstract

This dissertation examines the use of repetitive transcranial magnetic stimulation (rTMS) as a monotherapy as well as in combination with sensorimotor training technologies to improve the lives of individuals living with chronic pain. rTMS has the potential to promote analgesia and, when combined with technology to promote movement, is anticipated to have even greater effects that diminish pain intensity and improve function. Four experiments are included in the dissertation. Experiment 1 explores the use of rTMS in an individual living with neuropathic pain following spinal cord injury (SCI). Experiment 2 combines rTMS with hand sensorimotor training in a case report in complex regional pain syndrome (CRPS). Experiment 3 explores the effects of rTMS in an open label feasibility study in CRPS. Experiment 4 combines rTMS with augmented reality sensorimotor training (ARST) in a sham-controlled feasibility study in chronic neck pain (CNP).

Of specific focus in this dissertation is the development of technologies that promote movement and can be implemented immediately following rTMS, to potentially enhance analgesia and function in chronic pain. Two separate sensorimotor training technologies were developed during this dissertation. The first technology is discussed in Chapter 2, involved hand sensorimotor training which used nerve stimulation to cue goal directed movements of the right-hand digits performed on a custom-built hand device. The second discussed in Chapter 4, used augmented reality to present virtual objects in a user’s environment to complete goal directed cervical movements. The latter technology has been filed as intellectual property with McMaster University. Further, this dissertation emphasizes rigorous interventional periods of rTMS with or without adjunct technology, to enhance patient outcomes. Therefore, the focus is on feasibility aspects of trial design to ensure that the intensive intervention and methodologies used in this dissertation are feasible to be tested in larger samples.

Overall, in Chapter 2 and 4 this dissertation has shown that rTMS may be effective at reducing neuropathic pain and CRPS, with certain pain phenotypes exhibiting greater propensity for change. In addition, in Chapter 3, rTMS combined with hand sensorimotor training is effective at reducing pain, allodynia, and improving physical function in a patient with CRPS of the upper limb. Lastly, in Chapter 5, rTMS with ARST is effective at reducing pain, neck disability, and increasing physical function in CNP. Interestingly, the data obtained to date suggest that the effects observed in CNP may be associated with ARST and not rTMS per se. In addition, this dissertation illustrates that chronic pain interventions delivered three to five times per week for four to nine weeks is feasible however, long term follow-ups may be challenging in certain pain populations. Last, these studies have demonstrated that rTMS combined with adjunct therapies are tolerated in pain populations and demonstrate effective reductions in pain, creating an opportunity to explore their effects in large scale trials.