Real-time Video Projection in an MRI for Characterization of Neural Correlates Associated with Mirror Therapy for Phantom Limb Pain

Summary

We present a novel combined behavioral and neuroimaging protocol employing real-time video projection for the purpose of characterizing the neural correlates associated with mirror therapy within the magnetic resonance imaging scanner environment in leg amputee subjects with phantom limb pain.

Abstract

Mirror therapy (MT) has been proposed as an effective rehabilitative strategy to alleviate pain symptoms in amputees with phantom limb pain (PLP). However, establishing the neural correlates associated with MT therapy have been challenging given that it is difficult to administer the therapy effectively within a magnetic resonance imaging (MRI) scanner environment. To characterize the functional organization of cortical regions associated with this rehabilitative strategy, we have developed a combined behavioral and functional neuroimaging protocol that can be applied in participants with a leg amputation. This novel approach allows participants to undergo MT within the MRI scanner environment by viewing real-time video images captured by a camera. The images are viewed by the participant through a system of mirrors and a monitor that the participant views while lying on the scanner bed. In this manner, functional changes in cortical areas of interest (e.g., sensorimotor cortex) can be characterized in response to the direct application of MT.

Introduction

PLP refers to the sensation of pain perceived within the area corresponding to the missing limb postamputation^1,2. This condition is a significant chronic health care burden and can have a dramatic impact on an individual's quality of life^3,4. It has been suggested that alterations in the brain structure and function play a fundamental role in the development and neuropathophysiology of PLP^5,6. However, the underlying neural correlates of how pain symptoms develop and how they can be allevi....

Protocol

1. Preparation of the subject

1. Prior to participation, have the participant complete a consent form and an MRI safety screening evaluation, the latter carried out by the neuroimaging technician at the scanning facility, to ensure that the participant does not have any known contraindications to being scanned (e.g., metal in their body, a history of claustrophobia, or pregnancy).
2. Provide the participant with detailed instructions with regard to the experimental procedure.
3. Have the subject li.......

Discussion

This protocol describes a novel, feasible procedure that allows investigators to accurately characterize the neural correlates associated with MT in individuals with PLP.

As previously mentioned, past studies have attempted to investigate the neural correlates associated with MT treatment by incorporating various techniques such as video recording, virtual reality, and prerecorded animations^9,33,34. H.......

Materials

Name	Company	Catalog Number	Comments
Scanner	Phillips	NA	3 Tesla Philips Acheiva MRI scanner
Camera	Logitech	NA	HD Pro Webcam C910
Monitor	Cambridge Research Systems	NA	3D BOLD screen for MRI
Mirror	TAP Plastics	99999	Mirrored Acrylic Sheets (Cut­to­Size) ­ Clear 1/8 (.118)" Thick, 10" Wide, 40" Long
Mirror stand		NA	Mirror stand was built by the co-investigators from a rectangular piece of wood
Headphones	Westone Sensimetrics	PN 79245	Replacement comply foam tips for universal-fit earphones. Canal size: Standard 6 pieces/ 3 pair
			MR compatible in ear headphones
MRI Scanner	Phillips	3.0 T Philips Achieva System