Central Mechanisms of Calmare: an fMRI Trial
Condition: Peripheral Neuropathy
MeSH terms: Peripheral Nervous System Diseases
Study type: Interventional

Summary: 
      Pilot one-treatment and extended 10-treatment studies are carried out on participants with
      peripheral neuropathy comparing traditional TENS and Calmare stimulation protocols using a
      double-blind apparatus. Resting fMRI scans are obtained before and after the treatment, as
      well as after most of the pain has returned.
    

Detailed description: 
      Pain can be either useful or harmful. Acute pain conveys information to the brain about real
      or potential damage that can productively lead to avoidance or treatment of the damage.
      However, chronic pain, which extends beyond these useful purposes, becomes a potentially
      debilitating inconvenience. Estimations based on surveys report that as many as 33% of
      Americans suffer from chronic pain, with a significant portion being unable to successfully
      manage it.

      The current means to treating chronic pain include: surgery, drug therapy, physical therapy,
      psychological intervention, and others. Unfortunately, despite these options, many people
      continue to suffer from a chronic pain condition. Neuropathic pain, or pain caused by nervous
      system damage, is particularly hard to treat. Drug therapy and surgery have relatively low
      success rates and undesirable side effects. Thus, there is a need for additional research and
      new treatment methods for neuropathic pain patients.

      The Calmare device was designed as one such means to treat chronic neuropathic pain. It works
      through electrostimulation of the skin near the pain site, and, according to recent studies,
      has significantly reduced chronic neuropathic pain in most subjects (Majithia et al., 2016).

      Previous studies of Calmare effectiveness have defined the success of treatment as the
      reduction of reported pain levels by the patient. Though useful, these studies fail to
      provide an objective measurement of pain reduction and fail to discover the mechanisms by
      which it occurs. In addition, previous studies have been unable to perform a true
      double-blind experiment in which the placebo effect was entirely accounted for. The pilot
      study takes a step toward filling this gap by performing a double blind, randomized
      single-treatment trial comparing Calmare efficacy to traditional transcutaneous electrical
      nerve stimulation (TENS) efficacy. The ten-treatment study examines the durability of the
      pain relief for 12 weeks after the treatment period.

      The goal of these studies is two-fold: first, to use fMRI before and after a full therapeutic
      Calmare treatment course to determine the extent to which Calmare affects the connectivity of
      the pain centers of the brain, and second, to determine whether traditional TENS or Calmare
      is more effective in reducing neuropathic chronic pain. The Calmare treatment is administered
      in a double-blind fashion with neither the technician, nor the subject knowing whether the
      TENS or the Calmare is being administered. The investigator's hypothesis is that Calmare
      therapy decreases subject pain through a central mechanism that will be manifest in decreased
      functional connectivity of the brain's pain centers. The degree to which this happens is
      determined by comparing the decrease in pain intensity, as reported by the patient, with the
      difference in fMRI BOLD temporal correlations between pain centers.
    

Intervention name(s): Calmare; TENS
Intervention type(s): Device; Device
Intervention description(s): Skin is stimulated with an electrical voltage via electrode pads, variably distorted sine wave at ~47 Hz.; Skin is stimulated with an electrical voltage via electrode pads, 300 micro-second rectangle pulse at 47 Hz.
Other intervention name(s): Traditional TENS
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Equal numbers of participants are randomly assigned to either the Calmare or traditional TENS group. Using skin electrodes positioned by the therapist proximal to the limb pain, each participant is given the assigned stimulation mode for 30-minute therapy sessions. One therapy is used in the pilot study and ten therapies on consecutive weekdays in the extended study.
Masking: Double (Participant, Care Provider)
Primary purpose: Treatment
Keywords: Idiopathic; diabetic; chemotherapy-induced