Transcranial Magnetic Stimulation Effects on Pain Perception
Condition: Gastric Bypass Surgery Pain Management
Study type: Interventional

Summary: 
      The purpose of this research study is to investigate the effects of Transcranial Magnetic
      Stimulation on pain perception. TMS is a non - invasive technique that uses electromagnetic
      pulses to temporarily stimulate specific brain areas in awake people (without the need for
      surgery, anesthetic, or other invasive procedures)
    

Detailed description: 
      To test whether rTMS over the left prefrontal cortex significantly reduces post-operative
      pain and PCA use following gastric-bypass surgery relative to sham and an active control, in
      a mood- independent manner. Note that the active control is still mentioned in the aims and
      hypotheses, but was apparently removed from the study design.

      To determine the effects of timing (one immediately following surgery and one 4 hours later)
      and dose of TMS (0, 1, or 2 sessions of active rTMS) on post-operative pain and PCA use; To
      determine the effects of TMS on post-surgical recovery time (time to discharge) and clinical
      outcomes at 1-month, 3- months and 6-months follow-up. Again an active control is mentioned,
      though this was removed from the design. It appears that this aspect of the proposal was not
      edited to reflect the new study design.

      In the new design, 108 participants received two 20 minute sessions of 10 Hz rTMS (110% of
      motor threshold) over the left dorsolateral prefrontal cortex (one immediately following
      surgery and one 4 hours later). Participants were randomly assigned to receive two sessions
      of real rTMS, two sessions of sham, 1 real then 1 sham, or 1 sham then 1 real rTMS
      treatments.
    

Intervention name(s): Real TMS 45 min; Sham TMS 45 min; Real TMS 4 Hours; Sham TMS 4 Hours
Intervention type(s): Device; Device; Device; Device
Intervention description(s): Real TMS 45 minutes after surgery, first determined resting motor threshold (rMT) by starting with 40% of the machine output and 0.5 Hz stimulus frequency. The coil was positioned over the motor cortex and then adjusted until each pulse results in movement of the right thumb. The machine output was then adjusted to the lowest intensity that reliably produces thumb movement. Parameter estimation by sequential testing was used to determine the amount of machine energy necessary to visibly move the thumb 50% of the time. rMT was assessed before each rTMS treatment. The left prefrontal cortex was the cortical target for rTMS treatment. The EEG-10-20 system was used to locate the prefrontal cortex (F3).; Sham TMS 45 minutes after surgery used specifically designed rTMS coil that produces auditory signals identical to real (active) TMS coils but is shielded so that actual stimulation does not occur. The eSham system was used to mimic sensations of real rTMS. This system produces mild tingling on the scalp underneath the sham rTMS coil, making it difficult in differentiating between real and sham. The amount of electrical stimulation necessary to match real rTMS pulses was determined using an algorithm (parameter estimation by sequential testing). All subjects underwent the sham titration at the beginning of every rTMS session regardless of group assignment. The left prefrontal cortex was the cortical target for rTMS treatment, located using the EEG-10-20 system.; Real TMS 4 hours after surgery, first determined resting motor threshold (rMT) by starting with 40% of the machine output and 0.5 Hz stimulus frequency. The coil was positioned over the motor cortex and then adjusted until each pulse results in movement of the right thumb. The machine output was then adjusted to the lowest intensity that reliably produces thumb movement. Parameter estimation by sequential testing was used to determine the amount of machine energy necessary to visibly move the thumb 50% of the time. rMT was assessed before each rTMS treatment. The left prefrontal cortex was the cortical target for rTMS treatment. The EEG-10-20 system was used to locate the prefrontal cortex (F3).; Sham TMS 4 hours after surgery used specifically designed rTMS coil that produces auditory signals identical to real (active) TMS coils but is shielded so that actual stimulation does not occur. The eSham system was used to mimic sensations of real rTMS. This system produces mild tingling on the scalp underneath the sham rTMS coil, making it difficult in differentiating between real and sham. The amount of electrical stimulation necessary to match real rTMS pulses was determined using an algorithm (parameter estimation by sequential testing). All subjects underwent the sham titration at the beginning of every rTMS session regardless of group assignment. The left prefrontal cortex was the cortical target for rTMS treatment, located using the EEG-10-20 system.
Other intervention name(s): NeoPulse Neotonus Model 3600; NeoPulse Neotonus Model 3600; NeoPulse Neotonus Model 3600; NeoPulse Neotonus Model 3600
Allocation: Randomized
Intervention model: Crossover Assignment
Masking: Single (Participant)
Primary purpose: Other