Comprehensive Notes on Acupuncture and Neuroimaging Studies

Introduction to Neuroimaging Studies and Acupuncture

  • Vitaly Napadow is a pioneer in neuroimaging studies, specifically focusing on the effects of acupuncture on the brain.
  • The lecture will cover brain effects observed in hyperscan studies.

Neural Imager Background

  • Dr. Napadow works at the Martino Center for Biomedical Imaging.
  • His Ph.D. involved magnetic resonance imaging (MRI).
  • His research incorporates functional brain imaging, with nearly 20 years of experience in the field.

Multiple Components of Acupuncture

  • Acupuncture involves various components: TCM ritual, needles, somatosensory stimulation, and relaxation response.
  • Traditional Chinese Medicine (TCM) Ritual: Interaction between patient and acupuncturist, including history taking, palpation, and diagnosis, leading to a therapeutic alliance.
  • Somatosensory Stimulation:
    • Mechanical stimulation
    • Thermal stimulation (moxibustion)
    • Electrical stimulation (electroacupuncture)
  • Relaxation Response: Physiological changes during the resting period with needles in place.
  • Understanding which components are crucial for clinical outcomes is essential.

Importance of Understanding Mechanisms

  • Understanding the "why" behind acupuncture's efficacy is vital.
  • Example: A patient's description of pain originating from her husband's back and affecting her ears is a form of a mechanism.
  • Identifying true biological mechanisms is important for chronic pain.

Carpal Tunnel Syndrome (CTS) Study

  • CTS is the most common entrapment neuropathy, involving the median nerve within the carpal tunnel.
  • Increased pressure in the carpal tunnel leads to ischemia, inflammation, and nerve damage.
  • The nerve swells due to fibrosis, further increasing pressure, creating a vicious cycle.
  • Symptoms include pain and paresthesia in the first through fourth digits.

Objective Outcomes in CTS

  • Nerve conduction studies provide objective outcomes.
  • Impulses are enacted proximally to the carpal tunnel, with electrode pickups distally.
  • Latency (time for impulse to be picked up) is measured.
  • Mild CTS: Delayed sensory nerve conduction latencies.
  • Moderate CTS: Delayed sensory and motor latencies.
  • Severe CTS: All latencies delayed, reduced amplitude, and muscle wasting (thenar eminence).
  • Acupuncture aims to prevent progression to severe CTS or reverse damage in mild to moderate cases.

Prior Randomized Controlled Trials

  • Yang et al. (almost 10 years ago): Acupuncture was superior to oral steroids in symptom report and nerve conduction latencies at one-year follow-up.
  • Yow et al. (2012): Manual acupuncture showed no difference compared to non-insertive sham acupuncture for symptom improvement (did not include nerve conduction studies).

Pilot Study on CTS

  • Small cohort of CTS patients.
  • Evaluated at baseline via clinical testing and functional MRI with sensory stimulation (second and third digits vs. pinky).
  • Five weeks of acupuncture, with clinical testing midway and at the end.
  • Healthy adults tested five weeks apart for baseline stability comparison.

Acupuncture Protocol

  • Semi-individualized design with 13 treatments over five weeks.
  • Electroacupuncture between pericardium 7 (PC7) and triple warmer 5 (TW5) with low frequency, low intensity stimulation.
  • Additional points stimulated by manual acupuncture based on individual presentation.

Findings

  • Patients reported reduced symptom severity.
  • Reduction in nerve conduction latency:
    • Red bars represent CTS patients.
    • Blue bars represent healthy controls.
    • Yellow bars represent post-acupuncture patients, whose latencies moved closer to those of healthy controls.
    • The improvement was statistically significant for all three digits innervated by the median nerve.

Brain Imaging and Somatosensory Cortex (S1)

  • Novel idea to image the brains of CTS patients.
  • Focused on the primary somatosensory cortex (S1).
  • Wilder Penfield's Mapping: In the 1930s, Penfield mapped S1 during epilepsy surgeries by stimulating different brain areas and asking patients about sensations.
  • Unequal territory allocation: Larger area for face and hand due to higher sensitivity.

Functional MRI Mapping of S1

  • Functional MRI allows non-invasive mapping of S1.
  • Stimulating the second finger activates one part of S1, the third finger activates another, and the fifth finger yet another.
  • As the stimulus moves from the second to the third to the fifth digit, the center of mass of activation clusters moves up the gyrus, consistent with Penfield's findings.

Findings in CTS Brain Imaging

  • CTS patients exhibit a contracted separation of fingers innervated by the median nerve.
  • Healthy adults show clear separation between digit two, digit three, and digit three, digit five.
  • CTS patients show blurring between digit two and digit three representations.
  • After acupuncture, separation between digit two and digit three increases.
  • Test-retest reliability is consistent in healthy adults.

Larger Study with Sham Acupuncture

  • Three groups: local acupuncture, distal acupuncture, and sham acupuncture.
  • Local acupuncture: as in the pilot study.
  • Distal acupuncture: real acupuncture on the leg opposite the affected side.
  • Sham acupuncture: non-insertive placebo needles on non-acupuncture points with no electrical current.

Research protocol

  • Evaluated at baseline with MRI, questionnaires, and nerve conduction studies.
  • Eight weeks of acupuncture.
  • Post-acupuncture assessment with MRI and nerve conduction studies.
  • Three-month follow-up on symptom severity (Boston Carpal Tunnel Syndrome Questionnaire - BCTQ).
  • The reason for distal acupuncture is that clinically speaking there are many acupuncturists using the 'Tong' style of acupuncture with mirroring systems.

Enrollment and Retention

  • Able to enroll patients suffering from CTS.
  • Low dropout rate once patients were in the study.

Baseline Replication and Behavioral Testing

  • Replicated the previous pilot study results with a much larger sample.
  • Functional MRI and magnetoencephalography (MEG) both showed a reduction in D2D3 separation.
  • Did behavioral testing using finger agnosia: patients made more mistakes when the stimulus happened on the second and the third finger compared to the fifth finger.

Longitudinal Studies and Acupuncture

  • In terms of symptom severity, there was no difference between either of the two verum treatments.
  • Verum acupuncture improved nerve conduction latencies, whereas sham acupuncture got a little bit worse.
  • An increase in separation between D2 and D3 for the local acupuncture group compared to the sham acupuncture group.

Take Home Message

  • Both verum and sham acupuncture improve subjective psychological outcomes.
  • Only verum acupuncture improves objective physiological outcomes, such as nerve conduction studies and D2D3 cortical separation.

Time Taken To Produce Results

  • The study took a long period:
    • 2002-2003, pilot study planning
    • 2004-2005, study was complete
    • 2006-2007 publication struggle
    • Application for additional finding for funding
    • 2016 R01 level grant from NIH trial complete
    • 2017 longitudinal results from Brain publication

Acupuncture Benefits

  • Acupuncture is hard, but in the long run, its impact is substantial.
  • There has been increased insurance coverage.

Discussion

  • Differences between the distal acupuncture and the local acupuncture.
  • A slide showed that the distance between D2 and D3 in the brain and the S1 worked as separated, and the distal group compared to the local group.

Additional Acupuncture Questions

  • There are some findings around using a technique called diffusion tensor imaging, where they found remapping in the white matter.
  • What are the differences between lighter styles of acupuncture versus Chinese style?

Therapeutic Alliance in Clinical Settings

  • The therapeutic alliance is also an important component for other intervention types.
  • Social interactions shape how we feel or conceptualize pain.
  • In spinal manipulation and exercise, patient-rated therapeutic alliance was found to moderate outcomes.

Psychotherapy and Research

  • If compared in acupuncture, the differences between styles are going to have less of an impact.
  • The idea of the clinical encounter has not really been studied by brain imaging and is subsumed as the art of medicine.

Methodology

  • Hard to study effects as a single isolated individual; two-person methods are needed.
  • Use the patient and the clinician to understand the context through systems
  • Hyperscan Neural Imaging: Synchronously imaging more than one individual with EEG or Electrophysiology.
    • It is really fast
    • Piloting co-piloting
    • Juggling learning
    • Music performance

Synchronising

  • fMRI Hyperscanning is brain-to-brain Communication through Subcortical Responses with improved localization.
  • Two Synchronized MRIs, with Real Patients and Clinicians.
  • Fibromyalgia patients to make it valid and Clinical
  • Used Acupuncturists
  • Patients had Clinical Intake and then had MRI Social interaction.
  • They returned and paired with another acupuncturist and then had no interaction control with a social interaction.
  • The acupuncturist was told to do it in their own practice.

Technology

  • The set up was extremely hard to get running with MRI compatibles and audio microphones and transferring data through scanner ports.
  • Patients had cuffs in the MRI room and rating the actual cuff pain while the acupuncturist passed a current to reduce as much pain as possible.
  • Data between cardiac respiration or skin conductance.
  • During a time they are resting the subject looks at one another and Facial feedback, where patients were instructed with red or green colors.
  • They rate after, intensity or pain, then is then repeated 12 times. It then is repeated through actual patient ratings and clinician vicarious pain.

Outcomes

  • Data collected: cardiac data, respiratory data, skin conductance data
  • Functional MRI experiment setup: resting periods, anticipation cue (red or green frame), and pain experience.
  • Ratings: intensity of pain and affect
  • No differences were found between electroacupuncture or the lack thereof. It seemed to be a placebo.
  • Patients reported less pain was being treated and more positive affects.
  • The clinicians reported the same regarding vicarious pain.
  • The more that they mirror, the high the pain tolerance.

Mirroring & Expression

  • Babies learn to mirrors early on form creating a bond with their caregivers.
  • Change in video expressions with automated assistance in the change.
  • Mirroring has therapeutic alliance and great analgesia, creating empathy.

How does Mirroring Work?

  • Facial Prososocial
  • It activates social mirror circuitry. TPJ or Temporal Parietal.
  • The Acupuncturists actually activate more in the cue, a similar between the patient and acupuncturist.
  • There dynamic Brain Concordance that shows patient to patients.
  • This shows non verbal or pro social processing for better outcomes.
  • Only TPJ is Linked to analgesia, in this case, cognition over emotion.
  • Theory of Mind might be more important than empathy.

Summary

  • Understanding clinical interactions requires two-person mehtods.
  • Therapeutic Alliance needs a TPJ and enhanced by interaction.
  • The increased link to processing and non verbal usage makes for good outcomes.
  • This project was just published in "Science Advances" this year.