1. Non-Physiological Factors of Pain Steve T. Brewer, PhD Angelo State University DUDE, YOU’RE STANDING ON MY TOE!!!

2.  Webster  “the physical feeling caused by disease, injury, or something that hurts the body.”  International Association for the Study of Pain  “Pain is an unpleasant sensory and emotional experience associated with actual or potential tissue damage or described in terms of such damage.”  Purpose?  Warns of tissue injury or potential injury.  Provides incentive to rest and recuperate.  Is it always useful?  NO (think chronic pain) WHAT IS PAIN? WHAT PURPOSE DOES PAIN SERVE?

3.  Nociceptive Pain  Tissue injury pain  Sprains  Cancer  Headache  Viscera pain  Arthritis  Allodynia/Hyperalgesia  Neuropathic Pain:  Cancer pain  Diabetic Neuropathy  Phantom Limb Pain  Post-herpetic Neuralgia  Chronic Regional Pain Syndrome  Fibromyalgia TWO MAJOR “TYPES” OF PAIN

4. HOW IS PAIN GENERATED? Adapted from Basbaum lecture Modern Medical Model of Pain Transmission (Stimulus Model)

5. HOW IS PAIN GENERATED?

7.  NO!!!  Why is that?  Quite simply, the perception of pain depends on many non- physiological factors. IS PAIN PERCEIVED THE SAME WAY BY EVERYONE?

8.  If I stepped on your toe, would it hurt more if you thought I did it on purpose?  Yes  The context of pain is also built on a foundation of experience with pain. CONTEXT

9.  The perception of pain depends on the expectation of the pain experience.  One of the most powerful non-physiological factors  Placebo Effect  Hidden vs open injections  Nocebo effect (placebo’s annoying sibling) EXPECTATION

11.  The amount of attention being paid to pain evokes more brain activity. ATTENTION

12.  Medications  Opioids (Acute pain, some neuropathic pain)  Spinal cord pump  NSAIDS (Inflammatory pain)  SSRI’s/SNRI’s (chronic pain)  GABApentin (neuropathic pain)  Cannabinoids? (mixed research on this but leans toward positive benefit) TREATMENTS

13.  Non-Medication  Vibratory Stimuli (e.g. hand shaking)  TENS Unit  Spinal Cord Stimulators  Deep Brain Stimulation in PAG (mid-brain structure)  (this treatment is most often used for Parkinson’s Disease)  Placebo!!!  Hypnosis  Cognitive Behavioral Therapy (CBT)  Sleep!!  Activity/Exercise  GABAergic stem-cell replacement in spinal cord  Would be useful for neuropathic pain.  Still being developed  Works in mouse models TREATMENTS

14.  Pain is more than response to a stimulus.  Pain is emotional, contextual, and driven by personal experience.  The magnitude and quality of an individual’s pain cannot be predicted.  Pain treatment is diverse and should not rely on any single approach. SUMMARY