Lecture on Interpreting Pain Neurophysiology

Presenter

• Dr. Brook Coombs
• Musculoskeletal physiotherapist with chronic pain research experience

Learning Objectives

• Describe basic pathology underlying different types of pain presentations.
• Interpret patient interview findings to determine pain mechanism involvement.
• Use patient-reported outcomes (PROs) in pain assessment.

Understanding Pain Neurophysiology

• Pain is not directly proportional to bodily damage.
• Pain can exist without bodily damage.
• Pain is complex, involving cognitive, emotional, behavioral, social, and cultural dimensions.
• Aligns with ICF framework and biopsychosocial models.

Importance of Studying Pain

• Enhances understanding of patient pain experience.
• Guides interview and physical examination.
• Informs intervention and patient education about pain and movement roles.

Pain Classifications

1. Nociceptive Pain

• Caused by: Damage to body tissue.
• Characteristics: Sharp, aching, throbbing.
• Examples: Surgery, arthritis, osteoporosis, musculoskeletal conditions.
• Subtypes:
  • Mechanical: Localized, intermittent pain (e.g., calf bruise/tear).
  • Inflammatory: Constant, varying pain due to inflammation.
  • Ischemic: Pain due to reduced blood flow (e.g., peripheral arterial disease).

2. Neuropathic Pain

• Caused by: Damage/disease to the nervous system.
• Characteristics: Burning, shooting, numbness, tingling.
• Examples: Sciatic nerve injury, diabetic neuropathy.
• Features:
  • History of nervous system lesion/disease.
  • Relationship between pain and nerve movement.

3. Nociplastic Pain

• Characteristics:
  • No clear tissue damage evidence.
  • Pain disproportionate to tissue damage.
  • Weak relationship between pain and mechanical stress.
• Central Sensitization:
  • Amplification in central nervous system pathways.
  • Includes dorsal horn, thalamus, cortex involvements.
  • Linked with cognitive and emotional factors like fear of movement (kinesiophobia).

Red Flags in Pain Assessment

• Night wakening due to pain.
• Deep aching, throbbing, or constant pain.
• Progressive or cyclic symptoms.
• Unwell appearance, fatigue, weight loss.

Assessing Pain Neurophysiology

• Sensory Testing:
  • Algometry for pressure sensitivity.
  • Von Frey filaments for sensation loss.
  • Two-point discrimination.
  • Cold sensitivity testing.
• Questionnaires:
  • Pain Detect for neuropathic and central sensitization assessment.
  • Kinesiophobia scale for movement fear assessment.

Recommended Readings

• Suggested chapter for a different perspective on pain neurophysiology.

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End of lecture notes.