1. ESAT 3640 Therapeutic Modalities
PAIN
ESAT 3640
Therapeutic Modalities

2. What is Pain?
International Association for the Study of Pain defines pain as
“an unpleasant sensory and emotional experience associated with actual or potential tissue damage, or described in terms such as damage”

3. Pain Composed of a variety of human discomforts Not a single entity
Perception of pain can be subjectively modified by past experiences and expectations
We try to change perception of pain

4. What is the Purpose of Pain?
Warning system
Something is wrong, provoking withdrawal response
Can persist beyond its usefulness

5. Types of Pain
Acute
Chronic
Referred
Radiating

6. Tissue Sensitivity Order of sensitivity:
1 – Periosteum and joint capsule most sensitive
2 – Subchondral bone, tendons, and ligaments
3 – Muscle and cortical bone
4 – Synovium and articular cartilage

7. Sensory Receptors
Activation of sense organs with therapeutic agents will decrease perception of pain
4 groups
Mechanoreceptors
Nociceptors
Proprioceptors
Thermoreceptors

8. Meissner’s Corpuscles
Located near the surface at the dermal-epidermal junction
Sensitive to light pressure
Mechanoreceptor
Produces impulse when stimulus is increasing or decreasing
No impulse with sustained stimulus

9. Pacinian Corpuscles Deeper in the subcutaneous tissue
Respond to deep pressure
Mechanoreceptor
Produces impulse when stimulus is increasing or decreasing
No impulse with sustained stimulus

10. Merkel’s Corpuscles Located at the dermal–epidermal junction
Touch receptors
Sensitive to vertical pressure, not stretching
Mechanoreceptor

11. Ruffini Corpuscles In skin sensitive to touch, tension, and heat
In joint capsule and ligaments sensitive to change in position
Mechanoreceptors
Proprioceptors
Thermoreceptors

12. Krause’s End Bulbs Located in skin
React to decrease in temperature and touch
Thermoreceptors
Mechanoreceptors

13. Nociceptors Free nerve endings
Sensitive to extreme mechanical, thermal, or chemical energy
Respond to noxious stimuli
PAIN
Pretty much throughout the body

14. Muscle Spindles Bundle of specialized muscle fibers located in muscle
Respond to tension and length when muscle is stretched or contracted
Causes reflexive contraction of muscle
Tendon tap
Proprioceptors

15. Golgi Tendon Organs Musculotendinous junction
Respond to length and tension changes in muscle
Cause relaxation of muscle
Proprioceptors

16. Accommodation
Adaptation by the sensory receptors to various stimuli over an extended period of time
Phasic vs. Tonic receptors
Use of physical agents for extended period of time, may result in accommodation

17. Neural Transmission Afferent Efferent
Nerve fibers that transmit impulses from the sensory receptors to the CNS
Efferent
Nerve fibers that transmit impulses from the CNS to the periphery
Motor neurons

18. Simple Reflex Arc

19. Afferent System 1st order neurons 4 types of fibers
Transmit impulses from sensory receptors to the dorsal horn of the spinal cord
4 types of fibers
Alpha ()
Beta ()
Delta () C

21. Afferent System Continued
2nd order neurons
Carry sensory information from dorsal horn to the brain
Wide dynamic range or nociceptive specific
3rd order neurons
Carry information to various brain centers for integration, interpretation, and action response

22. Synaptic Transmission
Neurotransmitter – Passes information between neurons
Neuroactive peptides can facilitate or inhibit synaptic activity
Enkephalin
Serotonin
Norepinephrine
-endorphine
Dynorphin

23. Nociception Nociceptive neurons transmits pain signals
Cell body located in the dorsal root ganglion
Delta fibers = 25%, C fibers = 50%
Once stimulated – substance P is released
Size and conduction velocities different

24. Fast Pain Delta neurons
Brief, well-localized, & well-matched to stimulus
Originates from receptors in the skin

25. Slow pain C neurons Aching, throbbing, or burning Poorly localized
Less specificity to stimulus
Originate from both superficial and deep tissues

26. Afferent Pathways

27. Gate Control Theory
Pain modulation due to sensory stimulation and resultant increase in the impulses in the  afferent fibers
Stimulation of the substantia gelatinosa (SG)
Stimulation of the SG by  fibers inhibit synaptic transmission in the large and small fibers

28. Ascending Gate Control Theory
 and C fiber impulses inhibit SG, facilitating pain perception
Use of physical agents stimulate large-diameter fibers creating analgesic response

31. Endogenous Opioid Analogue to the Ascending Gate Control Theory
 fiber impulses trigger a release of enkephalin from neurons in the dorsal horn
Inhibit synaptic transmission in the  and C fibers

32. Central Biasing Descending pain control
Impulses from the thalamus and brain down the efferent fibers to the dorsal horn
Impulses from the higher centers close the gate and block transmission of pain message at the dorsal horn
Previous experience, emotional influences, sensory perception are factors which can influence transmission of pain

33. Endogenous Opioid Model of the Descending Pain Control Theory
Stimulation of the periaqueductal grey region and raphe nucleus by ascending inputs activates descending mechanisms
Stimulation of raphe nucleus sends impulses down the efferent fibers in the dorsal lateral tract
Synapse with enkephalin interneurons
Release of enkephalin

35. -Endorphin and Dynorphin
Stimulation of small-diameter afferents stimulates the release of BEP & Dynorphin
Prolonged stimulation of the small-diameter fibers is thought to trigger the release of BEP from the anterior pituitary gland
BEP does not cross blood-brain barrier
BEP probably release from area within brain

37. Pain Assessment Pain is difficult to evaluate and quantify
Subjective nature
Difficult to put into words

38. Pain Profiles Type of pain Quantify intensity of pain
Effect of pain experience on the athlete’s level of function
Assess psychosocial impact of pain

39. Pain Assessment Scales
Visual analogue scales
Pain charts
McGill Pain Questionnaire
Activity Pattern Indicators Pain Profile
Numeric Pain Scale
…Rate your pain on a scale from 1 to 10, with 10 being the worst pain you have every experienced or could imagine

40. Visual Analogue Scales

41. Pain Charts

42. McGill Pain Questionnaire