Ch. 7: Somatosensation - Clinical Application Flashcards
What are the Somatosensory Contributions to Function?
- Contributes to smooth, coordinated movement.
- Helps protect from injury.
- Contributes to understanding (perception) of our environment
How do we test somatosensation?
- Test conscious relay pathways
- Quick Screenings - if not problems indicated
- Complete Evaluations - if problems are indicated in screening or if refered to us for them.
What are the conscious relay pathways that we test?
What are their named neurons?
- Discriminative touch
- A-beta (exteroception), DC?ML
- Conscious proprioception
- Ia, Ib, II DC/ML
- Fast pain - tell sharp stimuli from dull
- A-delta, anterolateral column
- Discriminative temperature - discriminate hot from cold
- A-delta, anterolateral column
“Cortical” sensations” - intact operations of the first 4 - where cortex process sensory info to make meaning
What do we test in a Quick Screening?
- Vibration (distal joints)
- A-beta, DC/ML
- Conscious proprioception (distal joints)
- Ia, Ib, II DC/ML - position sense (ex: can they detect that big toe is flexed or extended with eyes closed)
- Fast pain
- A-delta, anterolateral column - sharp/dull
What do we evaluate in a Complete Evaluation?
- Sensory Threshold
- Myofilaments - lightest touch possible
- Sensitivity
- Two-point discrimination
- “Higher” (“cortical”) sensations
- “Stereognosis” - descirbe familiar objects w/o looking (ex: key)
- Pattern of loss
- Pain, temp, touch → pt education if stimulus not coming back.
What are the limits to formal sensory examination
- Unconscious
- Unresponsive
Cannot get good results
What is Anesthesia?
Lack of sensation
What is Analgesia?
Lack of pain sensation specifically
What is Hypesthesia?
Less than normal sensation
What is hypalgesia?
Less than normal amount of pain sensation
What is Paresthesia?
Abnormal sensation (painless, abnormal, tickling, tingling)
What is dysesthesia?
Absensce of direct stimuli
(unpleasant, abnormal, burning, shooting)
What is allodynia?
Type of Dysesthesia
- Patient perceives pain from a stimulus that normally does not cause pain
- Ex: how sensitive skin is after sun burn.
What is hyperalgesia?
- Normally perceived as pain → produces response out of proportion.
- Result of damage to nervous system.
What is Ataxia?
Lack of coordinated movement
What is the Order of LOSS of senstaion with compression?
- Conscious proprioception & discriminative touch
- Cold
- Fast pain
- Heat
- Slow pain
What is the Order of RETURN of senstaion after compression?
The reverse of loss:
- Slow pain
- Heat
- Fast pain
- Cold
- Conscious proprioception and discriminative touch
What is the definition of pain?
“Pain is an unpleasant sensory and emotional experience”
What is Referred Pain?
Convergence of somatic [body] and visceral [organs] axons in spinal cord
(ex: left arm & heart converge at same spot - heart never hurts, brain learns it is always arm pain. Heart attack = brain thinks arm pain)
How do you stop pain in the Periphery?
Remove stimulus/irritants
(ex: massage to remove edema)
How do you stop pain in the Dorsal Horn of the Spinal Cord?
Counterirritant Theory - presynaptic inhibition of pain neurons
(“rub it where it hurts”)
Ex: TENS unit, massage, etc.
How do you stop pain in the Brainstem Descending Systems?
- Your own thoughts can turn down pain.
- Periaqueductal gray = termination of spinomesencephalic → starter for all brainstem to spinal cord pathways
How do you stop pain at the subcortical level?
- Potential to slow pain messages body wide
- Hypothalamus, pituitary gland, adrenal medulla (opiate-mediated…endorphins!) → lasts longer than pain meds (up to several hours)
How do you stop pain at the cortical level?
Pathway from cortex to hormonal level -> can turn on body wide reduction system by thought. Can turn on brain stem decending pathway.
(Ex: placebos, distraction, perception)
What is the difference between Acute and Chronic Pain?
