Ch. 7: Somatosensation - Clinical Application Flashcards Preview

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Flashcards in Ch. 7: Somatosensation - Clinical Application Deck (46):

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?

  1. Conscious proprioception & discriminative touch
  2. Cold

  3. Fast pain

  4. Heat

  5. Slow pain


What is the Order of RETURN of senstaion after compression?

The reverse of loss:

  1. Slow pain
  2. Heat
  3. Fast pain
  4. Cold
  5. Conscious proprioception and discriminative touch


What is the definition of pain?

"Pain is an unpleasant sensory and emotional experience"


What locations of the brain may respond to pain?

  • Affective
  • Emotional 
  • Behavioral

Limbic terminaltes in the autonomic areas


What is Peripheral Sensitization?

Sensitize peripheral neuron = low threshold for activation, low amt of stimulus that produces an AP


What are the possible functions of FAST pain?

What named neurons are used?

Withdraw/escape from pain.

 (acute, A-delta, superficial)


What are the possible functions of SLOW pain?

What named neurons are used?

Rest damaged tissue

(chronic, C, deep)


FAST pain uses what pathway?

Spinothalamic pathway


SLOW pain uses what pathway?

Divergent Pathways


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)

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What is the Pain Matrix?

Brain structures that regulate pain. Can create pain in absence of stimulus.


The LATERAL pain system uses what pathway?


(Conscious Relay Pathway)


The MEDIAL pain system uses what pathway?


(Diverengent Pathways)


The pain experience envolves what 3 aspects?

What pathways do each of them use?

  1. Sensory → Discriminative aspects
    • Spinothalamic
  2. Motivational →Affective aspects
    • Spinolimbic and Spinoreticular
  3. Cognitive →Evaluative aspects
    • Prefrontal lobes


What are the 2 "Top-Down" responses to pain?

What do they do?

  1. Antinociception
    •  pain relief
  2. Pronociception
    • increase or amplify - ability to "experience" pain


What is the first place pain is recepted?

Dorsal Horn


What is the Dorsal Horn's NORMAL response to pain?

Action release, AP, normal reporting of pain


What is Suppressed Nociception in the Dorsal Horn?

Diminished pain

(ex: "rub it where it hurts")


What is "Sensitized" processing in the Dorsal Horn?

Temporary, short term increase in strength of pathway

Excessive pain!


What is "Reorganized" processing in the Dorsal Horn?

Long Term Potentiation (LTP) → excessive pain!

Reconstruction in synapses to make it easier to send signal 


What susbstance helps you preceive MORE pain?

Substance P


How do you stop pain in the Periphery?

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Remove stimulus/irritants

(ex: massage to remove edema)


How do you stop pain in the Dorsal Horn of the Spinal Cord?

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Counterirritant Theory - presynaptic inhibition of pain neurons

("rub it where it hurts")

Ex: TENS unit, massage, etc.

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How do you stop pain in the Brainstem Descending Systems?

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  • 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?

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  • 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?

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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)


How could you summarize WHY the pain matrix is important to us as PT's?

  • We can influence pain at multiple levels to decrease pain
    • Modalities in the periphery
    • Exercise for body wide
    • Mental for body wide 


What are examples of Pronociception at Level I, II & IV

  • Pain amplification
    • Level I: peripheral sensitization
      • pathological = pain w/o stimulus
    • Level II: LTP of pain pathway and other malfunctions
      • increase effectiveness of pathway = more pain
    • Level V: psychological stress can amplify pain
      • dispear, hopelessness


What is the difference between Acute and Chronic Pain?

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What is Chronic Pain?

healing extend beyond normal tissue healing time


Define the 2 types of Chronic Pain?


  1. Nociceptive
    • Continuing pain stimulus
    • Neurons functioning normally
  2. Neuropathic
    • NO continuing pain stimulus
    • Neurons NOT functioning normally
    • ***Hradest pain to deal wiht → cannot find cause