Ch. 7 Somatosensation: Clinical Application Flashcards
Somatosensation contributions to function
- contribute to smooth coordinated movement
- help protect from injury
- contribute to understanding environment
Quick Screening
- vibration (A-beta: DC/ML)
- Conscious Proprioception (Ia, Ib, II: DC/ML)
- Fast pain (A-delta: anterolat column)
Threshold
minimal detectable touch that can still be sensed
2 problems of sensation
- Nn fail to transmit signals (not enough sensation)
- Nn transmit inappropriate sensory messages (too much sensation)
Anesthesia
lack of sensation
Paresthesia
- extra sensation: painless, abnormal, tickling/tingling
- sign of NS irritation
Analgesia
lack of pain
hypalgesia
less pain
dysesthesia
- extra sensation: unpleasant, abnormal, burning, shooting
- sign of NS irritation
Allodynia
Normally nonpainful stimulus causes pain
Sensory ataxia
- uncoordinated movement due to disorder of sensation
- (specifically loss of unconscious proprioception)
Hyperalgesia
normally painful stimulus causes greater pain than expected
Pain
- an unpleasant sensory and emotional experience
- Multifaceted (sensory/physical, limbic/autonomic, cortical)
fast pain function
- withdraw/escape from pain
- Acute: A-delta, superficial
- alert to danger
peripheral sensitization
- by products of inflammation can sensitize free nerve endings
- decrease threshold (easier to elicit pain)
Components of testing somatosensation
- Discriminative Touch (A-beta; skin/subQ)
- Conscious proprioception (Ia; spindles)
- Fast Pain (A delta)
- Discriminative Temp (A-delta)
Complete Eval
(Quick eval plus:)
- threshold (monofilaments)
- Sensitivity (2 point discrim)
- higher (cortical) sensation (perception: stereognosis)
return of sensation order
- slow pain
- heat
- fast pain
- cold
- conscious proprioception (Ia, A-beta)
Order of loss of sensation
- Conscious sensation (Ia, A-beta)
- cold
- fast pain
- heat
- slow pain
Small diameter affected first by:
anesthetics, toxins, metabolic insufficiency
Hypesthesia
less sensation
Slow pain function
- rest damaged tissue
chronic: C, deep
3 Aspects of pain to treat
- sensory discriminative
- motivational/affective
- cognitive/evaluative
antinociception
- pain relief
- turn down pain
- pain control
Top-down response to pain
- antinociception
- pronociception
Pronociception
- turn up pain
- increase perception of pain
5 levels of pain control
I-periphery II-dorsal horn III-brain stem, descending IV-Subcortical (hormone) V-cortical
Level II pain control
- dorsal horn
- counter irritant
- presynaptic inhibition of pain neurons
- activate A-beta Nn in same area to decrease pain signal at synapse
Level III pain control
- brainstem descending
- presynaptic inhibition from above
- activated by level IV pain control
Level IV pain control
- Subcortical
- hormone level
- hypothal, pig gland and adrenal medulla release endogenous opiates into blood to decrease pain
- from aerobic exercise
- can outlast pain stimulus
Level V pain control
- cotrical
- mind over matter
- perception, attn, distraction, placebos, stress-induced analgesia etc
- thinking can turn on level III and IV
Level I pain control
- periphery
- remove stimulus/irritant
Chronic Pain
- nociceptive (continuing pain stimulus)=pain neurons functioning normally
- neuropathic=NS/pain neurons malfunctioning, no continuing stimulus
Level II pronociception
LTP of pain pathway and other malfunctions
Level I Pronociception
peripheral sensitization can turn on nociception
Level V pronociception
psychological stress can amplify pain perception
