Chapter 7 Flashcards
What are the two methods of testing function?
Nerve conduction study (NCS)
Somatosensory evoked potentials (SEP)
What does NCS measure?
peripheral nerve function
What does SEP measure?
peripheral nerves and central nervous system pathways
What is compared to determine if NCS is normal?
distal latency
amplitude of the evoked potential
conduction velocity
What are SEPs used to determine?
verify subtle signs and locate lesions of the dorsal roots, posterior columns, and brainstem.
What is ataxia?
incoordination that is not due to weakness
What are three types of ataxia?
sensory
vestibular
cerebellar
What is the Romberg test used for?
to distinguish between cerebellar ataxia and sensory ataxia
What is neuropathy?
general term for dysfunction or the pathologic condition of one or more peripheral nerves
What is the sensory loss in peripheral nerve lesions?
- conscious proprioception and discriminative touch
- Cold
- Fast pain
- Heat
- Slow pain
What are the common causes of dysfunction of the spinal region?
trauma
disease
virus
What happens with complete transection of cord?
All sensation is prevented at one or two levels below the lesion
Voluntary motor control below the lesion is also lost
What happens with hemisection of the spinal cord?
- complete loss of sensation in contralateral side 2-3 levels below lesion
- discriminative touch and conscious proprioception lost ipsilateral to lesion
Lesion in posterior column:
conscious proprioception, 2 point discrimination and vibration lost below level of lesion
-ataxic movements
Brainstem region lesion:
mix of ipsilateral and contralateral signs
-sensory loss can be contralateral in upper midbrain after discriminative sensation have crossed midline
Somatosensory Cortex Lesion:
Conscious proprioception
Two-point discrimination
Stereognosis
Localization of touch and pinprick (nociceptive) stimuli
-contralateral and decrease of above sensations
Fast and slow pain can occur with musculoskeletal injuried via what fibers?
A-delta and C fibers
What parts of the brain are included in processing and regulating pain information?
brainstem, amygdala, hypothalamus, thalamus, and areas of the cerebral cortex
What does understanding of pain matrix require?
understanding of:
- discriminative
- motivational affective
- congitive-evaluative component
Discriminative aspect of pain matrix refers to what?
the ability to localize the site, timing, and intensity of tissue damage or potential tissue damage
Motivational affective aspect of pain matrix refers to what?
the effects of the pain experience on emotions and behavior, including increased arousal and avoidance behavior.
Cognitive-evaluative aspect of pain matrix refers to what?
meaning that the person interprets /ascribes to the pain (punishment, burden
How is pain controlled?
- gate theory
- counterirritant theory
- dorsal horn processing of nociceptive information
- antinociceptive systems
What is the gate theory of pain?
Typical response to hitting one’s thumb with a hammer is to withdraw the thumb, yell, and apply pressure
- TENS
What is the counterirritant theory?
explains the inhibition of nociceptive signals by stimulation of non-nociceptive receptors occurs in the dorsal horn of the spinal cord
What is the dorsal horn processing of nociceptive information?
Processing of somatosensory information in the dorsal horn can be altered by abnormal neural activity or by tissue injury
What are the states of dorsal horn processing?
normal
suppressed
sensitized
reorganized
Normal state of dorsal horn processing:
normal physiologic activity
Suppressed state of dorsal horn processing:
segmental and descending inhibition
Sensitized state of dorsal horn processing:
changes in neurotransmitters and receptors
Reorganized state of dorsal horn processing:
cell death, degeneration of C fiber and sprouting that synapses with neurons in the nociceptive pathways
Neuropathic pain is produced by what?
neuroplasticity not by stimulation of nociceptors
Antinociception:
the suppression of pain in response to stimulation that would normally be painful.
What activates antinociceptive mechanisms?
endorphins and endogenous substances
Level I of antiociceptive site:
peipheral
Level II of antiociceptive site:
dorsal horn
Level III of antiociceptive site:
fast acting neuronal pathway from brainstem
Level IV of antiociceptive site:
hormonal
Level V of antiociceptive site;
descending cortical inhibition
What is primary hyperalgesia?
refers to excessive sensitivity to stimuli in injured tissue
