quiz 2: Sensory Flashcards
Most subjective aspect of neurologic exam
sensory examination
sensory exam
- most subjective
- diff ways to explain sensory system/sensory loss
- sensory loss explains neuro system
- impairment of sensory affect function
Critical parts of sensory system
- Transduction (mechanical E convert to electric E)
- Transmit electrical E via PNS to higher centers
- higher centers perceive impulse
- interpret perception
- motor output based on sensory input
Sensory Input –> Motor output
to make motor choices
sensory: how would diminished sensation affect motor performance?
aware of body proprioception
sensory: how are the various sensory modalities used for mobility?
feel the ground bumps in walking
sensory: does selective loss of one modality lead to unique functional limitations?
if do not know location of legs then cannot walk
sensory: grading of movement dependent on accurate sensory information
hold paper cup without squishing it: sensory –> motor
Potential Sources of Sensory Problems
3
- Receptor –> Sensory
- Nerve –> dorsal root –> spinal
- cord –> cortical sensors
Localization sensory pattern: Receptor
focal, dermatome otherwise intact (no sensation at that area but dermatome intact elsewhere)
Localization sensory pattern: Peripheral Nerve
median, ulnar, musculocutaneous etc.
Localization sensory pattern: Dermatomal
nerve root, cord (area of skin supplied by a single spinal nerve)
Localization sensory pattern: Cortical
diffuse, large area, non dermatomal
Localization sensory pattern: association cortex
difficulty with sensory interpretation
What are Localization sensory patterns
- receptor
- peripheral nerve
- dermatomal
- cortical
- association cortex
What are primary sensations?
- where are they processed?
- what are they mediated by?
- superficial light touch, sharp and dull
- deep proprioception, vibration
processed at: the primary somatosensory cortex
mediated by: anterolateral system and dorsal column; medial meniscus
What are cortical sensations?
- where are they processed?
- what are they mediated by?
- 2-point discrimination
- graphesthesia
- stereognosis
- double simultaneous extinction
processed in the association cortex in the parietal lobe
What do you do for a sensory exam?
- tools
- instructions
- document
Tools: cotton tip, safety pin/paper clip, tuning fork
Instructions are clear: “teach the test” and say what you will do so no ambiguity
Document: many descriptors, stay consistent
Sensory exam rules
6
- expose the part
- compare bilaterally (should be equal)
- by systematic (between size, but do randomly)
- “random testing”
- patient eyes closed
- patient responds YES or NO (ask, can you feel this?)
Documenting sensory exam (5)
Intact—-YAY
Absent (no response)
Diminished
Inconsistent- (sometimes correct, sometimes not)
Delayed (after touch takes time to answer)
Abnormal Sensory Findings
- Paraesthesia: tingling
- Dysesthsia: painful
- Analgesia: unable to distinguish pain
- Hyperaesthesia: excessive
- Hypoaesthesia: diminished
- Anaesthesia: absent
- Allodynia: non-noxious stimuli elicit pain
Paraesthesia
tingling (pins and needles, ants growing on feet)
Dysesthsia
painful
Analgesia
unable to distinguish pain
Hyperaesthesia
excessive
Hypoaesthesia
diminished (dont feel light touch, need to dig in)
Anaesthesia
absent (dont feel the touch)
Allodynia
non-noxious stimuli elicit pain
Findings on a sensory exam (7)
- Dermatomal vs Nondermatomal
- Peripheral Cutaneous
- Proximal vs Distal
- Ascending v descending
- Unilateral vs Bilateral
- UE vs LE
- Focal vs Diffuse
Dorsal Column/Medial Lemniscus
- light touch [cotton wisp, fingertip]
- vibration [tuning fork]
- position sense [proprioception and kinesthesia]
Light Touch Testing
- procedure
- what tool
-test intact area first (to train the patient)
-Symmes-Weinstein monofilaments provides for more exact documentation
[for peripheral neuropathy]
Proprioceptive Sensations
- definition
- what it tells us
- awareness of body position and of movements of parts of the body
- proprioception tells us the location and rate of movement of one body part in relation to others
What does proprioceptive sense informs us of? (4)
- the degree to which our muscles are being contracted
- the amount of tension created in the tendon
- change in position of a joint
- the orientation of the head relative to the ground in response to movements
What are proprioreceptors?
- muscle spindles
- tendon organs
- joint kinesthetic receptors
and the skin itself
only a slight adaptation, this allows the brain to be informed continually of the status of different parts of the body so that adjustments can be made (body does not adapt to proprioceptive input)
How to test proprioception?
Do they know it moved, do they know up or down
- grab great toe by bony prominence or nail
- demonstrate “ this is up and this is down”
- move toe up and down several times, then ask patient to identify
- start with large movements, go to small
- alternate method, mimicry of larger segments on intact or involved side
Testing technique for kines
up or down
mimic
tell me when you feel movement
try to hold by bony prominence, nails
Kinesthesia testing
“Did I move”
- hold the patient great toe as in proprioceptive test
- “tell me the instant you feel motion, but not direction”
- 1mm is normal (profound deviation is abnormal)
- kinesthetic loss can precede proprioceptive loss
vibration testing
- tool
- where
- what happens
- what to do
- significance of test
Tool: C128 tuning fork
where: bony prominence: (malleoli, ulnar and tibial tubercles, acromion) and great toe
what happens: bones conduct the vibration to much more proximal sites, where they can be detected by nerves far from the location being tested
what to do: hold fork by the base, hit on hand. pt should stop feeling vibration close to when you do
significance: vibratory loss often precedes loss of other modalities in peripheral neuropathies
Anterolateral System
-3 sensations
- pin prick (sharp/dull)
- thermal sense (not usually tested by PTs)
- deep pain (noxious stimuli)
Sharp Dull Test (6)
tests anterolateral system
- pin vs thumb
1. test the intact area first
2. establish consistent answers
3. randomize
4. test bilaterally
5. skin must be depressed
6. do not test open areas
Documenting the Sharp Dull Test
intact impaired inconsistent delayed RATION OF CORRECT: INCORRECT ANSWERS
Cortical/Discriminatory tests
brain making sense of input:
- double simultaneous stimulation
- point localization
- two point discrimination
- stereognosis
- graphesthesia
Double simultaneous stimulation
- presentation of paired sensory stimuli to the 2 sides simultaneously (visual, aural, tactile)
- patient may be able to attend to sides singly, but loses perception of involved side when stimulated simultaneously [test is positive if involved side doesnt feel it]
functional implications?
point localization
- rationale
- what to do in the test
-rationale: sensory lesions can impair accurate identification, even if they retain their sensation of light touch
- what to do in the test:
1. point locations: touch the surface of the skin and remove the stimulus quickly
2. ask the pt to touch the spot where the sensation was felt
2 point discrimination
distance where 2 points are felt as one–fingertips 2-4mm, worsening distally, use skinfold calipers
stereognosis
- cause
- test
-lesion of contralateral parietal association cortex
ability to identify what an object is by feeling its shape ie coin, pen, keys
graphesthesia
- cause
- test
cause: lesion of contralateral parietal association cortex
lost ability to identify numbers or letters on the skin
language/comprehension issues ( do shapes)
baclofen (clorisal)
anti-spasticity medication
(for CNS, UMN lesion)
oral vs pump: need to take a higher dose orally since it will be broken down as it travels through systems, also dont have to swallow the pump method
klonopin (clonazeprim)
anti-spasticity medication aslo treats anxiety
dantrium (dantrolene)
works at NMJ to decrease spasticity everywhere
zanaflex/ tizanidine
anti-spasticity medication
botox
can inject to specific muscle – good for focal spasticity but turns the whole muscle off, not just anti-spasticity medication
graphagnosia
lesion of the contralateral parietal association cortex (identify letters on patients skin)
stereognosia
lesion of the contralateral parietal association cortex (identify objects by shape)
