10-14 Sensory Exam

Question 1

decreased sensory input vs. hyperesthesia

Answer 1

-GOAL: looking for decreased sensory input & localize lesion

—hyperesthesia (excessive sensitivity) and hyperalgesia are usually NOT due to NS damage but rather chronic pain

Question 2

anesthesia vs. hypesthesia vs. analgesia

Answer 2

anesthesia = loss of sensation (usu helps localize)
hypesthesia = diminished
analgesia = loss of PAIN sensitivity

Question 3

allodynia

Answer 3

experience of innocuous stimulus as painful

Question 4

hyperalgesia vs. hyperesthesia

Answer 4

hyperalgesia = magnified sensation of pain
hyperesthesia = excessive sensitivity

Question 5

paresthesia

Answer 5

perception of a sensation where there is no identifiable stim

Question 6

dysesthesia

Answer 6

a painful paresthesia

Question 7

ALS vs DC-ML

Answer 7

ALS/STT - pain and temp sense

DC-ML - well-localized touch, pressure, vibratory and joint-position sense

Question 8

STT/ALS anatomy & testing

Answer 8

ANATOMY: un- & lightly-myelinated fibers follow periph nerves and nerve roots —> synapse in substantia gelatinosa of dorsal horn —> decussates immediately in ventral white commissure —> ascend AL cord and lateral b.s. —> VPL nuc of thal —> topographic projection to somatosens cortex

TESTING: sharp vs dull? warm vs cold (tuning fork)?

Question 9

DC/ML anatomy & testing

Answer 9

ANATOMY: large, heavily myelinated sensory nn. fibers conduct well-loc touch, pressure, vibe, and joint-position sense —> enter gracile fasic (lower) and cuneate fasic (upper) and ascend IPSI-laterally (vs. immed decuss. in ALS/STT)

TESTING: tuning fork vibe? sense mov’t of big toe or finger? recog objects by touch?

Question 10

CN V (Trigem) anatomy & testing: well-localized touch and pressure info

Answer 10

ANATOMY: large diam fibers -> chief sensory nucleus of trigem (pons) —>IPSI- and CONTRA-lateral VPM

TESTING: vibe sense?

Question 11

CN V (Trigem) anatomy & testing: pain/temp/light touch

Answer 11

ANATOMY: smal diam fibers -> spinal nucleus of trigem (caudal medulla) —> CONTRA-lateral VPM

TESTING: sharp vs. dull? touch face–do these feel the same to you? (can check temp, too?)

Question 12

Romberg sign presentation? reason?

Answer 12

steady when standing w/ feet together and eyes open, but unsteady with eyes closed
—b/c of decr joint position sensation (DC/ML)

Question 13

diminished muscle stretch reflexes: cause?

Answer 13

—caused by damaged large sensory axons (DC/ML, right?)

Question 14

Polyneuropathy: presentation/time course

Answer 14

“stocking” then once mid-calf “glove”

Question 15

presentaiton of decr sensation 2°to damage to a NERVE ROOT

Answer 15

—small, unilateral area of diminished sesnation with sharp borders
**re-call that dermatomes overlap

Question 16

presentation of decr sensation 2°to damage to TRACTS

Answer 16

—hemianesthesia unilateral sensory loss contralateral and inferior to site of TRACT lesion
—other signs needed to localize it

Question 17

presentation of unilateral SPINAL CORD damage

Answer 17

—on contralateral side: lose pain and temp on one side

—on ipsilateral side, just inferior to top of the lost temp/pain, lose vibration and joint-position sense

Question 18

Brown-Sequard Syndrome

Answer 18

loss of sensation and motor function (paralysis and anesthesia) that is caused by the lateral hemisection (cutting) of the spinal cord.

Question 19

proper vibe sense test technique

Answer 19

applying a vibrating, low frequency tuning fork to a BONY PROMINENCE in the distal limb

Question 20

“suspended” sensory loss

Answer 20

abnormal in the arms but preserved in the legs
—presents w/ lesions inside the spinal cord
—usu. syringomyelia (syrnix = cyst) or tumor

Question 21

lost pin-prick sensation on one side of face and contralateral side of body

Answer 21

damage to lateral brain stem: spinal trigem and STT

Question 22

hemianesthesia

Answer 22

thalamic lesions—>complete contralateral loss of sensation (head AND body)
—similar, less dense presentation w/ cortical lesion

Question 23

astereognosia: def and localization

Answer 23

inability to recog objects by touch despite nl sensation

—damage to parietal association area