Disorders of Consciousness

Question 1

Arousal

Answer 1

Level of consciousness, are the lights on?

Question 2

Awareness

Answer 2

Content of consciousness, is anyone home

Question 3

Is there a change in arousal with a transected medulla?

Answer 3

No, normal EEG. Only loss of arousal with transected mesencephlon (desynchronized EEG)

Question 4

ARAS location and transmitter

Answer 4

Ascending reticular activating system, at the pontomesencephalic junction, acetylcholine

Question 5

Neural correlates of arousal vs awareness?

Answer 5

Arousal: ARAS, thalamus, thalamo-cortical relays
Awareness: Cerebral cortex

Question 6

Epidural hematoma causing disruptions in consciousness

Answer 6

Causes uncal herniation, which presses on the arousal centers in the brainstem

Question 7

Thalamic Ischemia and consciousness

Answer 7

Disrupts

Question 8

Cortical disruptions of consciousness

Answer 8

CJD causing spongiform encephalopathy

Question 9

Levels of consciousness

Answer 9

Awake, drowsy, lethargic, obtunded, stuporous, comatose

Question 10

What indicators are rated in the glasgow coma scale?

Answer 10

Verbal responsiveness, eye opening, motor responsivity

Question 11

When you don’t know the where’s and why’s…

Answer 11

Listen to the breathing and look at the eyes.

Question 12

Cheyne-Stokes Respiration

Answer 12

Caused by diffuse forebrain dysfunction, periodic non breathing, followed by crescendo breathing

Question 13

Midbrain injury effect on breathing

Answer 13

Hyperventilation

Question 14

Rostral Pons injury effect on breathing

Answer 14

Apneusis: Breaths followed by pauses, followed by shallow release

Question 15

Caudal pons injury effect on breathing

Answer 15

Ataxic breathing, totally erratic

Question 16

Medullary injury effect on breathing

Answer 16

Respiratory arrest

Question 17

Control of pupillary sphincter

Answer 17

Light hits retinal cell, info transmitted to both edinger westphal nuclei. Via posterior commissure. Construction due to 3rd nerve

Question 18

Carotid dissection

Answer 18

Can cause miosis because sympathetics going to eye ascend on internal carotid.

Question 19

Thalamic pupils

Answer 19

Small reactive

Question 20

Pretectal Pupil

Answer 20

Fixed Dilated

Question 21

Herniation Pupil

Answer 21

One fixed dilated pupil

Question 22

Pontine pupil

Answer 22

Pinpoint

Question 23

Midbrain pupil

Answer 23

Fixed mid-size

Question 24

Corneal Reflex

Answer 24

Afferent Limb: V1- CNV main nucleus in pons

Efferent Limb: CN VII orbicularis oculi – CNVII nucleus in pons

Question 25

Doll's Eye Reflex

Answer 25

If eyes don't move when head is turning, the brainstem is not intact. Right side (PPRF) affected, can't look right

Question 26

Other test of brainstem function other than dolls eye?

Answer 26

Calorics

Question 27

Upper midbrain damage effect on motor system

Answer 27

Decorticate posture -- Flexors dominate

Question 28

Upper pons damage effect on motor system?

Answer 28

Decerebrate Posture- extensors dominate

Question 29

What looks like consciousness impairment, but isn't?

Answer 29

Locked-in syndrome: Structural/functional brainstem transection just below mid-pons. ARAS - lies right above mid pons is responsible for preserved consciousness, but disruption of descending efferent pathways.

Question 30

What can locked in people do?

Answer 30

Look up and down, convergence.

Question 31

Vegetative state arousal vs consciousness

Answer 31

Arousal, no awareness

Question 32

Coma/sleep/anesthesia arousal vs consciousness

Answer 32

No arousal, no awareness. Eyes closed

Question 33

Minimally conscious state

Answer 33

Arousal, varying levels of awareness

Question 34

Two types of vegetative states

Answer 34

Persistent vs permanent

Question 35

Brain death

Answer 35

Absent midbrain reflexes (pupillary reactivity), absent pontine reflexes (VOR, corneal reflex), absent medullary reflexes (apnea)