final exam

all answers to all quizzes

1

spinal

2

posterior inferior cerebellar

3

vertebral

4

anterior inferior cerebellar

5

superior cerebellar

6

posterior cerebral

7

anterior cerebral

8

anterior communicating

9

internal carotid

10

posterior communicating

11

middle cerebral

Which cortical potentials are likely to be affected by poor perfusion first?

median nerve

pressure at which a vessel’s wall collapses

critical closing pressure

pressure at which a closed vessel will open

critical opening pressure

To reperfuse a closed vessel, the COP must be much (greater/lesser) than the CCP

greater

Latency (increases/ decreases) when the patient's body temp increases

Decreases

Amplitude (increases/decreases)as body temp increases

Increases

Latency(increases/ decreases) as temp decreases

Increases

Amplitude (increases/ decreases) as temp decreases

Increases

Cortical SSEPs start to decrease at what temp?

32°

Peripheral steps start to increase at what temp?

32°

At what temp are cortical responses absent?

22°

At what temp are peripheral responses absent?

<18°

Hypoxia is indicated by a pulse oximetry below

95%

What responses are the first to be affected by any type of SSEP change?

Cortical

The condition of excessive cow above 45mmhg that decreases blood PH, causing blood to become more acidic

Hypercapnia

The normal pH of blood is between

7.36 -7.44

The percentage of blood solids is defined by

Hematocrit

A hematocrit below what percent y may cause steps to become decreased in amplitude and decreased in latency

10

An infarct of the middle cerebral artery would result in sensory and motor deficits where?

contralateral upper extremity/face

What is the function of the frontal lobe?

motor

What is the function of the parietal lobe?

sensory perception

What is the function of the temporal lobe?

hearing

What is the function of the occipital lobe?

vision

We monitor the posterior 1/3 of the spinal cord via

somatosensory evoked potentials

When recording compound muscle action potentials from the hands, the spinal cord tract that is activated is the

lateral corticospinal tract

The DCML pathway is composed of how many neurons?

3

The lateral corticospinal tract consists of how many neurons?

2

Cranial nerve 7 is the

facial nerve

Patients with a lesion in the lower motor neuron will experience what type of paralysis?

flaccid

The corticospinal tracts in the spinal cord are perfused by which artery?

anterior spinal

The vertex electrode position in the International 10/20 System that is located 50% along the midline anterior-posterior measurement is called

Cz

SSEP change criteria includes what percent amplitude and what latency?

50% amplitude decrease and/or 10% latency increase

During what phase of general anesthesia does intubation occur?

induction

The return of protective reflexes accompanies which phase of general anesthesia?

emergence

Which two anesthetic agents are most detrimental to MEPs and CMAPs?

halogenated agents and nitrous oxide

Which of the following is most potent?

2% isoflurane

Increasing concentrations of isoflurane will have what effect on subcortical potentials?

no effect

Which may be a part of a TIVA regimen?

all of these

What is the preferred level of muscle relaxing (TOF) for EMG monitoring?

4/4 twitches

A depolarizing muscle blocker

binds to acetylcholine receptors and causes prolonged depolarization of the end plate

When testing train of four to assess the level of muscle relaxation, the peripheral nerve should be stimulated how frequently?

2 times/second

Which of the following causes an increase in amplitude of cortical SSEP responses?

ketamine

Which medication is avoided during cranial surgery because it can cause an increase in intracranial pressure?

ketamine

All of the following can cause burst suppression of the EEG except

sufentanyl

What monitoring modality is most highly impacted by anesthetic medications?

visual evoked potentials

Loss of memory of an event

amnesia

All of the following will help create conditions favorable for IONM except

administering a bolus of propofol

A neuron fires an action potential because of a high frequency excitatory input. This is an example of what type of summation?

temporal

Myelinated actions conduct action potentials (rapidly/slowly) and exhibit _____ _____

rapidly; saltatory conduction

The sodium potassium pump pumps how many ions in and out of the cell?

3 Na+ out, 2 K+ in

These structures open and close as the membrane potential changes

voltage-gated ion channels

What is the process by which a neuron is brought to firing threshold by convergent excitatory inputs?

spatial summation

What is the process by which a neuronal membrane potential moves in the positive direction toward threshold of activation?

depolarization

Which neurotransmitter is active at the neuromuscular junction?

acetylcholine

This structure is the initiation point of the action potential

axon hillock

What is the function of the sodium potassium pump?

to establish and maintain the resting potential

What causes the decay of the action potential?

Action potentials do not decay

What effect does neurotransmitter binding to the post-synaptic membrane receptors have on the neuron

not enough information to determine

A monosynaptic reflex occurs

to prevent injury to the body before the central nervous system is even aware it has occurred

If regional blood flow drops below a critical threshold due to a period of significant hypotension, which of the following areas would demonstrate functional changes first?

cerebral cortical grey matter

When spinal cord cerebrospinal fluid pressure increases, _______ must be increased in order to maintain spinal cord blood flow?

spinal cord perfusion pressure

In a patient with chronic hypertension, the systemic blood pressure required to support autoregulation of spinal cord and cerebral perfusion pressure is _____ compared to normal.

increased

Which of the following occurring around the time of an observed attenuation or abolishment of evoked potentials may be the result of significant neurological trauma?

blood pressure spike

Mild to moderate hypothermia usually results in changes in ________ but leaves_______ unchanged.

latency, amplitude

Which of the following are the potential causes of an increase in amplitude of evoked potentials resulting from supramaximal stimulation?

reduction of inhalational agent

Which of the following structures has the greatest ischemic tolerance?

peripheral nerve

A progressive loss of the popliteal fossa, subcortical, and cortical recordings in the left tibial nerve SSEP over the course of 10 minutes during an anterior lumbar interbody fusion is likely the result of

retraction of the left iliac artery

Changes in evoked potentials due to significant acute hypotension causing spinal cord ischemia are generally observed

bilaterally

What is the term given to a region of tissue that is situated between the distributions of two major arterial distributions?

watershed zone

Where is the major spinal cord watershed zone located?

midthoracic

What would be the best first line intervention to significant evoked potential changes which are the result spinal cord ischemia caused by systemic hypotension?

increase the MAP

As a response to decreased blood pressure in the vascular bed of the spinal cord, autoregulation would (constrict/dilate) the arteries supplying the cord

constrict

Decrease in regional cerebral blood flow would cause a change in which modalities?

contralateral SSEP cortical responses and ipsilateral EEG

Which of the following best describes bipolar EMG recording in contrast to referential EMG recording?

bipolar indicates both electrodes are located within a single muscle for greater nerve root specificity

What is the threshold (mA) below which we consider the pedicure likely to be breached?

8

Which of the following could most likely cause a pedicure screw threshold of 3 mA?

medial breach of pedicure

What is the likely effect of testing pedicle screws with 1- twitches out of 4?

increased threshold value

Monitoring spontaneous EMG activity is based on the principle that

irritation or injury of motor nerve fibers in the surgical site results in the activation of muscle potentials

To monitor EMG for the C5 nerve root, you should place electrodes in the

deltoid

When stimulating pedicle screws, the stimulation probe should be plugged into the (anode/cathode)

cathode

A depolarizing muscle blocker

causes excessive release of acetylcholine at the neuromuscular junction

Which of the following is not a characteristic of muscle?

pull ability