ASET CNIM Exam 2023 Graded A+

Resting membrane potential is created by differences between the inside and outside of the cell in ion concentrations of 1. K+ 2. K+ and Ca++ 3. K+, Na+ and Cl- 4. Na+, Ca++ and Cl- - ANSWER-K+, Na+, and Cl- Excitation of the postsynaptic neuron is caused by the neurotransmitter 1. gamma amino butyric acid 2. glycine 3. para amino butyric acid 4. glutamate - ANSWER-Glutamate Wave III of the BAER is generated by the 1. superior olivary complex 2. inferior colliculus 3. lateral lemniscus 4. medial geniculate - ANSWER-Superior olivary complex Lying between the adjacent surfaces of the vertebral bodies and bonding them together, are the 1. pedicles 2. intervertebral discs 3. supraspinous ligaments 4. spinal nerves - ANSWER-Intervertebral discs Which of the following UE SSEP response is considered a "stationary potential" 1. N20 2. N13 3. P14 4. N18 - ANSWER-N13 The initial waveform recorded of a near-field potential is 1. always obscured by stimulus artifact 2. negative due to depolarization of membrane potentials 3. positive due to electronic depolarization of the membrane under the recording electrode 4. of very low amplitude due to the significant distance between the generator and recording electrode - ANSWER-Positive due to electrotonic depolarization of the membrane under the recording electrode Nerves of the body, such as the ulnar, median, and femoral, are formed from the 1. white matter of the spinal cord 2. dorsal and ventral rami 3. cervical spinal cord 4. ventral ganglion - ANSWER-Dorsal and ventral rami On the SSEP, the electrode at ________ records a spinal cord response 1. T12 2. CPz 3. the iliac crest 4. the popliteal fossa - ANSWER-T12 Projecting laterally from the junction of the pedicle and lamina and serving as a lever for muscle and ligaments, are the 1. intervertebral discs 2. mamillary processes 3. intervertebral foramen 4. transverse processes - ANSWER-Transverse processes Synaptic transmission, and/or changes in the thalamocortical projections, are believed to produce 1. subcortical potentials 2. cortical potentials 3. the erb's point potential 4. the P100 potential - ANSWER-Cortical potentials The section of the brainstem that is continuous with the spinal cord and includes the decussation of the pyramids, is the 1. medulla oblongata 2. pons 3. dorsal column 4. midbrain - ANSWER-medulla oblongata The ulnar nerve originates from nerve roots at 1. C5-C6 2. C6-C7 3. C7-C8 4. C7-T1 - ANSWER-C7-T1 The common peroneal nerve arises from the superior angle of the popliteal fossa of the 1. superior tibial nerve 2. superior femoral nerve 3. internal popliteal nerve 4. sciatic nerve - ANSWER-Sciatic nerve The resting membrane potential of a neuron is 1. +20mV 2. +70mV 3. -20mV 4. -70mV - ANSWER--70mV The innermost connective tissue membrane covering the brain is the 1. dura 2. pia 3. arachnoid 4. falx cerebri - ANSWER-Pia Which of the following can inhibit the postsynaptic neuron 1. gamma amino butyric acid 2. acetylcholine 3. para amino butyric acid 4. glutamate - ANSWER-gamma amino butyric acid (GABA) The median nerve originates from nerve roots 1. C5- T1 2. C3-C7 3. C5-C6 4. C4-C6 - ANSWER-C5-T1 An inhibitory transmitter causes the resting membrane potential of the post-synaptic neuron to 1. play a critical role in the development of the myelin sheath 2. be more negative 3. resist the effect of muscle relaxants 4. become hyperpolarized - ANSWER-Become hyperpolarized The peroneal and tibial nerves are divisions of the 1. brachial plexus 2. deep peroneal nerve 3. sciatic nerve 4. lumbar plexus - ANSWER-Sciatic nerve Cortical evoked potentials are largely produced by 1. depolarization propagated along the nerve fibers 2. actions potentials of the connecting axonal tracts 3. EPSPs and IPSPs 4. high energy magnetic fields of sodium ions within the cell membranes of the brain - ANSWER-EPSPs and IPSPs Spinal nerves are attached in series to the sides of the spinal cord and emerge through the 1. filum terminale 2. lamina 3. spinous process 4. intervertebral discs - ANSWER-Intervertebral foramina The vestibulocochlear nerve (CN VIII) appears 1. in the groove between the pons and the medulla oblongata 2. between the cerebellum and C3 3. at the base of the brain near the optic nerves 4. from the floor of the third ventricle - ANSWER-in the groove between the pons and medulla oblongata P14 is far-field, subcortically generated response which probably reflects 1. activity from the precentral gyrus 2. caudal medial lemniscal activity 3. passage of the afferent volley 4. a stationary cervical potential - ANSWER-Caudal medial lemniscal activity The facial nerve is cranial nerve _______ and it supplies the muscle for ____________ 1. V, jaw movement 2. V, eye movement 3. VI, facial expression 4. VII, facial expression - ANSWER-VII, facial expression The BAER measurement of the III-V interpeak interval represents 1. conduction through the upper-brainstem 2. conduction of the stimulus through the acoustic nerve 3. the time it takes for the sound to travel to the auditory cortex 4. an important tool in assessing cochlear ischemia - ANSWER-Conduction through the upper brainstem A nerve cell membrane can depolarize when 1. sodium channels are closed and potassium channels are opened 2. the summation of individual action potentials exceeds the membrane threshold 3. the resting membrane threshold reaches -70mV 4. chloride channels are opened - ANSWER-The summation of individual action potentials exceeds the membrane threshold In a normal adult, stimulation of the median nerve at the wrist will 1. elicit a primary cortical response at about 20msec 2. elicit an erb's point response at about 15msec 3. produce a visible twitch in the abductor hallucis muscle 4. elicit a cervical response at approximately 18msec - ANSWER-elicit a primary cortical response at about 20msec Because generator sites are typically deep within anatomic structures, most EPs are considered 1. far-field responses 2. multi-wave complexes 3. transient waveforms 4. steady state potentials - ANSWER-Far-field responses The posterior tibial nerve arises from which branch of the sciatic nerve 1. superior tibial 2. superior peroneal 3. internal popliteal 4. external popliteal - ANSWER-superior tibial A differential amplifier records 1. only the first two inputs 2. the second half the two inputs 3. the power of the sum of the two inputs 4. the difference between the two inputs - ANSWER-the difference between the two inputs To accurately represent the amplitude of an EP waveform, a match must be made between the 1. signal size and the vertical capacity of the digitizer 2. high-frequency noise and smoothing operation of the instrument 3. dwell time and sampling rate 4. horizontal resolution and signal size - ANSWER-signal size and the vertical capacity of the digitizer Due to a smaller surface area, subdermal needle electrodes will have an impedance that is 1. lower than disk electrodes 2. increased with improper insertion 3. improved by cleansing the skin with abrasive gel 4. higher than surface electrodes - ANSWER-higher than surface electrodes The difference between the voltages in input 1 and input 2 will make the display of the amplifier move 1. in a sinusoidal pattern 2. up 3. either up or down 4. down - ANSWER-either up or down in order to stimulate both tibial nerves asynchronously, you need 1. to delay the first stimulator 2. to delay the second stimulator 3. a positive trace delay 4. a negative trace delay - ANSWER-to delay the second stimulator The input impedance of a differential amplifier must be at least 1. 5k ohms 2. 10 megohms 3. 100 megohms 4. 10 megohms - ANSWER-100 megohms An EP recording system should allow averaging of 1. 6,000 trials or more 2. no more than 500 trials 3. a maximum of 2,000 trials 4. at least 4,000 - ANSWER-at least 4,000 trials Signal-to-noise ratio relates to which of the following 1. the amplitude of the evoked response components to the amplitude of the unrelated components 2. ability of the instrument to resolve data and noise vertically 3. two inputs of a differential amplifier with like negativity 4. sensitivity scaling - ANSWER-the amplitude of the evoked response components to the amplitude of the unrelated components Electrode impedance is defined as opposition to 1. direct current flow 2. alternating current flow 3. differential current flow 4. 60 Hz artifact - ANSWER-alternating current flow A constant voltage stimulator 1. varies the current in order to maintain a preset voltage level 2. maintains a constant voltage of 100 volts 3. varies the output in order to maintain a preset current level 4. maintains a current level of 10mA - ANSWER-varies the current in order to maintain a preset voltage level The sound stimulus intensity at the tympanic membrane depends on the 1. acoustic coupling between the sound stimulus generator and the ear 2. relation between SPL (dB) and the inverse peak equivalent SPL (dB) 3. relation between SPL (dB) and peak equivalent SPL (dB) 4. patients hearing threshold (dB) - ANSWER-acoustic coupling between the sound stimulus generator and the ear For the intraoperative recording of EEG, the impedance of a scalp electrode should range from 1. 250 - 500 ohms 2. 500 - 1,000 ohms 3. 1,000 - 5,000 ohms 4. 5,000 - 10,000 ohms - ANSWER-1,000-5,000 ohms The use of the 60hz notch filter is discouraged while recording because it can 1. produce a risk to the patient 2. produce a ringing activity that can contaminate the appearance of the response 3. cause the recording electrodes to form a salt bridge 4. filter slow activity, distorting the response - ANSWER-produce ringing activity that can contaminate the appearance of the response The gain of an amplifier, set to give an output signal of 1 volt for an input signal of 10uV is 1. 100 2. 1,000 3. 10,000 4. 100,000 - ANSWER-100,000 The following are examples of good insulating materials, inhibiting current flow 1. silicon and germanium 2. silver and copper 3. glass and rubber 4. gold and platinum - ANSWER-glass and rubber In selecting the horizontal parameters of analysis, the 1. sampling rate should be at least two times greater than the highest frequency in the signal 2. sampling rate should be the equivalent of the highest frequency in the signal 3. analysis period should be at least twice the Nyquist frequency 4. analysis period should approach the Nyquist frequency - ANSWER-sampling rate should be at least two times greater than the highest frequency in the signal The phenomenon called aliasing 1. may be avoided by proper placement of the ground and stimulating electrodes 2. is common during intraoperative recording of evoked potentials 3. refers to an erroneous representation of an analog signal by digital values 4. occurs when the analysis period is more than twice the Nyquist frequency - ANSWER-refers to an erroneous representation of an analog signal by digital values Brain activity recorded directly from the cortex (ECoG) is very high in amplitude and usually requires sensitivities in the range of 1. 10 to 50 uV/mm 2. 40 to 100 uV/mm 3. 100 to 150 uV/mm 4. 200 to 300 uV/mm - ANSWER-40 to 100 uV/mm The assumption that responses of excessive amplitude are likely to contain artifact forms the basis for 1. digital filtering 2. dwell time 3. artifact rejection 4. digital averaging - ANSWER-artifact rejection capacitors are electronic devices used to 1. store electrical energy 2. stop current flow when some critical power level is exceeded 3. enhance current flow 4. measure electrode impedance at the scalp - ANSWER-store electrical energy Prestimulus triggering 1. presents a positive signal to the averager prior to initiating the display 2. includes a period of recording before the stimulus 3. eliminates the problems associated with recording the stimulus artifact 4. delays the synchronizing pulse to the computer - ANSWER-includes a period of recording before the stimulus The horizontal resolution of an evoked potential system 1. should be 20 microseconds per data point or less 2. has no effect on the aliasing properties of the instrument 3. should be greater than 30 milliseconds per data point 4. is one half the Nyquist frequency - ANSWER-should be 20 microseconds per data point or less - ANSWER-A unit of resistance is symbolized by Given an electrical circuit with a resistance of 1000 ohms and voltage of 10 volts, the current flow will be 1. 0.1 A 2. .10 ohms 3. 10 A 4. 100 volts - ANSWER-.01 A The common mode rejection ratio of amplifiers used for EP recording should be at least 1. 100:1 2. 1,000:1 3. 10,000:1 4. 100,000:1 - ANSWER-10,000:1 Spectral edge is a function of 1. beta and alpha vs time 2. amplitude and latency vs time 3. power and frequency vs time 4. zero crossing intervals - ANSWER-power and frequency vs time With a sampling rate of 10kHz the shortest sine wave resolved would be 1. 2msec 2. .2msec 3. .4msec 4. .02msec - ANSWER-.2msec If you have a signal to noise ratio of 1:2, averaging 64 responses will 1. reduce the noise by 50% 2. not change the ratio 3. improve the ratio to 8:1 4. improve the ratio to 4:1 - ANSWER-improve the ratio to 4:1 A condensation click 1. delivers the loudest sounds to the tympanic membrane 2. causes the tympanic membrane to move outward 3. causes the headphone diaphragm to displace toward the tympanic membrane 4. causes the headphone diaphragm to move away from the tympanic membrane - ANSWER-causes the headphone diaphragm to displace toward the tympanic membrane the term "broadband click" refers to 1. peak acoustic power of 2-4kHz 2. short peak acoustic power of 1-2kHz 3. broad peak acoustic power of 1-5kHz 4. a peak acoustic power of 500 Hz to 2kHz - ANSWER-peak acoustic power of 2-4kHz Reduction of the high frequency filter 1. has no effect on EP latency 2. has an unpredictable effect on EP latency 3. increases EP latency 4. decreases EP latency - ANSWER-Increases EP latency The sensitivity setting on an amplifier set to produce a vertical deflection of 1 cm with an input of 10mV is 1. 1mV/mm 2. 1mV/cm 3. 10mV/mm 4. 20mV/cm - ANSWER-1mV/mm A rarefaction click occurs when the 1. initial movement of a transducer diaphragm is towards the tympanic membrane 2. initial movement of a transducer diaphragm is away from the tympanic membrane 3. movement of a transducer diaphragm alternates in polarity relative to the tympanic membrane every second trial 4. movement of a transducer diaphragm alternates in polarity relative to the tympanic membrane on a random basis - ANSWER-initial movement of a transducer diaphragm is away from the tympanic membrane Facial nerve EMG responses are best recorded from 1. masseter muscles 2. orbicularis oris and orbicularis oculi muscles 3. the facial nerve 4. stylomastoid foramen - ANSWER-orbicularis oris and obicularis oculi muscles Subdermal needle electrodes must be inserted symmetrically over the homologous brain areas to avoid 1. excessive high impedance 2. artificial amplitude asymmetries 3. excessive bleeding 4. common mode rejection of the EEG signal - ANSWER-artificial amplitude asymmetries All of the following are true of magnetic stimulation except 1. an electrical stimulator is required to pace the stimulus 2. the stimulation is not perceived as painful 3. pulses of current are delivered through a coil of wire 4. magnetic field created causes movement in cortical neurons - ANSWER-an electrical stimulator is required to pace the stimulus Well-maintained documentation is imperative throughout a surgical case in order to 1. provide details of events associated with a functional loss 2. require the technologist to focus on the operative procedure 3. justify billing for monitoring service 4. all of the above - ANSWER-provide details of events associated with a functional loss It is required that the monitoring tech be able to communicate effectively with 1. the surgical technologist 2. surgical residents 3. surgeon only 4. anesthesiologist and surgeon - ANSWER-anesthesia and surgeon With exposure provided by laminectomy, needle electrodes can record spinal activity with placement 1. on the spinal cord 2. in the epidural space 3. in the pedicle 4. in the spinal muscle - ANSWER-in the epidural space To record the compound action potential of the median nerve intraoperatively, the electrode should be placed at 1 antecubital fossa 2. the wrist 3. C2 4. the shoulder - ANSWER-antecubital fossa An advantage to using grid or strip electrodes over the "crown of thorns" for recording the ECoG is the ability to 1. place electrodes precisely on gyri 2. sterilize and reuse them 3. individually position each contact 4. slide them under the dura to unexposed areas - ANSWER-slide them under the dura to unexposed areas Instrumentation systems used to distract, compress, and de-rotate the spine to restore normal vertebral column alignment, include 1. Cotrel-Dubousset and Isola 2. CMRR and CMRO 3. Du Bois and Reymond 4. TCD and pedicle screw - ANSWER-Cotrel-Dubousset and Isola In order to monitor cranial nerve X, the recording electrodes are placed on the 1. trapezius muscle 2. soft palate 3. tongue 4. false vocal cords - ANSWER-false vocal cords The masking level suggested for the elimination of crossover responses is 1. 50 dB pe SPL 2. 60 dB nHL 3. 60 dB pe SPL 4. 50 dB Hl - ANSWER-60 dB pe SPL It is most appropriate to monitor the median nerve, not the tibial nerve, for 1. anterior cerebral artery aneurysms 2. middle cerebral artery aneuryms 3. posterior cerebral artery aneurysms 4. vertebral basilar artery aneurysms - ANSWER-Middle cerebral artery aneurysms What problem may occur when performing intraoperative BAERs using compressible tubing and headphones 1. patients post-op hearing can become impaired 2. a contamination of the sterile field can occur 3. the compressible tubing can become obstructed and obscure the sound to the ear 4. their use may cause trauma to the ear canal and should be avoided - ANSWER-Compressible tubing can become obstructed and obscure the sound to ear An "after-discharge" can occur on the cortical EEG recording following 1. a seizure recorded in the OR 2. electrical stimulation of the exposed cortex 3. introduction of 60 Hz artifact 4. electrocautery - ANSWER-electrical stimulation of the exposed cortex For median nerve stim, the cathode is placed 1. between the tendons of palmaris longus and flexor carpi radialis muscle 2. on the dorsal side of wrist, approx 2-3cm from the ulnar nerve 3. 4-5 cm distal to anode 4. midway between the tendon and the posterior border of the medial malleolus - ANSWER-between the tendons of palmaris longus and flexor carpi radialis muscle During MVD surgery to relieve a hemifacial spasm 1. it is necessary to monitor EMG from CN III 2. a stimulation of CN VIII elicits a response from the mentalis muscle 3. the buccal branch of CN V will likely show the most EMG activity 4. Cz-Fpz should be monitored for median nerve stimulation - ANSWER-stim of CN VII elicits a response from the mentalis muscle To minimize pain from stimulation during the recording of SSEPs, the contact impedance of the stimulator should be 1. less than 50 kohms 2. more than 10,000 ohms 3. less than 5,000 ohms 4. less than 10 megohms - ANSWER-less than 5,000 ohms The effects of Harrington rod distraction on the spinal cord can be tested by all of the following except 1. the stagnara wake-up test 2. SSEPs 3. MEPs 4. dorsal root stimulation - ANSWER-dorsal root stimulation It is important to begin monitoring EEG early during a carotid endarterectomy 1. to prevent the anesthesiologist from removing your electrodes 2. because emboli can break loose and cause changes, while prepping the neck 3. to record as much b eta activity as possible before the patient is put under anesthesia 4. to record the EEG before anesthesia and after induction for comparison during the case - ANSWER-to record the EEG before anesthesia and after induction for comparison during the case Stimulation of the motor pathway can be achieved with little movement in the surgical field by 1. decreasing muscle relaxants 2. slowing the stimulation rate 3. increasing the stimulation rate enough to produce muscle tetany 4. increasing the stimulation duration - ANSWER-Increasing the stimulation rate enough to produce muscle tetany While stimulating cranial nerve VII, a bipolar type stimulator has an advantage over a monopolar stimulator by 1. requiring less current 2. having greater specificity 3. being less expensive 4. presenting less rick of damage to the neural tissue - ANSWER-having greater specificity When recording a posterior tibial nerve SSEP, the Fpz-C5s channel records 1. subcortical far-field potentials 2. subcortical near-field potentials 3. stationary lumbar potentials 4. erb's point potential - ANSWER-subcortical far-field potentials When recording BAERs in the OR, some auditory stimulators utilize several inches of tubing to connect the transducer and ear inserts with 1. do not affect the latencies of the waveforms 2. are comparable to acoustically shielded headphones 3. delay the signal to the transducer and can cause 60 Hz artifact 4. delays the arrival of the sound to the ear and separates stimulus artifact - ANSWER-delays the arrival of the sound to the ear and separates stimulus artifact a contraindication for the use of transcranial magnetic stimulation is 1. patient obesity 2. cardiac pacemaker in place 3. MS 4. transverse myelitis - ANSWER-cardiac pacemaker in place An advantage of referential, as opposed to bipolar recording SSEPs is 1. ease of electrode placement 2. less invasion of the surgical field 3. the elimination of electromyographic artifact from the paraspinous muscles 4. avoiding cancellation of the potentials as a result of recording from adjacent levels - ANSWER-avoiding cancellation of the potentials as a result of recording from adjacent levels An electrode suggested as a sensitive stimulator during facial nerve recordings is the 1. single fiver needle 2. bipolar concentric EMG needle 3. gelled surface electrode 4. digital ring electrode - ANSWER-bipolar concentric EMG needle Crossover sound stimulation conducted by the skull during BAER stimulation, can be avoided by 1. utilizing a mastoid recording electrode 2. applying contralateral masking noise 3. repositioning the patient 4. using a bilateral click presentation - ANSWER-applying contralateral masking noise The median nerve SSEP- N18 potential is recorded 1. using a bipolar scalp derivation 2. from erb's point to an off-site reference 3. referentially from scalp electrodes ipsilateral to the stimulated nerve 4. from the cervical spine electrode - ANSWER-referentially from scalp electrodes ipsilateral to the stimulated nerve Electrodes embedded in a thin sheet of plastic material may be used for 1. electrocorticographic recordings 2. electrocochleographic recordings 3. electroretinographic recordings 4. electromechanical recordings - ANSWER-electrocorticographic recordings Monitoring procedures during CEA include 1. monitoring both hemispheres 2. cessation of monitoring following clamp removal 3. monitoring from the compromised hemisphere only 4. recording a full minute of EEG basline - ANSWER-monitoring both hemispheres Preoperative baselines, SSEP values are essential to IONM because 1. latencies and amplitudes are highly variable 2. it is necessary to compare IONM values with laboratory normative data 3. absolute boundaries for EPs obtained intra-op are not available 4. they help to establish the appropriate level of anesthesia - ANSWER-absolute boundaries for EPs obtained intra-op are not available A patient is admitted to the operating room diagnosed with a herniated C5/6 disc. Most appropriate nerve(s) to monitor during the resulting surgical procedure would be the 1. tibial and ulnar nerves 2. median and posterior tibial nerves 3. median and auditory nerves 4. ulnar nerve - ANSWER-median and posterior tibial nerves The median nerve SSEP can be helpful as a measure of 1. cerebral blood flow 2. lower spinal cord function 3. blood pressure variability4 4. anesthetic sensitivity - ANSWER-Cerebral blood flow In the OR, the stim intensity for activating a sensory nerve 1. should be set at double the sensory threshold 2. should be set for two to three times the motor threshold 3. does not have an established boundary 4. is set to slightly above motor threshold - ANSWER-does not have an established boundary The suggested rate of stimulation for intraoperative posterior tibial nerve evoked potential monitoring is: 1. 30 to 40 per second 2. 20 to 30 per second 3. 10 to 20 per second 4. 2 to 10 per second - ANSWER-2 to 10 per second When stimulating the posterior tibial at the ankle, stimulation can be confirmed by 1. turning the stimulator up to read 20mA 2. recording a cortical response at Cp4 3. reducing the impedance of the stimulating electrodes to less than 5k ohms 4. recording a response from the popliteal fossa - ANSWER-Recording a response from the popliteal fossa To record cortical SSEPs during intraoperative monitoring of cervical spinal cord surgery, electrodes should be placed 1. 2cm anterior to C3 and C4 2. 2cm posterior to C3 and C4 3. in the C3 and C4 positions of the 10-20 system 4. between Cz and Pz and between Pz and Oz - ANSWER-2 cm posterior to C3 and C4 "Hearing level" (HL) is defined as the 1. average threshold intensity of normally hearing young adults 2. intensity of along duration sound that has the same amplitude as the peak SPL of a short duration sound 3. lowest intensity that an average ear drum can her 4. inverse of the sound pressure level - ANSWER-average threshold intensity of normally hearing young adults In order to record cortical SSEPs during intraoperative monitoring of the thoracolumbar spinal cord (BLE SSEP), an electrode should be placed 1. 2cm posterior to Pz 2. 2cm anterior to Cz 3. 2cm posterior to Cz 4. 2cm posterior to C3 and C4 - ANSWER-2 cm posterior to Cz The recommended location for recording the cervical cord response to median nerve stimulation 1. C1 2. C2 3. C5 4. C8 - ANSWER-C5 A secure method for applying surface cup electrodes requires 1. application the day before surgery 2. a conductive paste and tape 3. water resistant tape 4. collodion and compressed air - ANSWER-collodion and compressed air The amplitude of the cortical response to posterior tibial SSEP stim is at least 80% attenuated by 1. stimulation rates of 15 per second or higher 2. large doses of muscle relaxant 3. a HLF of 5,000 Hz 4. a stimulation duration greater than 150 usec - ANSWER-stimulation rates of 15 per second or higher It is recommended that while recording intra-op BAERs, electrodes be sealed with tape in order to 1. keep the impedances high 2. prevent drying and to protect from fluids 3. keep stimulation artifact to a minimum 4. prevent them from oxidizing - ANSWER-prevent drying and to protect from fluids When using a bipolar montage during EEG recording, the localizing sign is 1. phase reversal between adjacent channels having a common electrode 2. the maximum amplitude activity is replicated in all channels displayed 3. the highest amplitude in the electrode referred