Cnim Board Prep
Every CNIM board prep question I could find from practice tests, prep classes, books, etc.
Questions and Answers
- 1.
If there is a 60Hz interference in all channels when recording median nerve somatosensory evoked potentials, which of the following electrodes should be adjusted first?
- A.
Cpi
- B.
Epc
- C.
Ground electrode
- D.
Stimulating electrode
Correct Answer
C. Ground electrodeExplanation
The ground electrode should be adjusted first because it is responsible for providing a reference point for the recording of electrical signals. If there is a 60Hz interference in all channels, it suggests that the ground electrode may not be properly placed or connected, leading to the interference. By adjusting the ground electrode, the electrical reference point can be improved, potentially reducing or eliminating the interference in the recorded signals.Rate this question:
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- 2.
Near Field
- A.
Corrected visual acuity
- B.
Stimulus field close to the eyes
- C.
Area within three feet of eyes
- D.
Generators close to the recording electrodes
Correct Answer
D. Generators close to the recording electrodesExplanation
The correct answer is "Generators close to the recording electrodes". This suggests that the generators, which are likely electrical devices or sources of signals, are located in close proximity to the recording electrodes. This proximity is important for accurate recording of the signals generated by these devices.Rate this question:
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- 3.
In what age group do early symptoms of multiple sclerosis usually occur?
- A.
Under 10 years
- B.
15-40 years
- C.
50-60 years
- D.
Over5 70 years
Correct Answer
B. 15-40 yearsExplanation
Early symptoms of multiple sclerosis usually occur in the age group of 15-40 years. This is the most common age range for the onset of multiple sclerosis, although it can occur at any age. The symptoms may vary from person to person but commonly include fatigue, difficulty walking, numbness or tingling in the limbs, muscle weakness, and problems with coordination and balance. It is important to note that these symptoms can also be caused by other conditions, so a proper diagnosis by a healthcare professional is necessary.Rate this question:
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- 4.
The cochlea generates what EP response?
- A.
Echo
- B.
ECOG
- C.
EcochG
- D.
BAEP
Correct Answer
C. EcochGExplanation
The cochlea generates the EcochG response. EcochG stands for Electrocochleography, which is a test used to measure the electrical potentials generated by the cochlea in response to sound stimulation. This test is commonly used to diagnose and monitor disorders of the inner ear, such as Meniere's disease.Rate this question:
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- 5.
Which of the following would best enhance resolution of evoked potential waveforms?
- A.
Decrease sensitivity
- B.
Decrease filter band width
- C.
Increase stimulation rate
- D.
Increase number of averaged stimuli
Correct Answer
D. Increase number of averaged stimuliExplanation
Increasing the number of averaged stimuli would best enhance the resolution of evoked potential waveforms. Averaging multiple stimuli helps to reduce random noise and increase the signal-to-noise ratio, resulting in a clearer and more reliable waveform. By increasing the number of averaged stimuli, any random variations can be averaged out, allowing the true response to be more easily detected and enhancing the resolution of the waveform.Rate this question:
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- 6.
What is the typical MINIMUM common mode rejction ratio of in-phase signals recommended for evoked potential instruments?
- A.
1,000:1
- B.
5,000:1
- C.
10,000:1
- D.
2:1
Correct Answer
C. 10,000:1Explanation
The typical MINIMUM common mode rejection ratio of in-phase signals recommended for evoked potential instruments is 10,000:1. This means that the instrument is able to reject common mode signals (signals that are present in both the desired signal and the noise) by a ratio of 10,000 to 1. A high common mode rejection ratio is important in evoked potential instruments to ensure that the desired signals are accurately measured and any unwanted noise or interference is minimized.Rate this question:
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- 7.
The long latency auditory EP, also called the cognitive EP or oddball paradyme, is the
- A.
ECOG
- B.
P100
- C.
Wave I
- D.
P300
Correct Answer
D. P300Explanation
The correct answer is P300. The long latency auditory EP, also known as the cognitive EP or oddball paradigm, refers to the P300 wave. The P300 wave is a positive waveform that occurs approximately 300 milliseconds after the presentation of a rare or unexpected stimulus. It is associated with cognitive processes such as attention, working memory, and decision-making. The P300 wave is often used in research and clinical settings to assess cognitive function and to study various neurological disorders.Rate this question:
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- 8.
Which of the following cranial nerves is most at risk during acoustic neuroma surgery?
- A.
CN X
- B.
CN VIII
- C.
CN VII
- D.
CN XI
Correct Answer
C. CN VIIExplanation
During acoustic neuroma surgery, the cranial nerve that is most at risk is CN VII, also known as the facial nerve. This nerve controls the muscles of facial expression, as well as the sense of taste in the front two-thirds of the tongue. It runs near the acoustic neuroma, which is a benign tumor that develops on the vestibulocochlear nerve (CN VIII). During surgery, there is a risk of damaging or compressing CN VII, leading to facial weakness or paralysis, loss of taste, and other facial nerve-related complications.Rate this question:
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- 9.
The impedance of cup electrodes is:
- A.
Lower than needle electrodes because of metal type
- B.
Higher than needle elecrodes because of their size
- C.
Lower than needle electrodes because of their size
- D.
Higher than needle electordes because of metal type
Correct Answer
C. Lower than needle electrodes because of their sizeExplanation
The impedance of cup electrodes is lower than needle electrodes because of their size. Cup electrodes have a larger surface area compared to needle electrodes, which allows for better contact with the skin. This increased contact area reduces the impedance, or resistance, between the electrode and the skin, resulting in a lower impedance value.Rate this question:
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- 10.
Afferent Nerves
- A.
Conduct impules away from the central nervous system
- B.
Control ability to speak
- C.
Control emotional responses
- D.
Conduct impulses toward the central nervous system
Correct Answer
D. Conduct impulses toward the central nervous systemExplanation
Afferent nerves conduct impulses toward the central nervous system. This means that they transmit sensory information from the body's sensory receptors to the brain and spinal cord. This allows the brain to receive information about the external environment and the internal state of the body. Afferent nerves are responsible for sensations such as touch, pain, temperature, and proprioception. They play a crucial role in allowing the body to respond to stimuli and maintain homeostasis.Rate this question:
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- 11.
Amplitude of an evoked potential depends on which of the following physiological actions in a sensory pathway?
- A.
The velocity of the neural impulses
- B.
The synchrony with which neural impulses travel
- C.
The number of normal neural generators sequentially excited
- D.
The number of cortical or subcortical generators simultaneously activated.
Correct Answer
B. The synchrony with which neural impulses travelExplanation
The amplitude of an evoked potential depends on the synchrony with which neural impulses travel. This means that if the neural impulses are synchronized and travel together, the amplitude of the evoked potential will be larger. On the other hand, if the neural impulses are not synchronized and travel at different times, the amplitude of the evoked potential will be smaller. Therefore, the synchrony of neural impulses is a crucial factor in determining the amplitude of an evoked potential.Rate this question:
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- 12.
Delayed absolute latencies of brainstem auditory evoked potentials which mimic a conductive hearing loss are most likely caused by
- A.
Rhinitis
- B.
Gingivitis
- C.
Otitis
- D.
Conjunctivitis
Correct Answer
C. OtitisExplanation
Delayed absolute latencies of brainstem auditory evoked potentials which mimic a conductive hearing loss are most likely caused by otitis. Otitis refers to inflammation or infection of the ear, which can affect the transmission of sound waves to the brainstem. This can result in delayed latencies of the brainstem auditory evoked potentials, leading to a similar pattern as seen in conductive hearing loss. Rhinitis, gingivitis, and conjunctivitis are not directly related to the auditory system and would not typically cause delayed latencies in brainstem auditory evoked potentials.Rate this question:
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- 13.
In a pattern reversal visual evoked potential, which of the following would be the most appropriate check size in minutes of arc to stimulate the fovea?
- A.
6
- B.
15
- C.
31
- D.
59
Correct Answer
C. 31Explanation
In a pattern reversal visual evoked potential, the most appropriate check size in minutes of arc to stimulate the fovea would be 31. This check size is likely to provide the optimal stimulation for the fovea, which is the central part of the retina responsible for detailed vision. It is important to choose a check size that is neither too small nor too large to ensure accurate and reliable results in the visual evoked potential test.Rate this question:
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- 14.
What is the approximate amplitude resolution of a 10-bit digitizer with a range of plus or minus 5 uV?
- A.
0.01uV
- B.
0.10uV
- C.
1.00uV
- D.
10.00uV
Correct Answer
A. 0.01uVExplanation
The amplitude resolution of a digitizer is determined by the number of bits it has. In this case, the digitizer is 10-bit, which means it can represent 2^10 or 1024 different levels. The range of plus or minus 5 uV is divided by these levels, resulting in an approximate amplitude resolution of 10 uV / 1024 = 0.01 uV.Rate this question:
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- 15.
What is the most appropriate bandpass for pattern reversal visual evoked potentials?
- A.
0.1-20 Hz
- B.
1-200 Hz
- C.
1-1000 Hz
- D.
100-1000 Hz
Correct Answer
B. 1-200 HzExplanation
The most appropriate bandpass for pattern reversal visual evoked potentials is 1-200 Hz. This range allows for the detection and analysis of the specific frequency components of the visual evoked potentials, while filtering out any unwanted noise or artifacts that may be present in the signal. A bandpass of 1-200 Hz is commonly used in studies and clinical settings to ensure accurate and reliable measurement of visual evoked potentials.Rate this question:
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- 16.
Resting Membrane Potential
- A.
-7uV
- B.
-7mV
- C.
-70uV
- D.
-70mV
Correct Answer
D. -70mVExplanation
The resting membrane potential refers to the electrical potential difference across the cell membrane when the cell is at rest. It is typically around -70mV, meaning that the inside of the cell is negatively charged compared to the outside. This negative charge is maintained by the active transport of ions across the membrane, such as the sodium-potassium pump. This potential is important for various cellular processes, including the transmission of nerve impulses.Rate this question:
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- 17.
The N13 of the median nerve somatosensory evoked potential is generated in the
- A.
Brachial plexus
- B.
Medial lemniscus
- C.
Cervical spinal cord
- D.
Primary somatosensory cortex
Correct Answer
C. Cervical spinal cordExplanation
The N13 of the median nerve somatosensory evoked potential is generated in the cervical spinal cord. This is because the N13 component represents the electrical activity generated in the spinal cord when the median nerve is stimulated. The brachial plexus is responsible for the generation of earlier components of the evoked potential, while the medial lemniscus and primary somatosensory cortex are not directly involved in the generation of the N13 component.Rate this question:
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- 18.
Blind Spot
- A.
Lens
- B.
Fovea
- C.
Macula
- D.
Optic Disc
Correct Answer
D. Optic DiscExplanation
The optic disc is the correct answer because it is the area on the retina where the optic nerve exits the eye. It is also known as the blind spot because it lacks photoreceptor cells, making it unable to detect light. This blind spot is compensated by the brain, which fills in the missing information from the surrounding visual field to create a seamless image.Rate this question:
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- 19.
The number of recording channels for full-field VEP should be
- A.
1
- B.
2
- C.
3
- D.
4
Correct Answer
D. 4Explanation
For full-field VEP (Visual Evoked Potential), which is a test used to assess the visual pathway, it is recommended to have four recording channels. These channels are used to measure the electrical activity generated by the visual system in response to a visual stimulus. Having four channels allows for a more comprehensive assessment of the visual pathway and helps to identify any abnormalities or dysfunction.Rate this question:
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- 20.
Posterior Fossa
- A.
Behind the Knee
- B.
Brainstem
- C.
Cauda Equina
- D.
Temperal Lobe
Correct Answer
B. BrainstemExplanation
The brainstem is the correct answer because it is located in the posterior fossa, which is the area at the back of the skull. The brainstem is responsible for many vital functions such as controlling breathing, heart rate, and consciousness. It connects the brain to the spinal cord and is composed of three main parts: the midbrain, pons, and medulla oblongata.Rate this question:
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- 21.
In the central nervous system, a myelin sheath forms around the
- A.
Axon
- B.
Gila
- C.
Cell body
- D.
Dendrites
Correct Answer
A. AxonExplanation
The myelin sheath is a protective covering that forms around the axon in the central nervous system. It helps to insulate and speed up the transmission of electrical signals along the axon. The myelin sheath is formed by specialized cells called oligodendrocytes in the central nervous system. It is not formed around the gila, cell body, or dendrites.Rate this question:
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- 22.
In the brainstem auditory evoked potential, which of the following is most likely to be associated with bilaterally prolonged I-III intervals?
- A.
Tuberous sclerosis
- B.
Sturge-Weber syndrome
- C.
Neurofibromatosis
- D.
Multiple Sclerosis
Correct Answer
C. NeurofibromatosisExplanation
Bilaterally prolonged I-III intervals in brainstem auditory evoked potential are most likely to be associated with Neurofibromatosis. This condition is characterized by the growth of tumors on nerves, including the auditory nerves. These tumors can affect the transmission of signals from the ear to the brain, leading to prolonged intervals in the auditory evoked potential. Tuberous sclerosis, Sturge-Weber syndrome, and Multiple Sclerosis are not typically associated with this specific auditory abnormality.Rate this question:
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- 23.
In a brainstem auditory evoked potential, decreaseing click intensity will result in
- A.
increased wave I amplitude
- B.
Decreased wave V latency
- C.
Unchanged interpeak intervals
- D.
Decreased peak latencies
Correct Answer
C. Unchanged interpeak intervalsExplanation
In a brainstem auditory evoked potential, decreasing click intensity will not affect the time intervals between the peaks (interpeak intervals). The interpeak intervals represent the time it takes for the electrical activity to travel between different parts of the auditory pathway in the brainstem. Therefore, reducing the click intensity will not alter these intervals as they are independent of the stimulus intensity.Rate this question:
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- 24.
Averaging improves the signal to noise ratio by:
- A.
The square of the number of epochs averaged
- B.
the square root of number of epochs averaged
- C.
50% of the number of epochs averaged
- D.
100% of the number of epochs averaged
Correct Answer
B. the square root of number of epochs averagedExplanation
Averaging improves the signal to noise ratio by the square root of the number of epochs averaged. This means that as the number of epochs averaged increases, the signal to noise ratio improves, but at a decreasing rate. The square root relationship indicates that the improvement in signal to noise ratio becomes less significant as more epochs are averaged.Rate this question:
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- 25.
Pattern reversal visual evoked potential latencies are most significantly affected by
- A.
Patient age
- B.
Ambient light
- C.
Ocular dominance
- D.
Refractive errors of less than 20/20
Correct Answer
A. Patient ageExplanation
Pattern reversal visual evoked potential (VEP) latencies refers to the time it takes for the brain to process visual stimuli. The given correct answer suggests that patient age has the most significant effect on these latencies. This means that as a person gets older, their VEP latencies may change. Age-related changes in the visual system, such as decreased nerve conduction speed or changes in the brain's processing capabilities, could contribute to this effect. Other factors such as ambient light, ocular dominance, and refractive errors may also influence VEP latencies, but patient age is considered the most significant factor.Rate this question:
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- 26.
Using the International 10-20 electrode placements, if the measurement from nasion to inion is 30 cm, what is the distance from Fz to Cz?
- A.
6 cm
- B.
9 cm
- C.
12 cm
- D.
18 cm
Correct Answer
A. 6 cmExplanation
The International 10-20 electrode placement system is a standardized method for positioning electrodes on the scalp for electroencephalography (EEG). In this system, Fz and Cz are two specific electrode positions. The distance from nasion to inion is the distance between the bridge of the nose (nasion) and the external occipital protuberance (inion) at the back of the head. It is not directly related to the distance between Fz and Cz. Therefore, the distance from Fz to Cz cannot be determined based on the given measurement of 30 cm.Rate this question:
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- 27.
A W-shaped pattern reversal visual evoked potential may be resolved with
- A.
Electroretinography
- B.
Flash stimulation
- C.
Steady state stimulation
- D.
Partial field stimulation
Correct Answer
D. Partial field stimulationExplanation
Partial field stimulation refers to a technique used in visual evoked potential (VEP) testing where only a specific portion of the visual field is stimulated. In the case of a W-shaped pattern reversal VEP, it indicates a specific abnormality in the visual system. By using partial field stimulation, it allows for a more targeted assessment of the affected area, helping to identify and diagnose the underlying cause of the abnormality. This technique is preferred over other options such as electroretinography, flash stimulation, or steady state stimulation, as they may not provide the same level of specificity in evaluating the W-shaped pattern reversal VEP.Rate this question:
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- 28.
Which of the following most likely results in increased firing of a neuron?
- A.
Inhibitory presynaptic potential
- B.
Inhibitory postsynaptic potential
- C.
Excitatory postsynaptic potential
- D.
Hyperpolarization of resting membrane potential
Correct Answer
C. Excitatory postsynaptic potentialExplanation
Excitatory postsynaptic potential (EPSP) is the most likely to result in increased firing of a neuron. EPSP is a graded potential that depolarizes the postsynaptic membrane, bringing it closer to the threshold for generating an action potential. This occurs when excitatory neurotransmitters bind to receptors on the postsynaptic membrane, causing ion channels to open and allowing positive ions to enter the cell. The influx of positive ions depolarizes the membrane, making it more likely for an action potential to be generated. In contrast, inhibitory presynaptic potential, inhibitory postsynaptic potential, and hyperpolarization of the resting membrane potential would all decrease the likelihood of a neuron firing.Rate this question:
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- 29.
Which of the following is the normal interocular latency difference of P100?
- A.
Less than 15 msec
- B.
15 to 25 msec
- C.
30 to 50 msec
- D.
More than 50 msec
Correct Answer
A. Less than 15 msecExplanation
The normal interocular latency difference of P100 is less than 15 msec. This means that the time it takes for the P100 wave to occur after a visual stimulus is presented is less than 15 milliseconds between the two eyes.Rate this question:
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- 30.
Wave V is usually the most prominent peak after
- A.
4.5 msec
- B.
4.7 msec
- C.
5.0 msec
- D.
5.5 msec
Correct Answer
D. 5.5 msecExplanation
Wave V is usually the most prominent peak after 5.5 msec. This is because the auditory nerve fibers that generate Wave V have a longer conduction time compared to the other waves. Therefore, it takes more time for the neural activity to reach the auditory brainstem, resulting in a delayed peak.Rate this question:
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- 31.
Where is the P100 waveform generated?
- A.
Optic nerve
- B.
Broca's area
- C.
Striate cortex
- D.
Lateral geniculate
Correct Answer
C. Striate cortexExplanation
The P100 waveform is generated in the striate cortex. The striate cortex, also known as the primary visual cortex, is located in the occipital lobe at the back of the brain. It is responsible for processing visual information received from the eyes. The P100 waveform refers to a positive peak in the visual evoked potential (VEP) waveform that occurs approximately 100 milliseconds after a visual stimulus is presented. This peak reflects the neural activity in the striate cortex as it processes the visual input.Rate this question:
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- 32.
Compared to electrode impedance, the input impedance of the amplifier should be
- A.
Equal
- B.
Lower
- C.
Higher
- D.
Variable
Correct Answer
C. HigherExplanation
The input impedance of the amplifier should be higher compared to electrode impedance because a higher input impedance allows for better signal transfer and reduces the loading effect on the source. This means that the amplifier will draw less current from the source, resulting in less distortion and better overall performance.Rate this question:
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- 33.
Which of the following is determined by adding values and dividing by the number of values included?
- A.
Mode
- B.
Average
- C.
Mean
- D.
Standard deviation
Correct Answer
C. MeanExplanation
The mean is determined by adding all the values together and then dividing by the number of values included. It is a measure of central tendency that represents the average value of a set of numbers.Rate this question:
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- 34.
The appropriate stimulus intensity of stimulating median nerve at the wrist for recording SEP is:
- A.
Below motor threshold
- B.
At motor threshold
- C.
Just above motor threshold
- D.
Highest tolerable intensity
Correct Answer
C. Just above motor thresholdExplanation
The appropriate stimulus intensity for recording SEP (somatosensory evoked potential) is just above motor threshold. This means that the intensity should be slightly higher than the minimum level required to elicit a motor response. This ensures that the stimulation is strong enough to activate the sensory pathway without interfering with the motor response. Using a stimulus intensity just above motor threshold allows for accurate recording of the somatosensory response without causing unnecessary muscle activity.Rate this question:
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- 35.
Paresthesia
- A.
Fainting
- B.
Tingling
- C.
Weakness
- D.
Dizziness
Correct Answer
B. TinglingExplanation
Paresthesia refers to abnormal sensations like tingling, numbness, or burning. Fainting, weakness, and dizziness are not related to paresthesia. Therefore, the correct answer is tingling.Rate this question:
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- 36.
Which of the following is characteristic of alternating click polarity?
- A.
Produces abnormal I-V latencies
- B.
Has no effect on wave I amplitude
- C.
Is recommended for testing premature infants
- D.
Cancels the stimulus artifact
Correct Answer
D. Cancels the stimulus artifactExplanation
Alternating click polarity refers to the technique of reversing the polarity of the click stimulus during auditory brainstem response (ABR) testing. This technique is used to cancel out the stimulus artifact, which is an electrical artifact that occurs in the ABR waveform due to the click stimulus. By canceling the stimulus artifact, the ABR waveform becomes clearer and more accurate, allowing for more precise interpretation of the test results. Therefore, the characteristic of alternating click polarity is that it cancels the stimulus artifact.Rate this question:
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- 37.
The recommended amplitude resolution of the analog to digital converter must be a MINIMUM of
- A.
2 bits
- B.
4 bits
- C.
8 bits
- D.
16 bits
Correct Answer
C. 8 bitsExplanation
The recommended amplitude resolution of the analog to digital converter must be a minimum of 8 bits. This is because 8 bits allows for a greater range of values to be represented, providing more accurate and precise measurements of the analog signal. With a higher resolution, the analog to digital converter can capture more detail and nuances in the signal, resulting in a higher fidelity digital representation.Rate this question:
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- 38.
The nucleus of an atom contains
- A.
Anions
- B.
Electrons
- C.
Protons
- D.
Cations
Correct Answer
C. ProtonsExplanation
The nucleus of an atom contains protons. Protons are positively charged particles that are found in the center of the atom, along with neutrons. They are responsible for the overall positive charge of the nucleus, while electrons, which are negatively charged particles, orbit around the nucleus. Anions and cations are charged species that are formed when atoms gain or lose electrons, but they are not found in the nucleus itself.Rate this question:
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- 39.
If the trials are not reproducible
- A.
Turn on your notch filter
- B.
Perform an additional trial
- C.
Decrase the signal to noise ratio
- D.
Discontinue the procedure
Correct Answer
B. Perform an additional trialExplanation
Performing an additional trial is the most appropriate action if the trials are not reproducible. By conducting another trial, it allows for the possibility of identifying any inconsistencies or errors in the previous trials. This can help to determine the cause of the non-reproducibility and improve the reliability of the results.Rate this question:
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- 40.
If a 4 ohm resistor and a 2 ohm resistor are wired in series across a 6 volt battery, what is the curernt across each resistor?
- A.
1 amp
- B.
2 amps
- C.
1.5 amps across the larger and 3 amps across the smaller
- D.
4 amps across the larger and 1.5 amps across the smaller
Correct Answer
A. 1 ampExplanation
When resistors are wired in series, the total resistance is the sum of the individual resistances. In this case, the total resistance is 4 ohms + 2 ohms = 6 ohms. According to Ohm's Law (V = I * R), the current (I) flowing through a circuit is equal to the voltage (V) divided by the resistance (R). Given that the battery voltage is 6 volts and the total resistance is 6 ohms, the current across each resistor is 6 volts / 6 ohms = 1 amp.Rate this question:
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- 41.
Wave I of the auditory evoked potential cannot appear before
- A.
1.4 msec
- B.
1.5 msec
- C.
1.6 msec
- D.
2.0 msec
Correct Answer
A. 1.4 msecExplanation
The correct answer is 1.4 msec because the wave I of the auditory evoked potential represents the initial response of the auditory nerve to a sound stimulus. This wave is generated within the first few milliseconds after the stimulus is presented. Therefore, it cannot appear before 1.4 msec.Rate this question:
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- 42.
If the fastest component of a complex waveform is near 100Hz, which of the following is the most appropriate dwell time?
- A.
2 msec
- B.
5 msec
- C.
10 msec
- D.
20 msec
Correct Answer
B. 5 msecExplanation
The dwell time refers to the time it takes for a measurement instrument to sample a waveform. In this case, since the fastest component of the waveform is near 100Hz, the most appropriate dwell time would be one that allows for accurate sampling of this frequency. A dwell time of 5 msec would be suitable because it provides enough time to capture multiple cycles of the 100Hz waveform, ensuring accurate measurement and representation of the waveform.Rate this question:
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- 43.
What type of responses are subcortical evoked potentials?
- A.
Near field
- B.
Far field
- C.
Visual field
- D.
Receptive field
Correct Answer
B. Far fieldExplanation
Subcortical evoked potentials are considered far field responses. This is because they originate from neural activity occurring in subcortical structures, such as the brainstem or thalamus, and are recorded at a distance from the source. Far field responses are characterized by their longer latency and lower amplitude compared to near field responses, which are recorded closer to the source of neural activity.Rate this question:
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- 44.
Smaller surface of stimulating electrodes:
- A.
Lower current density
- B.
Higher current density
- C.
Constant current stimulation
- D.
Constant voltage stimulation
Correct Answer
B. Higher current densityExplanation
Higher current density is the correct answer because when the surface area of the stimulating electrodes is smaller, the same amount of current is concentrated in a smaller area, leading to a higher current density. This can result in a more intense and focused stimulation, which may be desirable in certain applications.Rate this question:
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- 45.
Somatosensory Evoked Potential
- A.
Ventral root
- B.
Choroid plexus
- C.
Dorsal root
- D.
Anterior horn cell
Correct Answer
C. Dorsal rootExplanation
The dorsal root is the correct answer because it is a part of the spinal nerve that carries sensory information from the body to the central nervous system. The somatosensory evoked potential refers to the electrical response generated by the sensory pathways in response to a sensory stimulus. Therefore, the dorsal root is involved in transmitting sensory information, making it the most appropriate choice among the given options.Rate this question:
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- 46.
An electrode recording from Erb's point is placed
- A.
On the shoulder
- B.
2-3 cm above the clavicle
- C.
Over the trapezius muscle
- D.
At the axilla
Correct Answer
B. 2-3 cm above the clavicleExplanation
The correct answer is 2-3 cm above the clavicle. This is the correct placement for an electrode recording from Erb's point. Placing the electrode at this location allows for accurate recording of the nerve conduction from the brachial plexus, which is located in this area. Placing the electrode on the shoulder, over the trapezius muscle, or at the axilla would not provide accurate recordings from Erb's point.Rate this question:
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- 47.
For posterior tibial somatosensory evoked potentials, which of the following would be the best ipsilateral location for the ground electrode?
- A.
Arm
- B.
Calf
- C.
Mastiod
- D.
Sole of foot
Correct Answer
B. CalfExplanation
The calf would be the best ipsilateral location for the ground electrode in posterior tibial somatosensory evoked potentials. This is because the calf is closer to the site of stimulation, which is the sole of the foot. Placing the ground electrode in the calf helps to minimize electrical interference and ensures accurate measurement of the somatosensory evoked potentials.Rate this question:
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- 48.
Which of the following symptoms is most closely correlated with somatosensory evoked potential abnormalities?
- A.
Vertigo
- B.
Tinnitus
- C.
Hemiparesis
- D.
Proprioception deficit
Correct Answer
D. Proprioception deficitExplanation
Proprioception deficit is the most closely correlated symptom with somatosensory evoked potential abnormalities. Somatosensory evoked potentials are electrical signals generated by the nervous system in response to sensory stimuli. Proprioception refers to the body's ability to sense its position and movement in space. Abnormalities in somatosensory evoked potentials indicate dysfunction in the sensory pathways responsible for proprioception. Therefore, a deficit in proprioception is likely to be closely correlated with abnormalities in somatosensory evoked potentials.Rate this question:
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- 49.
If a signal averager samples every millisecond, what is the theoretical maximum frequency resolution?
- A.
100 Hz
- B.
500 Hz
- C.
1000 Hz
- D.
2000 Hz
Correct Answer
B. 500 HzExplanation
The theoretical maximum frequency resolution is determined by the Nyquist-Shannon sampling theorem, which states that the maximum frequency that can be accurately represented is half the sampling frequency. In this case, since the signal averager samples every millisecond (1000 samples per second), the theoretical maximum frequency resolution would be 500 Hz (half of 1000 Hz).Rate this question:
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- 50.
Accuracy of electrode placement is MOST critical for which type of response?
- A.
Near field
- B.
Far field
- C.
Subcortical
- D.
Brainstem
Correct Answer
A. Near fieldExplanation
The accuracy of electrode placement is most critical for near field responses. Near field responses refer to signals that are generated close to the electrode, typically within a few millimeters. To accurately measure and interpret these signals, it is crucial to place the electrode precisely in the intended location. Any slight deviation in electrode placement can significantly affect the recorded near field response, leading to inaccurate results. Therefore, ensuring accurate electrode placement is of utmost importance for near field responses.Rate this question:
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Sep 02, 2024Quiz Edited by
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