Electrodiagnostics Flashcards
Bilateral periodic lateralizing epileptiform discharges (PLEDs) on EEG is diagnostic of which of the following?
● A. Creutzfeldt-Jakob disease
● B. Anoxic encephalopathy
● C. Brain death
● D. Herpes simplex encephalitis
● E. Bacterial meningitis
D. Herpes simplex encephalitis
Regarding common EEG rhythms, a frequency of >13 Hz is what?
● A. Alpha
● B. Beta
● C. Theta
● D. Delta
● E. Epsilon
B. Beta
Regarding brainstem auditory evoked responses (BAER), vestibular schwannoma may be suggested by which of the following?
● A. I peak latency
● B. I-III peak latency
● C. V peak latency
● D. N9-N18 peak latency
● E. P100 absolute latency
B. I-III peak latency
Regarding cervical electromyography (EMG), there are no good muscles to reliably test which of the following?
● A. C4
● B. C5
● C. C6
● D. C7
● E. C8
A. C4
Reduction of sensory nerve action potential (SNAP) with no paraspinal muscle fibrillations suggests which of the following?
● A. Monoradiculopathy
● B. Plexopathy
● C. Traumatic herniated lumbar disk
● D. Transverse myelitis
● E. Motor neuron disease
B. Plexopathy
The primary use of electroencephalogram (EEG) is the diagnosis and management of seizure disorder. Following statements regarding differential diagnosis on the basis of EEG pattern are correct except?
● A. Herpes simplex encephalitis causes periodic lateralizing epileptiform discharges on EEG
● B. Subacute sclerosing panencephalitis causes periodic high voltage with 4 to 15 seconds separation
● C. Creutzfeldt-Jakob disease causes bilateral sharp waves 1.5 to 2 per second
● D. Cannot differentiate between hydranencephaly and severe hydrocephalus
● E. Used as a clinical confirmation test in the determination of brain death
D. Cannot differentiate between hydranencephaly and severe hydrocephalus
Somatosensory evoked potential (SSEP) and brain stem auditory evoked potential (BAER) are used by neurosurgeons for intraoperative monitoring purposes. What should cause the surgeon to assess all variables (retractors, instruments, blood
pressure) and do surgery more carefully?
● A. A 10% increased latency of a major evoked potential peak
● B. A drop in amplitude of more than or equal to 50%
● C. Complete loss of waveform
● D. Increase in 50% latency
● E. A, B, and C
E. A, B, and C
Impulses during somatosensory evoked potential monitoring during spine surgery are carried through which tract of spinal cord?
● A. Spinothalamic tract
● B. Ipsilateral posterior column
● C. Dorsolateral fasciculus
● D. Both B and C
● E. Spinocerebellar tract
D. Both B and C
Transcranial motor evoked potentials (TCMEPs) are generated by stimulation of motor cortex of brain or descending axons in spinal cord using EMG recordings of motor potentials from representative muscle groups. What is the contraindication of using TCMEP?
● A. History of epilepsy or seizures
● B. Past surgical skull defects
● C. Metal in head or neck
● D. Implanted electronic devices
● E. All of the above
E. All of the above
Following statements regarding checklist for changes in SSEP or TCMEPs during spine surgery are correct except?
● A. Technical defect in recording such as connections or electrodes position
● B. Pause the surgery and eliminate possible distractions
● C. Stagnara wake up test is not useful in this situation
● D. Metabolic considerations such as anemia, mean arterial pressure, change in pH, body temperature
● E. Patient positions, retractors, instruments
C. Stagnara wake up test is not useful in this situation
Nerve conduction study (NCS) (nerve conduction velocity) is performed by applying electrical stimulation through surface electrodes at specified location, and electrical stimulation is recorded at receiving electrodes. Which of the following components of a nerve can be studied using NCS?
● A. Nerve conduction velocity
● B. Amplitude of nerve
● C. Latency
● D. Duration of motor and sensory nerves
● E. All of the above
E. All of the above
All of the following are the components of electromyographic study except?
● A. Sensory nerve action potential (SNAP)
● B. F-wave
● C. B-wave
● D. H-reflex
● E. Polyphasic potentials
C. B-wave
An EMG examination has three phases: insertional activity, spontaneous activity, and volitional activity. Which of the following are potentials or discharges that are observed in nerve disorders?
● A. Fibrillation potentials that are observed in lower motor neuron death or denervation
● B. Complex repetitive discharges that are seen in neuropathic or myopathic disorders
● C. Fasciculation potentials that are seen in motor neuron disease
● D. Motor unit action potential analysis in which change in amplitude or duration of nerve action potential shows disorder of LMN or myopathic disorder
● E. All of the above
E. All of the above
What are the EMG criteria for radiculopathy?
● A. Fibrillation potential or positive sharp waves in at least two muscles innervated by a single nerve root in question, with single peripheral nerve
● B. Fibrillation potential or positive sharp waves in at least two muscles innervated by a single nerve root in question but by two different peripheral nerves
● C. Fibrillation potential or positive sharp waves in two muscles innervated by two nerve roots with two different peripheral nerves
● D. Fibrillation potential in muscles irrespective of nerve root in question
● E. None of above
B. Fibrillation potential or positive sharp waves in at least two muscles innervated by a single nerve root in question but by two different peripheral nerves
On healing radiculopathy, which potential return first on EMG?
● A. Sensory potential
● B. Motor potential
● C. Fibrillation potential
● D. Fasciculation potential
● E. Positive sharp waves
B. Motor potential
