New Quiz 03 Jan Welcome to your Neurophysiology Name Email 1. [Which of the following statement is true regarding single-fiber needle EMG?] Normal patients have a jitter value of 100 Abnormal jitter is only seen with neuromuscular junction (NMJ) disorders Blocking is always present in myasthenia gravis Blocking may be seen in weak muscles in NMJ disorders None . 2. [The somatosensory evoked potential (SSEP) abnormalities in multiple sclerosis (MS) include all of the following except] Prolonged or absent P37 Prolonged or absent P14 Prolonged or absent N20 Reduced N9 amplitude None . 3. [Undersampling during analog-to-digital conversion can lead to which of the following?] Artificial reduction of low-frequency components Decrease in amplitude resolution Decreased ability to analyze direct current (DC) potentials Aliasing None . 4. [All of the following statements regarding the maintenance of wakefulness test (MWT) are true except] It assesses the ability of a subject to remain awake A preceding full-night polysomnogram (PSG) is required Four trials lasting 40 minutes each are performed at 2-hour intervals The room should be lit with low light None . 5. [Which of the following statements is true of photoparoxysmal response (PPR)?] It is never seen in focal seizures Its presence is always considered as abnormal It is most likely to be elicited by a flash frequency of 15–18 Hz in photosensitive epilepsy It is more likely to occur upon eye opening None . 6. [Shortened Waves I–V interpeak latency (IPL) is seen in which of the following conditions?] Multiple sclerosis (MS) plaque in brainstem Brainstem glioma Cochlear hearing loss Conductive hearing loss None . 7. [The peripheral ascending volley of the median somatosensory evoked potential (SSEP) is characterized by all of the following except] It is recorded at Erb’s point in the supraclavicular fossa It occurs about 9 ms after stimulation It has a triphasic morphology It is best seen when the reference electrode is placed over the shoulder on the stimulated side None . 8. [A 27” computer screen has a resolution of 1920 (horizontal) by 1080 (vertical) pixels with vertical borders of 250 pixels each. An EEG sampled at 1000 Hz is displayed at 15 seconds per page. What would be the maximum resolvable frequency if the margins of the screen are eliminated and the number of seconds per page is reduced from 15 seconds to 10 seconds?] 47 Hz 96 Hz 192 Hz 500 Hz None . 9. [All of the following statements regarding cone waves are true except] They are surface-positive waves They are seen when sleep transitions from the quiet sleep (QS) pattern to the adult NREM pattern They are seen in children less than 5 years of age They are typically seen in the fronto-central region None . 10. [Which of the following situations will lead to a phase shift to the left?] Decreasing the low-frequency filter; decreasing the high-frequency filter Decreasing the low-frequency filter; increasing the high-frequency filter Increasing the low-frequency filter; decreasing the high-frequency filter Increasing the low-frequency filter; increasing the high-frequency filter None . 11. [Which of the following statements regarding hypnagogic hypersynchrony is false?] It is most commonly seen in children aged 6 to 12 years It is characterized by high amplitude, synchronous, rhythmic activity It occurs as the infant transitions from wakefulness to sleep The activity can be paroxysmal or continuous for several minutes None . 12. [Below the minimal alveolar concentration (MAC) level of inhalation anesthesia, all of the following EEG patterns may be seen except] Widespread alpha and beta activity with anterior predominance Widespread attenuation with short bursts of mixed frequency activity Intermittent bursts of delta activity with anterior predominance Widespread polymorphic slow waves None . 13. [A patient is referred to the neuromuscular clinic for evaluation of a brachial plexopathy. On examination, he was noted to have weakness in the deltoid and triceps; however, the pronator teres muscle and biceps brachii were strong. Presuming that the pathology is in the brachial plexus, these findings are best localizable to which of the following structures?] Medial cord Lateral cord Posterior cord C5–C6 roots None . 14. [EEG in a patient with progressively deepening coma can show] Reactive high-voltage delta activity Reactive background attenuation with stimulation Nonreactive high-voltage delta activity All of the above None . 15. [The P100 waveform amplitude is decreased by which of the following?] Low contrast; low luminance Low contrast; high luminance High contrast; low luminance High contrast; high luminance None . 16. [Which of the following is shown in the figure below? (fig)] Many positive sharp waves and occasional fibrillation potentials Many positive sharp waves and large-amplitude motor unit potentials Complex repetitive discharges Myokymia None Comment . 17. [Which of the following statements is true regarding the homeostatic and circadian sleep drives?] The homeostatic drive decreases with sleep The circadian drive is controlled by the suprachiasmatic nucleus of the hypothalamus The ventrolateral preoptic nucleus of the hypothalamus promotes sleep All of the above None . 18. [A 20-year-old man suffered an injury while riding his bike. He developed weakness, pain, and sensory loss in the left upper limb. Nerve conduction studies performed a few weeks later revealed normal median motor and ulnar motor and sensory responses. Left lateral antebrachial antidromic sensory response was absent. Findings on needle EMG of selected muscles in the left upper limb are shown below. What is the most likely localization? (fig)] C5, C6, and C7 roots Upper trunk of brachial plexus Posterior cord of brachial plexus Lower trunk of brachial plexus None Comment . 19. [A 55-year-old man is referred to the electrodiagnostic lab for evaluation of large fiber polyneuropathy by his primary care physician. However, based on the history and examination, you suspect there is an underlying diffuse neurogenic process. Nerve conduction study reveals decreased motor amplitudes with normal sensory responses. Needle EMG revealed diffuse active denervation in multiple myotomes. Based on this, you suspect that the patient has a form of motor neuron disease. Which of the following is the most appropriate next step?] Tell the patient that he has amyotrophic lateral sclerosis (ALS) Mention ALS in the report but tell the patient that he has nerve damage Call the referring physician to explain your findings and concerns for motor neuron disease Since the referring physician is an internist and might not understand motor neuron disease, refer the patient to the local ALS clinic None . 20. [What is the relative current needed to depolarize the sciatic nerve with respect to that needed to stimulate the posterior tibial nerve?] Less More Same Cannot be determined None . 21. [A 30-year-old man initially noticed difficulty walking and tendency to fall in his late teenage years, followed by gradual progression of his condition over the next decade. On examination, he has severe spasticity in his lower limbs and sensorimotor neuropathy. His 28-year-old brother also has similar manifestations. Electrodiagnostic study in this patient will most likely reveal] Normal nerve conduction studies Primarily low compound muscle action potential (CMAP) amplitude with mild slowing Severe slowing of conduction velocity with mildly decreased amplitudes Normal nerve conduction studies but severe proximal denervation on needle EMG None . 22. [Which of the following statements is true regarding motor unit potential morphology in infants as compared to normal healthy adults?] Infants and adults have similar motor unit morphology Infants have significantly smaller motor unit amplitude than adults Infants have larger motor unit amplitude than adults because of higher synchrony among muscle fibers Only infants with myopathy have smaller motor unit amplitude than adults None . 23. [All of the following statements regarding continuous video-EEG monitoring (cEEG) in the ICU are true except] Monitoring can help characterize jerking events in terms of ictal and nonictal There is no added benefit of cEEG monitoring if no seizures were identified in the first 24 hours of monitoring in any critically ill patient It can help in prognostication after subarachnoid hemorrhage (SAH) A patient with a witnessed generalized tonic–clonic seizure, felt to be due to hypoglycemia, is back to his baseline mental state (Glasgow Coma Scale (GCS) 15) and does not need cEEG None . 24. [Which of the following statements is true regarding lambda waves?] They are not seen outside the occipital region They are most common in children and adolescents They can be triggered by eye closure immediately after scanning a complex picture They are usually asynchronous and asymmetric None . 25. [All of the following statements regarding EEG changes observed after carotid crossclamping during carotid endarterectomy are true except] EEG changes usually occur within the first 20 seconds in the majority of patients Decrease of anterior alpha and beta activity on the clamped side suggests ischemia Increase of delta amplitude on the clamped side suggests progression of ischemia Bilateral EEG changes always suggest change in anesthesia or blood pressure None .
