Cnim Test Study Guide

CNIM TEST STUDY GUIDE In BAEP's, cochlear nucleus lesion causes? - Increased III-V, increased I-V Which modality is most useful in monitoring the integrity of the corticospinal tracts during resection of an intramedullary spinal cord tumor? - D-Waves The stimulus used in a brainstem auditory evoked potential study is a click with a peak acoustic power in the range of - 2000 to 4000Hz Which of the following tibial nerve responses is not a near field response? - N31 How many amperes of current will flow in a circuit containing a 2V battery and 10 ohms of resistance? - 0.2 amps In BAEP's blood, betadine or irrigation fluid in tubing causes: - Increase in absolute latency, normal inter-peak latencies In averaging, the period of analysis is called _______ or ________. - Epoch, sweep length While monitoring BAEP, there was a prolongation of wave I through V by more than 2 msec. Which of the following choices is NOT a possible cause? - Increase of isoflurane anesthesia Involuntary movement - Ataxia Smaller surface of stimulating electrodes: - Higher Current Density During posterior fossa surgery, when BAEPs are used for monitoring brainstem function, it is most important to: - Stimulate and record from the contralateral side P100 of a VEP will have the highest amplitude in which derivation? - MO-Fz Cranial nerve VII must be monitored concurrently with BAERs. - True Nerves of the body, such as median, ulnar, and femoral are formed from the: - Dorsal and ventral rami Upper motor neuron extends from: - Precentral gyrus to ventral horn Increasing the stimulus rate of BAEPs - Decreases amplitude and increases latency Which of the following is the normal interocular latency difference of P100? - Less than 15 msec An amplifier sensitivity setting that produces a vertical deflection of 1cm with an input of 10mV is: - 1mV/mm When identifying wave IV and V of a BAEP, which of the following would be most helpful? - Cz-Contra ear montage The maximum leakage current should be - 100 uA Wave V is usually the most prominent peak after - 5.5 msec Which of the following montages will best demonstrate waves I through V of the BAEP? - Cz-ipsilateral ear P13 Generator - Spinomedullary junction An electrode recording from Erb's point is placed - 2-3 cm above the clavicle In BAEP's, perforated or hardened tympanic membrane causes: - Increase in absolute latency, normal inter-peak latencies Which of the following temperatures should be annotated as being hypothermic? - 34 degrees C Dyskinesia: - Abnormal Movement Sensory supply of the posterior 1/3rd of the tongue is from which nerve? - Glossopharyngeal What is the best montage for distinguishing a IV/V complex? - Cz-Contra Ear Loss of a unilateral waveform is never a concern as long as wave V is present on the other ear. - False Which of the following are thalamic nuclei for the somatosensory pathway? - VPL nucleus What does an increased N13-N20 central conduction time with normal N9-N20 conduction time and a normal nerve conduction velocity indicate? - Defect above the lower medulla at or below the somatosensory cortex The effect of hypotension on the evoked potential is: - Decreased amplitude, increased latency Using an amplification factor of 500,000, a 1uV brainstem auditory evoked potential waveform will be amplified to - 0.50v Which of the following monitoring modes is LEAST useful for skull base surgery? - Tibial nerve SSEP Which surgical approach will sacrifice hearing? - Translabyrinthine Which muscle is innervated by L4-S1 nerve roots? - Tibialis anterior Selective dorsal rhizotomy: - Reduces spasticity The fibers anterior to the chiasm in the visual pathway are called: - Optic nerves During posterior fossa surgery, wave V of the BAEPs may increase in latency due to: - Retraction of the cerebellum When is it most appropriate to alert the surgical team of a problem with the monitoring? - After a loss of 55% amplitude