Intraoperative monitoring of brain-stem auditory evoked potentials

1982 ◽  
Vol 57 (3) ◽  
pp. 341-348 ◽  
Author(s):  
Peter A. Raudzens ◽  
Andrew G. Shetter
Keyword(s):  
Evoked Potentials ◽  
Brain Stem ◽  
Auditory Evoked Potentials ◽  
Neurological Deficits ◽  
Additional Patient ◽  
Content Type ◽  
Intracranial Surgery ◽  
Surgical Measures ◽  
Evoked Potential Monitoring ◽  
Operating Surgeon

✓ Intraoperative brain-stem auditory evoked potentials (BAEP's) were monitored in 46 patients undergoing intracranial surgery for a variety of pathological conditions to determine whether this technique was capable of providing useful information to the operating surgeon. Intraoperative BAEP's were unchanged throughout surgery in 34 patients (74%), and these individuals had no postoperative hearing deficits. Four patients (9%) developed an abrupt ipsilateral loss of all waveform components beyond Wave I and had postoperative evidence of a pronounced hearing loss in the affected ear. An additional patient demonstrated BAEP loss contralateral to the side of surgery, and this was associated with subsequent signs of severe brain-stem dysfunction. Seven patients (15%) developed intraoperative delays of BAEP waveform latency values, but maintained recognizable waveforms beyond Wave I. Postoperatively, their hearing was either normal or mildly impaired, and there were no indications of other brain-stem abnormalities. This group represents the individuals who may have been benefited by evoked potential monitoring, since corrective surgical measures were taken when latency delays were observed. Intraoperative BAEP's can be reliably and routinely recorded in an operating room environment. They provide a good predictor of postoperative auditory status, and may have prevented permanent neurological deficits in a small segment of patients by alerting the surgeon to potentially reversible abnormalities.

Intraoperative monitoring of brain-stem auditory evoked potentials

1982 ◽  
Vol 57 (5) ◽  
pp. 674-681 ◽  
Author(s):  
Betty L. Grundy ◽  
Peter J. Jannetta ◽  
Phyllis T. Procopio ◽  
Agnes Lina ◽  
J. Robert Boston ◽  
...  
Keyword(s):  
Evoked Potentials ◽  
Brain Stem ◽  
Auditory Nerve ◽  
Intraoperative Monitoring ◽  
Cerebellopontine Angle ◽  
Auditory Evoked Potentials ◽  
Irreversible Loss ◽  
Content Type ◽  
Complete Obliteration ◽  
Fine Print

✓ Brain-stem auditory evoked potentials (BAEP) were monitored during 54 neurosurgical operations in the cerebellopontine angle. The BAEP were irreversibly obliterated in five patients who required deliberate section of the auditory nerve. Technical difficulties interfered with monitoring in three cases, and three patients had deafness and absent BAEP preoperatively. Reversible alterations in BAEP were seen during 32 operations, with recovery after as long as 177 minutes of virtually complete obliteration. Changes in BAEP were associated with surgical retraction, operative manipulation, positioning of the head and neck for retromastoid craniectomy, and the combination of hypocarbia and moderate hypotension. In 19 cases, waveforms improved after specific interventions made by the surgeon or anesthesiologist because of deteriorating BAEP. In 13 other cases, BAEP recovered after maneuvers not specifically related to the electrophysiological monitoring, most often completion of operative manipulation. Whenever BAEP returned toward normal by the end of anesthesia, even after transient obliteration, hearing was preserved. Irreversible loss of BAEP occurred only when the auditory nerve was deliberately sacrificed. The authors conclude that monitoring of BAEP may help prevent injury to the auditory nerve and brain stem during operations in the cerebellopontine angle.

Measurements of brain-stem auditory evoked potentials in patients with spontaneous intracerebral hemorrhage

1984 ◽  
Vol 60 (3) ◽  
pp. 548-552 ◽  
Author(s):  
Christianto B. Lumenta
Keyword(s):  
Glasgow Coma Scale ◽  
Intracerebral Hemorrhage ◽  
Evoked Potentials ◽  
Brain Stem ◽  
Auditory Evoked Potentials ◽  
Spontaneous Intracerebral Hemorrhage ◽  
Content Type ◽  
Different Types ◽  
The Brain ◽  
Fine Print

✓ Brain-stem auditory evoked potentials (BAEP's) were recorded in 19 patients with spontaneous intracerebral hemorrhage. More than half of the patients were deeply comatose. There was no correlation between BAEP changes and different types of spontaneous intracerebral hemorrhage or between BAEP's and coma grading by the Glasgow Coma Scale. However, BAEP's were a significant prognostic aid in these cases and useful in indicating the level of the brain-stem lesion.

Auditory evoked potentials recorded from the cochlear nucleus and its vicinity in man

1983 ◽  
Vol 59 (6) ◽  
pp. 1013-1018 ◽  
Author(s):  
Aage R. Møller ◽  
Peter J. Jannetta
Keyword(s):  
Evoked Potentials ◽  
Brain Stem ◽  
Cochlear Nucleus ◽  
Auditory Nerve ◽  
Auditory Evoked Potentials ◽  
Auditory Pathway ◽  
Content Type ◽  
Negative Peak ◽  
Auditory Brain Stem ◽  
Stimulation Of

✓ Intracranial responses from the auditory nerve and the cochlear nucleus were recorded from patients undergoing neurosurgical operations during which these structures were exposed. Responses to stimulation of the ipsilateral ear with short tonebursts from the vicinity of the cochlear nucleus show a large surface-negative peak, the latency of which is close to that of peak III in the auditory brain-stem evoked potentials recorded from scalp electrodes. There was also a response to contralateral stimulation, smaller in amplitude and with a longer latency. It is concluded that the cochlear nucleus is the main generator of peak III responses, and that structures of the ascending auditory pathway that are more central than the cochlear nucleus are unlikely to contribute to wave III of the auditory brain-stem evoked potentials.

Intraoperative brain-stem auditory evoked potentials during posterior fossa microvascular decompression

1985 ◽  
Vol 62 (4) ◽  
pp. 552-557 ◽  
Author(s):  
William A. Friedman ◽  
Barry J. Kaplan ◽  
Dietrich Gravenstein ◽  
Albert L. Rhoton
Keyword(s):  
Brain Stem ◽  
Posterior Fossa ◽  
Microvascular Decompression ◽  
Auditory Evoked Potentials ◽  
Evoked Potential ◽  
Auditory Evoked Potential ◽  
Complete Disappearance ◽  
Content Type ◽  
Technological Advances ◽  
Evoked Potential Monitoring

✓ Recent technological advances have led to increased interest in intraoperative evoked potential monitoring. Although theoretically valuable, its precise role remains to be defined, and useful criteria for predicting neurological deficit are not well established. The authors used brain-stem auditory evoked potential (BAEP) monitoring during 21 posterior fossa microvascular decompression procedures to assess the value of this technique in predicting postoperative deficit. The surgeon was notified only if there was complete disappearance of wave V. Although no patients had postoperative deafness, BAEP latencies changed significantly in all cases. In four patients, wave V totally disappeared during cerebellar retraction. The BAEP appears to be a very sensitive monitor of auditory function, such that “false positive” results will be frequent if latency criteria alone are used to trigger alterations in surgical technique.

A comparative study of brain-stem auditory evoked potentials and blink reflexes in posterior fossa tumor patients

1988 ◽  
Vol 69 (5) ◽  
pp. 660-668 ◽  
Author(s):  
Mehmet Zileli ◽  
Fethi İdiman ◽  
Tufan Hiçdönmez ◽  
İzzet Övül ◽  
Erdem Tunçbay
Keyword(s):  
Evoked Potentials ◽  
Brain Stem ◽  
Posterior Fossa ◽  
Cerebellopontine Angle ◽  
Auditory Evoked Potentials ◽  
Lesion Group ◽  
Control Group ◽  
Posterior Fossa Tumors ◽  
Content Type ◽  
Fine Print

✓ Brain-stem auditory evoked potentials (BAEP's) and blink reflexes (BR's) were recorded from 40 patients with clinical and radiological evidence of posterior fossa tumors. They were examined in three groups according to the anatomical location of the lesion: Group A included 15 patients with midline tumors; Group B included 14 patients with cerebellar hemispheric tumors; and Group C included 11 patients with cerebellopontine angle (CPA) tumors. More of the 40 patients had BAEP abnormalities (32) than BR abnormalities (24). All of the 11 patients with CPA tumors had some kind of BAEP and BR abnormalities. The 14 patients with cerebellar tumors showed the next most frequent abnormalities: 12 related to the BAEP's and seven to the BR's. The 15 patients with midline tumors showed the least number of abnormalities: nine related to BAEP's and six to the BR's. In the analysis of BAEP wave latencies and interpeak latencies, a wave III latency delay occurred in all groups; latencies of waves IV and V were more significantly delayed in patients with CPA and cerebellar hemispheric tumors, and the interpeak latencies of waves III–V and I–V were markedly prolonged only in patients with CPA tumors (p < 0.01). In all tumor groups, early response (R1) of BR's was significantly delayed in comparison to a healthy volunteer control group (p < 0.01), but R1 was more pronounced in cases of CPA tumors when compared with the other tumor groups. Although significant delays in direct and consensual late reflex components (R2) of BR's were noted in comparison to the control group, this delay could not differentiate one tumor group from another. It can be concluded that, while these tests reflect the functions of different cranial nerves and brain-stem tracts, BAEP monitoring is more sensitive than BR testing for the detection of brain-stem involvement in posterior fossa tumors. Cerebellopontine angle tumors almost always cause severe abnormalities in both tests. Cerebellar hemispheric tumors and midline tumors cause fewer changes in both BAEP's and BR's.

Use of intraoperative auditory evoked potentials to preserve hearing in unilateral acoustic neuroma removal

1984 ◽  
Vol 61 (5) ◽  
pp. 938-948 ◽  
Author(s):  
Robert G. Ojemann ◽  
Robert A. Levine ◽  
William M. Montgomery ◽  
Patricia McGaffigan
Keyword(s):  
Evoked Potentials ◽  
Brain Stem ◽  
Auditory Evoked Potentials ◽  
Compound Action Potential ◽  
Speech Discrimination ◽  
Sound Perception ◽  
Content Type ◽  
Increased Risk ◽  
The Status ◽  
Fine Print

✓ Twenty-two patients with unilateral acoustic neuromas and preoperative speech discrimination scores of 35% or more had intraoperative monitoring of the electrocochleogram (ECoG) using a transtympanic electrode, and of the brain-stem auditory evoked potentials (BAEP's) using scalp electrodes. Rapid feedback was provided about the status of the cochlear microphonics from the hair cells of the inner ear (CM of the ECoG), the compound action potential of the auditory nerve (N-1 of the ECoG or Wave I of the BAEP's) and the potentials from the lower brain stem (Wave V of the BAEP's). All patients had total removal of the tumor. In 21, the cochlear nerve was anatomically preserved, and 20 had good postoperative facial nerve function. Correlation of tumor size with postoperative hearing was as follows: discrimination scores of more than 35% in three of four patients with 1-cm tumors, two of eight with 1.5-cm tumors, two of six with 2- to 2.5-cm tumors, and one of four with tumors of 3 cm or more. Two other patients with 1.5-cm tumors had discrimination scores of less than 35%, and one patient with a 2-cm tumor had only sound perception. In two patients, the discrimination scores improved. At the end of the operation, all patients with hearing had a detectable N-1, and, when recorded, CM. All but one patient with no hearing had lost N-1, and CM was absent or reduced. Unless Wave V was unchanged, it was a poor predictor of postoperative hearing, and its absence did not preclude preservation of good hearing. The electrophysiological changes during each stage of the operation were analyzed and correlated with events during surgery. Areas in which there was an increased risk of loss of the potentials were determined. In some patients monitoring was unnecessary, because either there were no significant changes or the changes were abrupt and no recovery occurred. However, in other patients, monitoring alerted the surgeon to a possible problem and the method of dissection was altered. Possible mechanisms of hearing loss were suggested from the changes in the recordings.

scholarly journals Study of Short Latency Somatosensory and Brain Stem Auditory Evoked Potentials Patients with Acute Ischemic Stroke Involving Middle Cerebral Artery Territory

2021 ◽  
Author(s):  
Abhishek Miryala ◽  
Mahendra Javali ◽  
Anish Mehta ◽  
Pradeep R. ◽  
Purushottam Acharya ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Evoked Potentials ◽  
Middle Cerebral Artery ◽  
Acute Ischemic Stroke ◽  
Brain Stem ◽  
Functional Outcome ◽  
Cerebral Artery ◽  
Negative Correlation ◽  
Auditory Evoked Potentials ◽  
Positive Correlation

Abstract Background The precise timings of evoked potentials in evaluating the functional outcome of stroke have remained indistinct. Few studies in the Indian context have studied the outcome of early prognosis of stroke utilizing evoked potentials. Objective The aim of this study was to determine somatosensory evoked potentials (SSEPs) and brain stem auditory evoked potentials (BAEPs), their timing and abnormalities in acute ischemic stroke involving the middle cerebral artery (MCA) territory and to correlate SSEP and BAEP with the functional outcome (National Institutes of Health Stroke Scale (NIHSS), modified Rankin scale (mRS) and Barthel’s index) at 3 months. Methods MCA territory involved acute ischemic stroke patients (n = 30) presenting consecutively to the hospital within 3 days of symptoms onset were included. Details about clinical symptoms, neurological examination, treatment, NIHSS score, mRS scores were collected at the time of admission. All patients underwent imaging of the brain and were subjected to SSEP and BAEP on two occasions, first at 1 to 3 days and second at 4 to 7 days from the onset of stroke. At 3 months of follow-up, NIHSS, mRS, and Barthel’s index were recorded. Results P37 and N20 amplitude had a strong negative correlation (at 1–3 and 4–7 days) with NIHSS at admission, NIHSS at 3 months, mRS at admission, and mRS at 3 months and a significant positive correlation with Barthel’s index (p < 0.0001). BAEP wave V had a negative correlation (at 1–3 and 4–7 days) with NIHSS at admission, NIHSS at 3 months, mRS at admission, and mRS at 3 months and a positive correlation with Barthel’s index (p < 0.0001). Conclusion SSEP abnormalities recorded on days 4 to 7 from onset of stroke are more significant than those recorded within 1 to 3 days of onset of stroke; hence, the timing of 4 to 7 days after stroke onset can be considered as better for predicting functional outcome.

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