Use of Electrocochleography and Brain Stem Auditory Evoked Potentials in the Diagnosis of Cerebellopontine Angle Pathology

2015 ◽  
pp. 47-56 ◽  
Author(s):  
J. J. Eggermont
Keyword(s):  
Evoked Potentials ◽  
Brain Stem ◽  
Cerebellopontine Angle ◽  
Auditory Evoked Potentials

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.

Deterioration of auditory evoked potentials during cerebellopontine angle manipulations

1985 ◽  
Vol 63 (4) ◽  
pp. 598-607 ◽  
Author(s):  
Tetsuji Sekiya ◽  
Takashi Iwabuchi ◽  
Shigeki Kamata ◽  
Takashi Ishida
Keyword(s):  
Evoked Potentials ◽  
Brain Stem ◽  
Real Time ◽  
Action Potentials ◽  
Cerebellopontine Angle ◽  
Auditory Evoked Potentials ◽  
Cochlear Nerve ◽  
Cerebellar Hemisphere ◽  
Common Finding ◽  
Interpeak Latency

✓ Evoked action potentials from the internal auditory meatus portion of the cochlear nerve (IAM-EAP's) and brain-stem auditory evoked potentials (BAEP's) from the vertex were simultaneously recorded during cerebellopontine angle (CPA) manipulations (retractions of the cerebellar hemisphere and the cochlear nerve) in dogs. The BAEP changes noted in these dogs were the same as those seen in patients. The IAM-EAP's showed graded deterioration related to BAEP changes. The results are as follows: 1) Prolongation of the I–V interpeak latency of BAEP's, the most common finding during CPA manipulations, is the reflection of prolongation of the I–II interpeak latency, which is caused by conduction impairment or block of the nerve impulses between the extracranial portion of the cochlear nerve and the brain stem. The operative manipulations representing stretch or compression injury to the cochlear nerve in the CPA leads to an acute traumatic cranial nerve root lesion — a retrocochlear lesion. 2) The obliteration of all BAEP components including wave I cannot be caused by conduction block. This is caused by occlusion of the internal auditory artery. Wave I of the BAEP's and the P1-N1 complex of the IAM-EAP's are important indicators of cochlear blood flow during surgical intervention. 3) As possible causes of internal auditory artery obstruction, mechanical distortion of the relationship between the anterior inferior cerebellar artery (AICA) and the internal auditory artery at the junctional portion, mechanical vasospasm of the AICA-internal auditory artery complex, and ensuing noreflow phenomena are discussed. 4) Evoked action potentials are expected to be a useful intraoperative real-time monitor during CPA surgery that can detect rapid changes derived from cochlear artery insufficency. The real-time aspects can overcome some of the disadvantages of BAEP monitoring.

Monitoring Auditory Nerve Potentials during Operations in the Cerebellopontine Angle

1984 ◽  
Vol 92 (4) ◽  
pp. 434-439 ◽  
Author(s):  
Aage R. Øller ◽  
Peter J. Jannetta
Keyword(s):  
Hearing Loss ◽  
Evoked Potentials ◽  
Brain Stem ◽  
Microvascular Decompression ◽  
Auditory Nerve ◽  
Cerebellopontine Angle ◽  
Auditory Evoked Potentials ◽  
Cranial Nerves

Direct monitoring of auditory nerve potentials was performed in 19 patients undergoing retromastoid craniectomy and microvascular decompression of cranial nerves. In addition, brain stem auditory evoked potentials (BSEPs) were monitored in these patients. No patient suffered significant hearing loss. Direct monitoring of auditory nerve potentials complements the recording of BSEPs because the auditory nerve potentials can be visualized without averaging many responses. Therefore the effect of any intraoperative manipulation that is harmful to the auditory nerve can be detected instantaneously.

Preservation of Cochlear Nerve Function with the Aid of Brain Stem Auditory Evoked Potentials

Neurosurgery ◽  
1982 ◽  
Vol 11 (1_pt_1) ◽  
pp. 16-19 ◽  
Author(s):  
Russell W. Hardy ◽  
Sam E. Kinney ◽  
Hans Lueders ◽  
Ronald P. Lesser
Keyword(s):  
Evoked Potentials ◽  
General Anesthesia ◽  
Brain Stem ◽  
Cerebellopontine Angle ◽  
Auditory Evoked Potentials ◽  
Neurological Function ◽  
Cochlear Nerve ◽  
Nerve Function ◽  
Cochlear Function ◽  
Cerebellopontine Angle Tumors

Abstract Somatosensory, visual, and auditory evoked potentials have been used to monitor neurological function in patients under general anesthesia. This paper describes the preservation of useful hearing in three patients with cerebellopontine angle tumors. In each case, cochlear function was monitored during the procedure, and confirmation of intact conduction intraoperatively was associated with preserved hearing postoperatively.

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.

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.

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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