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PubMed2002

Epileptic spikes: magnetoencephalography versus simultaneous electrocorticography.

PURPOSE: To test the sensitivity of extracranial magnetoencephalography (MEG) for epileptic spikes in different cerebral sites. METHODS: We simultaneously recorded MEG and electrocorticography (ECoG) by using subdural electrodes with 1-cm interelectrode distances for one patient with lateral frontal epilepsy and one patient with basal temporal epilepsy. We analyzed MEG spikes associated with ECoG spikes and compared the maximal amplitude and number of electrodes involved. We estimated and evaluated the locations and moments of the equivalent current dipoles (ECDs) of MEG spikes. RESULTS: In patient 1, MEG detected 100 (53%) of 188 ECoG lateral frontal spikes, including 31 (46%) of 67 spikes that activated three subdural electrodes. MEG spike amplitudes correlated with ECoG spike amplitudes and the number of electrodes activated (p < 0.01). ECDs were perpendicular to the superior frontal sulcus. In patient 2, MEG detected 31 (26%) of 121 ECoG basal temporal spikes, but none that activated only three subdural electrodes. ECDs were localized in the entorhinal and parahippocampal gyri, oriented perpendicular to those basal temporal cortical surfaces. The ECD strength was 136.6 +/- 71.5 nAm in the frontal region, but 274.5 +/- 150.6 nAm in the temporal region (p < 0.01). CONCLUSIONS: When lateral frontal ECoG spikes extend >3 cm2 across the fissure, MEG can detect >50%, correlating with spatial activation and voltage. In the basal temporal region, MEG requires higher-amplitude discharges over a more extensive area. MEG shows a significantly higher sensitivity to lateral convexity epileptic discharges than to discharges in isolated deep basal temporal regions.

Adult↗

PubMed2002

Clinical determinants of survival in patients with 5-fluorouracil-based treatment for metastatic colorectal cancer: results of a multivariate analysis of 3825 patients.

BACKGROUND: Patients with metastatic colorectal cancer are usually offered systemic chemotherapy as palliative treatment. A multivariate analysis was performed in order to identify predictors and their constellation that allow a valid prediction of the outcome in patients treated with 5-fluorouracil (5-FU)-based therapy. PATIENTS AND METHODS: A total of 3825 patients treated with 5-FU within 19 prospective randomised and three phase II trials were separated into learning (n = 2549) and validation (n = 1276) samples. Data were analysed by tree analysis using the recursive partition and amalgamation method (RECPAM). A predictor could only enter the RECPAM analysis if the number of patients with missing values was < 33.3% within a node, and the minimal node size was set to 50 patients. Twenty-three potential predictors were grouped into subsets of laboratory variables (11 parameters), tumour-related variables (seven parameters) and clinical variables (five parameters). In the first step, tree analysis was performed separately for each predictor subset. The selected prognostic parameters of the resulting partial models (the 'winners') were entered into the general model. The classification rule from the data of the learning set was applied to the independent validation set. RESULTS: Winners of the subgroup analysis for laboratory variables were: platelets > or = 400 x 10(9)/l, alkaline phosphatase > or = 300 U/l, white blood cell (WBC) count > or = 10 x 10(9)/l and haemoglobin < 11 x 10(9)/l, and all predicted a worse outcome. Negative predictors within the subgroup of tumour parameters were: number of tumour sites more than one or more than two, presence of liver metastases or peritoneal carcinomatosis, which predicted a worse outcome. Furthermore, presence of lung metastases, a primary rectal cancer and presence of lymph node metastases all predicted a better outcome in the multivariate setting. Among the clinical parameters only performance status of ECOG 0 or 1 predicted better outcome. In the final regression tree, three risk groups could be identified: low risk group (n = 1111) with a median survival of 15 months for patients with ECOG 0/1 and only one tumour site; intermediate risk group (n = 904) with a median survival of 10.7 months for patients with ECOG 0/1 and more than one tumour site and alkaline phosphatase < 300 U/l or patients with ECOG > 1, WBC count < 10 x 10(9)/l and only one tumour site; high risk group (n = 534) with a median survival of 6.1 months for patients with ECOG 0/1 and more than one tumour site and alkaline phosphatase of > or = 300 U/l or patients with ECOG > 1 and more than one tumour site or WBC count > 10 x 10(9)/l. The median survival times for the good, intermediate and high risk groups in the validation sample were 14.7, 10.5 and 6.4 months, respectively. CONCLUSIONS: Patients can be divided into at least three risk groups depending on the four baseline clinical parameters: performance status, WBC count, alkaline phosphatase and number of metastatic sites. Any molecular or biological marker should be validated against these clinical parameters and decisions for more or less intensive treatments may be studied separately in these three risk groups. Also, clinical trials should be stratified according to the three risk groups.

Alkaline Phosphatase↗

PubMed2004

Eastern Cooperative Oncology Group performance status predicts bone metastasis in patients presenting with renal cell carcinoma: implication for preoperative bone scans.

PURPOSE: We identified a subset of patients with renal cell carcinoma (RCC) who have a high likelihood of presenting with bone metastasis and would most benefit from a preoperative bone scan. MATERIALS AND METHODS: A database of 1,357 patients undergoing nephrectomy and/or immunotherapy for RCC at our institution was queried. Patients presenting with metastasis to the bones were identified and stratified according to T stage, Eastern Cooperative Oncology Group (ECOG) score, musculoskeletal symptoms and alkaline phosphatase. RESULTS: Of the patients 37% presented with metastasis. Bone metastasis was identified in 14% of patients. The incidence of bone metastasis was 5.4%, 13.8%, 15.4% and 28.2% in patients with T1 to T4 lesions, and 1.4%, 19% and 41% in those with an ECOG score of 0 to 2 and greater, respectively. T stage and ECOG score were then integrated. Bone metastasis was confirmed in 0.046%, 3.8%, 1.4% and 0% of patients with T1 to T4/ECOG 0 disease, and in 13.4%, 20%, 21.5% and 31% of those with T1 to T4/ECOG greater than 0 disease, respectively (p < 0.0001). Only 1.4% of patients with an ECOG score of 0 harbored bone metastasis, of whom 71% complained of musculoskeletal pain, 100% manifested extraosseous metastases and 25% had increased alkaline phosphatase at presentation. CONCLUSIONS: Performance status is an important predictor of bone metastasis in patients presenting with presumed RCC lesions. Bone scan should be performed in patients with an ECOG score of greater than 0 regardless of T stage but is unnecessary in those presenting with an ECOG score of 0, particularly when lacking symptoms and extraosseous metastasis.

Adult↗

PubMed2006

Cerebral cortical effects of desflurane in sheep: comparison with isoflurane, sevoflurane and enflurane.

BACKGROUND: Different volatile anesthetic agents have differing propensities for inducing seizures. A measure of the predilection to develop seizures is the presence of interictal spike discharges (spikes) on the electrocorticogram (ECoG). In this study, we investigated the propensity of desflurane to induce cortical spikes and made a direct objective comparison with enflurane, isoflurane, and sevoflurane. The ECoG effects of desflurane have not been previously reported. METHODS: After establishment of invasive monitoring and a parasagittal array of eight electrodes to record the ECoG; eight adult merino sheep were given a series of short inhalational anesthetics (using desflurane, enflurane, sevoflurane and isoflurane); each titrated to ECoG burst suppression. Anesthetic effect was estimated by the effects on the approximate entropy of the ECoG. The effect of anesthetic on the spike-rate in the ECoG was analyzed using a non-linear mixed-effect method with a sigmoid Emax model. RESULTS: A similar 'depth of anesthesia' was achieved for each agent, as estimated by the approximate entropy. The mean (SD) values of Emax for the spike-rate vs. approximate entropy relationship were desflurane 0.5 (0.9), enflurane 17.2 (4.0), isoflurane 0.7 (1.2), and sevoflurane 5.3 (1.2) spikes/min. The spike rate caused by desflurane was similar to isoflurane and significantly lower than that of enflurane (P < 0.001), and sevoflurane (P = 0.009). CONCLUSION: Desflurane induces minimal cerebral cortical spike activity when administered to burst suppression, consistent with its low propensity for inducing seizures in non-epileptic brains. The agents can be ranked by their relative ability to cause spike activity: enflurane >> sevoflurane > isoflurane = desflurane.

Anesthetics, Inhalation↗

PubMed1998

Histopathological correlates of epileptogenicity as expressed by electrocorticographic spiking and seizure frequency.

PURPOSE: To study the correlation between histopathology and epileptogenicity, as measured by seizure frequency and electrocorticography (EcoG), in patients with cortical dysplasia (CD) as compared with control patients with gangliogliomas or gliomas. METHODS: The influence of the histopathological classification and the presence of balloon cells in CD on the frequency and extension of five predefined patterns of ECoG spiking, seizure frequency, age of seizure onset and 6-month postoperative outcome were analyzed in 32 patients with focal epilepsy undergoing presurgical evaluation with chronically implanted subdural electrodes. RESULTS: Comparison of patients with CD, gangliogliomas, and gliomas showed that the seizure frequency was greatest in patients with CD and ECoG spiking and was most extensive in patients with gangliogliomas. The onset of epilepsy was earlier in patients with CD and with gangliogliomas. None of these differences was significant. However, in patients with CD, the presence of balloon cells was associated with significantly greater seizure frequency (p=0.009), and a significantly greater number of electrodes recording continuous frequent spiking (p=0.03). The presence of continuous very frequent spiking correlated with the duration of the epilepsy and the number of seizures recorded during monitoring. No significant correlation was detected between histopathology, seizure frequency, or ECoG activity and postoperative outcome, which was relatively favorable in patients with balloon cells. CONCLUSIONS: CD refers to a variety of histopathological patterns associated with different epileptogenicity. In CD, increased clinical and ECoG epileptogenicity correlates with the presence of balloon cells. This finding confirms that balloon cells should be considered in the histopathological classification of CD. The predefined ECoG were not specific for any of the histopathologies investigated.

Adolescent↗

PubMed1994

Electrocorticography and stimulation.

Although acute electrocorticography (ECoG) is routinely used during epilepsy surgery there is little agreement as to its value nor criteria for its interpretation. Specific issues are reviewed on the basis of the literature and personal studies: does failure to resect the entire irritative zone prejudice seizure control, and are residual discharges predictive of failure; does activation of the ECoG by intravenous barbiturates provide information of clinical value; does intraoperative electrical stimulation help to improve localisation or avoid postoperative deficits; is the ECoG of value for monitoring functional procedures; can the value of ECoG be increased by new interpretive approaches? It is suggested that resection of the entire area of interictal discharge is not essential for satisfactory surgical outcome, but a distinction may need to be made between those discharging regions that function as pacemakers and those in which ECoG spikes appear secondarily. There is also evidence that, apart from any consideration of determining the area resected, the topography of epileptiform discharge may be predictive of pathology and surgical outcome. It is concluded that more detailed topographic and quantitative analysis of the ECoG is required before its value in planning surgery can be determined or objective interpretive criteria established.

Cerebral Cortex↗

PubMed1988

Effects of pilocarpine on breathing movements in normal, chemodenervated and brain stem-transected fetal sheep.

1. We examined the effects on fetal breathing movements (FBM) and electrocortical activity (ECoG) of the administration of pilocarpine to three groups of fetal sheep in utero: one group had peripheral chemodenervation; one group had peripheral chemodenervation and transection of the brain stem at the level of the colliculi; a third group of sham-operated animals acted as a control. 2. Pilocarpine induced a period of FBM characterized by their high amplitude (ca. 24 mmHg) and low frequency (ca. 0.65 Hz). It also produced low-voltage ECoG. These effects were seen both in normoxia and in hypoxia. They were independent of the ECoG state in which the drug was given. 3. In normoxia, pilocarpine-induced FBM were blocked by cholinergic antagonists which enter the central nervous system, atropine sulphate and scopolamine hydrobromide, but were either unaffected or were reduced in amplitude by antagonists with restricted access to the central nervous system, atropine methylnitrate and scopolamine methylbromide. In hypoxia, atropine sulphate and scopolamine hydrobromide again blocked FBM but now scopolamine methylbromide and atropine methylnitrate blocked the FBM in 42% of trials. In the remaining trials FBM remained virtually unchanged. 4. No differences were observed in the effects of pilocarpine on FBM or ECoG between chemodenervated fetuses and those which had been sham-operated. 5. In fetuses with transection of the brain stem, breathing was continuous irrespective of the ECoG. Pilocarpine increased the amplitude of FBM but did not alter the frequency of these FBM. These effects occurred both in normoxia and in hypoxia. 6. We conclude that pilocarpine produces effects on fetal behaviour via at least two sites in the central nervous system. One site lies in the pons or medulla and is responsible for the stimulation of FBM. The other site is above the level of the colliculi and is responsible for producing sustained low-voltage ECoG. These effects do not require the integrity of the peripheral chemoreceptors and we find no evidence to support the previous suggestion that the action of pilocarpine is via stimulation of these receptors.

Animals↗

PubMed1995

Alpha 1- and alpha 2-adrenoreceptor actions of phentolamine and prazosin on breathing movements in fetal sheep in utero.

1. We studied the effects of systemic administration of the alpha 1- and alpha 2-adrenoreceptor antagonist phentolamine and the selective alpha 1-adrenoreceptor antagonist prazosin on fetal breathing movements (FBM) and electrocortical activity (ECoG) in fetal sheep. In one group of fetuses (group I; n = 7) the effects of phentolamine were measured during normoxia and hypoxia. In the second group of fetuses (group II; n = 8) the effects of either phentolamine, or combined phentolamine and prazosin, or prazosin alone, were measured during normoxia. 2. In group I fetuses, the incidence of FBM increased after phentolamine treatment. An increase in the incidence and mean episode duration of low-voltage ECoG (LV-ECoG) was also measured after phentolamine treatment. These effects of phentolamine persisted during hypoxia. 3. In group II fetuses a pronounced decrease in the incidence of FBM occurred after administration of prazosin following either phentolamine or saline pretreatment. These effects of prazosin on FBM were independent of an effect on ECoG activity. 4. We conclude that catecholamines have a stimulatory role on FBM mediated via an alpha 1-adrenoreceptor mechanism. Phentolamine leads to an increase in FBM by preferentially antagonizing presynaptic alpha 2-adrenoreceptors over postsynaptic alpha 1-adrenoreceptors. This influence of phentolamine on FBM may be secondary to its effect on ECoG. Promotion of LV-ECoG by catecholamines is mediated via an alpha 1-independent mechanism.

Adrenergic alpha-1 Receptor Antagonists↗

PubMed1994

Effect of mild hypocapnia on fetal breathing and behavior in unanesthetized normoxic fetal lambs.

We hypothesized that the level of arterial PCO2 (PaCO2) affects the incidence of fetal breathing movements and electrocorticographic (ECoG) states in chronically instrumented fetal sheep. Six fetuses of 128-132 days gestational age were instrumented for recording fetal behavior and for later connection to an extracorporeal membrane oxygenation (ECMO) system to change fetal blood gases. Before ECMO fetal arterial pH and blood gases were pH 7.40 +/- 0.01, PaCO2 42.9 +/- 1.5 Torr, and arterial PO2 (PaCO2) 19.2 +/- 1.7 Torr; during ECMO in normocapnia they were pH 7.37 +/- 0.01, PaCO2 46.1 +/- 0.7 Torr, and PaCO2 27.6 +/- 3.0 Torr; and during ECMO in mild hypocapnia they were pH 7.47 +/- 0.01, PaCO2 35.3 +/- 1.7 Torr, and PaCO2 26.6 +/- 1.7 Torr. The overall incidence of breathing movements, the incidence of breathing movements during low-voltage (LV) ECoG activity, and the mean duration of periods of breathing decreased significantly during hypocapnia. Fetal ECoG activity showed normal cycling during the periods of mild hypocapnia, and the mean duration of LV ECoG periods did not change. During mild hypocapnia, eye movements remained associated with LV ECoG activity and nuchal electromyographic activity remained associated with high-voltage ECoG activity. These results suggest that the presence of breathing movements in fetal life is not only dependent on the behavioral state but also on the level of fetal PaCO2.

Animals↗

PubMed1988

Measurement of fetal responses to vibroacoustic stimuli. Habituation in fetal sheep.

Electrocortical (ECoG) and integrated electromyographic (EMG) activity was recorded in 6 chronically prepared fetal sheep (132-145 days). Recording were made in fetuses prior to and during repeated vibroacoustic stimulation. In the undisturbed fetus, two patterns of ECoG activity were apparent; high (HV) and low voltage (LV). The fetus responded to this broad spectrum stimulus during both LV and HV ECoG activity. In 18 of the 20 experiments, repeated stimulation was not associated with a change in the background ECoG activity. All fetuses responded at least once to the stimulus. Habituation of the EMG response was observed during both HV and LV ECoG activity. The rate of habituation was independent of the background ECoG activity and was unchanged when experiments were repeated at intervals of more than 3 days. These results show that fetal sheep also respond to vibroacoustic stimulation and with repetition habituation occurs.

Acoustic Stimulation↗

PubMed1997

A review of electrocochleography: instrumentation settings and meta-analysis of criteria for diagnosis of endolymphatic hydrops.

This paper reviews the literature on instrumentation settings used for transtympanic (TT-ECOG) an extratympanic electrocochleography (ET-ECOG). There is wide variation regard to the applied stimulus, the settings and interpretation of ECOG results. For most physicians, the presence of endolymphatic hydrops is indicated either by the summating/action potential (SP/AP) ratio for click stimuli or the SP amplitude after tone bursts. Different upper limits have been proposed to discriminate hydropic from non-hydropic ears. Based upon a meta-analysis and classification criteria obtained from multivariate statistics, the authors propose that an SP/AP ratio with click stimulation > 0.35 using TT-ECOG, or > 0.42 using ET-ECOG, is indicative of hydrops. With tone burst stimulation set at a repetition rate of 30-40 stimuli per second, a SP of < -2 microV using TT-ECOG for at least one frequency within the range 0.5-8.0 kHz is considered pathologic.

Action Potentials↗

PubMed1988

[Intraoperative electrophysiological monitoring for hearing preservation in acoustic neurinoma surgery].

Five acoustic neurinomas have been operated with hearing preservation as a goal. We monitored intraoperative brainstem auditory evoked potentials (BAEP) in all five cases, electrocochleogram (ECoG) using needle electrode in external auditory meatus in four, and compound action potentials directly recorded from the cochlear nerve (CAP VIII) in three. In all five cases the tumor was totally resected and cochlear nerve was anatomically preserved. However, in only one case useful hearing was preserved with preservation of all wave forms of the BAEP. Another patient with preservation of all wave forms of BAEP and the ECoG showed postoperative severe hearing loss. Other three patients showed postoperative severe hearing loss: only Wave I of BAEP and ECoG were preserved without preservation of the CAP VIII in one whose cochlear nerve was thought to be damaged in cerebellopontine angle cistern; Wave I of BAEP, ECoG and CAP VIII were preserved in one in whom it was suggested cochlear nerve near brainstem or cochlear nucleus was damaged; none of the BAEP, ECoG and CAP VIII was preserved in one in whom it was suggested distal cochlear nerve, or internal auditory artery was damaged. These different patterns of changes suggested that different causes for the hearing loss and difficulties in hearing preservation during acoustic neurinoma surgery. Having identified the putative mechanism of the hearing loss by monitoring those potentials, suggestions are made about how such hearing loss might be avoided. For preservation of the hearing in acoustic neurinoma surgery, all of those potentials including all wave forms of BAEP, ECoG and CAP VIII should be preserved during surgery.(ABSTRACT TRUNCATED AT 250 WORDS)

Action Potentials↗

PubMed1986

Blood glucose as a predictive measure for central nervous system oxygen toxicity in conscious rats.

Blood glucose concentration was measured during continuous electrocorticographic (ECoG) recording in conscious rats exposed to 3 and 5 atmosphere absolute oxygen (ATA O2). The preconvulsive oxygen-induced ECoG changes included increased slow wave activity in delta range, followed by the appearance of successive paroxysmal electrical discharges. A correlation between increases in blood glucose concentration and ECoG changes was observed at both 3 and 5 ATA O2. No significant changes in blood glucose concentration were found in the absence of the ECoG changes. Equivalent periods of exposure to N2-O2 normoxic pressures of 1, 3, and 5 ATA did not produce changes either in ECoG or blood glucose concentration. It is therefore considered possible that an increase in blood glucose concentration may be a useful predictive measure of the ECoG manifestations of oxygen toxicity in conscious unrestrained rats. The possible mechanisms for increase in blood glucose concentration during development of brain oxygen toxicity are discussed.

Animals↗

PubMed1984

[Electrical activity of the cerebral cortex in fasting dogs with preserved and disordered gastric innervation].

Chronic experiments on 6 hungry dogs were made to record the motor periodicity of the stomach from fistulas in the fundal area and the electrocorticograms (ECoG) from bipolar electrodes implanted into cranial bones. Five months before experiments 2 dogs of the six were subjected to selective distal vagotomy. Analysis of 700 ECoGs allowed the conclusion to be made that apart from stereotyped periodicity of the frequency spectrum of the ECoG according to the phases of gastric motor periodicity cycles, in each successive cycle there add up unique compositions of 5 main ECoG frequencies, which do not recur in other cycles (within the range from 2 to 30 Hz) consequent on the asymmetry in electric activity of the right and left hemisphere cortex and on the phenomenon of migrating wave activation. Denervation of the gastroduodenal zone organs leads to substantial restitution and destabilization of the frequency spectrum of the ECoG, disorders in the regulation of migrating wave activation. It is suggested that the features of the ECoG described are linked with the enterogastric mechanisms of hunger motivation.

Animals↗

PubMed1980

Electrocorticographic activity of the prepyriform cortex during the sleep-wakefulness cycle of the freely-behaving rat.

The electrocorticographic (ECoG) behavior of prepyriform cortex (PPC) was studied during the spontaneous sleep-wakefulness cycle (SWC) of freely-behaving rats in which recording electrodes had been chronically implanted in PPC, neocortex (NEO), entorhinal area, olfactory bulb (OB), hippocampus, and dorsal neck muscles. The different phases of the SWC were discerned by taking into account the NEO, OB and neck musculature electrical activities, and criteria were set for the identification of various PPC ECoG patterns. The existence of rather regular associations between the PPC ECoG and the various SWC phases was demonstrated, but it was also seen that these associations defied simplistic generalizations. Thus, whereas the level of ECoG activity (in terms of synchronization vs. desynchronization) was, in the majority of instances, equivalent in PPC and NEO in some SWC phases (alert wakefulness, synchronized sleep and paradoxical sleep), the same was not true in the case of the relaxed wakefulness, drowsiness, intermediary and preparadoxical phases. In the same context, when the time relationships between the alternations of different SWC phases and PPC ECoG patterns were analyzed, it became clear that although only rarely the PPC transition occurred after the correspondent SWC one, the former could either precede, or be simultaneous with the latter, depending on the particular SWC transition being considered. The neural control mechanisms possibly responsible for the coupling of PPC and NEo EcoG activities are briefly discussed.

Animals↗

PubMed1995

Comparison of tympanic membrane-recorded electrocochleography and the auditory brainstem response in threshold determination.

The purpose of this study was to evaluate the usefulness of electrocochleography (ECoG) recorded with a tympanic membrane electrode as an adjunctive measure to auditory brainstem response (ABR) in frequency-specific threshold estimation. In a group of 10 normally hearing and 10 sensorineural hearing-impaired subjects, ABR and ECoG were simultaneously recorded in response to tone-burst stimuli centered at 500, 1000, 2000, and 4000 Hz. At each frequency, stimulus intensity was reduced in 12-dB decrements from an initial level of 110 dB SPL until no replicable response could be discerned. Electrocochleography and ABR thresholds were determined at each frequency, and correlation to behavioral audiometric threshold was determined. Input/output functions were also computed. At 2000 and 4000 Hz, both ABR and ECoG thresholds correlated with behavioral audiometric threshold. At 1000 Hz, ABR threshold correlated with behavioral audiometric threshold; ECoG did not. At 500 Hz, neither ABR nor ECoG threshold correlated with behavioral audiometric threshold. Input/output functions were steeper for ECoG than for ABR at all frequencies tested in the normally hearing group.

Auditory Threshold↗

PubMed1997

Intra-operative electrocochleography in stapedectomy and ossicular reconstruction.

OBJECTIVE: The purpose of this study was to evaluate the effectiveness of intraoperative electrocochleography (ECOG) in predicating the postoperative hearing improvement in surgery for conductive hearing loss. STUDY DESIGN: This study was a prospective study of 22 patients undergoing intraoperative electrocochleography during a stapedectomy. SETTING: The study was performed in a tertiary referral center. PATIENTS: Intraoperative electrocochleography was performed in 22 patients 27-73 years of age undergoing a stapedectomy for otosclerosis under general anesthesia. INTERVENTION: For each patient, the N1 threshold to click stimulation was measured intraoperatively, before and after the reconstruction. MAIN OUTCOME MEASURES: The intraoperative ECOG thresholds were compared with the pre and postoperative audiograms. RESULTS: Postreconstruction ECOG's demonstrated improvements in the N1 threshold in 19 cases, and were unchanged in 1 case. In each of these cases, improvement in the intraoperative N1 threshold corresponded with improvement in the postoperative audiogram compared with the preoperative studies. In two other cases the postreconstruction ECOG was nearly unobtainable, despite improved hearing postoperatively. CONCLUSION: Intraoperative ECOG appears to be an effective tool for verifying the functional integrity of ossicular reconstructions as in stapedectomies. We speculate that intraoperative ECOG may allow the surgeon to "fine tune" the reconstruction to optimize the hearing results.

Adult↗

PubMed1976

Electrocochleography in children. A retrospective study.

A follow-up study of 35 children subjected to electrocochleography (Ecog) was conducted to determine (1) agreement of Ecog results with other audiometric measures obtained subsequently, and (2) accuracy of recommendations for patient management made on the basis of Ecog results. The latter was determined by parental experience, educational placement and achievement, and information from medical and paramedical personnel currently managing the children. These data indicate that Ecog test results are valuable in helping select between possible management alternatives in children who are not testable by behavioral means. However, discussion of two "problem" cases points to possible errors of management that could be made if Ecog results were the only available diagnostic information.

Acoustic Stimulation↗