Electrococleografía en implante coclear / Electrocochleography in cochlear implant

La electrococleografía es una técnica electrofisiológica desarrollada en modelos animales hace más de 90 años. En la actualidad se utiliza en la práctica clínica en audiolo-gía y otoneurología, ya que permite evaluar la función coclear, a través del registro del potencial microfónico coclear, y la funcionalidad del nervio auditivo por medio del registro del potencial de acción compuesto. Debido al avance de la tecnología de los implantes cocleares, actualmente existe la posibilidad de realizar mediciones clínicas a tiempo real con electrococleografía intraoperatoria, por lo que se puede monitorizar la función auditiva residual durante la inserción de los electrodos del implante coclear. En este artículo se presenta una revisión narrativa del uso y aplicación clínica de la electrococleografía en la evaluación de pacientes con implante coclear para predecir el desempeño auditivo y la percepción del habla. La literatura muestra que la electroco-cleografía es una técnica que se encuentra, plenamente, vigente para evaluar la función auditiva en pacientes usuarios de implantes cocleares. Si bien las respuestas cocleares han demostrado ser un buen predictor de los umbrales perceptuales auditivos y del habla en silencio en adultos, aún es una técnica que requiere más desarrollo para ser una herramienta clínica que permita predecir el habla en ruido y la función auditiva en niños y adultos mayores.

Electrocochleography is an electrophysiological technique developed in animal models more than 90 years ago. It is currently used in clinical practice in audiology and otoneurology, since it allows the evaluation of cochlear function, through the recording of the cochlear microphonic potentials, and the functionality of the auditory nerve by means of compound action potential recordings. Due to the advancement of cochlear implant technology, there is currently the possibility of real-time clinical measurements with intraoperative electrocochleography, so that residual hearing function can be monitored during the insertion of the cochlear implant electrodes. This article presents a narrative review of the use and clinical application of electrocochleography in the evaluation of patients with cochlear implants to predict auditory performance and speech perception. The literature shows that electrocochleography is a technique that is fully in force to assess hearing function in patients who use cochlear implants. Although cochlear responses have been shown to be a good predictor of auditory perceptual thresholds and speech in quiet in adults, it is still a technique that requires further development to become a clinical tool for predicting speech in noise and auditory function in children and older adults.

Brainstem auditory evoked potential combined with high resolution cranial base CT can optimize the diagnosis of auditory nerve injury / 中华创伤杂志(英文版)

PURPOSE@#Auditory nerve injury is one of the most common nerve injury complications of skull base fractures. However, there is currently a lack of auxiliary examination methods for its direct diagnosis. The purpose of this study was to find a more efficient and accurate means of diagnosis for auditory nerve injury.@*METHODS@#Through retrospectively analyzing the results of brainstem auditory evoked potential (BAEP) and high-resolution CT (HRCT) in 37 patients with hearing impairment following trauma from January 1, 2018 to July 31, 2020, the role of the two inspection methods in the diagnosis of auditory nerve injury was studied. Inclusion criteria were patient had a clear history of trauma and unilateral hearing impairment after trauma; while exclusion criteria were: (1) severe patient with a Glasgow coma scale score ≤5 because these patients were classified as severe head injury and admitted to the intensive care unit, (2) patient in the subacute stage admitted 72 h after trauma, and (3) patient with prior hearing impairment before trauma. According to Goodman's classification of hearing impairment, the patients were divided into low/medium/severe injury groups. In addition, patients were divided into HRCT-positive and negative groups for further investigation with their BAEP results. The positive rates of BEAP for each group were observed, and the results were analyzed by Chi-square test (p < 0.05, regarded as statistical difference).@*RESULTS@#A total of 37 patients were included, including 21 males and 16 females. All of them were hospitalized patients with GCS score of 6-15 at the time of admission. The BAEP positive rate in the medium and severe injury group was 100%, which was significantly higher than that in the low injury group (27.27%) (p < 0.01). The rate of BEAP positivity was significantly higher in the HRCT-positive group (20/30, 66.7%) than in the HRCT-negative group (1/7, 14.3%) (p < 0.05). Twenty patients (54.05%) were both positive for BEAP and HRCT test, and considered to have auditory nerve damage. Six patients (16.22%) were both negative for BEAP and HRCT test, and 10 patients (27.03%) were BAEP-negative but HRCT-positive: all the 16 patients were considered as non-neurological injury. The rest 1 case (2.70%) was BAEP-positive but HRCT-negative, which we speculate may have auditory nerve concussion.@*CONCLUSION@#By way of BAEP combining with skull base HRCT, we may improve the accuracy of the diagnosis of auditory nerve injury. Such a diagnostic strategy may be beneficial to guiding treatment plans and evaluating prognosis.

Ruido eléctrico de la ventana redonda / Round window electrical noise

Desde hace décadas se sabe que al colocar un electrodo cerca de la ventana redonda de la cóclea es posible registrar potenciales cocleares en respuesta a estímulos sonoros, tales como el potencial microfónico coclear o el potencial de acción compuesto del nervio auditivo. Sin embargo, hace algunos años, se ha descrito que al posicionar un electrodo en el nicho de la ventana redonda en animales de experimentación y en ausencia de estimulación acústica, se obtiene actividad eléctrica aparentemente aleatoria y no desencadenada por estímulo. Esta actividad eléctrica se ha denominado ruido eléctrico de ventana redonda (RWN, por su sigla en inglés Round Window Noise) y representaría la descarga espontánea de fibras del nervio auditivo. La técnica para su registro es similar a la utilizada en la electrococleografía para obtener potenciales cocleares en humanos. Esta señal se distingue del ruido eléctrico no biológico por tener un peak en su poder espectral centrado en torno a los 900 Hz. La amplitud de esta banda de frecuencia se correlaciona con la sensibilidad auditiva en la región basal de la cóclea, entre los 12 a 30 kHz en cobayos y gatos. El RWN se ha estudiado a través de estimulación acústica y bloqueo farmacológico, logrando caracterizar sus propiedades electrofisiológicas para desarrollar modelos de estudio con aplicación clínica.

For decades, it has been known that placing an electrode near the round window niche allows the recording of cochlear potentials in response to auditory stimuli, such as the cochlear microphonic potential and the compound action potential of the auditory nerve. However, some years ago, it was discovered, that by positioning an electrode in the round window niche of experimental animals, and in the absence of acoustic stimulation, apparently random electrical activity is obtained. This electrical activity is called round window electrical noise (RWN) and represents the spontaneous discharge of auditory nerve fibers. The recording technique is similar to that used in electrocochleography in humans. This bioelectrical signal is distinguished from that of non-biological electrical noise, as it has a power spectral peak centered around 900 Hz. The magnitude of this frequency peak is correlated with hearing sensitivity in the basal region of the cochlea, between 12 to 30 kHz in guinea pigs and cats. The RWN has been characterized using sound stimulation or pharmacologic suppression, and its electrophysiological properties could be used to develop models of auditory nerve function with possible clinical application.

Auditory Nerve Way Injury of Children with Cerebral Palsy:A 963-case Report / 中国康复理论与实践

@#Objective To investigate the incidence rate of auditory nerve way injury in children with cerebral palsy (CP) and the relationship with sexes, CP types and risk factors.MethodsThe clinic data of 963 children with CP were reviewed to find out the incidence rate of auditory nerve way injury in CP children and the relationship with sexes, CP types and risk factors.ResultsIn 963 CP children, the incidence rate of auditory nerve way injury was 24.5% (236/963), there was no sexes difference ( P>0.05), but there was a significant difference among different CP types ( P<0.05), athetosis and mixed CP had higher incidence rate ( P<0.01). Furthermore, pathological jaundice was high risk factor ( OR=2.0279, 95%CI:1.483～2.774).ConclusionCP children are often complicated with auditory nerve way injury, it not relate with sexes, but with CP type, athetosis and mixed CP have a higher incidence rate of auditory nerve way injury, and the pathological jaundice is a high risk factors.

Auditory Neuropathy Accompanying Bilateral Vestibular Hypofunction / 대한이비인후과학회지

Auditory neuropathy is a term used to describe the auditory neural pathway abnormality in the presence of cochlear outer hair cell functions. It is reported that 9 of 14 auditory neuropathy patients had abnormal findings in the caloric test. The authors present a case of auditory neuropathy accompanying bilateral vestibular loss. The patient was a 33-year-old female who had a family history of her mother having bilateral hearing loss. Auditory brain stem response (ABR) and otoacoustic emission (OAE) were checked and the results were compatible with auditory neuropathy. To evaluate her vestibular function, bithermal caloric test, rotatory chair, fundus photograph, vestibular evoked myogenic potential (VEMP), oculomotor test were checked. Laboratory findings were compatible with bilateral vestibular loss involving both superior and inferior division of vestibular nerve territory. Though bilateral vestibular hypofunction was substantial, she did not report any subjective discomfort from bilateral vestibular loss. Considering the presence of OAE and the abnormal findings in ABR in this patient, the pathologic lesion seems to be in the vestibular neural pathway rather then in the vestibular end organs. Routine vestibular evaluation seems to be necessary for comprehensive evaluation of the auditory neuropathy patients.

Clinical study of auditory nerve pathway injury complicated with cerebral palsy / 中华物理医学与康复杂志

Objective To investigate the incidence of auditory nerve pathway injury complicated with cere- bral palsy(CP) and its related factors relationship between the incidence rate of it and sexes,classification and risk factors. Methods The clinical data of 272 children with CP,including the data of brainstem auditory evoked po- tentials,were retrospectively reviewed.The incidence of auditory nerve pathway injury and the related factors were analyzed.Results In the 272 CP children,the incidence of auditory nerve pathway injury was 29.8% (81:272), which had a significantly relationship with the clinical types of CP (P0.05).In addition,it was found that the pathological jaundice (OR=2.945,95% CI:1.649-5.260) and intrauterine infection (OR=3.319,95% CI:1.037-10.625) were significantly related to auditory nerve pathway injury. Conclusion The auditory nerve pathway injury is common in CP children,especially in those with athetosis and mixed CP.Pathological jaundice and intrauterine infection are the risk factors of auditory nerve pathway injury.

Microsurgical treatment of large acoustic neurinoma / 中华显微外科杂志

Objective To discuss microsurgical experience for transsuboccipital retrosigmoid sinus approach of large acoustic neuronomas,and improve the rate of tumor removing,and facial nerve and auditory nerve preserving Methods A retrospective analysis of 39 patients with acoustic neuronomas which were more than 4 cm in diameter were treated by microsurgery between January 1994 and December 2000 Tumor's excision was performed by transsuboccipital retrosigmoid sinus approach The surgical main points of transsuboccipital retrosigmoid sinus approach,and their experience of total removal,and rate of facial nerve and auditory nerve preservation were described Results The tumors were totally removed microsurgically in 34 patients,the total removal rate was 87 2%,and subtotal removal in 5 patients Facial nerve was anatomically preserved in 31 cases,the rate of facial nerve preservation was 79 5%,but the function of facial nerve was recovered in 22 cases (56 4%) The auditory nerve was preserved anatomically in 15 cases (38 5%) and functionally in 7 cases (17 95%) Conclusions An minimally invasive microsurgical treatment are crucial for increasing a satisfactory living quality of the patients It is considered that the total removal rate of tumor,the preservative rate of facial nerve and auditory depend upon microsurgical technique and intraoperative facial nerve monitoring in acoustic neuromas surgery

Observation of the Spontaneous Discharge of Auditory Nerve Primary Fibers / 听力学及言语疾病杂志

Being fundamental preparation for the research of cochlear implants, study of tinnitus's mechanism and establishment of the animal model, the spontaneous discharge of single unit of auditory nerve primary fibers in normal cat was observed and analyzed. They include: Ⅰ, How to identify the spontaneous discharge potential in auditory nerve primary firbers. Ⅱ, The waveform of the spontaneous discharge potential in auditory never, Ⅲ, The discharge rate of spontaneous discharge in auditory nerve primary fibers. Ⅳ, The temporal feature of the spontaneous discharge. Ⅴ, The origin of the spontaneous discharge.

Utility of Brain-stem Auditory Evoked Potentials in Diagnosis and Surgery of the Posterior Fossa Lesions

The brain-stem auditory evoked potentials(BAEPs) were evaluated in 5 adult patients with various posterior fossa lesions in the diagnosis and during operative manipulation to determine whether this technique was capable of providing useful information to the operating surgeon. The BAEPs were not only very sensitive noninvasive screening test in the diagnosis of small acoustic neuroma, but also very to preserve hearing during dissection of the tumor from the auditory nerve. In case of large acoustic neuroma, intraoperative BAEPs were helpful to monitor the effect of an operative procedure even on the contralateral brain-stem auditory pathway. Besides BAEP monitoring was also useful for operative manipulation in the region of the 8th nerve such as microvascular decompression of cranial nerve.