Magnet migration in a cochlear implantee — a serendipitous diagnosis

The successful outcome of a cochlear implant habilitation program depends upon a multitude of vital factors, including the avid cooperation of the cochlear implantee, committed participation of the parents/family members and total dedication of the habilitation team of implant audiologists and auditory verbal therapists. In a rare situation, where the implantee’s performance is suboptimal or poor inspite of successful implantation, anxious moments engulf the parents and the implant team, with the morbid fear of a device failure lingering at the back of their minds. We report such an incident in a 13-year-old cochlear implantee, who was an excellent cochlear implant performer for 8 years, following which she had rapid deterioration of her auditory verbal skills within the next few weeks. The hidden etiology, was the inconspicuous migration of the internal magnet of the Receiver-Stimulator Coil placed in the mastoid temporal bone of her skull, due to unexplained reasons. We share our experience with the diagnosis and management of this condition and review the existing world literature on this rarely reported entity.     

Home auditory training program (HAP) for cochlear implantees and hearing impaired children using hearing aids—an outcome of a three-year research project

Introduction

Use of cochlear implants has been a turning point in the life of the hearing-impaired children enabling them to participate in the world of sounds. Research shows that even after cochlear implantation auditory training is necessary as it facilitates the development of verbal skills. A number of kits for auditory training are available in the West. The author had an exposure to a number of auditory training kits in the US, as a part of her Fulbright Research Fellowship. In our country, there is a dearth of such material for auditory training. Besides this, India being a multilingual country, it becomes difficult if not impossible to develop language specific auditory programs. Hence, the need for the project proposal which was to develop material in Hindi and Marathi in the form of kit and CD-ROMs for the various levels of auditory training.

Methodology

With the help of latest scientific techniques, material in the form of worksheets, audiocassettes and CD-ROMs were developed and field tested for all four levels of auditory training. Children with hearing impairment using hearing aids and cochlear implants were given auditory training using the developed material.

Results

t-test which was carried revealed that there is a significant difference between pre and post training performance of children.

Conclusions

A systematic approach in the form of a kit comprising of audio cassettes and CD-ROMs is now available in Hindi and Marathi for use at home for professionals and parents of children with hearing impairment.     

The Auditory Brainstem Responses in Patients with Unilateral Cochlear Hearing Loss

The aim of our study is to analyze changes occurring in the auditory brainstem response (ABR) according to stimulus parameters in unilateral cochlear hearing loss cases. Twenty-nine cases (14 male, 15 female) with unilateral sensorineural hearing loss (SNHL) were investigated. All cases had cochlear SNHL on one side whereas normal hearing on the other side. All cases underwent ABR testing with varying stimulus intensity levels and stimulus repetition rates (SRRs). Results were compared and their correlation with audiogram shapes investigated. As stimulus intensity levels decreased on both ears, latencies expanded and amplitudes decreased in all traces of ABR. Latencies of ears with cochlear hearing loss were observed to be longer than those in normal ears. Responses to SRR increases were similar on both ears. Audiogram shapes should be taken into consideration while performing ABR in order to address asymmetric SNHL. The interpretation of ABR changes with various stimulus levels may provide a better understanding of cochlear pathologies associated with hearing loss in the future.     

Profile of cranial nerve paralysis in head injury

Involvement of cranial nerves in patients following head injury is quite uncommon barring vestibular & cochlear involvement. The incidence of involvement of the cranial nerves in 70 cases of head injury, with special emphasis on the facial nerve, is discussed.     

Registering event-related auditory potentials (P300) in patients with cochlear implants

Event-related auditory evoked potentials can contribute to the evaluation of discrimination abilities of cochlear implant users. Auditory P300 potentials to a frequency contrast were obtained in six post-lingually deaf adults using a cochlear implant and in a control group of normal hearing subjects. The aim of this study was to investigate how these potentials were determined by the stimulation pattern of the cochlear implant. To visualise these stimulation patterns colour-coded plots (stimulograms) were calculated based on the stimulus and the fitting file of the individual subject as inputs. These stimulograms were used to evaluate the influence of various stimulation parameters on the stimulation contrast used in an oddball paradigm. The influence of discrimination difficulty on the P300 response is demonstrated.     

Trans-Aditus Approach: An Alternative Technique for Cochlear Implantation

The objective of this study was to report our preliminary experience with an alternative technique for cochlear implantation. Twenty patients underwent cochlear implantation via a trans-aditus ad antrum approach to the round window. The main steps involved in the surgical procedure are cortical mastoidectomy, elevation of tympanomeatal flap, incudostapedial joint dislocation, incus removal, preparation of a bed for the implant, cochleostomy via the external auditory canal, and finally insertion of the electrode into the cochlea via the aditus. Twenty-five implants were performed on 20 patients, 18 children (mean age of 3.2 years) and 2 adults. Twelve patients were males and eight were females. All the children were pre-lingual while the adults were post-lingual. Nucleus freedom cochlear implant system (Cochlear, Lane Cover, NSW, Australia) was used in four patients and a cochlear Nucleus 5 was used in six patients. A Med-el SONATA implant (MED-EL, Innsbruck, Austria) was used in 15 patients. The minimum follow-up was 5 months. Here, we describe a new alternative technique for cochlear implantation and report our preliminary results. The procedure has advantages over the existing techniques and avoids the potential complications of posterior tympanotomy, transcanal, and transmeatal techniques.     

Cochlear Implant in Prelingually Deaf Children: Our Experience

Retrospective study of the prelingual cochlear implantation programme under government scheme done at medical college hospital in central India. Forty-two prelingually deaf children screened and sent for cochlear implantation at our centre From March 2015 to Feb 2018 were reviewed with respect to their age, sex, preimplantation hearing aid use, surgical technique for cochlear implantation, type of FDA (USA) approved cochlear implant, post operative speech therapy and its outcome with respect to categories of auditory perception and speech intelligibility scoring were compared for children younger than 4 years and older than 4 years. For outcome measurement non parametric statistical method was used for any significance between the two groups. There was a wide range of children implanted ranging from 2 to 7 years. Both varia and mastoidectomy and posterior tympanotomy method of cochlear implantations were done with good rate complete insertion and electrode activation. There was no significant difference between the two group with regard to CAP and SIR outcomes after 1 year. In order to get better outcomes with respect to the speech language development, there is need to strengthen the early identification and cochlear implantation before 4 years of age in government approved schemes.     

Neurofibromatosis 2: Primary Modality of Hearing Rehabilitation with Cochlear Implant

Auditory Brainstem Implants have been recommended as the gold standard in hearing rehabilitation of Neurofibromatosis Type 2 patients who lose hearing completely in both the ears and the cochlear nerves are not stimulable. Some patients have undergone cochlear implantation, in whom the cochlear nerve was spared during surgery or have undergone stereotactic radiotherapy preserving the function of the cochlear nerve. Here we report a case in whom we chose cochlear implantation prior to any definitive treatment for the tumour itself during the ‘wait and watch’ period. The reasons in favour of this approach have been discussed in this article. Post switch-on the implant is benefitting the patient satisfactorily and she is on regular follow up for monitoring the bilateral tumours.     

Early detection of cisplatin ototoxicity. Selected case reports

A recently developed high frequency auditory measurement technique was applied to a sample of patients receiving the antineoplastic agent cis-dichlorodiammineplatinum II (cisplatin [CDDP, DDP]). Ototoxicity as a result of cisplatin administration is well documented. The ability to detect ototoxicity, however, varies with the methods and instrumentation utilized, and the criteria by which ototoxicity is defined. The auditory function of subjects receiving cisplatin for genitourinary tumors and head and neck cancers was serially monitored with conventional audiometry and with a high frequency testing system. Results reveal a high incidence of nonreversible cochlear toxicity with a predilection for involvement of the higher frequencies. Cochlear toxicity was detected earlier with the high frequency evaluation system than with conventional audiometry. The case reports presented are characteristic of the type and magnitude of auditory changes observed.     

Our Experience with Split Electrode Array Implant for Obliterated Cochlea

To study the outcomes of split electrode array cochlear implantation in ossified cochlea using the CAP scoring system. Retrospective case study. Tertiary referral center. Six cochleae in three adult and three pediatric patients with ossification. Intervention(s): All Patients underwent cochlear implantation with a split electrode array system. Major outcome parameter(s): Number of electrodes inserted during surgery, number of functioning electrodes on follow-up and auditory performance evaluation using the CAP score—Category of Auditory Perception [TSC Revised Version, based on Nottingham CI Program, 1995]. Six patients (three children and three adults) had insertion of split electrode array system. The mean number of electrodes inserted were 18.3 (range 15–21) and functioning electrodes at follow-up were mean of 14.3 (range 7–21). Auditory performance was measured using CAP score at 1 year post implant follow up, mean score in children was six and that in adult was eight. One pt had facial nerve twitching which was corrected by switching off the concerned electrode. No complications in sort of facial palsy or vestibular disorder were observed. Patients of ossified cochlea having profound deafness do well with split electrode array cochlear implantation as evaluated with CAP scoring system. The split electrode array results in more number of electrodes within the cochlear lumen. Retro graded apical array insertion has less chances of facial nerve stimulation as it is placed away from the nerve.     

Speech Recognition Performance in Children with Cochlear Implants Using Bimodal Stimulation

Cochlear implantees have considerably good speech understanding abilities in quiet surroundings. But, ambient noise poses significant difficulties in understanding speech for these individuals. Bimodal stimulation is still not used by many Indian implantees in spite of reports that bimodal stimulation is beneficial for speech understanding in noise as compared to cochlear implant alone and also prevents auditory deprivation in the un-implanted ear. The aim of the study is to evaluate the benefits of bimodal stimulation in children in an Indian cochlear implant clinic. A group of 14 children who have been using cochlear implants served as subjects in this study. They were fitted with advanced digital hearing aids in their un-implanted ears to provide bimodal stimulation. Results revealed that bimodal stimulation did not bring greater change in speech scores in quiet surroundings but have shown a noticeable improvement in noisy ambience. Hence the present study suggests that bimodal stimulation would benefit children with cochlear implants especially in adverse listening conditions.     

An electrophysiological study on the safety of the endoscope-assisted microsurgical removal of vestibular schwannomas

Background

Endoscopy is being increasingly used in skull base surgery. The issue of its safety, however, has not been definitely solved.

Methods

We evaluated the risk of thermal or mechanical iatrogenic nerve injury related to endoscope application during microsurgical removal of vestibular schwannomas (VS) in a prospective group of 30 patients (Group A). Main analysed parameters were electrophysiological monitoring data (auditory evoked potentials and EMG) during and after endoscopic observation. The structural and functional preservation of facial and cochlear nerves, radicality of tumour removal, and CSF leak rate were evaluated and compared to historical group of 50 patients (Group B), operated consecutively with classical microsurgical technique.

Results

No electrophysiological changes directly related to endoscope were registered. The rate of loss of waves I, II, and V did not depend on application of endoscope and was similar in both groups. The functional and general outcome was also similar. Endoscopic inspection provided early and detailed view of anatomical relations within cerebellopontine angle and internal auditory canal and confirmed completeness of tumour removal. Total tumour removal was achieved in all patients from Group A and in 49/50 from Group B. Useful hearing after the surgery had 17/30 patients in Group A and 26/50 in Group B.

Conclusions

The application of endoscope during microsurgical removal of VS is a safe procedure that does not lead to heat-related or mechanical neural or vascular injuries. The actual significance of this additional endoscopic information, however, is related to the particular operative technique and experience of the surgeon.     

Early Speech Perception Test Outcome in Children with Severe Sensorineural Hearing Loss with Unilateral Cochlear Implants Alone versus Bimodal Stimulation

Bilateral stimulation of the auditory system has clear advantages over unilateral hearing. Hearing-impaired children are, therefore, generally fitted with hearing aids in both ears so that they can have the benefits of binaural hearing. Children who use acochlear implant in one ear and no acoustic stimulation in the opposite ear are at a definite disadvantage. This study was undertaken to determine the advantages of bimodal stimulation in pediatric population especially in terms of speech recognition. This study comprised of 30 children between 3 and 6 years of age with profound bilateral sensorineural hearing loss with cochlear implant in one ear and fitted with digital hearing aid in non-implanted ear. Speech recognition performance was compared in unilateral cochlear implant only and with bimodal hearing stimulation in the same set of children. A statistically significant difference was found between speech reception scores in children with a unilateral cochlear implant only and those with a cochlear implant in one ear and a hearing aid in the non implanted ear in quiet surroundings. It is suggested that the use of bimodal fitting be considered as an effective management method to obtain the advantage of binaural hearing in children who undergo unilateral cochlear implantation.     

Stereotactic radiosurgery, X: clinical isodosimetry of gamma knife versus linear accelerator X-knife for pituitary and acoustic tumours

Several review articles have compared gamma unit versus linear accelerator (linac)-based radiosurgery systems, concluding that the dose gradient 'fall-off' at the margin of the target (expressed as the distance between isodoses) is very similar for both techniques as far as single isocentre treatment volumes up to 1.5 cm diameter are concerned, and that the two radiosurgical systems are, in general, comparable. 'Fine tuning' of the gamma unit can be carried out by using multiple isocentre plans, the differential use of small collimator sizes (down to 4 mm) and field weightings, and adroit use of the gamma angle, and selective beam blocking. Multiple isocentre plans, beam modification, restriction of gantry angles and arc lengths, and microcollimation can similarly improve the isodose gradients from linac units. In both instances, the dosimetric advantages occur along selected aspects of the target perimeter border. However, the more frequent use of multiple isocentred 'shots' on the gamma unit achieves greater conformity indices for more complex target volumes, but at the expense of steeper internal dose gradients. We studied two patients with tumours close to or arising from radiosensitive special sensory nerves (optic and cochlear) to compare and contrast fine tuning of the two technologies. In a previously irradiated patient with a pituitary adenoma, the dose gradient achieved at the rostral margin, adjacent to the optic chiasma, was steeper on the gamma unit (due to the concentration of small collimator shots rostrally and beam blocking), which was therefore the dosimetrically preferred technique. In contrast, the vastly smaller internal dose gradient (11% for linac/X-knife versus 100% for Gamma Knife) and the ability to fractionate on the X-knife system, gave a large dosimetric advantage to the X-knife plan in the treatment of an acoustic neuroma, where the intracanalicular component of the cochlear nerve traversed the target volume. This advantage also pertains to the cochlear ramus of the internal auditory (labyrinthine) artery and the facial nerve. Our published work on X-knife radiosurgery of acoustic neuroma has documented improvement of hearing after therapy and may be relevant in this regard. That there are advantages in physical dose distribution and fractionation, producing a reduction in the biological dose in normal tissue, argues for the use of linac technology in acoustic neuromas. Craniopharyngiomas enveloping the optic nerve/chiasma will similarly be better treated by the linac X-knife system. It is apparent that different radiosurgery systems may be indicated in particular neuro-oncological situations.     

The current status of cochlear implants

In the University of Sydney cochlear implant programmes, 109 adults and teenagers have received a 22 electrode cochlear implant (Cochlear? implant) since 1984; and 127 children have received a Cochlear? implant since 1987. The results were analysed when all patients were still using the MSP speech processors rather than the newer SPEAK processors. Seventy five percent of adults and teenagers deafened after learning speech for a period of less than 15 years were able to recognise some words by audition alone. Only 30 percent of adults and teenagers deafened for over 15 years regaining hearing were able to recognise any words by audition alone but most found the device very helpful in aiding lipreading. None of adults and teenagers who were born deaf who received a cochlear implant found they could recognise any sounds and half of them abandoned using the device. Children who were deafened after learning speech usually did extremely well with a cochlear implant and could remain in their regular school situation. Children who had done well with hearing aids were also very likely to succeed with a cochlear implant. Children who had learnt to communicate by gestures or signs who had reached an age of over 6 years did poorly with the cochlear implant with 73 percent unable to recognise speech by listening alone and unable to improve their speech production to an intelligible level. Children born deaf who received the implant early in life and were taught primarily through audition could be very successful with 52% recognising words by audition alone and gaining intelligible speech. Preliminary studies suggested that the younger the child received the cochlear implant the greater the possibility of success. Neural plasticity or the ability to the brain to learn or relearn tasks appear to be the most important factor affecting the selection of candidates for a cochlear implant. It appeared that after the age of 6 years, if a child had not utilised the auditory and motor areas of spech production within the brain, the neural plasticity remaining was insufficient to allow effective use of a cochlear implant. The cochlear implant is a device which can restore when a person is too deaf to be able to use a conventional hearing aid. The cochlear implant does not provide normal hearing but may provide sufficient information for the recipient to distinguish several words without the need for lipreading. Evidence will be presented which shows that the device can enable children suffering from congenital deafness to gain excellent speech and listening providing it is fitted at an early age and there is an appropriate training programme to teach the child.     

Downregulation of ABI1 expression affects the progression and prognosis of human gastric carcinoma

Abelson interactor protein-1 (ABI1) is a promising candidate tumor suppressor, and plays critical roles both in the pathogenesis of BCR-Abl-induced leukemia and in the spread of several solid tumors. The expression of ABI1 and its role in cancer progression and prognosis are largely unknown in the majority of solid tumors, including gastric cancer. In this study, we analyzed the correlation between ABI1 expression and the clinicopathological characteristics, tumor progression, and prognosis of patients with gastric carcinoma. Tissue specimens were from 103 gastric cancer patients who underwent gastrectomy in our hospital between January 2000 and December 2007. Among them 59 tumor tissue samples were matched with normal tissue samples. The expression of ABI1 protein was measured using immunohistochemical staining of paraffin-embedded tissue specimens. Meanwhile, quantitative real-time RT-PCR and Western blotting were used to identify the expression of ABI1 in human gastric normal mucosal cell line (GES-1) and gastric cancer cell lines (N87, AGS). We performed a statistical analysis of the potential correlation between ABI1 expression and the patients’ clinicopathological characteristics, 5-year survival, and median survival time. The immunohistochemical staining results of 59 patients showed that ABI1 was expressed in 28.8% (17/59) of gastric cancer tissues, compared to 91.5% (54/59) of normal samples. ABI1 expression in 103 patients was strongly correlated with tumor differentiation, clinical stage, and lymph node status (P < 0.01). The 5-year survival rate was 15.3% in the ABI1-negative group and 63.7% in the ABI1-positive group. Median survival time in the ABI1-negative and ABI1-positive groups was 25.0 months (95% CI: 19.7–30.3) and 74.0 months (95% CI: 54.6–93.3), respectively. There was a significant difference between the two groups (χ² = 10.888, P = 0.001). Furthermore, we found that ABI1 expressed lowly in poor differentiated AGS, whereas highly in GES-1 and well-differentiated N87. Downregulation of ABI1 expression in human gastric carcinoma may play a critical role in tumor progression and in determining patient prognosis. ABI1 may be a useful diagnostic or prognostic molecular biomarker, and might be a potential target for therapeutic intervention.     

Auditory neuropathy : Diagnostic and therapeutic challenge report of first series of four cases from india

Auditory neuropathy (AN), a recently described clinical entity, is a sensorineural disorder where the patient has hearing loss with impaired word discrimination out of proportion to pure tone loss in the pressence of abnormal / absent auditory brain stem responses, and normal outer hair cell as measured by otoacoustic emissions and / cochlear microphonics. It is essential that the practicing, ENT surgeon have a high degree of suspicion of AN in patients complaining of difficulty in understanding speech with hearing loss and audiological evidence of dissociation between pure-tone and speech audiometry. Appropriate newer diagnostic tests of ABR and OAE and /or CM for confirmation of AN is essential. We present a series of four patients with auditory neuropathy from a tertiary care teaching hospital. This is the first Series of 4 cases of this clinical entity from the Indian subcontinent.     

The Use of 3D Conformal Radiotherapy (3D CRT) to Spare the Cochlea in Patients with Medulloblastoma

Purpose: Radiation therapy in combination with cis-platinum chemotherapy is associated with ototoxicity due to destruction of cochlear hair cells. This is a significant problem, especially in pediatric patients, because it may lead to difficulties with communication, speech, language, and development of learning skills. The use of 3D conformal radiotherapy (3D CRT) may be useful in sparing auditory structures. This paper discusses a technique using 3D CRT to spare the cochlea in patients with medulloblastoma.Methods and Materials: Five pediatric patients with medulloblastoma were planned using 3D CRT. All had MRI and CT obtained specifically for treatment planning. Multiple structures were contoured, including the cochlea and posterior fossa, and conformal beams designed in beam’s eye view and dose distribution analysis were edited to provide 3D dose coverage to the target while sparing the inner ear. Patients received 36 Gy to the craniospinal axis followed by an 18–20 Gy boost to the posterior fossa.Results: A 3D CRT cochlear sparing technique was designed, using an axial pair of posterior oblique fields to treat the posterior fossa while sparing the cochlea for all patients in this analysis. Dose–volume information, obtained from 3D calculations, demonstrates that the average dose received by the cochlea was 65% of the prescribed dose using the cochlear sparing plan, as compared to 101% using standard opposed-lateral beams. Both plans delivered ≥ 100% of the prescribed dose to the posterior fossa.Conclusion: 3D CRT allows for cochlear sparing in the treatment of medulloblastoma. Further follow-up is necessary to determine the long-term benefit in these patients.