Vittorio Colletti

Treatment of mixed hearing losses via implantation of a vibratory transducer on the round window

Early clinical findings are reported for subjects implanted with the Vibrant Med-El Soundbridge® (VSB) device. The present criteria for the VSB, limiting its application to patients with normal middle ear function, have been extended to include patients with ossicular chain defects. Seven patients with severe mixed hearing loss were implanted with the transducer placed onto the round window. All had undergone previous surgery: six had multiple ossiculoplasties, and one had the VSB crimped on the incus with unsuccessful results. Round window implantation bypasses the normal conductive path and provides amplified input to the cochlea. Post-operative aided thresholds of 30 dB HL were achieved for most subjects, as compared with unaided thresholds ranging from 60–80 dB HL. Aided speech reception thresholds at 50% intelligibility were 50 dB HL, with most subjects reaching 100% intelligibility at conversational levels, while unaided thresholds averaged 80 dB HL, with only one subject reaching 100% intelligibility. These results suggest that round window implantation may offer a viable treatment option for individuals with severe mixed hearing losses who have undergone unsuccessful ossiculoplasties.

Cochlear Implantation at under 12 months: Report on 10 Patients†

Objectives: There is growing evidence that early application of a cochlear implant in children affected by profound congenital hearing loss is of paramount importance for the development of an adequate auditory performance and language skills. For these reasons and as a result of advances in audiologic diagnosis and an enhanced awareness of the safety of cochlear implants, the age of implantation has substantially decreased over recent years. Children aged as little as 12 months are now being implanted in some centers. On the basis of our experience with very young children, we believe that the date of implantation may be further reduced to only 4 to 6 months of age.

Open set speech perception with auditory brainstem implant

Objective: Only a small percentage of auditory brainstem implant (ABI) recipients treated for neurofibromatosis type 2 (NF2) have proved capable of identifying words using only the sound from the ABI. Recently, the ABI was applied to a series of patients with no cochlear nerve or with cochlear disorders that could not benefit from a cochlear implant (i.e., cochlear nerve aplasia or posttraumatic avulsion) or whose benefit was or would be severely compromised. A significant number of these patients have proven capable of understanding speech, including effortless telephone use. In the present study, a series of psychophysical tests were administered to determine the cause of the difference in performance between tumor (T) and nontumor (NT) ABI patients.

Results from a European clinical investigation of the Nucleus multichannel auditory brainstem implant.

Objective This study was designed to investigate the perceptual benefits and potential risks of implanting the Nucleus® multichannel auditory brainstem implant. Design Between September 1992 and October 1997 a total of 27 subjects received a Nucleus 20- or 21-channel Auditory Brainstem Implant (ABI). All subjects involved in the trial had bilateral acoustic tumour as a result of neurofibromatosis type 2 (NF2) resulting in complete dysfunction of the VIIIth nerve. The study used each subject as their own control without a preoperative baseline because residual hearing, if existing, was destroyed at surgery by tumour removal. A battery of speech tests was conducted to evaluate each patient’s performance and communication abilities. Tests were conducted, where possible, in the auditory-only, visual-only, and auditory-visual conditions at 3 days postoperatively (baseline), at 3-mo intervals for the first year and every 12 mo thereafter. A subjective performance questionnaire was administered together with an extensive neurological examination at each test interval. Results 27 subjects involved in this trial were successfully implanted with a Nucleus ABI. One subject died 2 days postoperatively due to a lung embolism unrelated to the device. Twenty-six subjects underwent device activation and all but one patient received auditory sensation at initial stimulation (96.2%). On average 8.6 (±4.2) of the available 21 electrodes were used in the patients’ MAPs. Performance evaluation measures showed that the majority of users had access to auditory information such as environmental sound awareness together with stress and rhythm cues in speech that assist with lipreading. Although most subjects did not achieve any functional auditory-alone, open-set speech understanding, two subjects from this series (7.4%) did receive sufficient benefit to be able to use the ABI in conversation without lipreading. Conclusions Although the medical risks and surgical complexity associated with ABI device implantation are far greater than those for a cochlear implant, the clinical results from this trial show that the Nucleus multichannel ABI is capable of providing a significant patient benefit over risk ratio for subjects suffering loss of hearing due to bilateral retrocochlear lesions.

Auditory brainstem implant (ABI): new frontiers in adults and children.

Previous studies have considered only patients with neurofibromatosis type 2 (NF2) older than 12 years as candidates for an auditory brainstem implant (ABI). Our study expands the potential criteria to include both children and adult subjects with other cochlear or cochlear nerve malfunctions who either would not benefit at all from a cochlear implant (eg, cochlear nerve aplasia or avulsion) or whose benefit was or would be severely compromised (eg, cochlear ossification, cochlear fracture). STUDY DESIGN: In our department, over the period from April 1997 to September 2002, 29 patients, 20 adults and 9 children, were fitted with ABIs. Their ages ranged from 14 months to 70 years. Thirteen subjects had tumors, 10 NF2 and 3 solitary vestibular schwannoma, and 16 patients had a variety of nontumor (NT) cochlear or cochlear nerve diseases. A retrosigmoid-transmeatal approach was used in T and a retrosigmoid approach in NT patients. The electrode array was inserted into the lateral recess of the fourth ventricle and correct electrode positioning was monitored with the aid of electrically evoked auditory brainstem responses (EABRs). RESULTS: Correct implantation was achieved in all patients. No complications were observed due to implantation surgery or related to ABI activation or long-term use. Auditory sensations were induced in all patients with various numbers of electrodes (from 5 to 15). Different pitch sensations were identifiable with different electrode stimulation. Closed-set word recognition, open-set sentence recognition, and speech tracking scores achieved by the patients are reported in detail. The auditory performance of the patients showed significantly better outcomes than controls (Multicentric European clinical investigations on ABI with NF2). CONCLUSION: We have shown that the indications for the ABI can be extended to include NT patients with severe cochlear and/or cochlear nerve abnormalities. The degree of auditory benefit varies as a function of the underlying pathological conditions, with NT subjects exhibiting significantly better outcomes than the T patients.

Outcomes in nontumor adults fitted with the auditory brainstem implant: 10 years' experience.

Objectives: Recently, open-set speech recognition performance has been observed with electric stimulation of the brainstem in some nontumor (NT) patients. These outcomes require that we reevaluate the criteria for patient selection and the rationale for expanding the application for the auditory brainstem implant (ABI) to NT adult patients with profound hearing loss. This study presents results from up to 10 years in adults, with analysis based on cause. Materials and Methods: In our Department, from April 1997 to September 2007, ABIs have been implanted in 112 patients (83 adults and 29 children) with tumor (T) and NT disorders. Of the 112 patients, 15 have previously had a cochlear implant elsewhere with no sound detection. This article presents speech recognition results from the 80 patients (32 neurofibromatosis type 2 and 48 NT) who had achieved at least 1-year follow-up. The retrosigmoid approach was used in all NT patients, and the retrosigmoid-transmeatal approach was used in all T patients. Results: All patients had a functioning implantation, and no complications were observed during the operation, activation, or long-term use of the ABI. At the most recent follow-up, NT adults scored from 10 to 100% in open-set speech perception tests (average, 59%), and T patients scored from 5 to 31% (average, 10%). The differences between these results are statistically significant (p = 0.0007). The best performance was observed in patients who lost their nerve VIII from head trauma or severe ossification. Lowest performance (although still highly beneficial to the patient) was observed in patients with neurologic disorders, neuropathy, and cochlear malformations. Conclusion: Our experience clearly indicates that the ABI is an effective tool for hearing rehabilitation in patients with profound hearing loss who cannot be fitted with cochlear implants.

Hearing restoration with auditory brainstem implant in three children with cochlear nerve aplasia.

Objective To verify the possibility of auditory habilitation in children with aplasia and hypoplasia of the cochlear nerve by direct electrical stimulation of the cochlear nuclei with an auditory brainstem implant. Study Design Retrospective case review. Setting Study conducted at the Ear, Nose, and Throat Department of the University of Verona, Italy. Patients Three children, aged 4, 3, and 2 years, respectively, with severe bilateral cochlear malformations and cochlear nerve aplasia have received an auditory brainstem implant at this institution in the past 2 years. Intervention The classic retrosigmoid approach was used. Correct positioning of the electrodes was evaluated using electric auditory brainstem responses and neural response telemetry. Before the patients were discharged, high-resolution computed tomography with a bone algorithm reconstruction technique was performed to evaluate electrode placement. The auditory brainstem implant was activated 30 to 60 days after implantation. Results No postoperative complications were observed. To date, 21, 18, and 8 electrodes, respectively, have been activated in the three children. The first patient, 12 months after activation, had achieved good environmental sound awareness, good speech detection, and some speech recognition. The second child, 8 months after activation, had achieved good environmental sound awareness and moderate speech detection. The third patient, 1 month after activation, had obtained good environmental sound awareness. Conclusion This study indicates that auditory brainstem implantation is technically feasible in children with cochlear nerve aplasia. The early results suggest the possibility of achieving auditory habilitation with auditory brainstem implantation in this population.

Infants versus older children fitted with cochlear implants: performance over 10 years.

OBJECTIVES To investigate the efficacy of cochlear implants (CIs) in infants versus children operated at later age in term of spoken language skills and cognitive performances. METHOD The present prospective cohort study focuses on 19 children fitted with CIs between 2 and 11 months (X=6.4 months; SD=2.8 months). The results were compared with two groups of children implanted at 12-23 and 24-35 months. Auditory abilities were evaluated up to 10 years of CI use with: Category of Auditory Performance (CAP); Infant-Toddler Meaningful Auditory Integration Scale (IT-MAIS); Peabody Picture Vocabulary Test (PPVT-R); Test of Reception of Grammar (TROG) and Speech Intelligibility Rating (SIR). Cognitive evaluation was performed using selected subclasses from the Griffiths Mental Development Scale (GMDS, 0-8 years of age) and Leiter International Performance Scale-Revised (LIPS-R, 8-13 years of age). RESULTS The infant group showed significantly better results at the CAP than the older children from 12 months to 36 months after surgery (p<.05). Infants PPVT-R outcomes did not differ significantly from normal hearing children, whereas the older age groups never reached the values of normal hearing peers even after 10 years of CI use. TROG outcomes showed that infants developed significantly better grammar skills at 5 and 10 years of follow up (p<.001). Scores for the more complex subtests of the GMDS and LIPS-R were significantly higher in youngest age group (p<.05). CONCLUSION This study demonstrates improved auditory, speech language and cognitive performances in children implanted below 12 months of age compared to children implanted later.

Preliminary results of auditory brainstem implantation in prelingually deaf children with inner ear malformations including severe stenosis of the cochlear aperture and aplasia of the cochlear nerve.

Objective: The aim of our study is to present the results of 11 children where auditory brainstem implantation (ABI) was successfully performed to restore hearing. Study Design: Case presentation. This study was conducted at the departments of Otolaryngology and Neurosurgery at Hacettepe University Ankara, Turkey. Patients: Between July 2006 and April 2008, 11 prelingual (30-56 mo) deaf children with several cochlear malformations had ABI. Intervention: All patients were programmed and were enrolled in auditory verbal therapy sessions and family counseling programs at Hacettepe Auditory Verbal Center. The evaluation was performed at preimplant and again 1, 3, 6, 9, and 12 months post-switch on. Main Outcome Measures: The main test components composing this test battery were Ling 6 Sound Detection-Identification Test, Word Identification Test in Turkish, Meaningful Auditory Integration Scale, and Meaningful Use of Speech Scale. Results: Successful brainstem implantations were performed in all patients with retrosigmoid approach. Six children gained basic audiologic functions and were able to recognize and discriminate sounds, and many could identify environmental sounds such as a doorbell and telephone ring by the third month of ABI. Improvement in mean performance on Meaningful Auditory Integration Scale is apparent for all ABI children. Improvement in Meaningful Use of Speech Scale scores in 2 patients, demonstrating that the child using its own voice for speech performance, was observed between the baseline and 12th month. First, 5 children were able to identify Lings 6 sound by the end of 2 to 6 months, and 2 of them also started to identify words due to their pattern differences and multisyllabic word identification by 6 to 9 months. Two children with Attention Deficit Hyperactivity Disorder have made slower progress than the other children with ABIs. Conclusion: Our preliminary results show that there is adequate contribution of brainstem implants in the development of auditory-verbal skills. Additional handicaps slow the progress of the prelingually deaf children.

Auditory Brainstem Implant in Posttraumatic Cochlear Nerve Avulsion

Patients aged over 12 years with neurofibromatosis type 2 are considered candidates for an auditory brainstem implant (ABI). This study extends the indication criteria of ABI to subjects with profound hearing loss due to damaged cochleas and/or cochlear nerves (CNs) following head injuries. In our department, over the period from April 1997 to November 2002, 32 patients, 23 adults and 9 children, were fitted with ABIs. Their ages ranged from 14 months to 70 years. These patients were suffering from a variety of tumor (13 subjects) and nontumor CN or cochlear diseases (19 subjects). Six patients, 5 adults and 1 child, had profound hearing loss following head injury. Their mean age was 25 years (range: 16–48 years). Five were male and 1 female. The retrosigmoid approach was used in all 6 patients. The electrode array was inserted into the lateral recess of the fourth ventricle and correct electrode positioning was monitored with the aid of electrically evoked auditory brainstem responses and neural response telemetry. Correct implantation was achieved in all patients. No complications were observed due to implantation surgery or related to ABI activation and stimulation of the cochlear nuclei. At activation, an average of 9.8 electrodes (range 5–13) were switched on without side effects. One to 6 electrodes were activated in the following sessions after time periods ranging from 2 to 16 months. All patients achieved auditory-alone-mode closed-set word recognition scores ranging from 40 to 100%; 3 had auditory-alone-mode open-set sentence recognition scores of 60–100%; 2 of these even had speech-tracking performance scores of 38 and 43 words, respectively, showing an ability to engage in normal conversation and converse over the phone. The present study demonstrates that the ABI is a useful rehabilitation instrument in subjects with damaged cochleas and/or CN avulsion following head injury who are unamenable or poorly responsive to auditory rehabilitation using cochlear implants.