Hearing Restoration in Neurofibromatosis Type II Patients.

Patients with neurofibromatosis type II will eventually succumb to bilateral deafness. For patients with hearing loss, modern medical science technology can provide efficient hearing restoration through a number of various methods. In this article, several hearing restoration methods for patients with neurofibromatosis type II are introduced.

Hearing Restoration in Neurofibromatosis Type II Patients

Patients with neurofibromatosis type II will eventually succumb to bilateral deafness. For patients with hearing loss, modern medical science technology can provide efficient hearing restoration through a number of various methods. In this article, several hearing restoration methods for patients with neurofibromatosis type II are introduced.

Protective effect of silymarin on noise-induced hearing loss in Guinea pigs.

BACKGROUND: Hearing capability plays a principal role on human's communication. Noise-induced hearing loss (NIHL) caused by exposure to high noise levels is a serious socio-economic problem in modern societies. NIHL can either be reversible, resulting in a temporary threshold shifts (TTS) or irreversible, resulting in a permanent threshold shifts (PTS). PTS is often confirmed in the time span of between 2 - 6 weeks. NIHL may be prevented by avoidance of excessive amounts of noise or reducing the sound energy entering the inner ear using hearing protective devices. However, there are some conditions that such prevention is not possible such as noise exceeding the protective capabilities of the hearing protection device, working in military or the person does not tolerate the protection device. Thus the protective agent for preventing NIHL would be useful. OBJECTIVE: Free radical molecules and consequence oxidative stress have been shown to play a significant role in noise-induced hearing loss. Silymarin is an antioxidant flavonoid complex derived from the herb milk thistle has ability to mitigating the oxidative stress, scavenge free radicals. In the current study, we aimed to evaluate the protective effect of silymarin on noise induced hearing loss in guinea pig by auditory brain stem response. MATERIALS AND METHODS: Twenty guinea pigs randomly divided into 2 groups. The animals in the experimental group were intraperitoneally injected with 100 mg/kg/day silymarin dissolved in propylene glycol for 6 consecutive days. The control subjects were intraperitoneally injected with propylene glycol for 6 consecutive days. All animals were exposed to 4 kHz octave band noise at 120 dB SPL for 6 hours. Auditory brainstem responses (ABRs) at frequencies of 2, 4, 6, 8, 12, 16 and 20 kHz were precisely recorded before intervention and then on intervals of 0, 3, 10 and 15 days after noise exposure. Data were analyzed using repeated measures ANOVA. RESULTS: Threshold shifts for the experimental group at all frequencies immediately, 3, 10 and 15 days after noise exposure were significantly reduced compared to the control group (P < 0.01). CONCLUSIONS: The findings indicate a protective effect of silymarin on temporary and permanent noise-induced hearing loss.

Implante auditivo de tronco cerebral: técnica cirúrgica e resultados auditivos precoces em pacientes com neurofibromatose tipo 2 / Auditory Brainstem Implant: surgical technique and early audiological results in patients with neurofibromatosis type 2

O implante auditivo de tronco cerebral foi desenvolvido para restaurar alguma audição útil em pacientes que apresentam ausência de nervo coclear bilateralmente. OBJETIVOS: Discutir a indicação, cirurgia e resultados em quatro pacientes submetidos à cirurgia para colocação de implante auditivo de tronco cerebral. CASUÍSTICA E MÉTODOS: Quatro pacientes com diagnóstico de schwannomas vestibulares bilaterais foram submetidos à cirurgia para colocação de Implante Auditivo de Tronco Cerebral durante o mesmo ato cirúrgico utilizado para a exérese de um dos tumores. Aspectos clínicos e técnicos e as referências anatômicas da cirurgia e os resultados auditivos foram analisados. RESULTADOS: Em todos os casos foram identificados as referências anatômicas ao forame de Luschka. As complicações cirúrgicas se resumiram à fístula liquórica em dois pacientes. Os eletrodos foram bem posicionados e a sensação auditiva foi suficiente para reconhecimento de sons e auxílio à leitura labial. CONCLUSÃO: Os resultados auditivos de nossos pacientes abrem uma perspectiva importante aos pacientes com surdez profunda bilateral sem integridade anatômica das vias auditivas centrais.

Auditory Brainstem Implants were developed to partially restore the hearing capabilities of patients without cochlear nerves bilaterally. AIM: this paper aims to discuss the clinical and surgical findings of four ABI patients. MATERIALS AND METHOD: four patients diagnosed with bilateral schwannomas received auditory brainstem implants (ABI) and had one of their tumors resected in the same surgical procedure. Clinical aspects, surgical technique, anatomic landmarks, and outcomes were analyzed. RESULTS: the anatomic landmarks were identified in all four patients in relation to the foramina of Luschka. Two patients had CSF leaks. The electrodes were well positioned and hearing sensation was good enough to allow for sound recognition and assist patients perform lip reading. CONCLUSION: the outcomes observed in our patients were quite encouraging and offer great perspectives for those suffering from deep bilateral deafness and impaired central auditory pathways.

Implante auditivo de tronco encefálico: revisão de literatura / Auditory brainstem implant: a review

OBJETIVO: pesquisar aspectos relevantes sobre implante auditivo de tronco encefálico como conceito, finalidade, métodos de implantação, indicações do procedimento e benefícios. MÉTODOS: realizou-se compilação dos trabalhos disponíveis nas bases de dados LILACS, MEDLINE e SCIELO utilizando os descritores: implante auditivo de tronco encefálico, reabilitação de deficientes auditivos, perda auditiva neurossensorial, procedimentos cirúrgicos otológicos. RESULTADOS: o implante auditivo de tronco encefálico é semelhante ao implante coclear, exceto pela configuração do eletrodo que é projetado para ser colocado no complexo do núcleo coclear, no tronco encefálico. Originalmente foi desenvolvido para restaurar a audição em pacientes com ausência ou lesão no nervo coclear. Hoje é indicado para pacientes que por motivos anatômicos ou funcionais não podem receber estímulos elétricos pela orelha interna, como em casos de malformação/ausência de nervo coclear, ossificação coclear e neuropatia auditiva. Os efeitos relatados são: restabelecimento da audição em pacientes com perda auditiva total, níveis de detecção e discriminação dos sons similares às obtidas com implante coclear e acesso a sons ambientais e da fala. CONCLUSÃO: o implante auditivo de tronco encefálico proporciona o restabelecimento da sensação auditiva em sujeitos não beneficiados pelo uso de próteses auditivas e implante coclear. A quase totalidade dos pacientes implantados obteve algum benefício na comunicação.

PURPOSE: to study important aspects about auditory brainstem implant, such as concept, purpose, methods of implantation, indication of the procedure and benefits. METHODS: a compilation was carried out of the available works in LILACS, MEDLINE and SCIELO databases, using the descriptors: auditory brainstem implantation, rehabilitation of hearing impaired, sensorineural hearing loss, otologic surgical procedures. RESULTS: the auditory brainstem implant is similar to cochlear Implant, except for the configuration of the electrode that is designed to be placed in the cochlear nucleus complex, at the brain stem. It was developed originally to restore the hearing in patients with absence of or injury in the cochlear nerve. Today it is indicated for patients who for anatomical or functional reasons can not receive electric stimulations by the inner ear, as in cases of malformation/absence of cochlear nerve, ossified cochleae, and auditory neuropathy. The effects showed are hearing recovery in patients with total hearing loss, levels of detection obtained discrimination of sounds similar to those obtained with cochlear Implant and access to environmental and speech sounds. CONCLUSIONS: the auditory brainstem implant provides hearing recovery in subjects that are not benefited by the use of hearing aids and cochlear Implant. Almost the totality of the implanted patients got some communication benefit.