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Sep 2025 DOI 10.14302/issn.2379-8572.joa-25-5687
Depending upon the species, the brainstem auditory evoked potential (BAEP) consists of four or five major high frequency components. According to longstanding doctrine, each wave represents the sequential activation of successively higher nuclei and tracts from the 8th (auditory) nerve to the midbrain (inferior colliculus). Although this conceptual framework has acquired the status of near dogma, surprisingly little evidence exists in support. In the present analysis, a new interpretation of the electrogenesis of the BAEP is proposed which is simpler although it retains skeletal elements of the older explanation. The revised model is mostly derived from two distinct sources. In the first, the timing of the BAEP waves is compared with that of cortical activity for a range of mammals including humans, monkeys, cats, rats and guinea pigs. It is demonstrated that for each of these, the conduction time of the acoustic signal to the cortex from the putative midbrain component (wave IV or V) is so unrealistically long that it implies that the entire waveform must arise in the peripheral pathways of the auditory system. In the second, a retrospective analysis is made of click repetition rates on the BAEP using extradural electrodes. It was shown that at high rates of stimulation (about 100/sec), the behavior of the waveform is almost totally at variance with the expectations of the conventional model. The essence of the revised conception is that all BAEP waves are just variations of the compound action potential of the 8th nerve, albeit generated or regenerated via separate routes and different methods. Such an explanation would thereby account for their near uniform sharp morphology as well as creating the impression of a composite neuronal response. More specifically, in the case of a four component BAEP, wave I is assumed to be generated by the normal air conduction route in an identical manner to the conventional explanation. In contrast, wave ll is assumed to be generated via bone conduction in the temporal skull thereby bypassing the transduction process in the middle ear. Wave lll is assumed to be generated by the first echo of the bone-conducted sound wave. Likewise, the second rebound within the temporal bone serves as the stimulation to evoke wave lV. As the energy of the auditory stimulus gradually dissipates, it may still continue to generate a train of lower amplitude potentials. It is concluded that the BAEP may contain little or no brainstem or midbrain activity and therefore the term BAEP may be a misnomer. A more appropriate epithet might therefore be the auditory nerve evoked potential or ANEP.
Feb 2018 DOI 10.14302/issn.2641-5518.jcci-17-1880
Objective: Presentation of rare case report of primary non-Hodgkin Lymphoma of temporal bone secondary to immunodeficiency after prolonged steroid administration in a diabetic patient. Then review the literature of similar case reports. Method: 49 years old female presented with hearing loss, facial paralysis and otalgia. Biopsy revealed high grade non Hodgkin’s B-lymphoma. She underwent chemotherapy and had remarkable response. Result: Rapidly progressive deafness, facial paralysis and otalgia are common presentations of external canal Non-Hodgkin lymphoma. The disease is common in middle age, females and has a fair response to chemotherapy, good to radiotherapy. Surgery is an alternative method in isolated lesions or recurrent cases. Conclusion: High dose steroid and type II diabetes are potential risks for acquired immunodeficiency. External Auditory canal lymphoma is uncommon sequel. Chemotherapy is very effective in treatment of isolated cases without B symptoms
Aug 2017 DOI 10.14302/issn.2379-8572.joa-16-1368
We report a case of cholesteatoma associated with unilateral congenital aural atresia (CAA) and microtia, resulting in extracranial complication. A 13-year-old girl presented with right ear purulent discharge from pre and post auricular area with mastoid tenderness. On clinical examination, she had right grade II microtia with pre-auricular skin tag and healed scar tissue in periauricular region. On High Resolution Computerized Tomography (HRCT) scan of temporal bones, there was CAA of right ear with extensive cholesteatoma in middle ear cleft. The cholesteatoma was subsequently removed by radical mastoidectomy with uneventful post-operative period. Cholesteatoma associated with CAA may remain undiagnosed in early childhood resulting in life threatening temporal and intracranial complications.
Feb 2016 DOI 10.14302/issn.2379-8572.joa-15-906
Objective: We compared preoperative data of physical examination, CT and diffusion MRI findings of temporal bone with our intraoperative observations. We investigated the diagnostic efficiency of single-shot spin echo echoplanar diffusion MRI (SS SE EPI) on primary cholesteatoma. Methods: 33 patients with chronic otitis media who had been admitted to Otolaryngology Department of Haydarpasa Numune Training and Research Hospital between June 2010 and September 2011 were involved in this study. All patients did undergo otoscopic and audiometric examination. After imaging of temporal bone by CT and diffusion MRI, patients were operated and intraoperative observations were recorded. Patients with intraoperatively approved cholesteatoma were defined as group 1 and those without cholesteatoma were defined as group 2. Perioperative and preoperative findings of physical examination, CT and MRI of all patients were compared one by one. Results: Positive physical examination findings have been superior to MRI and CT, having a sensitivity of 96%, specifity of 87.5%, positive predictive value of 96% and negative predictive value of 87.5%. In terms of effectiveness of MRI in diagnosing intraoperative cholesteatoma, we had a sensitivity of 80%, specifity of 50%, positive predictive value of 83.3% and negative predictive value of 44.4%. These values are also lower than previously reported results. Conclusion: When we had preoperative suspection of cholesteatoma on physical examination and diffusion MRI, in addition with bone tissue erosion on CT, we found that physical examination is superior to MRI and CT in terms of capability of diagnosing the disease.
Jun 2015 DOI 10.14302/issn.2379-8572.joa-14-548
This article has been retracted on 25 March 2016. VIEW THE RETRACTION NOTICE (https://doi.org/10.14302/issn.2379-8572.joa-25-5867) Fibrous dysplasia is a rare disorder of bone that is uncommon in the head and neck region. Herein, we present a rare case of polyostotic fibrous dysplasia involving the right temporal bone and thyroid cartilage in a 19-year-old male. This unique location necessitates close surveillance due to the proximity to the airway and the potential for malignant degeneration.