Hemifacial spasm caused by arachnoid cyst

The authors report a rare case of left cerebellopontine angle arachnoid cyst in a 38 year old man presenting with hemifacial spasm. Decompression of the cyst was followed by a total recovery from hemifacial spasm. Various space occupying lesions in the cerebellopontine angle have been reported to be associated with hemifacial spasm. The most common cause of hemifacial pasm observed is vascular compression of facial nerve. However, arachnoid cyst at the cerebellopontine angle is a very rare cause of hemifacial spasm.     

Auditory neuropathy in systemic sclerosis: a speech perception and evoked potential study before and after cochlear implantation

We report the results of speech perception and electrophysiological evaluation of the auditory periphery performed before and after cochlear implantation in a 18-year-old girl with systemic sclerosis (SS) who presented the clinical picture of auditory neuropathy. Transtympanic electrocochleography (ECochG) in response to 0.1 ms clicks was recorded 1 month before cochlear implantation on both sides while the electrically evoked neural response was obtained intraoperatively in the right ear through cochlear implant stimulation. The ECochG recordings revealed the presence of the cochlear microphonic with normal amplitude and threshold on both sides. A compound action potential was only detected in the left ear at high stimulation intensity, while the electrically evoked neural response was clearly identifiable at all the recording sites during neural response telemetry. Standardized speech perception tests were performed 1 month before cochlear implantation and several times after cochlear implant connection. Speech perception scores were close to chance before cochlear implantation while they showed a remarkable improvement thereafter. The results of this study show that subjects affected by SS could present the clinical picture of auditory neuropathy which is possibly underlain by lesions involving the distal portion of auditory nerve fibers and/or synapses with inner hair cells. The restoration of synchronous neural discharge could be achieved by electrical stimulation through cochlear implant.     

Arachnoid cyst of the cranial posterior fossa causing sensorineural hearing loss and tinnitus: a case report

Arachnoid cysts are developmental collections of cerebrospinal fluid covered by layers of arachnoidal epithelium and are usually located in the middle cranial fossa. Localizations in the posterior fossa are uncommon and generally remain asymptomatic or cause vague and non-specific symptoms. We here report the unusual case of a young patient with an arachnoid cyst of the posterior fossa that had become manifest in the form of left-sided hypoacusia and tinnitus. Audiometric evaluation, auditory brainstem responses and transient-evoked otoacoustic emissions tests revealed a progressive monolateral sensorineural retrocochlear hearing loss with cochlear involvement. Magnetic-resonance imaging showed an arachnoid cyst of the cerebellar convexity compressing the cerebellar hemisphere and thus the homolateral cerebellopontine angle. Because of the progressive worsening of the retrocochlear impairment after a 6-month wait-and-see period, the patient finally underwent endoscopic cyst decompression. This was judged to be successful as it stopped the progression of hearing loss and the impairment of the auditory brainstem responses and made the tinnitus more tolerable.     

儿童单侧听神经病附三例分析

目的 探讨儿童单侧听神经病的听力学特征。方法 对3例单侧听神经病患儿进行纯音听阈(PTT)、声反射(AR)、听性脑干反应(ABR)和畸变产物耳声发射(DPOAE)检查，并对其结果进行综合分析。结果 3例患儿的PTT均呈1侧耳听力正常，另1侧耳听力丧失。健耳的同侧和交叉AR能引出，患耳的同侧和交叉AR未能引出。健耳的ABR各波潜伏期正常，患耳的ABR各波未能引出。双耳DPOAE各频率反应幅值正常。结论：DPOAE正常或基本正常，PTT、AR和ABR异常是听神经病的重要特征。单侧听神经病的听力学特征与双侧听神经病基本一致。对儿童表现为单侧感音神经性聋者宜进行系统的听力学检查，以期作出正确的诊断。     

Sudden hearing loss due to meningeal carcinomatosis from rectal carcinoma

We present a case of meningeal carcinomatosis with bilateral hearing loss secondary to a rectal adenocarcinoma. A 60-year-old woman developed progressive loss of hearing in the left ear 19 months after an abdominoperineal resection for an adenocarcinoma of the rectum. Three months after the onset of left hearing loss, she visited our hospital. Pure tone audiometry revealed profound sensorineural hearing loss in the left ear and mild sensorineural hearing loss in the right ear. Gadolinium-enhanced MRI revealed tumor in the left internal auditory canal and cerebellopontine angle and enhancement in the right internal auditory canal. Six days after the first examination, pure tone audiometry revealed profound loss of hearing in the right ear. DPOAE of the right ear were still detected 6 days after the first examination, but were clearly decreased 9 days after it, and reached noise level 10 days after it. Gadolinium-enhanced MRI revealed rapid growth of the tumor of the right internal auditory canal and cerebellopontine angle. We clearly demonstrate here the rapid course of hearing loss using pure tone audiometry, MRI, and DPOAE.     

A minimally invasive endoscope assisted retrosigmoid approach for removal of arachnoid cysts in the internal auditory canal: a step by step description

IntroductionArachnoid cyst in the internal auditory canal is a quite rare pathology but due to its compressive action on the nerves in this district should be surgically removed. Several surgical techniques have been proposed but no surgeons have used the minimally assisted endoscope retrosigmoid approach for its removal.ObjectiveTo investigate the feasibility of using a minimally invasive endoscope assisted retro-sigmoid approach for surgical removal of arachnoid cysts in the internal auditory canal.MethodsMinimally invasive endoscope assisted retrosigmoid approach allows to access to the internal auditory canal through a minimally invasive retrosigmoid approach that combines the use of a microscope and an endoscope. It is performed in six steps: soft tissue step, bone step, dura step, cerebellopontine angle step (performed using an endoscope and a microscope), microscope-endoscope assisted arachnoid cysts removal and closure. We tested minimally invasive endoscope assisted retrosigmoid approach for removal of arachnoid cysts in the internal auditory canal on two human cadaveric heads (specimens) of subjects affected from audio-vestibular disorders and with arachnoid cysts in the internal auditory canal confirmed by magnetic resonance imaging.ResultsThe mass was completely and successfully removed from the two specimens with no damage to the nerves and/or vessels in the surgical area.ConclusionThe results of our study are encouraging and support the feasibility of using minimally invasive endoscope assisted retrosigmoid approach for removal of arachnoid cysts in the internal auditory canal. While further clinical in-vivo studies are needed to confirm the accuracy and safety of using the minimally invasive endoscope assisted retrosigmoid approach for this specific surgery, our group has successfully used the minimally invasive endoscope assisted retrosigmoid approach in the treatment of microvascular compressive syndrome, schwannoma removal and vestibular nerve resection.     

听神经病患者的耳蜗电图特征

目的:了解听神经病患者的耳蜗电图特征。方法:用外耳道银球电极记录听神经病组和正常对照组的耳蜗电图,比较两者的-SP波幅差异,统计患耳AP出现的情况。结果:听神经病患者-SP波的引出率为100％,并且其波幅与正常对照组的差异有显著性意义(P<0.01)。AP波幅较小,但引出率高达84％。结论:听神经病患者的-SP可引出且波幅增大。     

Audiological and electrocochleography findings in hearing-impaired children with connexin 26 mutations and otoacoustic emissions

We recorded cochlear potentials by transtympanic electrocochleography (ECochG) in three hearing-impaired children with GJB2 mutation who showed otoacoustic emissions. Pure tone thresholds, distortion product otoacoustic emissions (DPOAEs) and, auditory brainstem responses (ABRs) were also obtained. Subjects 1 (35delG/35delG) and 3 (M34T/wt) had profound hearing loss and showed the picture of auditory neuropathy (AN) as DPOAEs were detected with absent ABRs in both ears. The hearing impairment found in subject 2 (35delG/35delG) was profound in the right ear and moderate in the left ear. Both DPOAEs and ABRs with normal latencies and morphology were recorded only from the left ear. On the ECochG recording the cochlear microphonic was obtained from all children. No compound action potential (CAP) was detected in subject 1. A neural response was recorded only from the left ear in subject 2 with a threshold corresponding to the audiometric threshold while no CAP was detected on the right side. The ECochG obtained from subject 3 showed a low-amplitude broad negative deflection which was identifiable down to low stimulus levels. This response decreased in amplitude and duration when utilizing a high-rate stimulation paradigm. The amount of amplitude reduction was close to that calculated for normal ears, thus revealing the presence of an adapting neural component. These findings indicate that patients with GJB2 mutations and preserved outer hair cells function could present with the picture of AN. The hearing impairment is underlain by a selective inner hair cell loss or a lesion involving the synapses and/or the auditory nerve terminals. We suggest that neonatal hyperbilirubinemia may play a role in protecting outer hair cells against the damage induced by GJB2 mutations.     

Unilateral hearing loss as a presenting manifestation of granulocytic sarcoma (chloroma).

OBJECTIVE: To present a case of acute granulocytic sarcoma of the cerebellopontine angle whose presenting symptom was sudden onset unilateral sensorineural hearing loss. STUDY DESIGN: Case report and review of the literature (MEDLINE, 1962-2005). METHODS: A 34-year-old female patient with acute myeloid leukemia on remission admitted because of sudden hearing loss in her right ear for 10 days. She had experienced occasional tinnitus, ear fullness, and dizziness for a couple of months. After confirmation of her audiometric findings with auditory brainstem responses, the patient was put on a treatment regimen for sudden hearing loss. RESULTS: On the second day of treatment, she developed ipsilateral facial paralysis, hoarseness caused by ipsilateral vocal fold paralysis, and nystagmus. Magnetic resonance imaging of the cranium revealed findings consistent with granulocytic sarcoma at the cerebellopontine angle, infiltrating the internal acoustic canal. As increased intracranial pressure symptoms developed subsequently, subtotal tumor resection was performed. However, the patient was lost, with Cushing's triad at the second postoperative month during postoperative chemotherapy. CONCLUSION: Although up to 40% of leukemic patients may have otologic symptoms, sudden onset of sensorineural hearing loss is very rare. The patient presented in this report is the first reported case with a granulocytic sarcoma of the cerebellopontine angle who presented with acute sensorineural hearing loss. Despite the rarity of such a case, we would like to emphasize that leukemia must be kept in mind as an etiologic factor in sensorineural hearing loss and suggest that complete blood count and temporal bone imaging be routinely obtained.     

Dichotic sentence identification test in Portuguese: a study in young adults

IntroductionAmong the currently-applied auditory processing tests, dichotic listening tests have been widely used, since they allow investigating the hemispheric and inter-hemispheric function and their respective skills to process the received auditory information.ObjectiveTo obtain normality reference measures with the new dichotic sentence identification test in right-handed adults with normal hearing.MethodsQuantitative, observational, cross-sectional study. 72 subjects were assessed, aged 19–44 years, right-handed, with normal hearing, without hearing complaints. The dichotic sentence identification test consists of different lists of sentences, which were combined two by two and presented at the same time, using earphones in both ears, at 50 dB Sensation Level. The test was applied in four stages: training of the 3 stages, free attention, right and left directed attention, thus evaluating different auditory skills.ResultsIn the free attention task, the average percentage of correct answers in the right ear was 93.59% and in the left ear 86.06%, with a statistically significant difference between the ears, with an advantage for the right ear. In the directed attention task, the average percentage of correct answers was 99.37% in the right ear and 98.8% in the left ear, with no statistical difference between the ears.ConclusionIt is suggested, as a normality reference for the stage of free attention, 90%–100% for correct answers for the right ear and for the left ear, from 80% to 100%. When there is asymmetry between the ears, differences of up to 20% are expected, with an advantage for the right ear For the directed attention stage, the expected normality reference values ??are 100% for the right ear and for the left ear, with no asymmetry between the ears; however, if it occurs, a difference of 10% is expected between the ears, with an advantage for the right ear.     

Otologic manifestations of neurofibromatosis

A chart review of 440 patients with neurofibromatosis seen at the Children's Hospital of Philadelphia Neurofibromatosis Clinic between 1980 and 1991 was performed to look for otologic manifestations. Neurofibromatosis 1 was present in 434 patients, and neurofibromatosis 2 was present in 6. A total of 31 otologic abnormalities related to neurofibromatosis were found in 28 patients. Neurofibromas of the external ear, including the pinna and the external auditory canal, were the most common finding. Middle ear neurofibromas were found in two patients. Acoustic neuromas were seen exclusively in patients believed to have neurofibromatosis 2. One cerebellopontine angle neurofibrosarcoma was found in a patient with neurofibromatosis 1.     

Evaluation of inner hair cell and nerve fiber loss as sufficient pathologies underlying auditory neuropathy

Auditory neuropathy is a hearing disorder characterized by normal function of outer hair cells, evidenced by intact cochlear microphonic (CM) potentials and otoacoustic emissions (OAEs), with absent or severely dys-synchronized auditory brainstem responses (ABRs). To determine if selective lesions of inner hair cells (IHCs) and auditory nerve fibers (ANFs) can account for these primary clinical features of auditory neuropathy, we measured physiological responses from chinchillas with large lesions of ANFs (about 85%) and IHCs (45% loss in the apical half of the cochlea; 73% in the basal half). Distortion product OAEs and CM potentials were significantly enhanced, whereas summating potentials and compound action potentials (CAPs) were significantly reduced. CAP threshold was elevated by 7.5 dB, but response synchrony was well preserved down to threshold levels of stimulation. Similarly, ABR threshold was elevated by 5.6 dB, but all waves were present and well synchronized down to threshold levels in all animals. Thus, large lesions of IHCs and ANFs reduced response amplitudes but did not abolish or severely dys-synchronize CAPs or ABRs. Pathologies other than or in addition to ANF and IHC loss are likely to account for the evoked potential dys-synchrony that is a clinical hallmark of auditory neuropathy in humans.     

Magnetic resonance imaging of facial nerve neuromas

Facial nerve neuromas are uncommon tumors often confused with other tumors of the temporal bone and cerebellopontine angle. Radiologically, it may be impossible to differentiate an intracanalicu-lar facial nerve neuroma from an acoustic neuroma. We present three case reports of facial nerve neuromas arising within the internal auditory canal to show the important magnetic resonance imaging features of these tumors. One tumor extended into the cerebellopontine angle, middle cranial fossa, and middle ear. Another filled the internal auditory canal and extended through the cerebellopontine angle to the brain stem. The third occurred in a patient who had neurofibromatosis as well as numerous other intracranial tumors. We feel that gadolinium-enhanced magnetic resonance imaging provides the most useful information in the preoperative assessment of this disorder.     

Post-traumatic pseudomeningocele presenting as a cyst of external auditory canal: report of a case

Pseudomeningoceles are formed by extravasation of cerebrospinal fluid through a dural defect into soft tissue. They mostly form as a result of surgical trauma to the dural covering of the lumbar or cervical spine surgery, especially during laminectomy. Howerver, post-traumatic pseudomeningocele rarely occurs in the head and neck. A 32-year-old female presented with a 10-year history of right ear fullness following head trauma. A soft, non-pulsatile and cystic mass was noted in the right external auditory canal. The MRI scan demonstrated the connection between subarachnoid space and cyst of the right external auditory canal. The right ear was explored and mastoid antrum was partially filled with a cyst connected to the dural defect. The extradural portion of the mass was removed, the dural defect was repaired with a temporalis fascia-cartilage graft. Clinical manifestations, diagnosis and surgical approaches for post-traumatic pseudomeningocele arising in the head and neck region are briefly discussed.     

Auditory Cortical Responses in Patients with Bell?s Palsy

We recorded auditory evoked magnetic responses with a whole-scalp 122-channel SQUID neuromagnetometer in 14 patients with Bell?s palsy (9 with left-sided and 5 with right-sided) and in 10 controls. The stimuli were 50-ms 1-kHz tone bursts, delivered first to the left and then to the right ear at interstimulus intervals (ISIs) of 1, 2 and 4 s. In patients, the N100m, the 100-ms response originating in the auditory cortices peaked, on average, 8 ms earlier and the response strengths were, on average, 7 nAm stronger over the contralateral than ipsilateral hemisphere. The response latencies and strengths did not differ significantly from those of controls and there were no significant differences in response latencies and strengths between the stimulation of the affected and healthy side. On average, the response latencies and strengths increased as a function of ISI over both hemispheres both in patients and in controls. These findings suggest that Bell?s palsy is an isolated peripheral neuropathy that does not affect the function of the auditory pathways.     

听神经病的纯音听阈检查结果分析

目的 探讨听神经病纯音听阈(PTT)检查的特征。方法 对48例听神经病患者的PTT检查结果进行分析，并与耳蜗性聋进行对照比较。结果 听神经病的PTT图有上升型、峰型、匙型、W型、倒S型、水平型和缓降型。双耳对称的PTT图有38例，不对称的有10例。听神经病的听阈升高程度呈轻、中度。左右耳听阈升高程度基本一致。低频听阈升高或以低频听阈升高为主的PTT图型占93．75％(90／96耳)。结论 双耳对称或基本对称的低频听阈升高或以低频听阈升高为主是听神经病的重要特征。     

Acoustic schwannoma presenting as a tumor of the external auditory canal. Case report

An acoustic neurinoma involving the internal auditory canal, the vestibule, the cochlea, the middle ear, and extending into the cerebellopontine angle and the external auditory canal, is described in a 56-year-old woman. An initial episode of vertigo was followed by a 27-year history of progressive unilateral hearing loss leading to complete deafness and areflexia with central compensation. The tumor was removed by a two-step surgical procedure, and the histologic features were those of a schwannoma.     

桥小脑角脑神经病变显微手术510例病因分析

目的 总结桥小脑角脑神经病变510例显微手术的经验，并对病因进行分析。方法 经乙状窦后入路进入桥小脑角，在手术显微镜下对有关神经构成压迫和各种病灶分别给予相应的减压等处理。结果 桥小脑角脑神经病变510例全部治愈。术中发现因责任血管压迫者466例，占91．37％；肿瘤15例，占2．94％；蛛网膜粘连者29例，占5．69％。结论 桥小脑角脑神经病变510例，致病因素以责任血管压迫为主，部分为肿瘤压迫，而蛛网膜粘连致病者亦占相当比例；蛛网膜粘连是引起舌咽神经痛的重要因素。     

听神经病小儿60例分析

目的对60例听神经病小儿进行临床听力学分析,以便提高对此病的认识,避免漏诊及误诊。方法2003年-2005年我院临床医学听觉言语康复中心门诊,对4个月-6岁婴幼儿及儿童诊疗中发现60例聋儿,对声音有反应,但不会讲话,给于ABR、ASSR、OAE、声导抗、影像学检查后,发现异常反应。结果60例(120耳)聋儿ABR严重异常,ASSR、行为测听有部分残余听力、OAE正常、声导抗及影像学方面未发现异常。结论听神经病是一种近期提出的病因不明的听觉障碍性疾病。此病引起具有特殊临床表现与听力学检查表现的感音神经性聋,有助于与感音性聋的鉴别。     

Intraoperative monitoring with transtympanic electrocochleography]

Transtympanic electrocochleography (ECoG) enables auditory evoked potentials to be recorded directly from the peripheral organ, and ECoG recordings can be used as a routine during operations. Examples of cochlear and eighth nerve monitoring in middle ear, inner ear, and cerebellopontine angle surgery are given. This monitoring tool provides a continuous feedback to the surgeon of the effects of the operation on the cochlea and the auditory pathway.