Unilateral Hearing Research Articles

Effect of conductive hearing loss on the activation pattern of the primary auditory cortex as assessed by functional MRI

Objectives. To investigate the activation pattern of the human auditory cortex to monaural sound stimuli using functional magnetic resonance imaging (fMRI) in volunteers with normal hearing or unilateral conductive hearing loss. Method. Ten normal hearing volunteers and seven volunteers with unilateral conductive hearing loss were subjected to a random sequence of monaural sound stimuli and silence, whilst undergoing fMRI in a 3 Tesla scanner. The sound stimuli consisted of narrowband noise (250 Hz and 4000 Hz), as well as wideband noise (250–4000 Hz). A signal averaging algorithm was used to detect the response in the primary auditory cortex. A laterality index was calculated and compared between the study groups. Results. In the normal hearing group the auditory areas of both hemispheres showed activity in response to monaural stimuli, but the responses were consistently greater in the contralateral primary auditory cortex. Wideband stimuli produced the greatest degree of contralaterality and the largest response across the auditory cortex. The responses to high and low frequency stimuli were found to be conform with established tonotopic organization of the primary auditory cortex. There was no difference in the laterality index between the study groups. Conclusions. We have developed a non-invasive way to investigate the response pattern of the primary auditory cortex to sound stimuli using fMRI. A similar activation pattern of the auditory cortex was found in both study groups suggesting a preservation of the organisation of the ascending auditory pathways and auditory cortex in unilateral conductive hearing loss.

Cochlear implantation in Refsum's disease

Refsum's disease is a rare disorder characterized by accumulation of phytanic acid in plasma and tissues. The main clinical features are retinitis pigmentosa, cerebellar ataxia and chronic polyneuropathy. Sensorineural hearing loss of varying severity can be an additional feature. This study reports our experience with two patients with Refsum's disease who underwent successful cochlear implantation. Both patients had good audiological outcomes after implantation and were overall very satisfied. Bilateral implantation should be considered with patients with severe dual sensory loss. One patient was implanted bilaterally the other unilaterally, primarily due to prolonged duration of unaided unilateral profound hearing loss. Copyright © 2008 John Wiley & Sons, Ltd.

Letter to the Editor

Objectives:We sought to confirm earlier findings in the literature that microvascular compression of the vestibulocochlear nerve might cause unilateral sensorineural hearing loss. We measured the l...

Sudden deafness and biometric function analysis of the cervical spine

Theories concerning the influence of function disturbances of the cervical spine on the development of sudden hearing loss should be re-examined. Forty-eight patients with unilateral sudden hearing loss and 94 controls were examined. X-rays of the cervical spine were made in lateral projection in normal position, and in maximum flexion and extension. The posture and movement of the vertebrae were recorded using a computer digitalization program. Overall mobility of the cervical spine was reduced in the group with sudden hearing loss: reduced movement was found in segments C2/C3, C5/C6, and C6/C7. Segments P0/P1 and C1/C2 were conspicuous by very high standard deviations in the group with sudden hearing loss. The results indicate that sudden hearing loss and function disorders of the cervical spine are related.

Delayed Endolymphatic Hydrops: A Case Study

Delayed endolymphatic hydrops (DEH) is an unusual variation of Ménière's disease characterized by episodic vertigo that develops some time after the onset of a profound, typically unilateral sensorineural hearing loss. This case study describes a 48-year-old male who presented with complaints of episodic vertigo and disequilibrium 15 years following the onset of unilateral sensorineural hearing loss. The patient's history, audiologic findings, and vestibular evaluation led to the diagnosis of DEH. The case highlights the diagnostic and treatment challenges associated with this condition and focuses attention on principles that guide the audiologist in collecting evidence that aids in solving these challenges.

Steroid responsive fluctuating sensorineural hearing loss due to juvenile pilocytic astrocytoma involving the cerebellopontine angle

Tumors of the cerebellopontine angle (CPA) are common and represent up to 10% of all intracranial tumors. Rarely, intrinsic brainstem tumors can involve the CPA and present with auditory symptoms typical of CPA tumors such as hearing loss, vertigo and tinnitus. We report on a rare case of an intrinsic brainstem neoplasm presenting with steroid responsive fluctuating sensorineural hearing loss in a child. The patient initially presented with an acute worsening of an unilateral sensorineural hearing loss, without additional symptoms, that responded to oral steroids. Otoacoustic emission testing demonstrated normal outer hair cell function suggesting retrocochlear pathology. Magnetic resonance imaging with contrast enhancement revealed an intrinsic neoplasm of the middle cerebellar peduncle impinging on the 7th/8th neurovascular bundle within the CPA. The patient underwent gross total resection of the juvenile pilocytic astrocytoma via retrosigmoid craniotomy and remains disease free at 2 years postoperatively. This case highlights that suspicion of central nervous system pathology should be heightened in the presence of steroid responsive, fluctuating sensorineural hearing loss with normal outer hair cell function.

The Bone-Anchored Hearing Aid for children: Recent developments

In 1984 the Bone-Anchored Hearing Aid, or BAHA, system was introduced. Its transducer is coupled directly to the skull percutaneously to form a highly effective bone-conduction hearing device. Clinical studies on adults with conductive hearing loss have shown that the BAHA system outperforms conventional bone-conduction hearing aids. Therefore, the next step was to apply the BAHA system in children with congenital or acquired conductive hearing loss. Reviewed data showed that, on average, such children benefited significantly more from the BAHA than from reconstructive surgery. Thus, BAHA application appears to be the best option to achieve normal communication and speech and language development in children with bilateral conductive hearing loss. However, in children under the age of three to four years, a conventional solution must be applied, e.g. a bone conductor with a transcutaneous coupling, because they are too young to undergo BAHA implant surgery. In the case of unilateral congenital conductive hearing loss, there is no convincing evidence in the clinical literature for early intervention.In summary, the BAHA system can be considered a new, indispensable tool for children with bilateral conductive hearing loss.

Hearing problems at working age: Audiometric features and the aetiology of hearing impairment

Sixty patients, 37 women and 23 men, aged 30−65 years, were included in the study. All had adult-onset hearing loss to an extent that necessitated hearing-aid fitting. The objective was to describe the audiometric features and extent of hearing loss, and to determine the aetiology of hearing impairments in hard-of-hearing patients in working life. The extent of hearing loss varied considerably; about one-third of the patients had moderate to severe hearing loss in both ears, about one-third had bilateral, mild hearing loss, and somewhat less than one-third had unilateral or asymmetrical hearing loss, with mild loss or even normal hearing in one ear. In 77% of the cases a diagnosis, verified or tentative, could be established. Middle ear disease with conductive or mixed hearing loss was found in 20% of the cases. Noise-induced hearing loss was diagnosed in 10% of the cases. The most common, but highly tentative, diagnosis was hereditary hearing loss. Including cases of otosclerosis, genetic hearing loss wa...

Vestibular evoked myogenic potential induced by bone-conducted stimuli in patients with conductive hearing loss

Conclusions. Bone-conducted vestibular evoked myogenic potentials (B-VEMPs) showed high specificity for the presence of vertigo in patients with unilateral chronic otitis media (COM). These results suggest that vestibular function can be evaluated with B-VEMPs, even in patients with conductive hearing loss. Objective. The purpose of this study was to investigate the VEMPs induced by bone-conducted stimuli (B-VEMPs) in patients with conductive hearing loss due to perforated COM. Subjects and methods. The subjects were 48 patients with unilateral perforated COM and conductive hearing loss. The disequilibrium group consisted of 25 patients, and the non-disequilibrium group consisted of 23 patients. The control group comprised 35 healthy volunteers. B-VEMPs were stimulated with tone burst sound of 60 dB nHL and 250 Hz delivered from a bone vibrator and were recorded for each subject. The results of B-VEMP were compared between disequilibrium and non-disequilibrium groups. Results. The mean interaural ratio was 16.5±12.1% in the control group, thus the normal range was <40.7%. Abnormal results were not found in any subject in the non-disequilibrium group but were found in 13 patients (54.0%) in the disequilibrium group (p<0.001). The ear with COM showed lower responses than the intact ear in all subjects with abnormal results.

Unilateral sudden hearing loss as the first sign of chronic myeloid leukemia

Chronic myeloid leukemia (CML) is one of the etiologic causes of sudden hearing loss and vertigo. However, deafness in association with vestibular symptoms rarely occurs in CML as the first sign. In this article, a 50-year-old male with CML whose first signs and symptoms were unilateral sudden hearing loss and tinnitus in the right ear, vertigo and nausea was presented. Aetiopathogenetic mechanisms, clinical and radiological aspects and therapeutic options for CML with deafness and vertigo were discussed reviewing the literature.

Hearing Rehabilitation after Lateral Skull Base Surgery

Introduction: The treatment of unilateral sensorineural hearing loss resulting from lateral skull base lesions involving the cochlear nerve remains a challenging problem. The resection of neoplasms in this area may result in damage to or removal of the cochlear nerve. The resulting hearing handicap can negatively impact a patient's quality of life. This paper analyzes the results of the bone-anchored cochlear stimulator (BAHA) in patients with lateral skull base lesions. Methods: The inpatient, outpatient, and surgical charts of 73 patients who underwent BAHA placement between September 2003 and October 2005 were reviewed. Patients whose hearing loss resulted from a vestibular schwannoma were selected, and the preoperative, postoperative, and audiometric data were analyzed. Results: There were 11 patients who underwent unilateral BAHA placement after vestibular schwannoma resection. There were 5 males and 6 females with an average age of 56 years. One patient had skin growth over the implant. There were no major wound complications, CSF leaks, abdominal fat graft infections, or implant extrusions. All patients expressed satisfaction with the device based on hearing questionnaires. Conclusions: The BAHA can be used to improve the hearing handicap in patients with deafness secondary to vestibular schwannoma. The device is well tolerated with a low complication rate and good patient satisfaction.

Assessment of Objective Pulsatile Tinnitus in a Patient with Syringohydromyelia

We examined a 38-year-old male with syringohydromyelia and concomitant symptoms suggestive of intracranial hypertension including unilateral low-frequency sensorineural hearing loss and objective pulsatile tinnitus. The tinnitus was heard by the authors (through a hearing aid stethoscope tube), measured objectively (with a probe microphone), measured subjectively (as minimum masking levels and with fixed frequency Bekesy), and altered by changes in ear canal pressure (subjectively reported and measured objectively with a probe microphone). The audiologic symptoms were likely associated with elevated cerebrospinal fluid pressure that traveled to the cochlea through the cochlear aqueduct. The tinnitus may have originated from pulsations of central vascular structures that traveled through the cochlear aqueduct or the endolymphatic duct. Hearing loss likely resulted from tinnitus masking or a stiffening of the cochlear partition or stapes footplate.

Is simultaneous bilateral mastoidectomy ever advisable?

We report our experience with bilateral, simultaneous tympanomastoidectomies and the results of an opinion survey of otologists. A chart review of 116 tympanomastoidectomies revealed 12 patients who underwent bilateral, simultaneous tympanomastoidectomies. An opinion survey generated 121 responses. Of the 12 patients, none suffered any outcome which would have been avoided by staging the procedures. Twenty-three of 24 operated ears had the same or better hearing post-operatively. Of the survey respondents, 74 felt that performing bilateral, simultaneous tympanomastoidectomies was unsafe, largely because of the risk of bilateral sensorineural hearing loss. Although bilateral, simultaneous tympanomastoidectomies carry double the risk of unilateral sensorineural hearing loss, compared with the unilateral procedure, the risk of bilateral sensorineural hearing loss is only 0.006-0.2 per cent, as derived mathematically from historical data. Respondents to the survey were mostly opposed to bilateral, simultaneous tympanomastoidectomies, but even those opposed gave indications for simultaneous procedures. This finding probably reflects an ambivalence about the theoretical risks of the operation versus the potential patient benefits. A decision tree for proceeding to the second case is presented.

Non-organic hearing loss

Conclusion. Most non-organic hearing loss (NOHL) patients were young females. The discrepancy between the results of pure tone audiometry and objective auditory testing suggests NOHL. The diagnostic problem is that objective audiometry is not included in routine examinations and we have to suspect NOHL in order to perform further examination. The correct diagnosis can be difficult in patients who present with unilateral sudden hearing loss or who also have moderate to profound organic hearing loss. Objective. Symptoms and results of auditory tests for NOHL patients were reviewed. Patients and methods. This study comprised 31 patients with NOHL. Age, symptoms, and the results of subjective and objective audiometry were collected. Results. Twenty-four patients were female and 7 were male. The age at attendance ranged from 7 to 39 years old, with an average age of 16.6 years. Eight patients received steroids before the correct diagnosis was made. Six of them presented with unilateral sudden hearing loss, and the other two patients had accompanying bilateral organic hearing loss.

Perlak pierwotny ucha środkowego i szczytu piramidy

Petrosal cholesteatomas are rare lesions, which may be primary or acquired in nature. We report a case of primary cholesteatoma in petrous bone occurring in 51-year old woman who presented with a unilateral facial nerve palsy and conductive hearing loss, despite normal tympanic membrane appearance. Early diagnosis was facilitated by computed tomography scanning and magnetic resonance imaging. Complete cholesteatoma removal was accomplished using a transtemporal supralabyrinthine approach, which allowed hearing preservation. Facial nerve function is the main complication of these lesion. We suggest that use of CT scanning and MRI in unilateral conductive hearing loss may allow the earlier detection of the most cases of petrosal cholesteatomas.

Hearing progress and fluctuations in bimodal–binaural hearing users (unilateral cochlear implants and contralateral hearing aid)

Conclusions. Mean scores achieved using a cochlear implant (CI) plus a hearing aid (HA) were consistently higher (statistically non-significant) than those for CI alone. The addition of a contralateral HA partially compensated for the negative hearing fluctuations as well as for the slow initial progress with the CI. Objectives. To examine hearing progress over the first 3 years after unilateral cochlear implantation in users who had residual hearing in the non-implanted ear at the time of surgery and continued to use a HA in that ear thereafter. Patients and methods. Thirteen patients were followed up for 36months after continuous concomitant use of a CI and a contralateral HA. To evaluate hearing progress, sentence identification in background noise (presentation level, 55dB; S/N ratio, +10 dB) was tested for CI alone and for CI with contralateral HA (CI+HA). Subjects were tested after 6, 12, 18, 24, and 36months of concomitant use of both devices. Mixed regression model was used to evaluate the group's progression of scores and the added value of a contralateral HA over time. Results. When last tested (36 months after CI) the mean group score for CI alone was 72.6%±19.3%, and 12/13 patients scored at least 65% with either CI alone or CI+HA. Mean scores achieved using CI+HA were consistently higher than those for CI alone. Percentage improvement in CI+HA relative to CI alone was highest (19.2%) after 18 months of concomitant usage and then diminished gradually to 7.7% at 36months. Most patients showed some negative fluctuations in performance with CI alone at some point during the 36months of post-CI follow-up.

Hearing changes in the contralateral ear with juvenile unilateral profound hearing loss of unknown origin

Hearing changes in the contralateral ear with juvenile unilateral profound hearing loss of unknown origin

Hearing changes in the contralateral ear with juvenile unilateral profound hearing loss of unknown origin

Summary Objectives : Investigate contralateral hearing changes in patients with juvenile unilateral profound hearing loss (JUPHL) of unknown origin because patients with JUPHL have potentially bilateral hearing loss. Study design : A retrospective study. Setting : A tertiary referral center. Patients : Fifty patients with JUPHL of unknown origin included 42 unilaterally deaf patients and 8 patients with hearing loss over 70dB HL. The age of the patients was less than 15 years old at the first visit to our outpatient clinic. Patients with inner ear anomalies were excluded using CT images. Main outcome measures : The results of pure tone audiometry (PTA) were investigated. To obtain reliable PTA results, patients were over 6 years old. The following items were examined: level, fluctuation and worsening of hearing. Results : A hearing level over 30dB was observed at 20%, 4%, and 10% of patients in the low, middle and high frequencies, respectively. Hearing fluctuations were observed in 72%, 42% and 64% at the low, middle and high frequencies, respectively. Hearing worsening was observed in 8%, 4% and 4% at the low, middle and high frequencies, respectively. Conclusion : Seventy-two percent of patients with JUPHL had fluctuating hearing at low frequencies, and 8% of them had worsening hearing. These results imply that over 70% of patients with JUPHL may develop contralateral hearing loss and that we have to follow-up patients with unilateral juvenile profound hearing loss for a long time.

Autoantibodies against inner ear proteins in patients with delayed endolymphatic hydrops and unilateral juvenile deafness

Conclusions. Patients with the contralateral type of delayed endolymphatic hydrops (DEH) may undergo an autoimmune attack against the other inner ear. As patients with unilateral juvenile deafness show no progression, despite lengthy observation, the autoantibody against the 68-kDa protein may be unrelated to the pathogenesis of DEH. Objective. The contralateral type of DEH is believed to have an autoimmune etiology, and sometimes develops from unilateral juvenile deafness. The purpose of this study was to determine whether autoantibodies are pathogenetically important in DEH. Material and methods. Sera from 9 patients with DEH, 18 patients with profound unilateral juvenile hearing loss and 15 control volunteer without inner ear diseases were investigated by means of Western blot assay against rat inner ear proteins. Results. Among 8 patients with the contralateral type of DEH, 6 (75%) showed at least 1 reactive band on Western blotting. The protein that reacted most frequently had a molecular weight of 28 kDa, which was consistent with our previous results. Among 18 patients with unilateral juvenile deafness, 5 (28%) showed reactive bands, exclusively at 68 kDa.

Sub-acute neuropathy in patients with African tick bite fever

African tick bite fever (ATBF) caused by Rickettsia africae is an emerging health problem in travellers to sub-Saharan Africa. We here present 6 patients with evidence of long-lasting sub-acute neuropathy following ATBF contracted during safari trips to southern Africa. Three patients developed radiating pain, paresthaesia and/or motor weakness of extremities, 2 had hemi-facial pain and paresthaesia, and 1 developed unilateral sensorineural hearing loss. When evaluated 3-26 months after symptom onset, cerebrospinal fluid samples from 5 patients were negative for R. africae PCR and serology, but revealed elevated protein content in 3 and mild pleocytosis in 1 case. Despite extensive investigations, no plausible alternative causes of neuropathy could be identified. Treatment with doxycycline in 2 patients had no clinical effect. Given the current increase of international safari tourism to sub-Saharan Africa, more cases of sub-acute neuropathy following ATBF may well be encountered in Europe and elsewhere in the y to come.