Profound Unilateral Hearing Loss Research Articles

Changes in Structure and Connectivity of Auditory Cortex in Patients with Unilateral Hearing Loss

The purpose of this study was to investigate cortical structural and connectivity changes in the auditory system due to the absence of unilateral input signals from the hearing-impaired ear in patients with unilateral hearing loss. Twenty-seven patients who have severe to profound unilateral hearing loss participated. T-1 images were acquired to calculate the normalized cortcial volume (nCV), and seed-based connectivity analysis was performed. It was shown that the nCV of Te 3.0 was decreased in the left unilateral hearing loss (LUHL). In LUHL group, a significant structural correlation was observed between region of interests (ROIs) within the auditory cortices of bilateral hemispheres, while right unilateral hearing loss (RUHL) group showed significant correlation between thalamus and auditory cortical regions. We proposed that cortical structural reorganization in unilateral hearing loss patients, that is different by deafness side. These results are expected to be related to individual binaural hearing performance in unilateral hearing loss.

Epidemiology, aetiology and diagnosis of congenital hearing loss via hearing screening of 153 913 newborns.

Congenital hearing loss (HL), one of the most common paediatric chronic conditions, significantly affects speech and language development. Its early diagnosis and medical intervention can be achieved via newborn hearing screening. However, data on the prevalence and aetiology of congenital HL in infants who fail newborn hearing screening are limited. The sample population included 153 913 infants who underwent newborn hearing screening, and the prevalence of congenital HL, defined as moderate to profound bilateral HL (BHL) or unilateral HL (UHL) (≥40 dB HL), in one prefecture of Japan was measured to minimize the loss-to-follow-up rate, a common factor affecting the screening procedure. Comprehensive aetiological investigation, including physiology, imaging, genetic tests, and congenital cytomegalovirus screening, was performed on children diagnosed with congenital HL. The calculated prevalence of congenital HL was 1.62 per 1000 newborns (bilateral, 0.84; unilateral, 0.77). More than half of the cases with congenital bilateral or severe to profound UHL showed genetic aetiology or cochlear nerve deficiency (CND), respectively. Approximately 4% and 6% of the cases of congenital BHL and UHL were associated with congenital cytomegalovirus infection and auditory neuropathy spectrum disorder, respectively. This is an epidemiological and comprehensive aetiological study of congenital HL, as determined via newborn hearing screening according to its severity and laterality, in a large-scale general population of a developed country. Our findings can serve as a reference for optimizing care and intervention options for children with HL and their families.

Language and health-related quality of life outcomes of children early-detected with unilateral and mild bilateral hearing loss.

We aimed to describe the language and health-related quality of life (HRQoL) outcomes of children early-identified with unilateral or mild bilateral permanent hearing loss. This was a cross-sectional community-based study of children with mild bilateral or unilateral permanent hearing loss (including unilateral auditory neuropathy spectrum disorder (ANSD)), drawn from a population-based databank in Victoria, Australia. Enrolment in this databank is independent of early intervention and amplification approaches. Language and caregiver-reported HRQoL outcomes are described by type and degree of loss at three timepoints across child development: at age 2 years (n = 255), 5-7 years (n = 173) and 9-12 years (n = 45). Across all age groups, average language outcomes were poorer than population normative scores by between a half to two thirds of a standard deviation. Children with mild bilateral hearing loss demonstrated poorer average language outcomes than children with unilateral hearing loss, particularly at younger ages. Children with unilateral ANSD showed language outcomes comparable to their peers with unilateral profound hearing loss. Children had poorer HRQoL psychosocial scores compared to physical scores, without obvious patterns of outcomes linked to degree or type of hearing loss. This study demonstrates children with early-identified unilateral or mild bilateral hearing loss have average language and HRQoL outcomes poorer than population normative expectations from an early age. These outcomes are observed at later ages across childhood. These findings provide a contemporary description of language and quality of life outcomes for children identified but not targeted by universal newborn hearing screening and raise questions of how to provide better support for these populations of children and their families.

Functional connectivity changes in infants with varying degrees of unilateral hearing loss.

It has been proved that unilateral hearing loss (UHL) can cause functional connectivity alterations in adults. However, the mechanism of the human brain coping with the challenge of unilateral hearing deprivation at very early developmental phases remains poorly understood. Here, we performed a resting-state functional near-infrared spectroscopy (fNIRS) study on 3- to 10-month-old infants with varying degrees of unilateral hearing loss to investigate the effect of unilateral auditory deprivation in infants. Using network-based statistics, increased functional connectivity was observed in single-sided deafness (SSD) compared with normal hearing infants, and the right middle temporal gyrus was the most involved nodes. In addition, changes in cortical function in infants were related to the degree of hearing loss, with significantly increased functional connectivity in infants with severe to profound unilateral hearing loss compared with the ones with mild to moderate. Moreover, more significant cortical functional recombination changes were found in right-SSD than in left-SSD infants. For the first time, our study provides evidence for the effects of unilateral hearing deprivation on the early cortical development of the human brain, which would also act as a reference for intervention decisions in children with unilateral hearing loss in clinical settings.

Transient profound hearing loss and severe facial nerve palsy in schwannomas within the internal acoustic canal: A case report.

Vestibular schwannoma is the most common intracranial schwannoma and constitutes ~8% of all intracranial tumors in adults with an estimated incidence rate of ~1.3/100.000. Facial nerve schwannomas and cochlear nerve schwannomas are rare, and information regarding incidence rates of these is still missing in the literature. All three variants of nerve origin present most frequently with unilateral hearing loss, unilateral tinnitus and disequilibrium. Facial nerve palsy is a common finding in facial nerve schwannomas but a rare finding with vestibular schwannomas. The symptoms are normally persistent and often progress over time, leading to therapeutic interventions that predispose to quality of life-reducing morbidities, e.g., deafness and/or imbalance. The case report describes a 17-year-old male who, during a 1-month period, presented with profound unilateral hearing loss and severe facial nerve palsy followed by complete remission. An MRI scan showed a 5×8-mm schwannoma within the internal acoustic canal. Profound hearing loss together with concomitant severe peripheral facial nerve palsy in small schwannomas within the internal acoustic canal may show spontaneous and total remission within weeks of symptom debut. This knowledge, as well as possible remission of objective findings, should be considered before interventions with potential severe morbidity are suggested.

Lateralization Pattern of the Weber Tuning Fork Test in Longstanding Unilateral Profound Hearing Loss: Implications for Cochlear Implantation.

The Weber tuning fork test is a standard otologic examination tool in patients with unilateral hearing loss. Sound should typically lateralize to the contralateral side in unilateral sensorineural hearing loss. The observation that the Weber test does not lateralize in some patients with longstanding unilateral deafness has been previously described but remains poorly understood. In the present study, we conducted a retrospective analysis of the medical records of patients with unilateral profound hearing loss (single-sided deafness or asymmetric hearing loss) for at least ten years. In this patient cohort, childhood-onset unilateral profound hearing loss was significantly associated with the lack of lateralization of the Weber tuning fork test (Fisher’s exact test, p < 0.05) and the absence of tinnitus in the affected ear (Fisher’s exact test, p < 0.001). The findings may imply a central adaptation process due to chronic unilateral auditory deprivation starting before the critical period of auditory maturation. This notion may partially explain the poor outcome of adult cochlear implantation in longstanding single-sided deafness. The findings may suggest a role for the Weber test as a simple, quick, and economical tool for screening poor cochlear implant candidates, thus potentially supporting the decision-making and counseling of patients with longstanding single-sided deafness.

Two Cases of Cochlear Implantation in Patients With Unilateral Profound Hearing Loss Due to Intralabyrinthine Schwannoma

When vestibular schwannoma originates from the segment within the labyrinth of the vestibulocochlear nerve, it is termed intralabyrinthine schwannoma (ILS). As most of the cases are presented with profound sensorineural hearing loss on the affected side, for auditory rehabilitation, cochlear implantation can be considered simultaneously as the tumor removal. Successful results of cochlear implantation were reported in patients with ILS even after partial resection of the mass. In this study, we report the cases of two patients with ILS with unilateral deafness. In one patient, a mass found in the basal turn of cochlea was removed totally and a cochlear implantation electrode was fully inserted. In the other patient, a mass found in the basal turn and vestibule was partially removed and an electrode was inserted. Postoperatively, hearing was improved and tinnitus was reduced.

Current criteria for selecting cochlear implant in deaf patients: a review

Cochlear implantation is indicated in patients with severe to profound hearing loss that cannot be adequately treated by other auditory rehabilitation measures. The definitive indication of cochlear implantation is made on the basis of an extensive interdisciplinary clinical, audiological, radiological, and psychological diagnostic work-up. There are numerous changes are happening in cochlear implant candidacy. These have been associated with concomitant changes in surgical techniques, which enhanced the utility and safety of cochlear implantation. Currently, cochlear implants are approved for individuals with severe to profound unilateral hearing loss rather than previously needed for bilateral profound hearing loss. Studies have begun using the short electrode arrays for shallow insertion in patients with low-frequency residual hearing loss. The advancement in designs of the cochlear implant along with improvements in surgical techniques reduce the complications and result in the safety and efficacy of the cochlear implant which further encourages the use of these devices. This review article aims to discuss the new concepts in the candidacy of the cochlear implant, cochlear implant in younger children and hearing preservation, a cochlear implant for unilateral deafness, bilateral cochlear implant, and cochlear implant with neural plasticity and selection of patients for the cochlear implant.

Update cochlear-implantation: indications and surgical aspects

In childhood, inadequately rehabilitated hearing loss leads to impaired language acquisition and social, mental and emotional development. In adults, social withdrawal due to limited communication skills is often a consequence of unsatisfactory hearing rehabilitation. Therefore, in patients with profound hearing loss, the indication for cochlear implantation should be considered. Technical advances in cochlear implant development, as well as in microsurgical techniques and the rehabilitation process, have led to an expansion of indications in recent years. Adequate hearing rehabilitation is associated not only with an improvement in hearing function and speech understanding, but also with an increase in quality of life at all ages. In patients with unilateral profound hearing loss, cochlear implantation leads to an improvement of speech understanding and localization ability as well as to a reduction of the head shadow effect and tinnitus. The indication process, surgical treatment and the subsequent rehabilitation process require interprofessional cooperation in specialized centers.

Rehabilitation of sound localization ability in patients with unilateral hearing loss or single-sided deafness

The prevalence of unilateral hearing loss（UHL） is higher, and the clinical attention to the hearing rehabilitation of UHL is not enough, resulting in many UHL patients cannot get rehabilitation timely and effectively. Severe to profound UHL（also known as single-sided deafness） patients lack binaural hearing superiority, especially the inadequate ability of sound localization, which will seriously affect their daily life and academic performance. At present, the main rehabilitation methods of UHL include various kinds of bone conduction hearing aids, vibrant soundbridge and cochlear implantation, etc. However, the rehabilitation effect of UHL patients' ability to locate the sound source is affected by the occurrence age, the type, the degree and the duration of the hearing loss. The results of rehabilitation in different literature vary greatly. This paper reviews the effects of different rehabilitation strategies on the ability of sound location and analyzes its possible causes and mechanisms.

Impacto de la hipoacusia unilateral en el desarrollo del lenguaje

Background and objectiveEven if apparently unilateral hearing loss (UHL) goes unnoticed, it has been known for 40 years that its presence leads to academic and behavioural problems. Due to the shortage of published studies and the variability of the results, our purpose is to evaluate the impact of this condition by making a formal study of language in children with UHL, analysing predisposing factors and including the parents’ point of view. MethodsA group of 16 children between 3 to 15 years old were selected; all had an early diagnosis of prelingual UHL, with a variability in grade and type. Several language tests have been applied: “EMLE”, “EDAF”, “PLON-R/BLOC-SR” and “Evaluación Fonológica del habla infantil” (Laura Bosch). In addition, we obtained the parents’ opinion about the impact on their children's language development with UHL, through an ad hoc questionnaire. ResultsRegardless of the impaired ear, the grade and type of UHL, the global development of language showed a normal range, which improved with age and possibly depends on the socio-educational level of the family. The main alterations were found in morphosyntax. In profound UHL, the outcome in the phonological registry and in reading and writing are lower than in the other categories. According to the parental questionnaire responses, more educational and speech language support is required and some behavioural changes were also detected, mostly at school. ConclusionsOnly a few language alterations were detected; we realize that parents do not attach much importance to this deficit. Although the impact of UHL on the development of a specific child cannot be determined, for prevention information is essential on possible consequences, as well as early detection of any variation through close monitoring, speech and hearing therapy.

An Unusual Cause of Unilateral Profound Hearing Loss and Disabling Tinnitus - A Case Report

An Unusual Cause of Unilateral Profound Hearing Loss and Disabling Tinnitus - A Case Report

Cochlear Implants in Patients with Fluctuant or Progressive Hearing Loss on the Better Ear.

Introduction Cochlear implants have been proposed for cases of unilateral hearing loss, especially in patients with tinnitus impairment. Several studies have shown that they result in definite improvement of sound localization and speech understanding, both in quiet and noisy environments. On the other hand, there are few references regarding cochlear implants in patients whose better ears present hearing loss. Objective To report the audiological outcomes of three patients with unilateral deafness, in whom the better ears presented hearing losses, submitted to cochlear implants. Methods Three patients with unilateral profound hearing loss underwent a cochlear implant performed by the same surgeon. Results The patients' data are presented in detail. Conclusion The indications for cochlear implants are becoming more diverse with the expansion of clinical experience and the observation that they definitely help patients with special hearing problems.

Hearing with One Ear: Consequences and Treatments for Profound Unilateral Hearing Loss.

There is an increasing global recognition of the negative impact of hearing loss, and its association to many chronic health conditions. The deficits and disabilities associated with profound unilateral hearing loss, however, continue to be under-recognized and lack public awareness. Profound unilateral hearing loss significantly impairs spatial hearing abilities, which is reliant on the complex interaction of monaural and binaural hearing cues. Unilaterally deafened listeners lose access to critical binaural hearing cues. Consequently, this leads to a reduced ability to understand speech in competing noise and to localize sounds. The functional deficits of profound unilateral hearing loss have a substantial impact on socialization, learning and work productivity. In recognition of this, rehabilitative solutions such as the rerouting of signal and hearing implants are on the rise. This review focuses on the latest insights into the deficits of profound unilateral hearing impairment, and current treatment approaches.

Early Prelingual Auditory Development of Infants and Toddlers With Unilateral Hearing Loss.

To assess the influence of congenital and permanent unilateral hearing loss (UHL) on early prelingual auditory development (EPLAD) of infants and toddlers. A cross-sectional and case-controlled design. Tertiary referral center. Sixty-five young children (median with interquartile ranges: 4.4 [3.3, 7.7] mo) with UHL, 70 children (6.0 [3.8, 9.0] mo) with bilateral normal hearing (BNH) and 32 children (5.8 [3.9, 12.1] mo) with bilateral mild hearing loss (BMHL) were enrolled and grouped. Children with UHL were further grouped according to the severity of impairment and the ear that was impaired. Children involved were assessed by the 9-item Infant-toddler Meaningful Auditory Integration Scale (ITMAIS). 1) EPLAD assessed by ITMAIS, 2) functions of sound detection, sound discrimination and identification and preverbal vocalization assessed by dividing ITMAIS into three sections, 3) trajectories of EPLAD estimated by ITMAIS. Compared with BNH, children with UHL lagged behind in the function of sound discrimination and identification, preverbal vocalization, as well as trajectory of EPLAD. Children with severe to profound UHL exhibited more severe EPLAD handicaps than children with mild to moderate losses. The auditory functions and EPLAD trajectory of children with UHL were similar to those with BMHL. Children with congenital and permanent UHL demonstrate delays in EPLAD, which are evident soon after birth before initial development of speech and language. The ITMAIS is an appropriate tool to identify these delays both in children with unilateral and bilateral hearing impairment.

Effects of Simulated and Profound Unilateral Sensorineural Hearing Loss on Recognition of Speech in Competing Speech

Unilateral hearing loss (UHL) is a condition as common as bilateral hearing loss in adults. Because of the unilaterally reduced audibility associated with UHL, binaural processing of sounds may be disrupted. As a consequence, daily tasks such as listening to speech in a background of spatially distinct competing sounds may be challenging. A growing body of subjective and objective data suggests that spatial hearing is negatively affected by UHL. However, the type and degree of UHL vary considerably in previous studies. The aim here was to determine the effect of a profound sensorineural UHL, and of a simulated UHL, on recognition of speech in competing speech, and the binaural and monaural contributions to spatial release from masking, in a demanding multisource listening environment. Nine subjects (25 to 61 years) with profound sensorineural UHL [mean pure-tone average (PTA) across 0.5, 1, 2, and 4 kHz = 105 dB HL] and normal contralateral hearing (mean PTA = 7.2 dB HL) were included based on the criterion that the target and competing speech were inaudible in the ear with hearing loss. Thirteen subjects with normal hearing (19 to 60 years; mean left PTA = 4.1 dB HL; mean right PTA = 5.5 dB HL) contributed data in normal and simulated "mild-to-moderate" UHL conditions (PTA = 38.6 dB HL). The main outcome measure was the threshold for 40% correct speech recognition in colocated (0°) and spatially and symmetrically separated (±30° and ±150°) competing speech conditions. Spatial release from masking was quantified as the threshold difference between colocated and separated conditions. Thresholds in profound UHL were higher (worse) than normal hearing in separated and colocated conditions, and comparable to simulated UHL. Monaural spatial release from masking, that is, the spatial release achieved by subjects with profound UHL, was significantly different from zero and 49% of the magnitude of the spatial release from masking achieved by subjects with normal hearing. There were subjects with profound UHL who showed negative spatial release, whereas subjects with normal hearing consistently showed positive spatial release from masking in the normal condition. The simulated UHL had a larger effect on the speech recognition threshold for separated than for colocated conditions, resulting in decreased spatial release from masking. The difference in spatial release between normal-hearing and simulated UHL conditions increased with age. The results demonstrate that while recognition of speech in colocated and separated competing speech is impaired for profound sensorineural UHL, spatial release from masking may be possible when competing speech is symmetrically distributed around the listener. A "mild-to-moderate" simulated UHL decreases spatial release from masking compared with normal-hearing conditions and interacts with age, indicating that small amounts of residual hearing in the UHL ear may be more beneficial for separated than for colocated interferer conditions for young listeners.

Cross-modal plasticity in adult single-sided deafness revealed by alpha band resting-state functional connectivity

Single-sided deafness (SSD) or profound unilateral hearing loss is the condition where the transfer of acoustic information to the brain is restricted to one ear. SSD impairment is most evident under adverse acoustic environments with overlapping interference, which burdens cognitive resources. It is known that bilateral deafness induces cross-modal brain plasticity within visual cortical areas. Here we investigate whether similar cross-modal plasticity is observed in adult-onset SSD. In SSD patients (n ​= ​29) and matched controls (n ​= ​29) we estimated voxel level resting-state power and functional connectivity in the alpha band (8–12 ​Hz) from magnetoencephalography (MEG) data. We examined both global functional connectivity (mean functional connectivity of each voxel with the rest of the brain), and seeded functional connectivity of primary auditory cortices (A1), primary visual cortices (V1) and posterior cingulate cortex (PCC) of the default mode network (DMN). Power reduction was observed in left auditory cortex. Global functional connectivity showed reduction in frontal cortices and enhancement in visual cortex. Seeded functional connectivity of auditory cortices showed reduction in temporal, frontal and occipital regions, and enhancement in parietal cortex. Interestingly, seeded functional connectivity of visual cortices showed enhancement in visual cortices, inferior parietal lobe, post-central gyrus, and the precuneus, and reduction in auditory cortex. Seeded functional connectivity of PCC showed reduction in frontal cortical regions that are part of the DMN, attention, and working memory networks. Adult-onset SSD exhibited widespread cross-modal brain plasticity involving alterations in auditory, visual, attention, working memory and default mode networks.

Imaging findings in pediatric single-sided deafness and asymmetric hearing loss.

To examine the imaging findings on computer tomography (CT) and magnetic resonance imaging (MRI) in pediatric single-sided deafness (SSD) and asymmetric hearing loss (ASH). The medical records of 189 pediatric patients with SSD and ASH were retrospectively reviewed, and imaging findings were compared. SSD was defined as unilateral profound hearing loss and contralateral normal hearing ear. In the ASH group, ASHw was defined as the worse hearing ear with profound hearing loss, while ASHb was defined as the better hearing ear with mild-moderate hearing loss. There were 170 patients with SSD and 19 patients with ASH. In the SSD group, 83 patients (48.8%) had imaging findings associated with hearing loss. In the ASH group, such imaging findings were found in six (31.6%) of the ASHw and in five (26.3%) of the ASHb ears. The most common finding in the SSD group was cochlear nerve deficiency (50.6%), followed by cochlear dysplasia (39.8%) and enlarged vestibular aqueduct (26.5%). In the ASH groups, cochlear dysplasia was seen in three (50%) of ASHw ears and in two (40%) of the ASHb ears, and enlarged vestibular aqueduct was seen in three (50%) of ASHw ears and in two (40%) of the ASHb ears. Imaging studies identified the etiology in half of the cases of SSD and in one-third of ASH patients. Our findings strongly support the use of imaging studies in the evaluation of pediatric SSD and ASH. 4 Laryngoscope, 130:1007-1010, 2020.

Multifactorial positive influence of cochlear implantation on patients with single-sided deafness.

Single-sided deafness (SSD) is an extreme case with profound unilateral hearing loss in the poorer ear and regular hearing in the other ear. The aim of this study is to investigate the impairment in the daily life of SSD patients and the influence of cochlear implants (CI) on their health-related quality of life (HRQoL), the impact on existing tinnitus distress and psychological comorbidities, and audiometric parameters. In total, 21 patients (8 male and 13 female) were included, and the Charité Test Battery was applied for all patients. Data on HRQoL were collected with the Nijmegen Cochlear Implant Questionnaire and the Medical Outcome Study Short Form 36 (SF-36) Survey. Tinnitus distress was assessed with the Tinnitus Questionnaire (TQ). Data with regard to psychological comorbidities were collected using four validated questionnaires. Speech perception was assessed with the Freiburg Monosyllable Test (FMS), the Oldenburg Sentence Test (OLSA), and the Oldenburg Inventory (OI). HRQoL improved in the subdomain social interactions. Tinnitus distress dropped significantly 6 months postoperatively. SSD patients preoperatively showed elevated levels of stress, depressive symptoms, and anxiety. Postoperatively, these psychological symptoms improved with regard to stress, tension, and demands. The audiometry tools revealed a significant improvement in directional hearing (OI), speech perception in silence, and in the speech intelligibility threshold (OLSA). There was an improvement in HRQoL and a reduction of tinnitus and cognitive distress. The preoperatively elevated stress level decreased significantly, and psychological comorbidities such as depressive symptoms and anxiety all improved postimplantation. II-2 Laryngoscope, 130:500-506, 2020.

Binaural advantages in using a cochlear implant for adults with profound unilateral hearing loss

Background: Recent studies of cochlear implants (CIs) in profound unilateral hearing loss (UHL) patients have demonstrated a restoration of some binaural hearing.Aims/Objectives: The objective was to evaluate three possible advantages of binaural hearing in CIs adult users with UHL including single-side deafness (SSD) and asymmetric hearing loss (AHL) subgroups.Material and methods: A prospective study was conducted that included 70 sequentially implanted patients. Subgroups of these subjects included 64 with a postlingual onset of a profound hearing loss on the implanted side and 6 with a prelingual onset of that loss. Three binaural effects – redundancy, head shadow, and squelch – were evaluated.Results: Significant differences between the ‘CI on’ and ‘CI off’ conditions were found for all three binaural effects for the study group as a whole and for the postlingual subgroup. However, results for the subjects in the prelingual subgroup did not demonstrate any of the binaural advantages.Conclusion and significance: Patients with a postlingual onset of a profound hearing loss in one ear and normal hearing or only a moderate loss in the other ear are able to make the effective use of a CI in the profound-loss ear in conjunction with acoustic stimulation of the other ear.