Effect of cochlear implant electrode insertion on middle-ear function as measured by intra-operative laser Doppler vibrometry

Hypothesis: The aim of this study was to investigate the impact of cochlear implant electrode insertion on middle-ear low frequency function in humans.Background: Preservation of residual low frequency hearing with addition of electrical speech processing can improve the speech perception abilities and hearing in noise of cochlear implant users. Preservation of low frequency hearing requires an intact middle-ear conductive mechanism in addition to intact inner-ear mechanisms. Little is known about the effect of a cochlear implant electrode on middle-ear function.Methods: Stapes displacement was measured in seven patients undergoing cochlear implantation. Measurements were carried out intra-operatively before and after electrode insertion. Each patient acted as his or her own control. Sound was delivered into the external auditory canal via a speaker and calibrated via a probe microphone. The speaker and probe microphone were integrated into an individually custom-made ear mould. Ossicular displacement in response to a multisine stimulus at 80 dB SPL was measured at the incudostapedial joint via the posterior tympanotomy, using an operating microscope mounted laser Doppler vibrometry system.Results: Insertion of a cochlear implant electrode into the scala tympani had a variable effect on stapes displacement. In three patients, there was little change in stapes displacement following electrode insertion. In two patients, there was a significant increase, while in a further two there was a significant reduction in stapes displacement. This variability may reflect alteration of cochlear impedance, possibly due to differing loss of perilymph associated with the electrode insertion.Conclusion: Insertion of a cochlear implant electrode produces a change in stapes displacement at low frequencies, which may have an effect on residual low frequency hearing thresholds

Effectiveness of the Auditory Temporal Ordering and Resolution Tests to Detect Central Auditory Processing Disorder in Adults With Evidence of Brain Pathology: A Systematic Review and Meta-Analysis

Background: Auditory temporal processing tests are key clinical measures in order to diagnose central auditory processing disorder (CAPD). Although these tests have been used for decades, there is no up-to-date evidence to determine the effectiveness of detecting the abnormalities in central auditory processing in adults while the available national CAPD guidelines predominantly address CAPD in the pediatric population. Purpose: To determine the efficacy of the auditory temporal ordering tests [duration pattern test (DPT) and frequency pattern test (FPT)], and a temporal resolution test [gaps-in-noise (GIN) test] for detecting the central auditory processing abnormalities in adults with documented brain pathology. Research Design: Systematic reviews and meta-analyses. Study samples: Four databases, including PubMed, Web of Science, Embase, and Scopus, were systematically searched. The publications in the English language that recruited adults (above 16 years old) with pathologic brain conditions and described the diagnostic tests for auditory temporal processing were selected for review. Data Collections and Analysis: All data were systematically evaluated, extracted, categorized, and summarized in tables. The meta-analysis was done in order to determine the effectiveness of the DPT, FPT, and GIN tests. Results: The results showed significantly poorer performance of DPT and FPT, compared between participants with confirmed brain disease and normal controls, at the mean differences of percent correct −21.93 (95% CI, −26.58 to −17.29) and −31.37 (95% CI, −40.55 to −22.19), respectively. Subjects with brain pathology also performed poorer in GIN test at the mean difference of 3.19 milliseconds (95% CI, 2.51 to 3.87). Conclusion: The results from the meta-analysis provide evidence that DPT, FPT, and GIN clinical measures are effective in the diagnosis of CAPD in adults with neurological disorders. Poor performance on these tests is significantly related to the confirmed brain pathology. However, different units in results presentation and variety of testing strategies are limitations for this meta-analysis. The standard pattern of result reporting and international protocols test strategies should be developed in order to conduct better meta-analyses with a larger collection of suitable studies and less heterogeneity

Non-verbal sound processing in the primary progressive aphasias

Little is known about the processing of non-verbal sounds in the primary progressive aphasias. Here, we investigated the processing of complex non-verbal sounds in detail, in a consecutive series of 20 patients with primary progressive aphasia [12 with progressive non-fluent aphasia; eight with semantic dementia]. We designed a novel experimental neuropsychological battery to probe complex sound processing at early perceptual, apperceptive and semantic levels, using within-modality response procedures that minimized other cognitive demands and matching tests in the visual modality. Patients with primary progressive aphasia had deficits of non-verbal sound analysis compared with healthy age-matched individuals. Deficits of auditory early perceptual analysis were more common in progressive non-fluent aphasia, deficits of apperceptive processing occurred in both progressive non-fluent aphasia and semantic dementia, and deficits of semantic processing also occurred in both syndromes, but were relatively modality specific in progressive non-fluent aphasia and part of a more severe generic semantic deficit in semantic dementia. Patients with progressive non-fluent aphasia were more likely to show severe auditory than visual deficits as compared to patients with semantic dementia. These findings argue for the existence of core disorders of complex non-verbal sound perception and recognition in primary progressive aphasia and specific disorders at perceptual and semantic levels of cortical auditory processing in progressive non-fluent aphasia and semantic dementia, respectively

Auditory Rehabilitation after Stroke: Treatment of Auditory Processing Disorders in Stroke Patients with Personal Frequency-Modulated (FM) Systems

Purpose: Auditory disability due to impaired auditory processing (AP) despite normal pure-tone thresholds is common after stroke, and it leads to isolation, reduced quality of life and physical decline. There are currently no proven remedial interventions for AP deficits in stroke patients. This is the first study to investigate the benefits of personal frequency-modulated (FM) systems in stroke patients with disordered AP. Methods: Fifty stroke patients had baseline audiological assessments, AP tests and completed the (modified) Amsterdam Inventory for Auditory Disability (AIAD) and Hearing Handicap Inventory for Elderly (HHIE) questionnaires. Nine out of these fifty patients were diagnosed with disordered AP based on severe deficits in understanding speech in background noise but with normal pure-tone thresholds. These nine patients underwent spatial speech-in-noise testing in a sound-attenuating chamber (the “crescent of sound”) with and without FM systems. Results: The signal-to-noise-ratio (SNR) for 50% correct speech recognition performance was measured with speech presented from 0° azimuth and competing babble from ±90° azimuth. Spatial release from masking (SRM) was defined as the difference between SNRs measured with co-located speech and babble and SNRs measured with spatially separated speech and babble. The SRM significantly improved when babble was spatially separated from target speech, while the patients had the FM systems in their ears compared to without the FM systems. Conclusions: Personal FM systems may substantially improve speech-in-noise deficits in stroke patients who are not eligible for conventional hearing aids. FMs are feasible in stroke patients and show promise to address impaired AP after stroke

Auditory processing in patients with structural lesions of the brain.

This thesis investigated structure versus function in the central auditory nervous system (CANS) by using the lesion study approach and by utilising a validated clinical test battery for the assessment of auditory processing as well as self- or parent report measures. The central auditory test results were correlated with the macroscopical appearance of the CANS on brain MRI and with patient reported hearing difficulties. The two regions of interest for this study were the insula (first group of studies) and the interhemispheric pathway, comprised by the corpus callosum and the anterior commissure (second group of studies). First group of studies: Patients with a history of ischemic or haemorrhagic cerebral stroke of the CANS were identified by their scans. Exclusion criteria were significant psychiatric or expressive language disorders. Second group of studies: Adults and children with congenital aniridia and abnormality of the interhemispheric pathway due to a PAX6 mutation were recruited. The assessment included questionnaire of auditory capabilities, baseline audiometry (pure tone audiometry, tympanometry and otoacoustic emissions) and central auditory tests (speech and non-speech). The brain MRIs of these patients were visually inspected (1st and 2nd group of studies). The corpus callosum area was measured in the children participants of the 2nd group of studies

Case Report: Auditory Neuropathy and Central Auditory Processing Deficits in a Neuro-Otological Case-Study of Infratentorial Superficial Siderosis

Hearing and balance impairment are the most frequently reported features of infratentorial (classical) superficial siderosis (iSS). There are few comprehensive descriptions of audiovestibular function in iSS and therefore limited understanding of the affected segment(s) of the audiovestibular pathway. In addition, monitoring disease progression and response to treatment is challenging and currently mainly guided by subjective patient reports and magnetic resonance imaging. To the best of our knowledge, there have been no previous reports assessing central auditory function in iSS. We describe such findings in a patient with iSS in an attempt to precisely localize the site of the audiovestibular dysfunction, determine its severity and functional impact. We confirm the presence of (asymmetrical) auditory neuropathy and identify central auditory processing deficits, suggesting involvement of the central auditory pathway beyond the brainstem. We correlate the audiological and vestibular findings with self-report measures and the siderosis appearances on brain magnetic resonance images

Auditory Phenotypic Variability in Friedreich's Ataxia Patients

Auditory neural impairment is a key clinical feature of Friedreich's Ataxia (FRDA). We aimed to characterize the phenotypical spectrum of the auditory impairment in FRDA in order to facilitate early identification and timely management of auditory impairment in FRDA patients and to explore the relationship between the severity of auditory impairment with genetic variables (the expansion size of GAA trinucleotide repeats, GAA1 and GAA2), when controlled for variables such as disease duration, severity of the disease and cognitive status. Twenty-seven patients with genetically confirmed FRDA underwent baseline audiological assessment (pure-tone audiometry, otoacoustic emissions, auditory brainstem response). Twenty of these patients had additional psychophysical auditory processing evaluation including an auditory temporal processing test (gaps in noise test) and a binaural speech perception test that assesses spatial processing (Listening in Spatialized Noise-Sentences Test). Auditory spatial and auditory temporal processing ability were significantly associated with the repeat length of GAA1. Patients with GAA1 greater than 500 repeats had more severe auditory temporal and spatial processing deficits, leading to poorer speech perception. Furthermore, the spatial processing ability was strongly correlated with the Montreal Cognitive Assessment (MoCA) score. To our knowledge, this is the first study to demonstrate an association between genotype and auditory spatial processing phenotype in patients with FRDA. Auditory temporal processing, neural sound conduction, spatial processing and speech perception were more severely affected in patients with GAA1 greater than 500 repeats. The results of our study may indicate that auditory deprivation plays a role in the development of mild cognitive impairment in FRDA patients

Experiences of Patients With Auditory Processing Disorder in Getting Support in Health, Education, and Work Settings: Findings From an Online Survey

OBJECTIVE: To explore the views and experiences of individuals with Auditory Processing Disorder (APD) and/or their families in getting support from services and to receive their suggestions for improvement. DESIGN: Cross-sectional random sample survey with descriptive analysis. SETTINGS: Online survey. PARTICIPANTS: One hundred and fifty six individuals with APD and/or their family members from the APD Support UK patient support organization and four associated APD Facebook groups. MAIN OUTCOME MEASURE: A 16-item questionnaire on negative and positive experiences in getting a referral for diagnosis, funding for the FM system, and overall support for APD. RESULTS: The key findings that emerged included reports of difficulty in getting a referral for diagnosis (54%), obtaining funding for an FM system (45%), getting support for APD (61%), and poor recognition and awareness of APD (63%) in Education, Health or Work settings. The positive experiences reported were ease in getting a referral for diagnosis (46%), in obtaining an FM system (20%), and with diagnosis leading to help at school or to a better understanding of the condition and the required adjustments. The recommended improvement areas were raising awareness of APD and related management in Education (30%), the Health sector (25%), and the public (18%). CONCLUSIONS: Individuals and families of individuals with APD overwhelmingly report a lack of awareness of APD across health, education, and work sectors, and difficulties in getting access to diagnosis and support. This information may provide an initial understanding of the patients' needs for clinical services for APD, identify research priorities, and influence longer-term public health decisions toward improved care