Flat Sensorineural Hearing Loss Research Articles

Effect of Frequency Discrimination Training on Tinnitus in Individuals with Flat Sensorineural Hearing loss.

Tinnitus is associated with sensorineural hearing loss irrespective of its severity and configuration. Frequency discrimination training is a contemporary method used for the treatment of tinnitus. However, its efficacy in treating tinnitus associated with flat sensorineural hearing loss is not studied yet. The objectives were to assess (a) treatment effect across sessions on tinnitus percept using subjective questionnaires (b) association in the severity and handicap of tinnitus before and after FDT treatment. A total of 16 participants with mean age of 56years, who had subjective tinnitus and flat sensorineural hearing loss ranging from mild to moderate were included in the study. However, only 11 participants completed the treatment regime. Each participant was provided FDT in a game format for 15days. The Quantitative (tinnitus pitch and loudness in each session) and qualitative measurements (THI and TFI) were assessed in each participant. Friedman test revealed a significant reduction in handicap from tinnitus as reflected in THI and reduced functionality impairment from tinnitus as reflected in TFI across sessions. Besides, a significant association was observed in the Chi-square test in severity and handicap of tinnitus before and after therapy. A change in pitch and reduced loudness was noted in eight of 11 participants. Three of them had no tinnitus perception at the end of the treatment regime. The current study findings demonstrate the efficacy of FDT using a game module in treating tinnitus associated with flat sensorineural hearing loss. The perceived severity and handicap of tinnitus reduces as a function of treatment.

Verbal Auditory Agnosia Developed after Unilateral Temporal Lobe Infarction

Stroke results in sudden loss of function related to its damaged portion. When this occurs in temporal lobe, the function of hearing and listening may be affected, although receptive language processing is affected while hearing perception is relatively spared. This is called as “central deafness.” It has been known that hearing ability is seldom impaired in the case of temporal lobe stroke except in the case of bilateral lesions. However, we experienced a 72-year-old, right-handed woman who presented with both sudden hearing difficulty due to unilateral temporal lobe infarctions after suddenly not being able to respond to any verbal questions except environmental sounds. Pure-tone audiometry showed both flat sensorineural hearing loss of mild degree in both ears but she could not understand any verbal sound. Brain MRI demonstrated extensive ischemic infarcts in the left temporal lobes involving primary auditory cortex. She was diagnosed as verbal auditory agnosia and has received speech-language therapy.

Efficacy of Directional Microphones in Hearing Aids Equipped with Wireless Synchronization Technology.

This study aimed to evaluate the use of directionality in hearing aids with wireless synchronization on localization and speech intelligibility in noise. This study included 25 individuals with bilateral mild to moderate flat sensorineural hearing loss. For the localization experiment, eight loudspeakers (Genelec 8020B) arranged in a circle covering a 0-360° angle and the Cubase 6 software were used for presenting the stimulus. A car horn of 260 ms was presented from these loudspeakers, one at a time, randomly. The listener was instructed to point to the direction of the source. The degree of the localization error was obtained with and without directionality and wireless synchronization options. For speech perception in a noise experiment, signal to noise ratio-50 (SNR-50) was obtained using sentences played through a speaker at a fixed angle of 0°. A calibrated eight-talker speech babble was used as noise and the babble was routed either through 0°, 90°, 270° (through one speaker at a time) or through both 90° and 270° speakers. The results revealed that the conditions where both the wireless synchronization and directionality were activated resulted in a significantly better performance in both localization and speech perception in noise tasks. It can be concluded that the directionality in the wireless synchronization hearing aids coordinates with each other binaurally for better preservation of binaural cues, thus reducing the localization errors and improving speech perception in noise. The results of this study could be used to counsel and justify the selection of the directional wireless synchronization hearing aids.

Effects of nonlinear amplification on differential sensitivity measures in individuals with cochlear hearing impairment

Objective: The current study focused on exploring the influence of multichannel amplification with wide dynamic range compression (WDRC) on frequency, intensity, and duration discrimination measures at two frequencies in different channels of amplification. Methods: Discrimination measures were performed on twenty ears with moderate flat sensorineural hearing loss using 2-down and 1-up adaptive procedure to achieve 70.7% response on the psychometric function. All stimuli were generated through AUX script and presented using Psycon version 2.18 experimental software and delivered through the speakers oriented at an angle of 0° azimuth. Discrimination measures were performed in both aided and unaided conditions for two pure tone frequencies of 750 and 1500 Hz with 500 ms duration (on/off ramp duration of 80 ms to avoid spectral splatter) presented at a level of 20 dBSL (with reference to the threshold separately in each condition). The responses were recorded through three interval alternative forced choice paradigm with visual feedback. An average of final four reversals out of eight was considered for discrimination threshold estimation. Results and Conclusions: Results revealed a statistically significant deterioration in intensity discrimination and a significant improvement in difference limen for frequency and duration with nonlinear amplification. The deteriorated intensity discrimination scores were explained in perspectives of WDRC acting in amplification device.

Clinical and Radiological Diagnosis of Rarely Seen OSMED Syndrome

Otospondylomegaepiphyseal dysplasia (OSMED) (MIM 215150) is an autosomal recessive syndrome. It is a skeletal dysplasia characterized by multiple skeletal anomalies, flat nasal bridge, mid-face hypoplasia, anteverted nostrils and sensorineural hearing loss. In this case report, we evaluated a 3-year-old Turkish girl born to consanguineous parents. She had a medical history of bilateral sensorineural hearing loss, frontal bossing and strabismus. The radiographic findings supported OSMED syndrome with her phenotype. Our aim was to facilitate the early diagnosis of this rarely seen syndrome and to contribute to the natural history of patients with OSMED syndrome. J Med Cases. 2016;7(5):161-163 doi: http://dx.doi.org/10.14740/jmc2431w

Cortical auditory evoked potentials in children using hearing aids

Cortical auditory evoked potentials (CAEPs) are considered the electrophysiological equivalent of the pure tone audiogram (PTA) and can be used to assess the functional consequences of auditory deprivation and hearing aid acclimatization. Objectives: Threshold estimation and central auditory system evaluation in normal hearing children and those with hearing loss using cortical auditory evoked potentials. Study design: This work involved two groups: GI (20 normal hearing children) and GII (36 children with moderately-severe flat sensorineural hearing loss. The second group was divided into two subgroups: GIIa (20 children fitted with hearing aids) and GIIb (16 children not yet fitted with a hearing aid). Methodology: Basic audiological evaluation and CAEPs using speech and tone stimuli were performed and compared. The latencies and amplitude of different CAEP components were compared between both groups at the same sensation level. Results: GIIb showed a larger difference at 500 Hz compared to other frequencies, in contrast to GI and GIIa. CAEP latencies were significantly delayed in GIIb compared to GI or GIIa but CAEP amplitude showed no significant difference. Conclusions: Tone or speech evoked-cortical potentials can be used for threshold estimation in children with a high degree of consistency across different frequencies. Hearing aids can impact on cortical processing of simple or complex stimuli.

Ranking Hearing Aid Input–Output Functions for Understanding Low-, Conversational-, and High-Level Speech in Multitalker Babble

To determine the rankings of 6 input-output functions for understanding low-level, conversational, and high-level speech in multitalker babble without manipulating volume control for listeners with normal hearing, flat sensorineural hearing loss, and mildly sloping sensorineural hearing loss. Peak clipping, compression limiting, and 4 wide dynamic range compression (WDRC) input-output functions were compared in a repeated-measure design. Interactions among the compression characteristics were minimized. Speech and babble were processed and recorded at 3 input levels: 45, 65, and 90 dB sound pressure level. Speech recognition of 3 groups of listeners (n = 6/group) was tested for speech processed by each input-output function and at each input level. Input-output functions that made low-level speech audible and high-level speech less distorted by avoiding peak clipping or severe compression yielded higher speech recognition scores. These results are consistent with previous findings in the literature. WDRCs with the low compression ratio region extended to a high input level or with a high compression limiting threshold were the best for speech recognition in babble when the hearing aid user cannot or does not want to manipulate the volume control. Future studies on subjective preferences of different input-output functions are needed.

Cochlear Function in Ears with Immunomediated Inner Ear Disorder

The aim of the present study was to evaluate the performance of ears with inner ear disorder, responsive to immunosuppressive drugs, in advanced tests designed to assess primary cochlear functions (temporal integration, frequency selectivity, cochlear mechanics). The results of this study suggest that immunomediated inner ear disease results, in the acute clinical stage, in the development of endolymphatic hydrops, which increases the stiffness of the vibrating structures within the inner ear and causes dysfunctions of the outer hair cells. Our patients presented with upsloping or flat sensorineural hearing loss, absence of evoked otoacoustic emissions and distortion-product otoacoustic evoked emissions and abnormal temporal integration, frequency selectivity and cochlear mechanics. Following immunosuppressive treatment, hydrops recovered, hearing subsequently returned to normal, the audiometric curve became flat at low-to-middle frequencies and primary cochlear function tended to normalize. This study seems to support the usefulness of testing primary cochlear functions in order to monitor the clinical course of immunomediated inner ear disorders.

Auditory brain stem responses in patients with human immunotropic virus infection of different stages.

Thirty patients (26 men, 4 women) with human immunotropic virus infection of different stages were examined. Eleven patients had a history of i.v. drug abuse, nine patients had a history of treated lues infection, and one patient suffered from Kaposi's sarcoma. At the time of the examination, opportunistic infections or acute encephalitis were not apparent in any patient. All patients underwent otoneurological examinations, including pure-tone audiometry, caloric vestibular testing, and recording of the auditory brain stem responses (ABR). Six patients reported onset of hearing impairment during the last 3 yr. Two of them had flat sensorineural hearing loss; in the other cases, pure-tone audiometry showed high tone hearing loss with negative recruitment. ABRs were normal in 19 cases, with the latencies for waves III and V and for the I-V interpeak latency significantly delayed when compared to the values of the control group. The frequency of abnormal ABR findings did not correlate to the stage of the disease. The results of the study indicate that auditory and, more specifically, ABR abnormalities commonly occur in human immunotropic virus disease. More studies are necessary to prove whether the ABR is suitable to monitor therapeutic effects.

Tone detection and synthetic speech discrimination in band-reject noise by hearing-impaired listeners.

Frequency resolution was evaluated for two normal-hearing and seven hearing-impaired subjects with moderate, flat sensorineural hearing loss by measuring percent correct detection of a 2000-Hz tone as the width of a notch in band-reject noise increased. The level of the tone was fixed for each subject at a criterion performance level in broadband noise. Discrimination of synthetic speech syllables that differed in spectral content in the 2000-Hz region was evaluated as a function of the notch width in the same band-reject noise. Recognition of natural speech consonant/vowel syllables in quiet was also tested; results were analyzed for percent correct performance and relative information transmitted for voicing and place features. In the hearing-impaired subjects, frequency resolution at 2000 Hz was significantly correlated with the discrimination of synthetic speech information in the 2000-Hz region and was not related to the recognition of natural speech nonsense syllables unless (a) the speech stimuli contained the vowel /i/ rather than /a/, and (b) the score reflected information transmitted for place of articulation rather than percent correct.

Effect of monaural hearing aid use on dichotic test results for individuals with high-frequency hearing impairment.

It is well documented that the majority of individuals with normal hearing have a right ear advantage for dichotic speech material. There is evidence, however, that individuals with flat sensorineural hearing loss demonstrate a left ear advantage after they have used amplification on the left side. The present study examined whether these findings could be extended to a population with high-frequency hearing impairment. The subjects were administered dichotic consonant-vowel syllable tests prior to a monaural hearing aid fitting, and the tests were repeated after 1 month and again after 6 months of hearing aid use. The results revealed a group right ear advantage prior to the hearing aid fitting, although there was considerable individual variability. No consistent changes in the test scores were shown to be associated with monaural hearing aid use in either the right ear or the left ear.

Influence of age and hearing loss on the latency shifts of the auditory brainstem response as a result of increased stimulus rate.

Latency shifts of auditory brainstem response waves, I, III and V were studied as a function of increasing the stimulus repetition rate from 9 to 21, 42 and 63/s. There appears to be an accumulative retardation of the successive waves when faster click rates are administered that yield a prolongation of the interpeak intervals I-III and III-V. The effect on wave V and on the interpeak interval III-V seems to intensify with age (especially over 55 years). In ears with a flat sensorineural hearing loss, the adaptation of waves III and V is found to be somewhat smaller than in normal ears at the same intensity in dB SPL.

Frequency selectivity and consonant intelligibility in sensorineural hearing loss.

The relations between frequency selectivity and consonant intelligibility were investigated in subjects with sensorineural hearing loss in an attempt to derive predictive indices. Three matched pairs of subjects with similar audiometric configurations (high-frequency, flat or low-frequency hearing loss) but significantly different word-intelligibility scores were tested. Characteristics of psychophysical tuning curves (PTCs) for high- and low-frequency probes were compared with speech-intelligibility performance for high- and low-frequency consonant-vowel syllables. Frequency-specific relations between PTC characteristics and consonant-intelligibility performance were observed in the subject pairs with high-frequency and flat sensorineural hearing loss. Corresponding results for the subject pair with low-frequency sensorineural hearing loss were equivocal.

Pitfalls in myringoplasty.

The results of myringoplasty on 172 ears examined after an average follow-up time of 1.5 years are reported. The fascial underlay technique with swing-door plasty was employed in 78% of the cases. The graft take was successful in 150 ears (87%), three of which (2%) later revealed adhesive changes in the middle ear. Three ears were reoperated, the percentage of healed perforations being 89. A high tone hearing loss occurred in two ears and a moderate flat sensorineural hearing loss in another two (2%). Successful graft take was obtained in 92% of the operations performed by specialists and in 59% of the ears operated upon by residents. Successful myringoplasty presupposes acquisition of a faultless surgical technique and strict adherence to it at all phases of surgery.

Audiological Assessment of Middle and Low Frequency Thresholds by Brain Stem and Frequency Following Responses

The frequency specificity of the brain stem response (BSR) and the frequency-following response (FFR) evoked by 500Hz tone bursts were studied in 20 cases of flat, high-frequency and low-frequency hearing losses.In nine cases of flat sensorineural hearing loss, both the thresholds of the BSR and the FFR corresponded well to pure tone audiometric thresholds. In cases of both high- (five cases) and low-frequency (six cases) sensorineural hearing losses, the threshold of the 500Hz FFR corresponded well to the pure tone audiometric thresholds at 500Hz. At the same time, the thresholds of the 500Hz BSR corresponded well to the pure tone audiometric thresholds at 500Hz and 1, 000Hz.Thus, our conclusion was that the FFR evoked by 500Hz tone bursts was applicable in the objective assessment of the hearing threshold at 500Hz. At the same time, the BSR evoked by 500Hz tone bursts was also applicable in the hearing thresholds at 500Hz and 1, 000Hz.

Simultaneous recordings of the brain stem response and the frequency-following response to low-frequency tone

The brain stem response (BSR) and the frequency-following response (FFR) evoked by 500 c/sec tone bursts were simultaneously recorded from the twenty normal hearing and twenty-eight hearing-impaired subjects. By reversing the stimulus phase and the polarity of the recordings, the BSR and FFR could also be recorded in isolation from one another. In normal hearing subjects the FFR could be recorded at intensities of 30 dB HL or 40 dB HL, while the BSR could be discerned at even lower stimulus levels. In cases of severe high frequency hearing loss, both the BSR and the FFR could be recorded at normally low stimulus levels which is inconsistent with the view that BSR and FFR originate from the basal turn of cochlea. In cases of flat conductive hearing loss, the discrepancies between the BSR thresholds and the FFR thresholds were in the normal range (20–30 dB), but in cases of flat sensorineural hearing loss, these discrepancies were absent or very small (within 10 dB). We attribute this to recruiting.

Dimensions of consonant perception in normal and hearing-impaired listeners.

Judgments of consonant similarity were obtained from subjects who had normal hearing, high-frequency sensorineural hearing loss, or relatively flat sensorineural hearing loss. The individual differences model through program INDSCAL was used to derive a set of perceptual features empirically from the similarity judgments, and to group the subjects on the basis of strength of feature usage. The analysis revealed that sonorance was the dominant dimension in the similarity judgments of the subjects with high-frequency hearing losses, while sibilance tended to dominate the judgments of the subjects with flat audiometric configurations. The normal-hearing subjects tended to weight these two dimensions approximately equally. These differences in similarity judgments were observed based upon audiometric configuration, despite the fact that the two hearing-impaired groups were not unique in word-recognition ability.