Biomedical subjects

S Arlinger

Publications and source records attributed to S Arlinger.

At least 37 records · Page 2Linked to original sources

PubMed1998

Dichotic speech tests.

When central auditory dysfunction is present, ability to understand speech in difficult listening situations can be affected. To study this phenomenon, dichotic speech tests were performed with test material in the Swedish language. Digits, spondees, sentences and consonant-vowel syllables were used as stimuli and the reporting was free or directed. The test material was recorded on CD. The study includes a normal group of 30 people in three different age categories; 11 years, 23-27 years and 67-70 years. It also includes two different groups of subjects with suspected central auditory lesions; 11 children with reading and writing difficulties and 4 adults earlier exposed to organic solvents. The results from the normal group do not show any differences in performance due to age. The children with reading and writing difficulties show a significant deviation for one test with digits and one test with syllables. Three of the four adults exposed to solvents show a significant deviation from the normal group.

Adult↗

PubMed1998

Non-linear signal processing in digital hearing aids.

Three different non-linear digital signal processing algorithms were developed; LinEar, DynEar and RangeEar. All three provided individual frequency shaping via a seven-band low-power filterbank and compression in two channels. RangeEar and DynEar used wide dynamic range syllabic compression in the low-frequency (LF) channel, while LinEar used compression limiting. In the high-frequency (HF) channel, RangeEar used a slow-acting automatic volume control, while DynEar and LinEar used compression limiting. Wearable digital signal processing-based experimental instruments were used to evaluate the fitting algorithms under real world conditions with experienced hearing aid users. Evaluation included laboratory testing of speech recognition in noise and questionnaires on sound quality ratings. Results did not indicate one general good-for-all algorithm, but different algorithms resulting in preference and performance depending on the hearing loss configuration. Preference for any of the new algorithms could be predicted based on auditory dynamic range measurements. It was hypothesized that the different preferences were affected by different susceptibility to masking of HF sounds by amplified LF sounds.

Adult↗

PubMed1998

Audiological disturbances caused by long-term exposure to industrial solvents. Relation to the diagnosis of toxic encephalopathy.

Sixty workers, consecutively admitted due to suspicion of solvent-induced chronic toxic encephalopathy (CTE), were investigated with pure-tone audiometry, determination of speech recognition of monosyllabic words and distorted speech and cortical response audiometry (CRA). Eighteen workers not exposed to occupational solvents and noise were also investigated. The scores in the distorted speech test were significantly lower and the CRA latencies were significantly longer in the solvent group than in the control group. There was no difference between the groups in the pure-tone and monosyllabic speech recognition tests. In the solvent group, 19 subjects had one or several pathological audiological test results (values exceeding the mean result of the control group by 2 SD). Independently of the audiological examination all the workers in the solvent group underwent the traditional clinical assessment of CTE, which is based on symptoms, history of exposure, clinical neurological examination and a neuropsychological investigation. They were classified in three groups--CTE, incipient CTE and non-CTE. There was no correlation between these groups and the audiological test results. A previous report on vestibular pathology in the same group of subjects and the present investigation on hearing deficits suggest that long-term exposure to solvents causes disturbances of the central pathways in the otovestibular system. Hitherto, no attention has been paid to these disturbances in the definition of the CTE syndrome.

Adult↗

PubMed1998

Phonological representation and speech understanding with cochlear implants in deafened adults.

In the present study cognitive performance in 15 deafened adult cochlear implant candidates was examined and related to level of speech understanding after 12 months of experience with the implant. The implant group performed on par with normal hearing controls in all cognitive tasks used in the study with one exception: Performance was significantly lower in cognitive tasks where use of a phonological representation of sound is a key task-demand. Observations of the implanted individuals' level of speech understanding indicate that only those individuals who, pre-operatively, were in possession of phonological representations comparable to that of normal hearing could follow and understand a speaker that was out of sight. The results are discussed with respect to (a) deterioration in the phonological representation of sounds as a function of absence of external auditory stimulation, and (b) the role of cognitive factors in predicting success in speech understanding with the implant.

Adult↗

PubMed1997

A digital filterbank hearing aid: predicting user preference and performance for two signal processing algorithms.

OBJECTIVE: In a series of experiments with a wearable binaural digital hearing aid, two hearing aid processing algorithms were compared. Both algorithms provided individual frequency shaping via a seven-band filterbank with compression limiting in the high-frequency channel. They differed in the processing of the low-frequency channel, using dynamic range compression for one (DynEar) and linear processing with compression limiting for the other (LinEar). In a pilot field test we found that LinEar/ DynEar preference based on use time could be predicted from auditory dynamic range data. For the subjects who preferred DynEar, the mean dynamic range was broader for low and mid frequencies and narrower for high frequencies, as compared with the LinEar preference subjects. These groupings were tested as predictors of user preference and performance in a main field test. DESIGN: The main study included 26 hearing aid users with symmetrical sensorineural losses. The algorithms were compared in a one-mo-long blind field test. A data logger function was included for objective recording of the total time each algorithm was used and how the volume controls were used. The preference was based on the time used for each algorithm and on subjective statements. Threshold signal-to-noise ratio (S/N-threshold) for speech was tested, and sound quality ratings were obtained through a questionnaire. We also tested the S/N-thresholds for the subjects' conventional (own) aids. RESULTS: The preference was correctly predicted by the dynamic range data on 12 out of 15 new cases. S/N-thresholds were lower for the preferred fittings compared with the nonpreferred fittings and with the subjects' own aids. In the questionnaire the preferred fittings were rated significantly higher in terms of overall impression and clearness. Because of the systematic way the DynEar-preference subjects adjusted the high-frequency DynEar gain, we speculate that upward spread of masking may have been a factor in preference and performance. Additionally, LinEar-preference subjects' preference and performance might have been influenced by excessive compression ratios with the DynEar processing in these cases. CONCLUSIONS: 1. Preference for DynEar versus LinEar depends on the auditory dynamic range. 2. S/N-thresholds for speech were better for the preferred fittings, which also were rated higher in terms of overall impression of sound quality and clearness.

Adult↗

PubMed1997

A digital filterbank hearing aid: three digital signal processing algorithms--user preference and performance.

OBJECTIVE: Three digital signal processing algorithms named RangeEar, DynEar, and LinEar were compared with regard to user preference and performance when a wearable digital filterbank hearing aid was used. All three algorithms provided individual frequency shaping via a seven-band filterbank. Compression was used in a low-frequency (LF) and a high-frequency (HF) channel. RangeEar and DynEar used wide dynamic range syllabic compression in the LF channel, whereas LinEar used compression limiting. In the HF channel, RangeEar used a slow acting automatic volume control, whereas DynEar and LinEar used compression limiting. The subjects had access to a manual volume control when using the LinEar or DynEar options. DESIGN: The study included 13 hearing aid users with symmetrical sensorineural losses. In a 1 mo long blind field test, the RangeEar algorithm was compared with the preferred algorithm from an earlier study, DynEar or LinEar. A data logger function was included for objective recording of the total time each algorithm was used and how the volume controls were used. The preference was based on the time used for each algorithm and from subjective statements. Threshold signal-to-noise ratio (S/N-threshold) for speech was tested, and sound quality ratings were obtained through a questionnaire. RESULTS: Of the 13 subjects, six preferred the RangeEar fitting and another four preferred the DynEar fitting. Two subjects preferred the LinEar fitting and one had equal preference for RangeEar and LinEar. The results from the questionnaire showed that the preferred fittings were rated higher concerning overall impression of sound quality and clearness, whereas the S/N for the speech test did not show any differences. Preferences, where stated, could be predicted from auditory dynamic range measurements in the LF and HF frequency ranges. The mean dynamic range was broader for low and narrower for high frequencies for those who preferred the RangeEar or DynEar fitting as compared with those who preferred the LinEar fitting. The preference between RangeEar and DynEar was predicted by differences in the HF range, with the narrower dynamic range for the DynEar preference subjects. CONCLUSION: Most subjects preferred the option of having a wide dynamic range syllabic compressor in the LF channel and having the overall gain in the HF channel adjustable, either manually (DynEar) or automatically (RangeEar).

Adult↗

PubMed1997

A digital filterbank hearing aid. Improving a prescriptive fitting with subjective adjustments.

Two fitting algorithms for linear hearing aids were compared using a wearable digital hearing aid in a one-month blind field test: a prescriptive method (POGO II) and a new algorithm, LinEar. Both used seven bands for frequency shaping, and two channel compression limiting. When fitting LinEar, the subjects individually adjusted the frequency response according to specified criteria. LinEar used a lower compression threshold setting than prescribed by POGO II. Eight subjects tested the two algorithms in a one-months blind field test as well as in the laboratory. The individual LF- and HF-gain adjustments of the frequency response in LinEar showed rather large variations compared to the POGO II prescription. Measures of S/N for speech did not show any significant differences between LinEar and POGO II, while overall sound quality ratings in laboratory and field test showed that LinEar was rated significantly higher than POGO II.

Adult↗

PubMed1997

Recent developments in air-conduction hearing aids.

From a history of hearing aids based on analog signal processing, the door has just opened to a new "room," the digital hearing aid room. Previously, the more complex signal processing schemes could be tested only at the lab and rarely in real-life environments. The advent of wearable digital hearing aids primarily means that we have much more powerful tools available now, allowing us to test various ideas for signal processing in true field tests over sufficient durations. Since the different processing schemes will be controlled by software (the program or algorithm that has been stored in the hearing aid), we will be able to design truly blind field tests for the comparison of different processing, thereby avoiding the bias for the new aid versus the old aid which has always plagued clinical trials of hearing aids thus far. It is not very likely that the digital era in hearing aids will solve all problems in a short time. I am convinced that we have just started on a slow process into this "digital room." What, precisely, we will find there of value is hard to tell, but I am equally convinced that the main effects will be of noticeable benefit to the user. It is also very likely that some of the lessons we will learn in our future digital experiments will be useful not only for air-conduction hearing aids, but also for other types of technical aids for the hearing-impaired and the deaf.

Air↗

PubMed1997

Immediate effects of middle ear pressure changes on the electrocochleographic recordings in patients with Menière's disease: a clinical placebo-controlled study.

OBJECTIVE: The aim of the study was to evaluate effects of middle ear pressure changes on the electrocochleographic responses in patients with well-defined Menière's disease. STUDY DESIGN AND INTERVENTIONS: The investigation was conducted as a placebo-controlled, randomized clinical study. Electrocochleographic measurements were performed before and after the insertion of a transtympanic ventilation tube and immediately after the exposure to active or placebo treatment. SETTING: The study was carried out in one secondary referral center and one tertiary referral center on an ambulatory basis. PATIENTS: Thirty-nine patients with well-defined Menière's disease were included in the study. MAIN OUTCOME MEASURES: The summating potential/action potential ratio of the electrocochleographic response complex was chosen as the main variable for statistical evaluation of results. Other parameters of the recordings such as responses to low-frequency burst stimulation also were evaluated. Subjective symptoms (e.g., vertigo, tinnitus, and aural pressure) were assessed before and after insertion of the ventilation tube and before and after exposure to treatment. RESULTS: A statistical difference was shown in the electrocochleographic response in the active group before and after exposure to middle ear pressure changes. In the placebo group, no change was found. Changes in electrocochleographic parameters in the active group indicated an improvement in inner ear electrophysiology. No significant changes were found in subjective symptoms in the active or the placebo group. Evaluation before and after insertion of the ventilation tube showed no significant improvement in any variable. CONCLUSIONS: This is the first study in which electrophysiologic parameters were evaluated in a placebo-controlled clinical trial of overpressure treatment in Menière's disease. The results show that electrophysiologic parameters can be improved by the application of positive pressure pulses of low amplitude in the middle ear.

Adult↗

PubMed1996

Verbal information-processing capabilities and cochlear implants: implications for preoperative predictors of speech understanding.

In this study, we examined preoperative verbal cognitive capacity in 11 deafened adults who were cochlear implant candidates and reexamined level of speech understanding after 6-8 months' experience with the implant. Verbal cognitive performance in the implant group was compared in a group of normal hearing subjects and in nonimplanted group of deafened adults. The three groups performed on par with each other with an exception: The individuals in the cochlear implant group and the nonimplanted group of deafened adults performed significatly worse than those of normal hearing in tasks in which use of internal speech is a key feature (i.e., rhyme judgement and lexical decision tasks). Postoperative observations of the implanted individuals' level of speech understanding suggest that it is possible to predict the level of speech understanding by means of a properative cognitive assessment. The characteristics of three verbal cognitive abilities prove to be critical indicators of 6 - 8 months' postoperative outcome: internal speech functioning, speed of verval information processing, and working memory capacity - the first factor proved the most decisive. We discuss the results with respect to direct versus indirect predictors of outcomes from cochlear implant operations and the effect of auditory deprivation on deafened adults' capability to process auditory information.

Journal Article↗

PubMed1996

Report of the Eriksholm Workshop on auditory deprivation and acclimatization.

The terminology used in studies documenting changes in auditory performance following fitting of hearing aids has been diverse. Definitions for the auditory deprivation effect and auditory acclimatization are offered as a first step in rationalization. Two statements summarize current knowledge concerning auditory deprivation effects and auditory acclimatization, as well as considering the potential implications for research, field trial and clinical practice applications. Potential areas for future research are identified.

Auditory Perception↗

PubMed1996

Lipreading with auditory low-frequency information. Contextual constraints.

The present experimental study investigated potential relations among three variables: (1) an audiovisual speech signal (i.e., low-frequency supplemented lipreading as opposed to pure lipreading), (2) typical, as opposed to atypical, sentences in a particular script (e.g., in a restaurant), and (3) the presence/absence of additional context (in the particular script) in 60 normal hearing subjects. All three variables revealed significant main effects, but no interactions were observed. The general facilitatory effect for the audiovisual signal is in line with previous research, but this effect was relatively weak compared to the main effect of typicality, which relies on cognitive activation of scripts. In a separate analysis, the typicality variable was also the only variable that interacted significantly with speechreading skill, typical sentences being perceived relatively easier by the skilled as opposed to the less skilled individual. The clinical implications of cognitive factors in hearing-aid fitting procedures, the construction of speech materials, and selection of individuals for rehabilitation were discussed.

Humans↗

PubMed1996

Predictors of daily assessed hearing aid use and hearing capability using visual analogue scales.

Following the fitting of hearing aids, 53 patients rated themselves daily during one week on visual analogue scales dealing with aspects of the hearing aids (HA) and hearing capability. Before this, the prescribing audiology assistant categorized the patient into one of four groups depending on whether she thought the patient was going to be successful or not at home after the fitting. Also compared were the effects of type of audiogram, type of hearing aid and monaural or binaural fitting on the self-assessed and audiological variables. Finally, a series of multiple regressions were performed on the data set. The results showed that the audiology assistant could predict some aspects of HA usage, but not hearing capability. Patients rated the BTE and the ITC aids as clearer than the ITE aids, but a wide range of aids were prescribed making conclusions difficult. No clear effects were found for type of audiogram or type of fitting. Multiple regressions showed that clearness of sound in the HA was the most important variable in predicting the results on hearing capability. The use of repeated daily measures is recommended in research on the effects of HA fitting.

Aged↗

PubMed1995

Short term effects of induced middle ear pressure changes on the electrocochleogram in Menière's disease.

Electrocochleographic recordings were made in 17 patients with Menièr's disease before and immediately after exposure to pressure applications in their middle ear. The variables of the response to clicks such as the SP/AP ratio and the width of the complex as well as the amplitudes of the SP in response to long tone bursts were evaluated. Improvement of electrocochleographic recordings, characterized by normalization of the waveforms and reduction of the SP, was found to be significant. The results indicate a mechanoelectric change in the hydroptic cochlea registered directly after exposure to middle ear pressure changes.

Audiometry, Evoked Response↗

PubMed1993

8-channel digital filter bank for hearing aid use: preliminary results in monaural, diotic and dichotic modes.

A digital 8-channel signal processing system has been implemented using a TMS 320C25 signal processor. Tests with hearing-impaired subjects showed that the system allows a better fit to a specified frequency response than when using conventional aids with analog filtering. The filter bank has also been tested in dichotic listening experiments, where odd-number channels were fed to one ear and even-number channels to the other. The preliminary results on three hearing-impaired subjects in repeated tests of speech recognition in noise showed an improvement in the order of 2 dB in speech-to-noise ratio for 50% correct recognition as compared to the complete broadband signal presented diotically. Temporal splitting of the signal by periodically switching of the odd and even bands between left and right ears did not show any improvement.

Acoustic Stimulation↗

PubMed1992

Normal-hearing and hearing-impaired subjects' ability to just follow conversation in competing speech, reversed speech, and noise backgrounds.

The performance on a conversation-following task by 24 hearing-impaired persons was compared with that of 24 matched controls with normal hearing in the presence of three background noises: (a) speech-spectrum random noise, (b) a male voice, and (c) the male voice played in reverse. The subjects' task was to readjust the sound level of a female voice (signal), every time the signal voice was attenuated, to the subjective level at which it was just possible to understand what was being said. To assess the benefit of lipreading, half of the material was presented audiovisually and half auditorily only. It was predicted that background speech would have a greater masking effect than reversed speech, which would in turn have a lesser masking effect than random noise. It was predicted that hearing-impaired subjects would perform more poorly than the normal-hearing controls in a background of speech. The influence of lipreading was expected to be constant across groups and conditions. The results showed that the hearing-impaired subjects were equally affected by the three background noises and that normal-hearing persons were less affected by the background speech than by noise. The performance of the normal-hearing persons was superior to that of the hearing-impaired subjects. The prediction about lipreading was confirmed. The results were explained in terms of the reduced temporal resolution by the hearing-impaired subjects.

Audiometry↗

PubMed1992

Speech recognition in noise when wearing amplitude-sensitive ear-muffs.

Speech recognition in background noise when wearing amplitude sensitive (non-linear) ear muffs was studied in the laboratory in 15 young normal-hearing test subjects. Low-redundancy sentences were presented from a loudspeaker in a background noise level of 70 dB (A) and the speech-to-noise (S/N) ratio yielding 50% correctly recognized words was determined. Three background noise spectra were tested: white noise, low-pass filtered noise (-12 dB/octave) and high-pass filtered noise (12 dB/octave). Five listening conditions were used: no protectors, a pair of normal ear-muffs, a passive amplitude-sensitive ear-muff and two types of electronic amplitude-sensitive ear-muffs. An ANOVA shows that speech recognition is significantly influenced by type of hearing protector and by noise spectrum. The interaction between these factors was not statistically significant. In general, the test subjects obtained somewhat better speech recognition thresholds in noise when wearing electronic amplitude-sensitive ear muffs than without muffs, whereas the opposite was true for the passive amplitude-sensitive and the normal ear muffs.

Acoustic Stimulation↗

PubMed1990

Audiometric profile in presbycusis.

A group of 40 elderly subjects were evaluated using a variety of audiological tests. Their mean age was 68 years. They had all come to the clinic because of hearing problems. The subjects were selected for this study because no cause of their hearing loss could be found other than presbycusis. They all had the typical moderately sloping pure tone audiogram configuration. The pure tone average hearing loss (PTA, average of 0.5, 1 and 2 kHz) ranged from 11 to 70 dBHL with a median of 40. The average air-bone gap was 3 dB. In addition to pure tone audiometry the following tests were performed: most comfortable loudness level and uncomfortable loudness level for pure tone; stapedius reflex thresholds; speech recognition threshold and maximum speech recognition score in quiet; distorted speech recognition; detection thresholds for frequency and intensity glides of a pure tone; slow evoked cortical potentials in response to frequency and intensity glides of a pure tone. The test results, when compared with those obtained on young subjects with normal hearing and with cochlear lesions, show a mixture of characteristics typical of cochlear, retrocochlear and central lesions.

Aged↗