International Speech Test Signal Research Articles

Objective verification of audibility in bone conduction devices

Objective To objectively measure audibility in patients wearing bone conduction devices (BCDs) with a new approach using a skin microphone at the patient’s forehead. Design The skin microphone was attached by a softband and shielded by an earmuff. This set-up was confirmed not to be influenced by neither noise floor nor sound bypassing the BCD. Sound field warble tones were used for measuring aided hearing thresholds and maximum power output (MPO) whereas an international speech test signal (ISTS) was presented at different speech levels. Study sample 29 patients were tested (two were bilateral), 19 used percutaneous, eight used active transcutaneous and two used passive transcutaneous devices. Results The skin microphone responses at ISTS levels, hearing threshold and MPO, could be obtained in all patients. Two patients with poor audibility are highlighted in this article as examples. After adjusting the gain of the BCD, they were retested with the skin microphone (for verification) and with speech-in-noise tests (for validation). Both tests confirmed an improved audibility after the adjustments. Conclusion In summary, the proposed measurement of audibility of speech using a skin microphone is a promising method that can be used in a clinical setting for all types of BCDs.

Speech intelligibility and hearing aid benefit in a living room: Comparison of real and simulated acoustics

For hearing-impaired patients, a disparity between hearing aid benefit determined by conventional audiological assessment and observed in everyday life has been reported. Hence, ecologically valid testing methods to better reflect performance in real-world scenarios are required. Hereby, the living room is a highly relevant (home) environment for speech communication involving various target and interfering sources. This study examines speech intelligibility in an average German living room with a connected kitchen and acoustic reproductions of the real room using loudspeakers. Speech recognition thresholds were measured using the Oldenburg Sentence Test (OLSA) and a male-transformed version of the ISTS (International Speech Test Signal) as a masker. Aided and unaided hearing-impaired listeners, as well as a normal-hearing control group, participated. Three target positions were investigated, with the most challenging target position in the adjacent kitchen with an obstructed direct sound path. Interactive room acoustics simulation (allowing for head movements) was used to replicate the living room via a small-scale (four) loudspeaker array, as applicable in the clinical environment, and a large-scale, three-dimensional array with 86 loudspeakers. The study discusses the impact of room acoustics on speech intelligibility at different target positions and the relationship between real and simulated environments regarding hearing aid benefit.

Development of the Polish Speech Test Signal and its Comparison with the International Speech Test Signal

The aim of this study was to create a single-language counterpart of the International Speech Test Signal (ISTS) and to compare both with respect to their acoustical characteristics. The development procedure of the Polish Speech Test Signal (PSTS) was analogous to the one of ISTS. The main difference was that instead of multi-lingual recordings, speech recordings of five Polish speakers were used. The recordings were cut into 100–600 ms long segments and composed into one-minute long signal, obeying a set of composition rules, imposed mainly to preserve a natural, speech-like features of the signal. Analyses revealed some differences between ISTS and PSTS. The latter has about twice as high volume of voiceless fragments of speech. PSTS’s sound pressure levels in 1/3-octave bands resemble the shape of the Polish long-term average female speech spectrum, having distinctive maxima at 3–4 and 8–10 kHz which ISTS lacks. As PSTS is representative of Polish language and contains inputs from multiple speakers, it can potentially find an application as a standardized signal used during the procedure of fitting hearing aids for patients that use Polish as their main language.

Reliability and Validity of the Korean Matrix Sentence-in-Noise Recognition Test for Older Listeners with Normal Hearing and with Hearing Impairment

Purpose: The aim of this study was to examine test-retest reliability and validity of the adaptive Korean matrix sentence-in-noise test for elderly group with normal hearing (ENH) and elderly group with hearing impairment (EHI).Methods: Twenty ENH listeners and 20 EHI listeners based on the World Health Organization (WHO)-proposed hearing-impairment grade participated. For the test-retest reliability of the Korean matrix sentence-in-noise test, each subject was assessed twice in a 2-week interval using three types of noise: speech-shaped noise, International Collegium of Rehabilitative Audiology noise, and International Speech Test Signal. The test-retest agreement was judged by the intraclass correlation coefficient (ICC) and Bland-Altman plots. To differentiate between real change and random measurement error, the standard error of measurement (SEM) and the minimal detectable change (MDC) were also obtained as another reliability index. For the concurrent validity, the results of the Matrix test were compared to the results of the Korean-version Hearing In Noise Test (K-HINT).Results: The test-retest reliability was good to excellent for ENH and EHI groups (ICC, 0.84~0.98). Both groups showed stable reliability, but the ENH group showed smaller SEM and MDC values than the EHI group. No systematic errors were found from the Bland-Altman plots. The correlation between the results of the Matrix test and the K-HINT test was high, revealing good concurrent validity.Conclusion: The Korean matrix sentence-in-noise test appeared to be valid and reliable for the elderly. The Korean matrix sentence-in-noise test can be utilized for clinical measurement of the speech-in-noise ability of elderly individuals.

The Intelligibility of the Reversed-Stethoscope Technique in Age-Related Hearing Loss.

BackgroundThis study evaluated the effectiveness of the reverse stethoscope technique in improving speech intelligibility. In this technique, a clinician places the earpieces of their stethoscope into the ears of a hearing-impaired patient and speaks into the chest piece.MethodsThe International Speech Test Signal was presented to four Littman® stethoscope models and a Pocketalker® personal voice amplifier using an Audioscan® hearing instrument test box. The acoustic outputs of the stethoscopes and voice amplifier were measured across the frequency spectrum of speech. The Speech Intelligibility Index of the resulting speech was calculated for natural speech and for each device in relation to 10 standardized hearing losses representing the population of older adults.ResultsFor each of the 10 hearing losses, the speech signal emitted by the stethoscopes was quieter and yielded lower speech intelligibility scores than regular speech. In contrast, the voice amplifier provided mid- and high-frequency amplification and improved speech intelligibility scores for all but the mildest hearing losses.ConclusionsThe reverse stethoscope technique worsens the clarity of speech and should not be used with older, hearing-impaired patients. Instead, clinicians should use regular speech or, preferably, personal voice amplifiers.

Comparing the Effect of Digital Noise Reduction Technique on Frequency Gain of Behind-the-Ear Digital Hearing Aids

Background and Aim: Background noise as a serious challenge mainly affects the speech perception in people with hearing loss. One of the methods used to control noise is digital noise reduction (DNR) technique. The present study aimed to investigate the effect of DNR program (activated and deactivated) on the frequency gain of basic and advanced behind-the-ear (BTE) Oticon hearing aids, using different DNR strategies to reduce background noise.
 Methods: Two behind-the-ear Oticon hearing aids (Opn1 S105 and GetP) were used in this study. The Affinity 2.0 test box was first used to measure their DNR (off/on) gains using the national acoustic laboratories-non linear2 (NAL-NL2) and desired sensation level multi-stage [input/output] (DSLm[I/O]) formulas at sound pressure levels of 45, 65 and 85 dB SPL at a frequency range of 250-8000 Hz for three hearing loss (HL) patterns using the international speech test signal and broad band noise.
 Results: There was a significant difference in DNR performance between the Opn1 S105 and GetP models for all three HL patterns at 45 and 65 dB SPL and most frequencies.
 Conclusion: The DNR performance of advanced and basic hearing aids is different for different HLs at 45 and 65 dB SPL and most frequencies. The performance of advanced hearing aids is significant using the DSLm[I/O] formula at most frequencies.
 Keywords: Digital noise reduction; international speech test signal; frequency response; broad band noise

Test-retest Reliability of the Korean Matrix Sentence-in-noise Recognition in Sound-field Testing Condition

Purpose: This study aimed to measure the test-retest reliability of the Korean Matrix sentence-in-noise test in a sound-field testing condition.Methods: Fifty-five listeners with normal hearing participated. The sound-field speech-in-noise test was administered with a front loudspeaker by presenting noise at a fixed level (65 dB SPL) while adaptively adjusting the sentence level based on the listener’s response. The speech reception thresholds (SRTs) corresponding to 50% sentence-in-noise intelligibility were obtained using speech-shaped noise (SSN), International Collegium of Rehabilitative Audiology (ICRA) noise, and International Speech Test Signal (ISTS) noise. For the test-retest reliability, each subject was tested twice in a 2-week interval. The test-retest reliabilities were judged by the intraclass correlation coefficient (ICC), the minimal detectable change (MDC) values, and Bland-Altman plots.Results: The test-retest reliabilities of the Korean Matrix sentence test were good (ICC, 0.84~0.86) across SSN, ICRA, ISTS noises. The MDC was 0.92 dB SNR for SSN and 2.83 and 2.98 dB SNR for ICRA and ISTS, indicating the random measurement error varied across the types of noise.Conclusion: The Korean Matrix sentence-in-noise test can be used as a reliable tool to assess speech-in-noise intelligibility in sound-field testing condition. Further study across various sessions would strengthen the present finding.

Anticipating real-ear insertion response using an external auditory canal model

ObjectivesThis study aimed to determine the acoustic characteristics of the external auditory canal (EAC) and predict the real-ear aided response (REAR) using an EAC model that includes the standing wave effect. MethodsThe EAC transfer function equations were derived by summing the incoming and outgoing waves. First, we investigated the real-ear unaided gain (REUG). Second, seven patients (eight ears) wearing hearing aids (HAs) were enrolled as subjects to examine the REAR. We conducted wideband tympanometry (WBT) to measure the absorbance, the frequency response at 65 dB (65dB-FR) of the HAs, and the measured REAR for an international speech test signal (ISTS) at 65 dB. ResultsThe EAC model that includes the standing-wave effect is considered to be valid from examination of the REUG. A significant correlation was found between the measured and calculated REARs at 900 Hz, 1000 Hz, 2000 Hz, and 3000 Hz in an uncorrelated test. A two-way analysis of variance (ANOVA) found significant differences in the 65dB-FR and the measured REARs at 800, 900, 1000, and 2000 Hz, but this difference disappeared after correction of the calculated acoustic characteristics of the EAC. ConclusionsBy measuring the WBT characteristics and correcting them with an EAC model, the in-situ REAR can be determined from the HA characteristics in the mid-frequency range. There is a risk of insufficient HA amplification in the mid-frequency range when no real-ear measurements are performed.

A comparative study of the sound characteristics of hearing aids through the International Speech Test Signal.

A comparative study of the sound characteristics of hearing aids through the International Speech Test Signal.

Comparison of Preferred Real-Ear Insertion Gain between Open- and Closed-Canal Fitting Hearing Aids

Purpose: To calculate the real-ear insertion gain (REIG) according to the types of hearing aids, we evaluated the preferred REIGs of Korean hearing-impaired listeners and psychoacoustic differences between open-canal fitting (OF) and closed-canal fitting (CF).Methods: The subjects with sensorineural hearing loss were divided into OF group (4 monaural fittings, 15 binaural fittings with 34 ears), and CF group (8 monaural fittings, 13 binaural fittings with 34 ears). There were no statistical differences in hearing threshold level (HTL) at each octave frequencies, word recognition score (WRS) and Korean Adaptation of the International Outcome Inventory for Hearing Aids (K-IOI-HA) between the two groups. When there was no need for further electroacoustic adjustment of the hearing aid, sharpness and occlusion of amplified sound, clarity of sentence, and loudness of noise were evaluated based on the everyday experience. And REIGs with international speech test signal and WRS in sound-treated room were measured.Results: Preferred REIG for HTL was low for OF compared to CF in 0.5 kHz and 0.75 kHz at input SPL of 55 dB, 0.5 kHz at 60 dB SPL, 0.25 kHz and 0.5 kHz at 80 dB SPL. However, there were no differences in aided WRS and psychoacoustics between the two groups.Conclusion: In this study, the preferred REIG of OF and CF groups showed a difference under 0.75 kHz although there were no psychoacoustic differences between the two groups. Therefore, the results of this study should be considered when formulating Korean-type hearing aid fitting formula.

Frequency Modulation System and Bone Conduction Hearing Aid: Electroacoustic Verification.

Introduction A protocol has not yet been developed to perform electroacoustic measurements and behavioral tests to fit the frequency modulation (FM) system in bone conduction hearing aid (BCHA) users. Electroacoustic verification, with “FM transparency” achieved, ensures user audibility of FM transmitter and hearing aid signals. Objective To propose and validate a protocol for electroacoustic verification of the FM system coupled to the BCHA. Method Twenty-four sets of FM system and BCHA were submitted to electroacoustic verification, using a receiver and a plastic adapter to connect the BCHA to a 2cc coupler in the hearing instrument analyzer. The measurements were performed in the acoustic box, at 65 dB sound pressure level (SPL), with International Speech Test Signal (ISTS), first to the BCHA microphone and then to the FM system microphone, to determine the transparency, in which equivalent inputs for both microphones result in equivalent outputs. The FM gain or volume has been adjusted to try to gain transparency for the outputs of the two input devices. Results Transparency was achieved for all sets evaluated, but in some combinations, adjustments to the FM receiver gain over the manufacturer's default setting were required. Conclusion The proposed protocol proved to be effective for the electroacoustic verification of the FM system coupled to the BCHA.

Comparison of real-ear insertion gains in Japanese-speaking individuals wearing hearing aids with DSLv5 and NAL-NL2

ObjectiveWe used real-ear insertion gain (REIG), with the international speech test signal (ISTS), to evaluate the amplifying characteristics of hearing aids, set for patients who have been wearing such aids for a long time in a stable manner. We further compared this to the target values of the DSLv5 and NAL-NL2 methods. MethodsThe subjects were adults with moderate sensorineural hearing loss. We examined 40 ears in 25 individuals (15 people wearing hearing aids in both ears and ten people wearing aid in only one ear). Fit assessments were performed based on the speech performance-intensity functions and tolerance of environmental noise, and the ears studied were categorized as either ears with sufficient benefit or ears with insufficient benefit. Additionally, we evaluated the REIG for international speech test signals at 65-dB and 80-dB sound pressure level (SPL). We compared the REIG and target values for voice input at 65-dB and 80-dB SPL, calculated from the DSLv5 and NAL-NL2 methods. ResultsAmong the 40 ears, 34 received sufficient benefit and six received an insufficient benefit from hearing aids. The REIG for ISTS at 65-dB in the sufficient benefit ears, at frequencies of 1,000 Hz and 2,000 Hz, were similar to the target values of NAL-NL2 and DSLv5 but were significantly lower at 250 Hz, 500 Hz, and 4,000 Hz frequencies. The compression ratio of REIG for sufficient benefit ears was similar to that of DSLv5. The REIG for ISTS at 65-dB in the insufficient benefit ears was smaller than that in the sufficient benefit ears at frequencies of 2,000 Hz and 4,000 Hz. ConclusionThis study suggested that the target values of NAL-NL2 and DSLv5 are appropriate, even for Japanese-speaking individuals, at mid-pitch sounds. Although it is necessary to investigate the necessity for low-pitch and high-pitch gains further in the future, this study provides meaningful data regarding the amplifying characteristics in Japanese-speaking individuals who have been wearing hearing aids in a stable manner.

A Study on the Korean Conversation Speech Level and Spectrum in Sound-Treated Environment

Purpose: Several studies have reported the differences between Korean and other countries’ speech in long-term average speech spectrum (LTASS) and band importance function. Authors tried to identify the conversational speech level, the resulting spectrum, and the LTASS for Korean. The purpose of this study was to support the production of a Korean-type hearing aid fitting formula to effectively improve the sound quality of hearing aids and the communication abilities with hearing aids, and to standardize the sound stimuli required to measure the performance of hearing aids. Methods: A total of 73 participants with normal hearing and with no specific voice and language deficits was voluntarily recruited from capital, Gyeongsang and Jeolla areas. The conversational speech level was measured by vocalizing ‘soft,’ ‘moderate,’ ‘raised,’ and ‘loud’ at a distance of 1.0 m from the speaker. And LTASS was measured by vocalizing it at a distance of 0.2 m from the speaker. Results: There was a difference in the mean of males and females in the conversation level, but no significant regional differences were shown. The conversational speech level corresponding to 30th, 65th, and 99th percentiles was 59.67, 64.74, and 79.07 dB sound pressure level, respectively. And the speech spectrum of 30th, 65th, and 99th percentile and LTASS showed in different forms from the international speech test signal. Conclusion: The results of this study should help to calculate the Korean type hearing aid fitting formula and should be used as the basic data to determine the characteristics of the sound stimuli when measuring the performance of the hearing aid.

A Comparison of Acoustical Characteristics between International Speech Test Signal and Korean Speech Stimuli

A Comparison of Acoustical Characteristics between International Speech Test Signal and Korean Speech Stimuli

On the Cost of Introducing Speech-Like Properties to a Stimulus for Auditory Steady-State Response Measurements.

Validating hearing-aid fittings in prelingual infants is challenging because typical measures (aided audiometry, etc.) are impossible with infants. One objective alternative uses an aided auditory steady-state response (ASSR) measurement. To make an appropriate measurement, the hearing aid’s signal-processing features must be activated (or deactivated) as if the ASSR stimulus was real speech. Rather than manipulating the hearing-aid settings to achieve this, an ASSR stimulus with speech-like properties was developed. This promotes clinical simplicity and face validity of the validation. The stimulus consists of narrow-band CE-Chirps®, modified to mimic the International Speech Test Signal (ISTS). This study examines the cost of introducing the speech-like features into the ASSR stimulus. Thus, 90 to 100 Hz ASSRs were recorded to the ISTS-modified stimulus as well as an equivalent stimulus without the ISTS modification, presented through insert phones to 10 young normal-hearing subjects. Noise-corrected ASSR magnitudes and clinically relevant detection times were estimated and analyzed with mixed-model analyses of variance. As a supplement, the observed changes to the ASSR magnitudes were compared with an objective characterization of the stimuli based on modulation power. The main findings were a reduction in ASSR magnitude of 4 dB and an increase in detection time by a factor of 1.5 for the ISTS-modified stimulus compared with the standard. Detection rates were unaffected given sufficient recording time. For clinical use of the hearing-aid validation procedure, the key metric is the detection time. While this varied considerably across subjects, the observed 50% mean increase corresponds to less than 1 min of additional recording time.

Comparison of Acceptable Noise Levels Using Korean and Non-Semantic Speech Signals in Normal Hearing Subjects

Background and Objectives The acceptable noise level (ANL) test measures the maximum noise level that a subject can tolerate while following speech. Given the limited investigation of ANL across different languages, this study aimed to compare ANLs using both Korean semantic speech and non-semantic speech signals (reversed Korean speech and international speech test signal, ISTS) in normal-hearing subjects. Subjects and Method Twenty-five subjects with normal hearing (9 males, 16 females, with the mean age of 28.5±3.15 years) were included in the study. ANLs were obtained using three speech materials (Korean speech, reversed Korean speech, and ISTS) as the target speech material and an eight-talker babble noise as the competing background noise. Results Generally, the inter-subject variability was large. The ANLs did not differ statistically regardless of the type of speech signal. Conclusion The ANLs seemed to be unaffected by the meaningfulness or semantic contents of the target speech, at least in normal-hearing adults. Thus, non-meaningful speech signals or non-semantic material can be considered as the target signal for the implementation of ANL test. Key words: Acceptable noise level ㆍ Most comfortable level

The influence of voice quality on sentence processing and recall performance in school-age children with normal hearing

ABSTRACTPrevious findings suggest that working memory capacity (WMC) is influenced by a dysphonic voice quality. The present study examines the influence of voice quality on sentence processing and word recall in a working memory task. Fifty-seven children (8:1–9:1 years old) with normal hearing participated. Working memory capacity (WMC) was assessed using a competing language processing task (CLPT) which consists of a sentence processing segment (judgements of semantic acceptability in sentences) and a final word recall segment. All children completed two versions of the CLPT; once listening to a typical voice and once listening to a vocally loading induced dysphonic voice. The two voices were recorded from the same female speaker. In addition, the children’s executive functioning was assessed using Elithorn’s mazes. The dysphonic voice quality significantly decreases scores on the sentence processing segment but not on the recall segment. Children with better executive functioning (i.e., response inhibition, organizing, processing, and planning) were less disturbed by the dysphonic voice in the recall segment. Children’s judgements of semantic acceptability in sentences in a working memory task are affected by a dysphonic voice quality, but not the recall segment (the measure of WMC). However, children with lower executive functioning may be more disturbed by the dysphonic voice. These findings suggest that listening to a dysphonic voice seems to require more cognitive resources than listening to a typical voice, but only when the task is sufficiently easy to allow for allocation of cognitive resources to process the degraded signal content.Abbreviations: CLPT: Competing language processing task; ISTS: International speech test signal; RMS: root-mean-square; SLP: speech and language pathologists; WMC: Working memory capacity

Type of Speech Material Affects Acceptable Noise Level Test Outcome.

The acceptable noise level (ANL) test, in which individuals indicate what level of noise they are willing to put up with while following speech, has been used to guide hearing aid fitting decisions and has been found to relate to prospective hearing aid use. Unlike objective measures of speech perception ability, ANL outcome is not related to individual hearing loss or age, but rather reflects an individual’s inherent acceptance of competing noise while listening to speech. As such, the measure may predict aspects of hearing aid success. Crucially, however, recent studies have questioned its repeatability (test–retest reliability). The first question for this study was whether the inconsistent results regarding the repeatability of the ANL test may be due to differences in speech material types used in previous studies. Second, it is unclear whether meaningfulness and semantic coherence of the speech modify ANL outcome. To investigate these questions, we compared ANLs obtained with three types of materials: the International Speech Test Signal (ISTS), which is non-meaningful and semantically non-coherent by definition, passages consisting of concatenated meaningful standard audiology sentences, and longer fragments taken from conversational speech. We included conversational speech as this type of speech material is most representative of everyday listening. Additionally, we investigated whether ANL outcomes, obtained with these three different speech materials, were associated with self-reported limitations due to hearing problems and listening effort in everyday life, as assessed by a questionnaire. ANL data were collected for 57 relatively good-hearing adult participants with an age range representative for hearing aid users. Results showed that meaningfulness, but not semantic coherence of the speech material affected ANL. Less noise was accepted for the non-meaningful ISTS signal than for the meaningful speech materials. ANL repeatability was comparable across the speech materials. Furthermore, ANL was found to be associated with the outcome of a hearing-related questionnaire. This suggests that ANL may predict activity limitations for listening to speech-in-noise in everyday situations. In conclusion, more natural speech materials can be used in a clinical setting as their repeatability is not reduced compared to more standard materials.

High-Frequency Audibility: The Effects of Audiometric Configuration, Stimulus Type, and Device

For the last decade, the importance of providing amplification up to 9-10 kHz has been supported by multiple studies involving children and adults. The extent to which a listener with hearing loss can benefit from bandwidth expansion is dependent on the audibility of high-frequency cues. The American National Standards Institute (ANSI) devised a standard method for measuring and reporting hearing aid bandwidth for quality-control purposes. However, ANSI bandwidth measurements were never intended to reflect the true frequency range that is audible for a speech stimulus for a person with hearing loss. The purpose of this study was to (1) determine the maximum audible frequency of conventional hearing aids using a speech signal as the input through the hearing aid microphone for different degrees of hearing loss, (2) examine how the maximum audible frequency changes when the input stimulus is presented through hearing assistance technology (HAT) systems with cross-coupling of manufacturers' transmitters and receivers, and (3) evaluate how the maximum audible frequency compares with the upper limit of the ANSI bandwidth measure. Eight behind-the-ear hearing aids from five hearing aid manufacturers were selected based on a range of ANSI bandwidth upper frequency limits. Three audiometric configurations with varied degrees of high-frequency hearing loss were programmed into each hearing aid. Hearing aid responses were measured with the International Speech Test Signal (ISTS), broadband noise, and a short speech token (/asa/) as stimuli presented through a loudspeaker. HAT devices from three manufacturers were used to create five HAT scenarios. These instruments were coupled to the hearing aid programmed for the audiogram that provided the highest maximum audible frequency in the hearing aid analysis. The response from each HAT scenario was obtained using the same three stimuli as during the hearing aid analysis. All measurements were collected in an audiometric sound booth on a Knowles Electronic Manikin for Acoustic Research (KEMAR). A custom computer program was used to record responses from KEMAR. Maximum audible frequency was defined as the highest point where the Long-Term Average Speech Spectrum (LTASS) intersected the audiogram. The average maximum audible frequency measured through KEMAR ranged from 3.5 kHz to beyond 8 kHz and varied significantly across devices, audiograms, and stimuli. The specified upper limit of the ANSI bandwidth was not predictive of the maximum audible frequency across conditions. For most HAT systems, the maximum audible frequency for the hearing aid plus HAT condition was equivalent to the hearing aid for the same measurement configuration. In some cases, however, the HAT system imposed a lower maximum audible frequency than the hearing aid-only condition. The maximum audible frequency of behind-the-ear hearing aids is dependent on the degree of hearing loss, amplification device, and stimulus input. Estimating the maximum audible frequency by estimating the frequency where the speech spectrum intersects the audiogram in the high frequencies can assist clinicians in making decisions about which device or configuration of devices provides the greatest access to high-frequency information, as well as whether frequency-lowering technology should be used.

Examining Speech Perception in Noise and Cognitive Functions in the Elderly

The purpose of this study was to investigate the relationship of cognitive functions (i.e., working memory [WM]) and speech recognition against different background maskers in older individuals. Speech reception thresholds (SRTs) were determined using a matrix-sentence test. Unmodulated noise, modulated noise (International Collegium for Rehabilitative Audiology [ICRA] noise 5-250), and speech fragments (International Speech Test Signal [ISTS]) were used as background maskers. Verbal WM was assessed using the Verbal Learning and Memory Test (VLMT; Helmstaedter & Durwen, 1990). Measurements were conducted with 14 normal-hearing older individuals and a control group of 12 normal-hearing young listeners. Despite their normal hearing ability, the young listeners outperformed the older individuals in all background maskers. These differences were largest for the modulated maskers. SRTs were significantly correlated with the scores of the VLMT. A linear regression model also included WM as the only significant predictor variable. The results support the assumption that WM plays an important role for speech understanding and that it might have impact on results obtained using speech audiometry. Thus, an individual's WM capacity should be considered with aural diagnosis and rehabilitation. The VLMT proved to be a clinically applicable test for WM. Further cognitive functions important with speech understanding are currently being investigated within the SAKoLA (Sprachaudiometrie und kognitive Leistungen im Alter [Speech Audiometry and Cognitive Functions in the Elderly]) project.