Biomedical subjects

F K Kuk

Publications and source records attributed to F K Kuk.

At least 19 recordsLinked to original sources

PubMed1996

Effect of hearing aid experience on preferred insertion gain selection.

The effect of hearing aid experience (measured as years of hearing aid use and user insertion gain at octave frequencies from 250 Hz to 4000 Hz) on the selection of preferred insertion gain under six listening conditions and one vocalization condition was examined. Thirteen experienced hearing aid users selected their preferred insertion gain in each test condition using a modified simplex procedure. The results showed that for the listening conditions, preferred insertion gain was highly correlated with the subjects' hearing loss from 500 Hz to 2000 Hz. Hearing aid experience did not correlate at all with preferred insertion gain. On the other hand, user insertion gain at 250 Hz and 500 Hz correlated highly with preferred insertion gain selected during vocalization. Years of hearing aid use did not correlate with preferred insertion gain selection. These results suggest that user insertion gain can affect preferred insertion gain selection only when the test conditions are identical to those that the hearing aid wearers experience in everyday lives. In typical laboratory conditions, preferred insertion gain is likely determined by the stimulus characteristics and subjective preference.

Adult↗

PubMed1996

Comparison of preferred frequency gain settings obtained with category rating and modified simplex procedure.

We examined the relations between the preferred frequency gain settings obtained from the modified simplex procedure and those that were rated highest during category rating at three speech and noise levels (speech and noise levels at 60/65, 63/63, 65/60, all in dBA). During category rating, subjects rated short discourse passages on a 7-point scale using clarity and noise interference as criteria. Clarity was used as criterion in the modified simplex procedure. Results indicated that most subjects gave the same high rating to two or more frequency gain settings during category rating. Such settings varied across subjects and test conditions. The preferred frequency gain settings selected with the modified simplex procedure matched closely those rated highest in clarify and lowest in noise interference. This suggests that the modified simplex procedure may be used to determine preferred frequency gain setting on a hearing aid.

Adult↗

PubMed1995

Effect of initial setting on convergence to optimal hearing aid setting using a simplex method.

We examined the final preferred frequency gain response (i.e. final setting) selected using different starting points (i.e. initial settings) with a modified simplex procedure. These starting points included a frequency response close to the one recommended by NAL-R (Byrne and Dillon, 1986), a frequency response with the high and low frequency gain set to the maximum (max), a frequency response with the high and low frequency gain set to the minimum (min), and one in-between these values (mid). The time taken to converge to the final setting was also recorded. Subjects judged the clarity of short discourse passages presented at 63 dB(A) in the presence of babble noise (S/N = 0). The results indicated that the majority of subjects selected the same preferred frequency response regardless of initial settings. Variations in initial settings mainly affected the convergence time to the final choice. The frequency response recommended by NAL-R required the least time to converge, while those of the extremes (min and max) required the longest convergence time. Clinical implications are discussed.

Adult↗

PubMed1994

A screening procedure for modified simplex in frequency-gain response selection.

The preference for hearing aid frequency-gain responses selected using the modified simplex procedure over that prescribed by NAL-R is not universal. A screening protocol used before individualized fitting may help streamline its use and ensure effective use of clinical time. In this protocol, listeners compare the prescribed frequency-gain response with selected alternate frequency-gain responses. Evaluation with the modified simplex procedure is indicated only when listeners consistently prefer the alternate frequency-gain responses in the screening procedure. Ten hearing aid wearers completed the screening protocol and the full modified simplex procedure. In addition, subjects compared their satisfaction for the prescribed and individually selected frequency-gain responses. The results were examined for efficiency, reliability, sensitivity, and efficacy of the selected frequency-gain response. Findings revealed that the screening protocol allowed reliable identification of listeners who needed fine-tuning of the prescribed frequency-gain response. Furthermore, satisfaction for selected frequency-gain response over prescribed frequency-gain response increased as more differences between the two responses were noted.

Acoustics↗

PubMed1994

Maximum usable real-ear insertion gain with ten earmold designs.

The present study compared the maximum usable real-ear insertion gain (REIG) permitted by 10 earmold designs that varied in the amount of occlusion. These earmolds were coupled to a high-gain hearing aid (Phonak Super-Front PPCL). In addition, the specificity of a nonoccluding earmold for the Oticon E43 hearing aid was examined. Maximum usable REIG, defined as the insertion gain obtained with the hearing aid set to just below the point of acoustic feedback after jaw movement, was determined in 10 hearing-impaired subjects. The results showed that earmold style had a significant effect on the magnitude of maximum REIG. Among the occluding earmolds, no difference in REIG was noted among the shell, canal, and skeleton earmolds, while the standard earmold permitted the least amount of maximum REIG. For the nonoccluding earmolds, those that were more occluding permitted greater REIG than those that were less occluding. The amount of occlusion on a nonoccluding earmold affected the maximum REIG provided by the Oticon E43 hearing aid.

Adult↗

PubMed1994

Preferred real-ear insertion gain on a commercial hearing aid at different speech and noise levels.

In the present study, we measured preferred real-ear insertion gain (REIG) under different levels of speech and noise to assess whether current automatic gain control (AGC) and automatic signal processing (ASP) hearing aids are operating optimally. Preferred REIG for optimal speech clarity was determined under seven speech and noise conditions. In four conditions, speech (discourse passages) was varied from 55 dB SPL to 85 dB SPL in 10-dB steps at a fixed signal-to-noise ratio (S/N) of +5. In the remaining conditions, speech was fixed at 65 dB SPL while the noise level was varied in 5-dB steps to yield S/Ns from +10 to -5. The results showed that subjects selected less gain as speech or noise levels were increased. In general, less overall gain was selected as speech level was increased, and less overall gain, especially in the low-frequency region, was selected as the S/N ratio became progressively poorer. These results are discussed in relation to how hearing aids with adaptive frequency/gain responses should respond to varying input levels to achieve optimal clarity of speech.

Adult↗

PubMed1993

Relative satisfaction for frequency responses selected with a simplex procedure in different listening conditions.

The purpose of this study was to compare everyday satisfaction with hearing aid frequency responses selected using a Simplex procedure and those selected using the National Acoustic Laboratories' formula (NAL-R). Nineteen elderly subjects with impaired hearing selected their preferred frequency responses under six listening conditions. The conditions included syllable identification and discourse quality judgement in quiet, in moderate noise (65 dB SPL), and in loud noise (80 dB SPL) backgrounds. Subjects subsequently wore a multimemory hearing aid programmed with these frequency responses and compared their satisfaction with the various frequency responses in daily listening environments. Subjects showed differential preference across the available frequency responses. Subjects with sloping hearing losses did not show a difference in preference among the selected frequency responses, including that prescribed by NAL-R. On the other hand, subjects with a flat hearing loss showed a slight, but consistent, preference for frequency responses selected while listening to discourse passages in a moderate noise background. These observations suggest that the Simplex procedure may be useful for selecting preferred frequency responses for some hearing aid wearers.

Aged↗

PubMed1992

The reliability of a modified simplex procedure in hearing aid frequency-response selection.

The reliability of a modified simplex procedure to select the preferred frequency response on a programmable hearing aid was studied. The effect of stimulus materials on the selected frequency response, along with the consistency in which the selected frequency response was chosen in repeated test runs, was examined. Two groups of hearing-impaired elderly adults (from 59 to 88 years of age, with a mean age of 70 years) who had worn hearing aids for at least 1 year, participated in the study. Subjects were seen for six sessions lasting 2 to 3 hours each. During each session, subjects listened through a programmable hearing aid and selected a preferred frequency response for optimal hearing using a modified simplex procedure. Discourse passages and consonant nonsense syllables, presented in quiet and in noise, were used as the test conditions. Subjective judgment of discourse clarity and syllable recognition were used as criteria. Three estimates of preferred frequency response were obtained within a session when subjective judgment was used as a criterion and two estimates were obtained within a session when syllable recognition was used as a criterion. Subjects returned for a retest approximately 1 week after completion of all test conditions. The results of the study revealed that, depending on test conditions, approximately 30% of subjects selected the same frequency response and 80% of subjects showed test-retest deviation of less than one step size (one cell) in the selected frequency response. The consistency was highest for discourse material presented in noise and lowest for discourse material presented in quiet. Subjects preferred more high-frequency response when consonant syllables were used for recognition than when discourse was used for subjective judgment. On the other hand, more subjects preferred more low-frequency response for discourse judgment than for consonant-syllable recognition. These results suggest that the choice of stimulus materials affect the outcome and consistency in which these outcomes are generated with the simplex procedure.

Aged↗

PubMed1992

Evaluation of the efficacy of a multimemory hearing aid.

Although multimemory hearing aids have theoretical advantages over conventional "single memory" hearing aids, research and clinical data are not available to support their efficacy. The present study reports on the usefulness of a commercially available multimemory hearing aid in daily listening situations. Nineteen elderly hearing-aid wearers were fitted with the Quattro Q8 hearing aid. A modified Simplex procedure was used to select the electroacoustic characteristics for each memory. Subjects wore the device home and reported their satisfaction with each memory on the hearing aid in different listening situations. Their impressions on the whole hearing aid and on the remote feature were also sampled. Although a majority of subjects showed preference for multimemory design, such observations may not be readily evident until after extended use of the device. Inconvenience and cost of the device may prohibit some hearing-impaired listeners from using the device.

Aged↗

PubMed1992

Hollowness perception with noise-reduction hearing aids.

The efficacy of "noise-reduction" hearing aids in reducing the hollowness perception of one's own voice during vocalization was examined. Binaural Siemens 283 ASP hearing aids were worn by 2 groups of listeners, one with primarily high-frequency loss (Group A) and one with loss in both high- and low-frequencies (Group B). Electroacoustic parameters on the hearing aids were adjusted initially for optimal hearing in the "no-noise reduction" mode by rating the clarity of a discourse passage while following an adaptive forced-choice procedure. Afterwards, subjects compared the effect of the noise-reduction circuitry by vocalizing at 3 different voice levels and scaled the clarity-hollowness of their voices using a 0-100 scale with each noise-reduction mode. Group A subjects did not show a significant change in hollowness perception with noise-reduction circuitry, whereas Group B subjects showed significant reduction of hollowness perception at soft and normal voice levels with noise-reduction circuitry. These results demonstrated that some present-day noise-reduction circuitry can be effective in improving some wearers' perceived voice quality during vocalization.

Aged↗

PubMed1991

Perceptual consequence of vents in hearing aids.

The perceptual consequence of venting an earmould while maintaining the insertion gain at a preferred listening level was examined on nine hearing-impaired individuals with bilaterally symmetrical sloping sensorineural hearing loss. Subjects wore binaural programmable hearing aids and selected their preferred insertion gain while the hearing aids were coupled to vented (2.2 mm parallel vent) and unvented earmoulds. A modified Simplex procedure with discourse passages presented in quiet was used to determine preferred insertion gain. The results showed that venting enhanced subjects' quality rating of the hearing aids during listening and vocalization tasks, but did not change subjects' word recognition scores. These results suggest that vented earmoulds should be used to achieve target insertion gain in order to maximize patients' acceptance of hearing aids.

Adult↗

PubMed1990

Relationships among loudness indexes in cochlear-implant patients.

The purpose of the experiment was to determine if the most-confortable-listening (MCL) levels and loudness-discomfort levels (LDLs) can be predicted from threshold measurements obtained from patients with cochlear implants using direct electrical stimulation. Psychophysical measurements of thresholds, MCLs, and LDLs with 125-Hz and 2000-Hz sinusoids were obtained from 16 patients with cochlear-implants 1 month after the connection of their ineraid processor (an auditory prosthesis). In general, the correlation coefficients among the loudness indexes obtained with a 125-Hz stimulus were similar to those for a 2000-Hz stimulus. Correlations between thresholds and MCLs were moderate, whereas correlations for thresholds and LDLs were fair. Correlations between MCLs and LDLs were high. This suggests that LDLs cannot be predicted from thresholds. On the other hand, these preliminary data suggest that MCLs may be reliably predicted from thresholds or LDLs to set the gain on a cochlear-implant processor.

Adult↗

PubMed1990

Preferred insertion gain of hearing aids in listening and reading-aloud situations.

Nine hearing-impaired subjects with primarily high-frequency hearing loss (Group A) and 8 hearing-impaired subjects with hearing loss in both the high- and low-frequency regions (Group B) participated in the experiment. Subjects wore binaural programmable multimemory hearing aids and selected the preferred amount of insertion gain while they listened to discourse passages read by a male speaker (listen). Subjects also selected the preferred amount of gain while they listened to themselves as they were reading the same passages (read-aloud). Subjects' word-recognition performances and their subjective impressions of the hearing aids determined in listen and read-aloud conditions were examined on subsequent listening and reading tasks. Hearing-impaired subjects preferred more insertion gain in the listen condition than in the read-aloud condition. Different insertion gains led to different objective and subjective performances. Hearing-aid responses selected for a particular condition (listening vs. reading aloud) yielded the best performance in that condition. Assuming the primary purpose of a hearing aid is for amplifying the speech of others, these findings suggest that one should not adjust the gain of a hearing aid using one's own voice as the reference. In addition, one should be careful in soliciting subjective comments from hearing-impaired patients during hearing-aid fittings to avoid underamplifying those individuals in the low frequencies. Multimemory hearing aids may be necessary for some hearing-impaired patients to use their hearing aids satisfactorily in listening and speaking conditions.

Hearing Aids↗

PubMed1990

The psychometric properties of a tinnitus handicap questionnaire.

The psychometric properties of a tinnitus handicap questionnaire are reported. There were two phases in this study. In Phase I, 87 questions were administered to 100 tinnitus patients. From their responses, 59 items that were either redundant, insensitive, or had low item-total correlations were eliminated. In Phase II, the resulting 27-item questionnaire was administered to 319 patients. Fifty-three of these patients also completed psychological and psychophysical measures that were used to validate the questionnaire. A factor analysis of patients' responses revealed a three-factor structure. These three factors appeared to reflect the physical, emotional, and social consequences of tinnitus (Factor 1), hearing ability of the patient (Factor 2), and the patients' view of tinnitus (Factor 3). Although the 27-item questionnaire had high internal consistency reliability and validity as reflected by correlations with life satisfaction and depression scales, it is recommended that only the items on the Factor 1 and the Factor 2 subscales be scored because of the low internal consistency reliability of the Factor 3 subscale. This questionnaire can be used to compare a patient's tinnitus handicap with the norm, identify specific areas of handicaps, and to monitor a patient's progress with particular treatment programs.

Female↗

PubMed1990

Intensity operating range measures as predictors of word-recognition ability in cochlear implant subjects.

The purposes of the experiment were to examine the appropriateness of pre- and post-implant intensity measures (thresholds, most comfortable listening level, and loudness discomfort level) as predictors of post-implant phoneme-recognition ability and to study the relationship between pre- and post-implant intensity measures. Pre-implant intensity measures were obtained on 16 subjects who were eventually implanted with either a Nucleus device (n = 8) or a Symbion device (n = 8). Phoneme scores on a NU-6 word list were obtained on these 16 subjects at 1 month post-implant. Post-implant intensity measures were also made on the 8 Symbion subjects at 1 month post-implant. The results showed that none of the pre-implant intensity measures correlated significantly with post-implant phoneme scores. In addition, pre-implant intensity measures did not correlate with the same post-implant intensity measures. However, post-implant MCLs and LDLs correlated significantly with phoneme scores as reflected by correlation coefficients that were larger than 0.8. These preliminary results suggest that although intensity measures may relate to phoneme-recognition ability, their use as predictive measures (as in pre-implant measures) for post-implant ability is questionable.

Acoustics↗

PubMed1990

Subjective ratings of noise-reduction hearing aids.

The effectiveness of seven commercially available noise-reduction hearing aids was evaluated using subjective ratings of continuous discourse. Subjective scales of listening comfort, speech quality, speech understanding, noise interference, and overall liking were used. Fifteen experienced hearing-aid users participated. Two hearing aids that used amplitude compression (Audiotone A-54 and Telex 363C), two hearing aids that used the Zeta Noise Blocker (two versions of a Maico SP147), and three hearing aids that proportionally attenuated the low-frequencies (Rion HB-69AS, Richards ASE-B, and Siemens 283 ASP) were evaluated. None of the noise-reduction hearing aids significantly altered group performance on any subjective scale. Individually, however, subjects responded differently to different noise-reduction hearing aids, indicating that some noise-reduction hearing aids may help some hearing-impaired individuals.

Acoustic Stimulation↗

PubMed1990

Relationship between consonant recognition and subjective ratings of hearing aids.

The relationships between consonant recognition performance and subjective ratings (using continuous discourse and nonsense syllables as stimuli) of speech understanding, listening comfort, quality, noise interference and overall liking were examined in quiet and in noise using hearing-impaired subjects and seven different hearing aids. Correlations among the subjective scales varied depending on test conditions and test stimuli. Scores on the speech understanding and overall liking scales correlated moderately with scores on a consonant-recognition test presented in noise and when syllables were used as the materials for judgments. The overall liking scale (for a hearing aid) correlated with all other subjective scales and consonant recognition performance. However, the relative contribution of each subjective scale to overall liking varied depending on test conditions and test materials.

Adult↗

PubMed1990

Consonant recognition and quality judgments of noise-reduction hearing aids.

We evaluated seven different hearing aids worn by 13 experienced hearing-aid users. Two of the aids, the Audiotone A-54 and the Telex 363C, included amplitude compression. The others, two versions of a Maico aid (SP147), a Richards (ASE-B), a Rion (HB-69AS), and a Siemens (283ASP), have circuits designed to attenuate specific frequency regions in the presence of noise. Consonant recognition and quality judgments were measured with the processing circuit on and off in the presence of speech-babble noise and low-frequency noise. The results suggested that only a few subjects benefited from the processing circuits. Quality judgments and consonant recognition scores were not always in agreement.

Hearing Aids↗