Biomedical subjects

F K Kuk

Publications and source records attributed to F K Kuk.

25 records · Page 2Linked to original sources

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↗

PubMed1989

Effects of attention on the auditory evoked potentials recorded from the vertex (ABR) and the promontory (CAP) of human listeners.

Auditory brainstem response (ABR) and the compound whole nerve action potential (CAP) of four human listeners were recorded while they were performing either visual duration or auditory frequency discrimination tasks with both types of stimuli presented simultaneously. The evoking tone bursts had the same center frequency as the standard discrimination tones and were presented between the discrimination tones. Waveforms between the two discrimination tasks did not differ in shape or latency, suggesting that the attention demand of the present task is not a central factor in the control of the auditory efferents.

Adult↗

PubMed1989

Alternating current at the eardrum for tinnitus reduction.

The effectiveness of alternating current (AC) stimulus on tinnitus was investigated in 10 patients who reported constant tinnitus in at least one ear. Patients were first screened to determine their responsiveness to electrical stimulation in relation to tinnitus reduction. The responsive patients were then stimulated for a treatment period of at least 10 min, during which time the tinnitus was measured. The AC stimuli (62 Hz to 8000 Hz) were applied to the eardrum of the patients via a specially constructed electrode. Psychophysical measurements (pitch matching, loudness matching, minimum masking level, and loudness and annoyance scaling) of the patient's tinnitus were made before and after electrical stimulation. Minimal masking level was determined and tinnitus scaling was performed during the treatment period. Electrical stimulation was effective in tinnitus reduction in 5 of the 10 patients. These 5 patients reported that the loudness and the annoyance of their tinnitus decreased during the treatment period. These observations were consistent with psychophysical measures of contralateral broadband noise masking. Poststimulation reduction in tinnitus varied in duration among individuals from 40 s to about 4 hr.

Adult↗

PubMed1989

Performance of some of the better cochlear-implant patients.

The main purpose of this study was to provide an independent corroboration of open-set word recognition in some of the better cochlear-implant patients. These included the Chorimac, Nucleus (one group from the U.S.A. and one group from Hannover, Germany), Symbion, Duren/Cologne and 3M/Vienna implants. Three experiments are reported: (1) word recognition in word lists and in sentences; (2) environmental sound perception, and (3) gap detection. On word recognition, the scores of 6 Chorimac patients averaged 2.5% words and 0.7% words in sentences correct in the French tests. In the German tests, the scores averaged 17% words and 10% words in sentences for 10 Duren/Cologne patients, 15% words and 16% words in sentences for 9 3M/Vienna patients, and 10% words and 16% words in sentences (3% to 26%) for 10 Nucleus/Hannover patients. In the English tests, the scores averaged 11% words and 29.6% words in sentences for 10 Nucleus-U.S.A. patients, and 13.7% words and 35.7% words in sentences for the 9 Symbion patients. The ability to recognize recorded environmental sounds was measured with a closed set of 18 sounds. Performance averaged 23% correct for Chorimac patients, 41% correct for 3M/Vienna patients, 44% correct for Nucleus/Hannover patients, 21% correct for Duren/Cologne patients, 58% correct for Nucleus/U.S.A. patients, and 83% correct for Symbion patients. A multidimensional scaling analysis suggested that patients were, in part, utilizing information about the envelope and about the periodic/aperiodic nature of some of the sounds. Gap detection thresholds with a one-octave wide noise centered at 500 Hz varied widely among patients. Typically, patients with gap thresholds less than 40 ms showed a wide range of performance on speech perception tasks, whereas patients with gap-detection thresholds greater than 40 ms showed poor word recognition skills.

Adolescent↗

PubMed1989

The effects of "noise suppression" hearing aids on consonant recognition in speech-babble and low-frequency noise.

We evaluated the performance of experienced hearing-aid users wearing seven different commercially available "noise-suppression" hearing aids. Two hearing aids, the Audiotone A-54 and the Telex 363C, used amplitude compression. The others, two versions of a Maico hearing aid SP147, a Richards ASE-B, a Rion HB-69AS, and a Siemens 283ASP, are designed to attenuate specific frequency regions in the presence of noise. Sixteen subjects listened to 13 consonants in the form (i)-consonant-(i) with six replications per consonant (78 items). Performance was measured with the compression or noise-suppression circuit on and off in the presence of speech-babble noise and in continuous low-frequency noise. Measurements were also obtained with the suppression circuit "off" but without any background noise. The results suggested that only a few subjects benefitted from the noise-suppression circuits, and in several cases performance in noise was poorer with the noise suppression circuit than without it. An information-transfer analysis of the errors indicated that enhanced or decreased performance was generally a result of changes across all phonetic features, not specific ones.

Adult↗

PubMed1989

Single-channel versus multichannel electrical stimulation. Voicing-frequency and formant-transition difference limens.

The 'frequency' processing ability of 11 cochlear-implant patients wearing the Symbion device was evaluated with the stimuli presented in a multichannel mode and in a single-channel mode. A fixed-formant synthetic vowel /a/ was used to measure voicing-frequency difference limen. A voiced, synthetic single formant was used to measure the formant-transition difference limen. On the voicing-frequency test, patients obtained a median difference limen of 8 Hz when stimuli were presented in the multichannel mode and 14.7 Hz in the single-channel mode. On the formant-transition test, patients obtained a median difference limen of 589 Hz in the multichannel mode and 611 Hz in the single-channel mode. Three patients were unable to obtain a difference limen within the range of available stimuli. The performance with multichannel stimulation was significantly better (lower difference limen) than performance in the single channel stimulation. Temporal information in more channels and place information may contribute to the superior performance with multichannel stimulation.

Cochlear Implants↗

PubMedDate not supplied

Use of a digital hearing aid with directional microphones in school-aged children.

The efficacy of a digital hearing aid with a directional microphone was examined in a school-aged population. Twenty children (9 with a mild-to-moderately-severe hearing loss and 11 with a moderate-to-severe hearing loss) between 7 1/2 and 13 2/3 years of age wore the study hearing aids binaurally for 30 days prior to the evaluation. The testing protocol included speech recognition tests using the CID W-22 word lists presented at 72 dB SPL, 65 dB SPL, and 52 dB SPL (at 0 degrees azimuth) in the presence of a 65 dB SPL party noise (180 degrees azimuth). Subjective rating of hearing aid efficacy in the classroom was examined using the Listening Inventory For Education (LIFE) questionnaire. Parental impression on hearing aid efficacy was also collected at the end of the study. The results showed improved speech recognition in noise with the digital directional hearing aid at all presentation levels. Preference for the digital directional hearing aids over the subjects' own omnidirectional analog hearing aids was also seen on the LIFE questionnaire and parental impression. The degree of hearing loss did not seem to have affected the benefits offered by the digital directional hearing aids. These results were compared to results from other studies on the use of directional microphones in hearing aids.

Acoustic Stimulation↗