Biomedical subjects

M T Gauz

Publications and source records attributed to M T Gauz.

7 recordsLinked to original sources

PubMed1987

High-frequency Bekesy audiometry: VI. Pulsed vs. continuous signals.

Carefully screened normal-hearing young adults (5M, 25 F) performed a fixed-frequency version of high-frequency Bekesy audiometry (HFBA) with pure tones ranging from 2-16 kc/s, using the SHF E-800 unit (Gauz and Smith, J. Aud. Res., 1985, 25, 101-122). Pulsed (P) and Continuous (C) traces were recorded for 1 and 2 min, respectively. Data were described in types of response, amount of threshold decrement of the C trace re P traces, and rate of threshold decrement. P traces showed stability, while the majority (about 70-95%) of C traces overlapped P traces for 2-12 kc/s (our Type I). Some C traces (about 3-25% indicated adaptation followed by stabilization (Type II), while others (about 3-20% showed adaptation without stabilization (Type II/III), without regard for frequency. Rapid adaptation to the limits of the audiometer (Type III) was infrequently encountered below 14 kc/s, but showed an accelerated increase from 14-16 kc/s. During Min 2, a slight decrease in Type I responses and a corresponding increase in Type II responses were obtained. The rate of adaptation (in db/sec) increased with frequency and decreased with duration. This slope was relatively slight at 2-8 kc/s, increased at 10-12 kc/s, and increased notably at higher frequencies. Total amount of adaptation in db (P-C) increased with frequency, although mean values were rather small, most less than 5 db and none exceeding 10 db by the end of Min 2. Excluding Type III responses, no C-mode adaptation exceeded 24 db for any individual. The potential utility of HFBA and implications for future research were discussed.

Acoustic Stimulation↗

PubMed1986

The simplified HF E-800 high-frequency audiometer: clinical applications.

In a prior study (Gauz and Smith, J. Aud. Res., 1985, 25, 101-122) threshold tracings were collected at 8-20 kc/s on 108 Ss using a Bekesy-type Simplified High-Frequency Audiometer (SHF E-800) set in the fixed-frequency mode. Of these, 23 Ss did not meet screening criteria for a normative study; their data are reported here. Examples are given of HF audiometric results on Ss with one or more conditions affecting hearing thresholds, including age, conductive pathologies, noise exposure, cardiovascular disorders, hearing loss in the conventional audiometric frequencies, and a miscellaneous category. Results were obtained generally in line with expectations based on literature review. The present case studies provide information useful in the clinical application of HF audiometry.

Adult↗

PubMed1985

The simplified HF E-800 audiometer: calibration and normative aspects.

Although numerous viable applications of high frequency (HF) audiometry have been demonstrated in the past 20 yrs, a set of specifications analogous to those for diagnostic pure-tone audiometers (ANSI, 1969) is lacking. Thus, meaningful interpretation of HF thresholds must consider the system employed to assess auditory sensitivity. A cost-effective HF audiometer has recently been described based on the Grason-Stadler E-800 Bekesy audiometer in the fixed-frequency mode. Preliminary results indicate highly acceptable reliability and validity of thresholds. In the present study, 20 men and 65 women, all normally hearing young adults (170 ears) presenting with negative otoaudiologic histories produced HF ac thresholds from 8-20 kc/s. Excursion widths of pen tracings compared favorably with those of earlier reports in HF audiometer studies. The composite function (both sexes, both ears) was flat through 12 kc/s, with progressively greater SPLs required for higher frequencies. Neither gender nor ear-related differences were seen. Calibration was performed using the NBS 9 A 6-cc coupler and the manufacturer's flat-plate coupler for the Koss HV/X stereophone used. Conversion factors were presented so that either coupler could be used. A threshold function was recommended for use consisting of the composite median function for 170 ears. It was concluded that the Simplified HF E-800, or an analogous unit, could be used as a viable clinical tool, surpassing the cost effectiveness of a number of different HF audiometric systems.

Adolescent↗

PubMed1984

High-frequency Békésy audiometry. V. Excursion width.

26 normally hearing young adults produced Békésy-type tracings for pure tones ranging from 7 to 19 kHz. Tones were pulsed (2.5/s) and delivered in the fixed-frequency mode. Chart rate (1 octave/min) and rate of attenuation (2.5 dB/s) were analogous to that typically used in clinical Békésy audiometry. Results indicated that subjects typically produced median excursion widths ranging from 5 to 15 dB. No systematic change in excursion width for conventional-frequency Békésy audiometry. The results of the present study were discussed regarding their utility in validation of responses to Békésy audiometry.

Acoustic Stimulation↗

PubMed1981

High-frequency Bekesy audiometry: III. Reliability and validity revisited.

Normal-hearing young adults (N: 30) produced 3 fixed-frequency monaural audiograms by Bekesy tracking on a Grason-Stadler E-800 audiometer (modified for high frequencies) for pulsed pure tones in 2-kc/s steps progressively from 7-19 kc/s. The earphone was not moved between one pair of audiograms but was removed and replaced between another pair. After 1 mo, 16 Ss returned for retest on the HF E-800 audiometer and on a similar audiometer using the conventional Method of Limits. Maximum group mean retest HTL differences approximated 5 db. Statistical analysis indicated that the arrays of HTLs within and across sessions were equivalent. Reliability and validity coefficients were high and significantly different from zero. It was concluded that the HF E-800 could with such Ss be used with some confidence to assess high-frequency sensitivity.

Adult↗

PubMed1981

High frequency Bekesy audiometry: II. Threshold test procedure, reliability and validity.

Normal-hearing Ss (N: 20) produced 2 sets of Bekesy threshold tracings, from 2-8 kc/s, on a conventional Grason-Stadler E-800 audiometer, and from 2-20 kc/s on a unit (HF E-800) modified for high frequencies. Half the Ss then produced at least 2 sets of tracings each in the fixed-frequency mode on the HF E-800. The pulsed-tone fixed-frequency procedure is recommended for HF HTLs. Maximum mean test-retest HTL differences of 1-4 db were obtained. Reliability r's obtained from the HF E-800 were equivalent to or surpassed those from the E-800; a very high proportion of such coefficients was statistically significant. Reduced validity coefficients, calculated at the frequencies common to the units, were attributed at least in part to differences in methods of coupling the transducers to the ear. It was concluded that the HF E-800 unit in the fixed-frequency mode could be used with some confidence to assess HF HTLs.

Adult↗

PubMed1980

High frequency Bekesy audiometry. I: equipment and calibration.

A simple, straightforward and inexpensive conversion of the high-frequency (HF) range (up to 20 kc/s) of the Grason-Stadler E-800 Bekesy audiometer is described, incorporating as transducer a 1/2-inch condenser microphone loosely coupled to the ear canal by an adjustable headband, which provides also for a standard audiometric earphone-cushion unit on the non-test ear. A free field calibration is recommended. The system has a dynamic range of 135 db. Step-by-step instructions are provided for the conversion and for calibrations. Repeated calibrations of a prototype unit showed acceptable stability and validity. The HF E-800 audiometer could provide a valuable and cost-effective source of HF diagnostic information for the audiologist.

Audiometry↗