Biomedical subjects
Publications and source records attributed to J E Dengerink.
Psychophysical tuning curves (PTCs) at 2 kHz and auditory thresholds (2 kHz and 4 kHz) were obtained from 18 normal-hearing listeners before and after exposure to a 5-min 110 dB SPL white noise. PTCs were quantified on five dimensions (Q10 tip, Q10 probe, d1oct, tip level and tip frequency). PTCs revealed continued cochlear effects beyond the time when TTS at 2 kHz demonstrated complete recovery.
Reversible tinnitus was induced in 10 male and 8 female normal-hearing subjects following a 5 min 110 dB SPL exposure to white noise. Temporary threshold shift (TTS) was measured at 2 and 4 kHz. Characteristics of the tinnitus were determined by means of a written questionnaire administered 5 min following termination of the noise. Most of the subjects experienced a continuous tonal tinnitus of moderate loudness. Characterization of the tinnitus regarding spectral quality, type of sound, and perceived location differed as a function of gender. No difference in TTS measured at 2 and 4 kHz was seen as a function of gender. Positive relationships of fair to moderate strength were revealed between pre-exposure thresholds, TTS, and tinnitus pitch and level.
The Temporary Threshold Shifts (TTS) of 9 habitual smokers and 9 non-smokers were determined twice (via Békésy sweep procedures) after each of three conditions: 10 min of physical exercise, 10 min of 105 dB SPL exposure to a third octave band noise centered around 2 kHz, and 10 min of both exercise and noise. Smokers evidenced less TTS than did non-smokers, particularly when exposed to both noise and exercise and especially in the range of 2.5 to 5 kHz. Heart rate and systolic blood pressure increased more for smokers than for non-smokers, particularly when they were required to exercise. Oral temperature was positively correlated with the magnitude of TTS.
Cumulative auditory effects of repeated exposure to a 3-min 110 dB SPL white noise were examined in 20 subjects (10 male, 10 female). Statistical analysis revealed greater 8-kHz temporary threshold shift in female ears despite equivalent preexposure 8-kHz thresholds across gender. Cumulative effects were seen in thresholds of octave masking scores, especially in female subjects, possibly reflecting increased susceptibility following the second noise exposure.
Smoking and nonsmoking subjects were exposed either to 110- or 30-dB SPL white noise in both hot and cool ambient temperatures. Smokers evidenced less temporary threshold shift (TTS) than nonsmokers when exposed to loud noise. Nonsmokers evidenced greater TTS in the hot testing condition than in the cold condition when exposed to the loud noise. The temperature conditions did not influence the TTS of smokers. Smoking and the cold temperature both increased peripheral vasoconstriction.
The first experiment examined thresholds at 4 and 8 kHz and the threshold of octave masking at 4 kHz before and after noise for males, females, and females using oral contraceptives. Females using oral contraceptives evidenced greater threshold shifts at 4 kHz than either of the other two groups. The second experiment examined thresholds and the loudness discrimination index at 4 kHz for males and females before and after noise exposure. Females evidenced greater loudness discrimination index changes both with and without noise exposure than did males. In addition, females responded to the noise with cutaneous vasodilation while males evidenced vasoconstriction.
Acoustic reflex thresholds (ARTs) were determined at 0.5, 1, 2 and 4 kHz in 40 normal ears of college age subjects. Thresholds were redetermined at intervals of 3 min, 15 min and 1 week. Although statistical analysis revealed ARTs at 1 week to differ significantly from previously obtained values, this finding is not clinically significant as the greatest degree of variation was only 3.6 dB SL at 0.5 kHz. Furthermore, significant correlation coefficients at a particular frequency between times were obtained. The finding of a lack of correlation between frequencies serves to alert the audiologist to the potential error inherent to immittance screening programs which utilize reflex testing at one frequency only. The use of tympanometry and pure-tone testing in conjunction with reflexometry may reduce this potential error.
Test-retest reliability of auditory threshold and temporary threshold shift (TTS) at 4 kHz and 8 kHz was examined. Twenty normally hearing subjects were exposed to a 3-min 110 dBSPL white noise on three occasions. Results indicated reduced reliability of both threshold and TTS scores over time, rendering 1-week TTS correlations non-significant.
Plasma concentrations of the vasoconstrictor Angiotensin II (AII) were measured in male human subjects before and after either rest or exposure to 100-dB white noise. Plasma AII concentrations decreased for subjects in the control (no noise) condition but remained high in the noise condition. In the noise exposure condition both the pre- and post-exposure AII concentrations were negatively but nonsignificantly correlated with TTS. The cardiovascular effects of noise appear to be mediated in part by AII.
The relationship among a personality measure, peripheral vascular measures, and audiometric indexes of susceptibility to noise-induced hearing loss were studied. Seventy-four male human subjects were selected based upon their responses to a self-report measure of coronary-prone behaviors. Coronary-prone, nonprone, and median scores with normal hearing were included in the study. The audiometric measures were 4 kHz pure-tone thresholds, 4 kHz acoustic reflex thresholds, and thresholds of octave masking. Subjects were exposed to 5 min of either 110 dB SPL or 20 dB SPL white noise designated loud and soft noise, respectively. Temporary threshold shifts were assessed at three intervals after the noise exposure (0.25, 2, and 10 min). Blood pressure was assessed before the noise exposure. Digital and cephalic vasoconstriction were measured throughout the procedures. The results indicated that coronary-prone persons were significantly more likely to fail the pure-tone screening but did not differ from others on any additional measure. Temporary threshold shifts were negatively correlated with resting level blood pressure, vasoconstriction, and thresholds of octave masking.