John F. Corso

Age and Sex Differences in Pure‐Tone Thresholds

In recent years there has been an increased emphasis on medicolegal problems involving the assessment of hearing loss due to noise exposure. One of the attendant difficulties, however, has been the problem of separating the factors of noise exposure and of age as contributors to hearing disabilities. The present study was performed to determine the normal thresholds of hearing for pure tones for an age‐stratified sample of subjects drawn from a population exposed to minimal levels of industrial noise. Audiometric measurements from 250 to 8000 cps were made on a total of 500 subjects divided into four age groups: 18 to 24, 26 to 32, 34 to 40, and 43 to 49 years, inclusive. The results of this study indicate that, in general, only minor differences (less than 5 db) exist between the average thresholds of right and left ears, but that women have more sensitive hearing than men and show less intersubject variability. This sex difference is independent of age and is more marked at the higher frequencies. For b...

Bone‐Conduction Thresholds for Sonic and Ultrasonic Frequencies

Several investigators have reported that high‐intensity sounds in the ultrasonic region above 20 kc can produce auditory sensations in individuals with normal hearing. The present experiment was performed to establish bone‐conduction thresholds for pure tones from 5 to 100 kc in a group of subjects with no otological abnormalities. Fifty male and fifty female subjects, ranging in age from 18 to 24 years, were tested on only the left or right ear by a modified method of limits, with all tests being conducted in an anechoic chamber. A crystal transducer, calibrated in a water medium, was used to transmit the acoustic energy to the mastoid bone. The curve for the mean threshold of hearing (for subjects audiometrically screened by air conduction from 250 to 8000 cps) showed a very sharp rise between 10 and 20 kc with a slope of approximately 50 db/octave, and a gradual rise above 20 to 100 kc with a slope of approximately 18 db/octave. The maximal discrepancy between men and women was approximately 5.5 db (at...

Bodily position and auditory thresholds.

Traditional studies of perception have been concerned primarily with the effects of stimulation on one sensory modality at a time. Such isolated stimulation, however, seldom occurs in non-laboratory situations and increased attention has been directed recently to the problem of sensory interaction (Mowbray & Gebhard, 1956). In the field of hearing, Russian investigators have reported a few studies which indicate that, in general, accessory stimulation tends to improve auditory acuity (London, 1754). Kekcheev, et al. ( 1747) indicated that illumination of a white room with green light increases auditory sensitivity, but red light decreases it. Odors derived from geraniol and benzol were reported also as decreasing audicory thresholds (Bronshtein, 1946). Gustatory stimulation is said to improve the auditory receprion of low tones but deteriorate that of high tones (Keckcheev, el al., 1947). The accessory stimulation of cold and proprioceptive receptors has also been reported ro facilitate audicory perception (Mowbray & Gebhard, 1956). For the present study, the most relevant finding suggests that postural stimuli affect sensitivity. Specifically, Kekcheev (1946) claimed that higher auditory sensitivity is obtained when the listener is in a seated position, rather than in either a standing or horizontal position. The present experiment was performed, therefore, ( a ) to determine whether, in fact, bodily position affects auditory acuity as measured by pure-tone thresholds, and if it does, ( b ) to evaluate the magnitude of threshold shifts for different bodily positions and different pure-tone frequencies.

Pitch Discrimination by Air Conduction and by Bone Conduction for Sonic and Ultrasonic Frequencies

In an earlier paper (1962), the principal investigator reported bone‐conduction thresholds from 5–100 kc/sec and indicated that high‐intensity bone‐conducted sounds were capable of producing auditory sensations in normal‐hearing subjects. The present study was performed to investigate pitch discrimination for sonic and ultrasonic frequencies presented monaurally by air conduction and by bone conduction. Five groups of 5 subjects each, screened for normal hearing and high‐pitch ability, were tested in an anechoic chamber from 2–54 kc/sec at a loudness level of 20 phons by the method of constant stimuli. The results indicate that (1) from approximately 4–14 kc/sec, the difference limens for pitch discrimination by bone conduction are smaller than those for air conduction, and (2) pitch discrimination is absent for bone‐conducted tones in the ultrasonic region. The difference limens for bone conduction vary from a minimal value of 7 cycles at 2 kc/sec to 134 cycles at 14 kc/sec; for air conduction, the diffe...

Age and Sex Differences in Pure‐Tone Thresholds. Addendum I: Age Group 51 to 57 Years

The present paper is an addendum to a laboratory study published in 1959 on the normal thresholds of hearing for pure tones for an age‐stratified sample of subjects drawn from a population exposed to minimal levels of industrial noise. It provides audiometric data (250–8000 cps) for 205 subjects in a 51‐ to 57‐year‐old group to supplement the earlier data for 500 subjects in four age groups between 18 to 49 years. The results of this study confirm the previously reported findings that (1) there is less than 5 db difference in the average sensitivity between right and left ears, (2) there is a decrease in hearing sensitivity with advancing age for both men and women, and (3) hearing loss with advancing age spreads progressively from higher to lower frequencies. Although women in general have better hearing and less intersubject variability than men, this trend is reversed for the lower frequencies in the 51‐ to 57‐year‐old age group. It is concluded that while the onset of presbycusis is later for women than for men, auditory deterioration proceeds at a faster rate in women than in men after about 50 years of age.

Information processing for pure tones in older adults

The ability of three age groups to identify pure tones was measured by the method of absolute judgments. Group mean ages were approximately 20, 40, and 60 years, with 25, 20, and 18 subjects per group, respectively. Eight tones in equal logarithmic units from 100 to 8000 Hz were presented monaurally in random order in the better ear at a loudness level of 60 phons. After practice, subjects were required to identify each tone by a designated code number from one to eight (low to high frequency). The correct identification was provided after each judgment. These were 80 judgments per subject (10 trials × 8 tones). Analysis of variance showed a significant difference in the mean number of correct responses among age groups. The means in order of increasing age were 55.52 (69.39%), 51.55 (64.43%), and 48.44 (60.55%) (F ratio 8. 003, 2/120 df, p = 0.001). The last 40 trials yielded significantly better performance than the first 40 trials for the 20 and 60 year‐old groups, but the 40 year‐old group showed no c...

Temporal Summation Function in Presbycusis

The threshold‐duration function was measured by brief‐tone Bekesy audiometry at 250, 1000, and 4000 Hz. At each frequency, threshold was tracked continuously for 1 min; thresholds were then tracked successively for interrupted tones of 500‐, 200‐, 100‐, 50‐, 20‐, and 10‐msec duration. All interrupted tones were presented for 1 min at a repetition rate of 1/sec with a rise‐fall time of 10 msec; the attenuation rate for all tests was 2.5 dB/sec, on a Grason‐Stadler E‐800 audiometer. Subjects (nine male, seven female) were 51 to 57 years of age with no otological abnormalities; threshold‐duration functions were obtained on both right and left ears. The results indicate the presence of temporal summation; but, as frequency is increased, the threshold‐duration function is depressed compared to that of a young, normative group [H. N. Wright, J. Acoust. Soc. Amer. 53, 113(A) (1972)]. Five subjects from the older group with no previous history of noise exposure showed a pronounced frequency effect, with a shorten...

A quantitative model for deriving an age correction factor in noise‐induced hearing loss

This paper considers the factors of presbycusis and noise exposure in relation to permanent hearing loss and provides a quantitative model from which an age correction factor in occupational hearing loss may be derived. While extant physiological and audiometric data provide a justifiable rationale for a correction factor [J. F. Corso, in Henderson et el., Effects of noise on hearing (Raven, New York 1976), pp. 497–524], the conventional additivity hypothesis is deemed inappropriate. From selected empirical functions a quantitative model is derived for assessing the age component of occupational hearing loss. The model is based on the concept of a variable ratio for partitioning the effects of presbycusis and noise exposure. Consideration is given to the application of the model in medicolegal cases of occupational hearing loss in which the degree of hearing impairment must be assessed.

Information processing for complex tones in older adults

The ability of three age groups to identify complex tones was measured by the method of absolute judgments. Group mean ages were nominally 20, 40, and 60 yr., with ten matched subjects per group. Complex tones from ten different musical instruments were tape recorded and spliced to yield six experimental tone types per instrument with different waveforms and durations. After practice, the test tones were presented monaurally in random order in the subjects better ear at a loudness level of approximately 60 phons. Each subject made a total of 120 judgments with the correct instrumental identification being provided after each trial. Analysis of variance showed a significant difference in the mean number of correct responses for the four factors of age, instrument, tone type, and practice. For the ten instruments, the average amount of information transmitted per group in order of increasing age was 1.68, 1.49, and 1.42 bits. It is concluded that (1) the processing of complex‐tone information is adversely ...

Information Processing on Simultaneously Presented Auditory Tasks

This study primarily investigated the concept of a single limited‐capacity channel in information processing and the role of long‐term storage (memory) in controlling inputs to that channel. In a monotic pursuit situation, Ss (four groups of ten) tracked a 1000‐cps tone for 20 identical trials (53 sec each) during which the auditory course changed in intensity over a 35‐db range, approximately. Within each trial, the course followed a random pattern, but the pattern was repeated from trial to trial. During two intervals (8 sec each) which occurred randomly within each trial, Ss were required to judge simultaneously the longest in a series of five tonal pulses. The tonal pulses (four equal and one unequal in duration) were presented in Ss opposite ear at either 350 or 2250 cps and were relatively easy or relatively difficult to discriminate. It was found that in the simultaneous‐task situation, practiced Ss transmitted more information on the auditory tracking task and less on the tonal‐pulse task than...