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Biomedical subjects

R L McCroskey

Publications and source records attributed to R L McCroskey.

8 recordsLinked to original sources
PubMed1981

Sentence comprehension in elderly listeners: the factor of rate.

The study was designed to test the clinical observation that sentence comprehension in elderly listeners is enhanced when rate is slowed (time-expanded) and that comprehension is affected adversely when rate is speeded (time-compressed). Twenty normally-active elderly persons who ranged in age from 65 through 88 years listened to four matched sets of 10 sentences each that were modified electronically to produce the following four rate-alteration percentages: 100% (normal rate), 60% compression, 140% expansion, and 180% expansion. Sentences were presented binaurally to listeners who responded by selecting pictures that matched the sentences heard. Results indicated that sentence comprehension scores were significantly higher (p less than .01) at both the 60% and 140% alteration rates than at the normal speaking rate. Possible effects of the stimulus upon comprehension performance are discussed.

Aged↗
PubMed1981

Effects of stimulus frequency, level, and duration on auditory temporal ordering.

Auditory temporal ordering was investigated in 5 normal-hearing young adults. Ss made diotic 2IFC judgments for pure tones of 0.5, 1, 2, or 4 kc/s and critical-band noises centered at those frequencies, on duration (standard: 40 msec; variables: 10, 20, or 30 msec), level (standard: 70 db HL; variables: 40, 50 or 60 HL), and frequency (standard: 0.5 kc/s; variables: 1,2, or 4 kc/s). Interstimulus interval (ISI) was 5, 10, 20, 50, 100, or 200 msec. All stimuli were at 70 db HL except of course the variable stimuli in the level judgments. Performance improved with increasing ISI. Mean threshold ISIs (performance at 75%-correct) collapsed across pure tones and noise bands were 12.5, 6.25, and 6.25 msec for duration, level, and frequency, respectively. With ISI constant at 100 msec, ANOVAs revealed statistically significant differences among the variables for duration and for level but not for frequency (performance for frequency was nearly perfect at the shortest ISI). There were statistically significant differences between mean performance, and between mean threshold ISIs, for duration, level, and frequency, indicating that auditory temporal acuity is not independent of the kinds of sound, as has been suggested (Hirsh, J. Acoust. Soc. Am., 1959, 31, p. 759).

Adult↗
PubMed1980

Auditory fusion in children.

"Auditory fusion" was defined in terms of a listener's ability to distinguish paired acoustic events from single acoustic events. Children from the ages of 3-12 years listened to 270 pairs of tones controlled for frequency, intensity, and duration. Stimuli consisted of numerous pairs of tone pulses, separated by interpulse intervals that varied systematically from 0 through 40 msec. Results indicate that (a) auditory fusion improves rapidly and in an orderly fashion between 3 and 8 years of age, (b) signal intensity affects the fusion point, and (c) stimulus frequency--253 hertz through 4,000 hertz, at 5-octave intervals--does not affect the fusion point.

Auditory Perception↗
PubMedDate not supplied

Is eye color a predictor of noise-induced hearing loss?

This study investigated the hypothesis that eye color is related to permanent threshold shift. Hearing levels and eye color determinations (gray, blue, hazel, and brown) were obtained for 100 industrial employees. Discriminant function analyses were utilized to attempt to establish linear combinations of variables that would identify group membership (i.e., eye color) correctly. Linear combinations of variables were not effective in delineating group membership. Probabililty statistics were then utilized to evaluate the probability of the determined relationships. These results indicated predictive accuracy of 69% for blue-eyed workers and 59% for brown-eyed workers.

Adult↗
PubMedDate not supplied

Dynamic auditory localization by normal and learning disability children.

Twenty children from regular classrooms and 20 children from self-contained, learning disability classrooms tracked four different acoustic stimuli through three fixed paths in space. An apparatus specifically designed to provide objective data on accuracy of tracking was used. The results showed that learning disability children as a group were inferior in their abilities to follow a moving speech signal and a moving white noise. The position of the target with respect to the listeners' midlines affected accuracy of tracking, but this was not a function of the hand used to control the pointer.

Acoustic Stimulation↗
PubMedDate not supplied

Technical note: an apparatus for exploring dynamic auditory localization.

The purpose was to develop and test an apparatus for objective specification of localization of a moving acoustic target. The system involves computer analysis and graphic display of vectors created from rotational and linear potentiometers that are activated by listeners using a hand-held pointer as they track an acoustic event.

Acoustic Stimulation↗