Frequency and intensity discrimination measured in a maximum-likelihood procedure from young and aged normal-hearing subjects

Abstract

A maximum-likelihood method was applied in measurements of frequency and intensity discrimination for aged and young normal-hearing subjects with closely matched audiograms. This method was preferred over other psychophysical procedures because it is efficient and controls experimental variance, features that are highly desirable for testing aged subjects. In order to implement the method, psychometric functions for each task were also measured from young subjects using a constant-stimuli procedure. For the young subjects, the differential thresholds obtained from these two procedures were generally comparable. Further, both sets of data were consistent with previous literature, indicating that the maximum-likelihood method was successfully applied for frequency and intensity discrimination. A frequency-dependent difference between young and aged subjects in both frequency and intensity discrimination was observed. Even with closely matched audiograms, aged subjects demonstrated poorer discrimination abilities than young subjects. The age-related difference was always largest at 500 Hz and decreased as frequency increased.

Age-related differences in sensitivity to small changes in frequency assessed with cortical evoked potentials

“…Age-related differences in the ability to detect these changes may be associated with poorer speech recognition (Buss et al, 2004). Several behavioral studies have reported an age-related decline in frequency difference limen, either as reduced frequency discrimination (He et al, 1998;Humes, 1996;Konig, 1957) or frequency modulation detection (He et al, 2007). However, substantial variability has been observed both within and across studies (see Jesteadt and Sims 1975, for a review).…”

“…However, substantial variability has been observed both within and across studies (see Jesteadt and Sims 1975, for a review). This variability may reflect differences in tasks and procedures, such as the standard frequency examined, and the subject's hearing sensitivity, level of attention, or ability to perform the task (He et al, 1998;Turner et al, 1982). For instance, He et al (1998) examined frequency discrimination in younger and older adults with normal hearing and observed a frequency-dependent aging effect, such that age-related differences were larger at lower frequencies than at higher frequencies.…”

“…This variability may reflect differences in tasks and procedures, such as the standard frequency examined, and the subject's hearing sensitivity, level of attention, or ability to perform the task (He et al, 1998;Turner et al, 1982). For instance, He et al (1998) examined frequency discrimination in younger and older adults with normal hearing and observed a frequency-dependent aging effect, such that age-related differences were larger at lower frequencies than at higher frequencies. Similarly, frequency modulation detection was poorer in older than younger subjects and age-related differences were larger at 500 Hz than at 4000 Hz (He et al, 2007).…”

“…Several factors have been shown to affect frequency difference limens measured behaviorally, including subject age, stimulus paradigm (frequency discrimination vs frequency modulation), and carrier frequency. In general, regardless of stimulus paradigm, age-related effects on frequency difference limens are larger at lower carrier frequencies than at higher carrier frequencies (He et al, 1998;. In order to assess the effects of frequency, P1-N1-P2 responses in the current study were recorded in response to small changes in frequency in 500 Hz and 3000 Hz pure tones.…”

“…In order to assess the effects of frequency, P1-N1-P2 responses in the current study were recorded in response to small changes in frequency in 500 Hz and 3000 Hz pure tones. Based on the frequency-dependent aging effect reported for frequency discrimination and frequency modulation detection measured behaviorally (He et al, 1998;, we predicted that older adults would be less sensitive to frequency changes than younger adults, with larger age-related differences observed at lower frequencies (500 Hz) than at higher frequencies (3000 Hz).…”