Comprehension of a novel accent by young and older listeners.

The authors investigated perceptual learning of a novel accent in young and older listeners through measuring speech reception thresholds (SRTs) using speech materials spoken in a novel—unfamiliar—accent. Younger and older listeners adapted to this accent, but older listeners showed poorer comprehension of the accent. Furthermore, perceptual learning differed across groups: The older listeners stopped learning after the first block, whereas younger listeners showed further improvement with longer exposure. Among the older participants, hearing acuity predicted the SRT as well as the effect of the novel accent on SRT. Finally, a measure of executive function predicted the impact of accent on SRT. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Evidence for an across-frequency, between-channel process in asymptotic monaural temporal gap detection

Monaurally measured temporal gap detection (TGD) thresholds characteristically increase as the frequency difference is increased over a range of about half an octave to an octave between two sinusoids that mark the onset and offset of the silent gap. For greater sinusoidal frequency separations, the TGD thresholds often become asymptotic. This pattern probably reflects two different processes. The first process likely reflects within-channel processing within a single auditory filter or channel. The second process is less certain, but may reflect between-channel processing of the silent gap stimulus across two or more independent frequency channels. To evaluate the hypothesis that asymptotic monaural gap detection can be explained by a simple between-channel process, TGD thresholds were measured as a function of frequency separation between a pregap sinusoid presented to the left ear (channel 1) and a postgap sinusoid, of higher frequency, presented to the right ear (channel 2). The rationale for dichotic presentation of the sinusoidal markers and gap signal followed from the fact that the gap detection task must be performed between two independent channels by combining the outputs from each channel (ear) and recovering the gap information centrally. The resulting TGD thresholds for pregap sinusoids from 250 to 4000 Hz were relatively invariant and increased only slightly with increasing marker frequency separation. The average TGD thresholds for four listeners were in the range of 30 to 40 ms, which corresponded closely with their asymptotic TGD thresholds for the same set of stimulus conditions measured monaurally. This correspondence of the two data sets supports an across-frequency, between-channel process for asymptotic monaural gap detection at marker frequency separations greater than about half an octave.     

Gap encoding by inferior collicular neurons is altered by minimal changes in signal envelope

Neural correlates of temporal resolution in the central auditory system are currently under intense investigation. The gap detection paradigm offers a simple, yet important, test of temporal acuity because changes in behavioral gap thresholds have been correlated with deficits in complex stimulus processing, such as speech perception. In gap detection studies, silent gaps are typically shaped by rapid (< 1.0 ms) rise/fall (R/F) times, i.e., rapid decreases and increases in sound intensity. However, in nature, the envelopes surrounding silent periods can vary significantly in R/F time. Therefore, we investigated whether changes in the R/F time surrounding the silent gap affect neural processing by inferior collicular (IC) neurons. Gap R/F times were varied between 0.5 and 16 ms and the discharge pattern, response rate, and first spike latency of IC neurons were measured for gap widths up to 100 ms. Neurons were classified into phasic or tonic discharge patterns based on peri-stimulus time histograms elicited to 100 ms noise carriers. The results indicate that (1) minimal gap thresholds increased with R/F time regardless of response type, (2) first spike latency variance increased systematically with R/F time for units which had small first spike standard deviations at short R/F times, and (3) the response rate of some units (called 'gap-tuned') changed as a function of both R/F time and gap width. Gap-tuned units responded strongly to a particular gap width only when the envelope of the gap was shaped by a particular R/F time. For gap-tuned units, increases in R/F time shifted the tuning to larger gap widths and also broadened the response profile. These results show that temporal acuity of neurons in the IC, as measured by the gap detection paradigm, is sensitive to the envelope surrounding gaps embedded in noise carriers.     

Temporal analysis and stimulus fluctuation in listeners with normal and impaired hearing

The first experiment investigated the effects of mild to moderate sensorineural hearing impairment on temporal analysis for noise stimuli of varying bandwidth. Tasks of temporal gap detection, amplitude modulation (AM) detection, and AM discrimination were examined. Relatively high levels of stimulation were used in order to reduce the possibility that the results of the listeners with hearing impairment would be influenced strongly by audibility. A general summary of results was that there was relatively great interlistener variation among the listeners with hearing impairment, with most listeners showing normal performance and some showing degraded performance, regardless of the bandwidth of the stimulus carrying the temporal information. A second experiment investigated the hypothesis that listeners with sensorineural hearing impairment might have poor gap detection due to loudness recruitment. Here, gap markers were presented at levels where loudness growth was steeper for the listeners with hearing impairment than for the listeners with normal hearing. Although gap detection was sometimes poorer in listeners with hearing impairment than in listeners with normal hearing, there was no clear relation between gap detection performance and loudness recruitment in listeners with mild to moderate sensorineural hearing impairment.     

Dimensions of affective experience in three age groups.

The dimensions by which adults of differing ages experience emotion were studied by self-administering questionnaires administered to older adults (n?=?828) recruited from Elderhostel programs, middle-aged (aged 30–59 yrs) children of Elderhostel attenders (n?=?231), and young adult (aged 18–29 yrs) Ss recruited from college classes or through Elderhostel participants (n?=?207). Elders were higher in emotional control, mood stability, and emotional maturity through moderation and leveling of positive affect and lower in surgency, psychophysiological responsiveness, and sensation seeking. These findings are consistent with the hypothesized increase in self-regulatory capacity with age. These cross-sectional differences cannot, however, be distinguished from cohort-related explanations; they require considerable replication across different types of Ss and further characterization of the dimensions in terms of their functions for self-regulation. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cohort differences in attitudes toward mental health services among older persons.

In order to investigate historical shifts in attitudes toward mental health and mental health services, two independent samples of older adults separated by a 14-year time interval were administered questionnaires. There were 91 in the 1977 sample (mean age 69.91 yrs) and 116 in the 1991 sample (mean age 71.94 yrs). Four newly created, internally consistent scales assessed multiple dimensions of their mental health attitudes (breadth of conceptions, bias, openness to help, range of problems). Analyses suggested that the younger cohorts of older adults held more positive attitudes toward mental health and mental health services than the older cohorts. These cohort differences remained when controlled for age, level of education, self-reported health, and income. These data indicate a positive cohort shift in attitudes toward mental health, a finding with numerous implications for the design and implementation of mental health services for future cohorts of older persons. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Auditory suppression and frequency selectivity in older and younger adults

Age differences in auditory suppression were examined by comparing auditory-filter shapes obtained with simultaneous and forward masking at 2 kHz in young and elderly normal-hearing listeners. To compensate for the decay of forward masking, growth of masking functions were used to transform thresholds obtained with a notched-noise masker to the level of a continuous noise band that would give the same threshold values. Although both age groups exhibited smaller equivalent rectangular bandwidths (ERBs) when the filters derived from transformed thresholds were obtained with forward masking, the change from simultaneous to nonsimultaneous masking was significantly greater for young adults. Measures of the low- (Pl) and high- (Pu) frequency sides of the filters for young listeners indicated that the slopes of both sides increased following a change from simultaneous to forward masking but that the high-frequency side exhibited significantly greater sharpening. Filter slopes (both upper and lower) for older adults, in contrast, did not differ between the two masking procedures. The findings from the study are discussed as reflecting possible age differences in auditory suppression. However, it is also noted that conclusions regarding differences between filter shapes derived with simultaneous and forward masking are limited to filter parameters determined with transformed (as described above) thresholds.     

Signal detection and threshold measures for chronic back pain patients, chronic illness patients, and cohort controls to radiant heat stimuli.

15 chronic low back pain patients, 11 chronic respiratory patients, and 11 nonpatient controls (mean ages 47–56 yrs) were studied using a standard radiant heat signal detection methodology. Following determination by ascending limits of each S's stimulus detection and faint pain thresholds, 26 randomized trials at each of 5 stimulus levels were administered. Ss rated each stimulus on a 6-point subjective rating scale ranging from no pain to severe pain. Results indicate that the back pain Ss and respiratory Ss had higher radiant heat pain thresholds than the controls, and the back pain Ss had a discrimination deficit for mildly painful stimuli. Results fit the predictions of an adaptation model of pain perception in chronic pain patients as opposed to a hypochondriasis model. (9 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Inter-individual differences in binaural detection of low-frequency or high-frequency tonal signals masked by narrow-band or broadband noise

Detection thresholds for either 500-Hz tones or 4-kHz tones were measured for a group of 19 listeners utilizing the interaural configurations NoSo and NoS pi. Both broadband (100-8500 Hz) noises and narrow-band (50-Hz-wide) noises served as maskers. In addition, direct measures of the listeners' sensitivities to changes in interaural temporal differences (ITDs) and interaural intensitive differences (IIDs) were measured using 400-Hz-wide noises centered at 500 Hz or 4 kHz. A rather large range of inter-individual differences in threshold was observed for 4-kHz tonal signals masked by narrow-band noise in the NoS pi configuration. This result is consistent with several sets of data from our previous experiments conducted over more than a decade. A broad range of thresholds was also obtained for 500-Hz tonal signals masked by narrow-band noise in the NoS pi configuration. This outcome, coupled with the fact that the use of a broadband masker did not yield a large distribution of thresholds for the detection of a 500-Hz tone masked by a broad band of noise, suggests that it is the use of a narrow-band masker, per se, that results in a large range of thresholds. Statistical analyses revealed that thresholds in the NoS pi detection tasks were not highly correlated with thresholds measured in the ITD- and the IID-discrimination tasks. Nevertheless, the five listeners who were the most sensitive in the narrow-band NoS pi detection and the five listeners who were the least sensitive in the narrow-band NoS pi detection tasks were those who were the most and least sensitive, respectively, to changes in ITDs and to changes in IIDs.     

Impairment index versus T -score averaging in neuropsychological assessment.

Obtained neuropsychological data on 81 patients with cerebral lesions and 87 patients (mean ages, 32.9 and 39.3 yrs, respectively) presenting signs and symptoms of cerebral dysfunction but who received nonneurological discharge diagnoses. Two methods of combining neuropsychological test results were compared for percentage of accuracy in classifying Ss into appropriate groups. A standard deviation averaging method using T -score conversion tables for raw score data was found to be superior to the Halstead Impairment Index for the nonneurologic group only. The difference was attributed to the tendency of the Halstead index to misclassify older, normal Ss as brain damaged. The cutting score used by the averaging method (-1 standard deviation) was considered pathognomonic since very few nonneurological Ss scored lower than this point. (18 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The effects of aging on reaction time in a signal detection task.

The effects of aging on response time are examined in 2 simple signal detection tasks with young and older subjects (age 60 years and older). Older subjects were generally slower than young subjects, and standard Brinley plot analyses of response times showed typical results: slopes greater than 1 and (mostly) negative intercepts. R. Ratcliff, D. Spieler, and G. McKoon (2000) showed that the slopes of Brinley plots measure the relative standard deviations of the distributions of response times for older versus young subjects. Applying R. Ratcliffs (1978) diffusion model to fit the response times, their distributions, and response accuracy, it was found that the larger spread in older subjects' response times and their slowness relative to young subjects comes from a 50-ms slowing of the nondecision components of response time and more from conservative settings of response criteria. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Effects of bilateral auditory cortical lesions on gap-detection thresholds in the ferret (Mustela putorius).

Ferrets were tested for their ability to detect temporal gaps in noise before and after bilateral lesions of the primary auditory cortex. Thresholds for gap detection were determined first for normal animals with band-pass noises at various center frequencies (0.5 to 32 kHz) and at 8 kHz with various sound pressure levels (-10 to 70 dB). Gap-detection ability improved steadily as sound pressure increased up to 70 dB. No systematic relation was found between threshold and center frequency. To determine the effects of brain damage, ferrets were tested with 8-kHz band-pass noise at 70 dBSPL. After bilateral lesions of auditory cortex, ferrets were still capable of detecting gaps, but the mean threshold was elevated from 10.1 to 20.1 ms. The data demonstrate that auditory cortex is important for perceptual tasks requiring fine temporal resolution. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Detection of silent intervals between noises activating different perceptual channels: some properties of "central" auditory gap detection

This article describes four experiments on gap detection by normal listeners, with the general goal being to examine the consequences of using noises in different perceptual channels to delimit a silent temporal gap to be detected. In experiment 1, subjects were presented with pairs of narrow-band noise sequences. The leading element in each pair had a center frequency of 2 kHz and the trailing element's center frequency was parametrically varied. Gap detection thresholds became increasingly poor, sometimes by up to an order of magnitude, as the spectral disparity was increased between the noise bursts that marked the gap. These data suggested that gap-detection performance is impoverished when the underlying perceptual timing operation requires a comparison of activity in different perceptual channels rather than a discontinuity detection within a given channel. In experiment 2, we assessed the effect of leading-element duration in within-channel and between-channel gap detection tasks. Gap detection thresholds rose when the duration of the leading element was less than about 30 ms, but only in the between-channel case. In experiment 3, the gap-detection stimulus was redesigned so that we could probe the perceptual mechanisms that might be involved in stop consonant discrimination. The leading element was a wideband noise burst, and the trailing element was a 300-ms bandpassed noise centered on 1.0 kHz. The independent variable was the duration of the leading element, and the dependent variable was the smallest detectable gap between the elements. When the leading element was short in duration (5-10 ms), gap thresholds were close to 30 ms, which is close to the voice onset time that parses some voiced from unvoiced stop consonants. In experiment 4, the generality of the leading-element duration effect in between-channel gap detection was examined. Spectrally identical noises defining the leading and trailing edges of the gap were presented to the same or to different ears. There was a leading-element duration effect only for the between channel case. The mean gap threshold was again close to 30 ms for short leading-element durations. Taken together, the data suggest that gap detection requiring a temporal correlation of activity in different perceptual channels is a fundamentally different task to the discontinuity detection used to execute gap detection performance in the traditional, within-channel paradigm.     

Size of critical band in infants, children, and adults.

Masked thresholds at two signal frequencies (0.8 and 4 kHz) were obtained from listeners aged 6.5 months, 2 years, 5 years, and 20.5 years in the presence of constant spectrum level, narrow-band maskers of differing bandwidths. Consistent with the classical results of H. Fletcher (1940), masked threshold for all age groups increased with bandwidth up to a critical width, beyond which further increases in bandwidth were ineffective in increasing threshold. These critical widths (estimates of critical band size) did not change substantially with age (critical widths for infants were no more than 50% larger than those of adults) despite substantial changes in masked thresholds with age. Thus, contrary to previous claims, changes in auditory filter width cannot account for developmental changes in masked or absolute thresholds. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Testing global memory models using ROC curves.

Global memory models are evaluated by using data from recognition memory experiments. For recognition, each of the models gives a value of familiarity as the output from matching a test item against memory. The experiments provide ROC (receiver operating characteristic) curves that give information about the standard deviations of familiarity values for old and new test items in the models. The experimental results are consistent with normal distributions of familiarity (a prediction of the models). However, the results also show that the new-item familiarity standard deviation is about 0.8 that of the old-item familiarity standard deviation and independent of the strength of the old items (under the assumption of normality). The models are inconsistent with these results because they predict either nearly equal old and new standard deviations or increasing values of old standard deviation with strength. Thus, the data provide the basis for revision of current models or development of new models. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Auditory temporal order perception in younger and older adults

This investigation examined the abilities of younger and older listeners to discriminate and identify temporal order of sounds presented in tonal sequences. It was hypothesized that older listeners would exhibit greater difficulty than younger listeners on both temporal processing tasks, particularly for complex stimulus patterns. It was also anticipated that tone order discrimination would be easier than tone order identification for all listeners. Listeners were younger and older adults with either normal hearing or mild-to-moderate sensorineural hearing losses. Stimuli were temporally contiguous three-tone sequences within a 1/3 octave frequency range centered at 4000 Hz. For the discrimination task, listeners discerned differences between standard and comparison stimulus sequences that varied in tonal temporal order. For the identification task, listeners identified tone order of a single sequence using labels of relative pitch. Older listeners performed more poorly than younger listeners on the discrimination task for the more complex pitch patterns and on the identification task for faster stimulus presentation rates. The results also showed that order discrimination is easier than order identification for all listeners. The effects of hearing loss on the ordering tasks were minimal.     

Renal and hepatic 1 alpha-hydroxylation of 25-hydroxyvitamin D3 in piglets suffering from pseudo vitamin D-deficiency rickets, type I

Research has shown that speech articulated in a clear manner is easier to understand than conversationally spoken speech in both the auditory-only (A-only) and auditory-visual (AV) domains. Because this research has been conducted using younger adults, it is unknown whether age-related changes in auditory and/or visual processing affect older adults' ability to benefit when a talker speaks clearly. The present study examined how speaking mode (clear vs conversational) and presentation mode (A-only vs AV) influenced nonsense sentence recognition by older listeners. Results showed that neither age nor hearing loss limited the amount of benefit that older adults obtained from a talker speaking clearly. However, age was inversely correlated with identification of AV (but not A-only) conversational speech, even when pure-tone thresholds were controlled statistically.     

Orienting tasks as moderators of narrative and expository text recall in adulthood.

Incidental narrative and expository prose memory of 60 older adults (mean age 71.6 yrs) and 60 younger adults (mean age 23.6 yrs) was assessed following orienting tasks that emphasized either relational (sentence scrambling) or individual proposition (letter deletion) information or following a control condition. Orienting tasks were done capably, but older adults took longer and made more errors on the letter-deletion task than did younger adults. Age differences in recall were observed consistently for expository texts, but for narrative texts, age differences in recall were observed only when letters were deleted. If orienting tasks overtax older adults' processing resources or emphasize shallow information, recall gains may be minimal. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Increases in depressive symptomatology in the rural elderly: Results from a cross-sectional and longitudinal study.

Depressive symptomatology was examined in a large sample of noninstitutionalized older adults using the Center for Epidemiological Studies-Depression scale (CES-D). Both cross-sectional and longitudinal data showed age-related increases in mean CES-D scores and increases in the percentage of respondents scoring at or above the cutoff score of 16. Variables collected at baseline in the longitudinal study from 2,032 participants 65 yrs of age and older were significant predictors of depressive symptomatology 3 and 6 yrs later. Baseline CES-D scores accounted for the largest proportion of the variance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Verbal control of behavior: The effects of shouting.

Tested the implication of A. R. Luria's (1961, 1969) theory that children under 5 yrs of age would have more difficulty obeying instructions to inhibit a response the greater the intensity (loudness) of the instruction; this should not be true for children over 5 yrs of age. In the present study, 18 younger children (aged 3 yrs 6 mo to 4 yrs 9 mo) and 18 older children (aged 4 yrs 10 mo to 6 yrs 4 mo) played a game in which they were to follow instructions and either perform or refrain from performing simple acts. Instructions were loud, medium, or soft in intensity. Results for younger Ss were clear and significant in supporting Luria's theory. For older Ss, however, results do not neatly fit Luria's theory: Increased intensity facilitated compliance with instructions to inhibit a response. Data support the contention that an important aspect of language development is the decontextualization of meaning. (4 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)