The electrophysiological masking level difference: effects of age and mediation of hearing and cognition

OBJECTIVE

Evaluate the conceptual framework that age effects on the electrophysiological binaural masking level difference (MLD) are partially mediated by age-related hearing loss and/or global cognitive function via mediation analysis.

DESIGN

Participants underwent a series of audiometric tests. The MLD was measured via cortical auditory evoked potentials using a speech stimulus (/ɑ/) in speech-weighted background noise. We used mediation analyses to determine the total effect, natural direct effects, and natural indirect effects, which are displayed as regression coefficients ([95% CI]; p value).

STUDY SAMPLE

Twenty-eight individuals aged 19-87 years (mean [SD]: 53.3 [25.2]), recruited from the community.

RESULTS

Older age had a significant total effect on the MLD (-0.69 [95% CI: -0.96, -0.45]; p < 0.01). Neither pure tone average (-0.11 [95% CI: -0.43, 0.24; p = 0.54] nor global cognitive function (-0.02 [95% CI: -0.13, 0.02]; p = 0.55) mediated the relationship of age and the MLD and effect sizes were small. Results were insensitive to use of alternative hearing measures or inclusion of interaction terms.

CONCLUSIONS

The electrophysiological MLD may be an age-sensitive measure of binaural temporal processing that is minimally affected by age-related hearing loss and global cognitive function.

Auditory speed tasks as potential candidates for the study of cognitive ageing

Speed of information processing is an important cognitive ability. It facilitates the efficient operation of higher order cognitive functions, such as reasoning, and is implicated in various models of cognitive decline. The present study considers the potential benefits of expanding the measurement of processing speed to include the auditory modality. It examines the reliability and factorial structure of a variety of auditory and visual speed tasks in a sample of N = 138 older adults aged between 51 and 82 years. Our findings demonstrate that auditory measures can be used to assess processing speed as indexed by existing widely used tests of this ability. Moreover, the inclusion of auditory tasks significantly increases the relationship between processing speed and general cognitive ability. This novel research provides strong evidence of the suitability of auditory speed tasks for the study of cognitive function in older people, and demonstrates the importance of expanding cognitive measurement to include alternate modalities.

In search of the internal structure of the processes underlying interval timing in the sub-second and the second range: a confirmatory factor analysis approach

One of the earliest accounts of duration perception by Karl von Vierordt implied a common process underlying the timing of intervals in the sub-second and the second range. To date, there are two major explanatory approaches for the timing of brief intervals: the Common Timing Hypothesis and the Distinct Timing Hypothesis. While the common timing hypothesis also proceeds from a unitary timing process, the distinct timing hypothesis suggests two dissociable, independent mechanisms for the timing of intervals in the sub-second and the second range, respectively. In the present paper, we introduce confirmatory factor analysis (CFA) to elucidate the internal structure of interval timing in the sub-second and the second range. Our results indicate that the assumption of two mechanisms underlying the processing of intervals in the second and the sub-second range might be more appropriate than the assumption of a unitary timing mechanism. In contrast to the basic assumption of the distinct timing hypothesis, however, these two timing mechanisms are closely associated with each other and share 77% of common variance. This finding suggests either a strong functional relationship between the two timing mechanisms or a hierarchically organized internal structure. Findings are discussed in the light of existing psychophysical and neurophysiological data.

Effects of practice on variability in an isochronous serial interval production task: asymptotical levels of tapping variability after training are similar to those of musicians

Timing permeates everyday activities such as walking, dancing and music, yet the effect of short-term practice in this ubiquitous activity is largely unknown. In two training experiments involving sessions spread across several days, we examined short-term practice effects on timing variability in a sequential interval production task. In Experiment 1, we varied the mode of response (e.g., drumstick and finger tapping) and the level of sensory feedback. In Experiment 2 we varied the interval in 18 levels ranging from 500 ms to 1624 ms. Both experiments showed a substantial decrease in variability within the first hour of practice, but little thereafter. This effect was similar across mode of response, amount of feedback, and interval duration, and was manifested as a reduction in both local variability (between neighboring intervals) and drift (fluctuation across multiple intervals). The results suggest mainly effects on motor implementation rather than on cognitive timing processes, and have methodological implications for timing studies that have not controlled for practice.

Lapsed attention to elapsed time? Individual differences in working memory capacity and temporal reproduction

Working memory capacity (WMC) predicts individual differences in a wide range of mental abilities. In three experiments we examined whether WMC would predict temporal judgment. Low-WMC temporal reproductions were consistently too long for the shortest duration and too short for the longest, but were accurate (unbiased) for the intermediate. In contrast, high-WMC temporal reproductions were more accurate (unbiased) across the range. Thus low-WMC showed a classic "migration effect" (Vierordt's Law) to a greater extent than high-WMC. Furthermore reproduction errors depended more on temporal context than the absolute durations of "shortest," "longest," and "intermediate." Low-WMC reproductions were overall more variable than high-WMC. General fluid intelligence (gF) was also related to temporal bias and variability. However, WMC-related timing differences were only attenuated and not eliminated with gF as covariate. Results are discussed in terms of attention, memory, and other psychological constructs.

Processing Visual Temporal Information and Its Relationship to Psychometric Intelligence

According to previous studies there is a well-established functional relationship between temporal resolution power (TRP), assessed by auditory psychophysical timing tasks, and psychometric intelligence. Here we investigated whether the relationship between psychometric intelligence and temporal information processing can be also observed in the visual modality. For this purpose, performance on four visual psychophysical timing tasks (duration discrimination with filled and empty intervals, temporal generalization, and rhythm perception) was examined and related to performance on a psychometric test of intelligence. Correlational analyses indicated a reliable positive association between performance on each of the four temporal tasks and psychometric intelligence. Structural equation modeling suggested that performance on the four tasks can be assigned to one latent variable, referred to as TRP, which explained 16.5% of variance of psychometric intelligence. Findings indicate that the functional relationship previously observed between auditory temporal processing and psychometric intelligence can be generalized to the visual modality.

Processing of Temporal and Nontemporal Information as Predictors of Psychometric Intelligence: A Structural-Equation-Modeling Approach

Recent research suggests a functional link between temporal acuity and general intelligence. To better understand this relation, the present study took advantage of a large sample (N=260) and structural equation modelling to examine relations among temporal acuity, measured by various tasks, speed of information processing as measured by the Hick reaction time task, and psychometric intelligence. Temporal acuity and the Hick task showed common variance in predicting psychometric intelligence. Furthermore, timing performance was a better predictor of psychometric intelligence and mediated the relation between Hick task performance and psychometric intelligence. These findings are consistent with the idea that temporal acuity reflects a basic property of neural functioning that is relevant to intelligence-related aspects of mental activity including speed of information processing.