Are age-related changes in cognitive function driven by age-related changes in sensory processing?

Abstract

Although there has been keen interest in the association among measures of sensory function and cognitive function for many years, in general, measures of sensory function have been confined to one or two senses and measures of threshold sensitivity (acuity). In this study, rigorous psychophysical measures of threshold sensitivity, temporal gap detection, temporal order identification, and temporal masking have been obtained, in hearing, vision, and touch. In addition, all subjects completed 15 subtests of the Wechsler Adult Intelligence Scale, 3rd edition (WAIS–III). Data were obtained from 245 adults (18–87 years old) for the WAIS–III and for 40 measures of threshold sensitivity and temporal processing. The focus in this report is on individual differences in performance for the entire data set. Principal-components (PC) factor analysis reduced the 40 psychophysical measures to eight correlated factors, which were reduced further to a single global sensory processing factor. Similarly, PC factor analysis of the 15 WAIS–III scores resulted in three correlated factors that were further reduced to a single global cognitive function factor. Age, global sensory processing, and global cognitive function were all moderately and significantly correlated with one another. However, paired partial correlations, controlling for the third of these three measures, revealed that the moderate correlation between age and global cognitive function went to zero when global sensory processing was controlled for; the other two partial correlations remained intact. Structural models confirmed this result. These analyses suggest that the long-standing observation of age-related changes in cognitive function may be mediated by age-related changes in global sensory processing.

A Retrospective Examination of the Effect of Diabetes on Sensory Processing in Older Adults

“…With regard to sensory processing, the Tukey boxplots in Figure 1 display the medians and interquartile ranges for each of the eight sensory-processing factors from Humes et al (2013). Of these eight sensory measures, the only one that revealed a significant difference between groups was the auditory temporal-order/temporal-masking factor score (median test, p < .05).…”

“…There was considerable redundancy among the 40 psychophysical measures completed by the 245 adults in Humes et al (2013). As a result, principal-components factor analysis was used to reduce the 25 sensory-processing measures to eight factors and the 15 cognitive-processing measures to three factors.…”

“…The details of the stimuli and procedures used in the study by Humes et al (2013) can be found in that publication or earlier papers from that project (Busey, Craig, Clark, & Humes, 2010;Craig, Rhodes, Busey, KewleyPort, & Humes, 2010;Fogerty, Humes, & Kewley-Port, 2010). In brief, a total of 40 psychophysical measures were obtained in hearing, vision, and touch, with an emphasis on threshold sensitivity and temporal processing.…”

“…As a result, principal-components factor analysis was used to reduce the 25 sensory-processing measures to eight factors and the 15 cognitive-processing measures to three factors. For all the results presented here, we made use of the ensuing factor scores generated in Humes et al (2013) for the cognitive and sensory measures from the entire sample of 245 adults. Because all of the measures are factor scores, all with a mean of 0 and a standard deviation of 1, relative comparisons between diabetic and nondiabetic older adults can make use of the same scale.…”

“…We had the opportunity to investigate this further through retrospective analysis of an extensive dataset of sensory and cognitive processing measures obtained from 245 young, middle-aged, and older adults (Humes, Busey, Craig, & Kewley-Port, 2013). Here, we focus on just the 135 older adults in that study because none of the young or middle-aged adults self-reported diabetes in their case history.…”