Patricia A. Tun

Hearing loss and perceptual effort: Downstream effects on older adults’ memory for speech

A group of older adults with good hearing and a group with mild-to-moderate hearing loss were tested for recall of the final three words heard in a running memory task. Near perfect recall of the final words of the three-word sets by both good- and poor-hearing participants allowed the inference that all three words had been correctly identified. Nevertheless, the poor-hearing group recalled significantly fewer of the nonfinal words than did the better hearing group. This was true even though both groups were matched for age, education, and verbal ability. Results were taken as support for an effortfulness hypothesis: the notion that the extra effort that a hearing-impaired listener must expend to achieve perceptual success comes at the cost of processing resources that might otherwise be available for encoding the speech content in memory.

Hearing Loss in Older Adulthood What It Is and How It Interacts With Cognitive Performance

Adult aging is accompanied by declines in many areas of cognitive functioning, including reduced memory for new information. Potential sources of these declines are well established and include slowed processing, diminished working-memory capacity, and a reduced ability to inhibit interference. In addition, older adults often experience sensory decline, including decreased hearing acuity for high-frequency sounds and deficits in frequency and temporal resolution. These changes add to the challenge faced by older adults in comprehension and memory for everyday rapid speech. Use of contextual information and added perceptual and cognitive effort can partially offset the deleterious effects of these sensory declines. This may, however, come at a cost to resources that might otherwise be available for “downstream” operations such as encoding the speech content in memory. We argue that future research should focus not only on sensory and cognitive functioning as separate domains but also on the dynamics of their interaction.

Aging, Hearing Acuity, and the Attentional Costs of Effortful Listening

A dual-task interference paradigm was used to investigate the effect of perceptual effort on recall of spoken word lists by young and older adults with good hearing and with mild-to-moderate hearing loss. In addition to poorer recall accuracy, listeners with hearing loss, especially older adults, showed larger secondary task costs while recalling the word lists even though the stimuli were presented at a sound intensity that allowed correct word identification. Findings support the hypothesis that extra effort at the sensory-perceptual level attendant to hearing loss has negative consequences to downstream recall, an effect that may be further magnified with increased age.

Response latencies for false memories: Gist-based processes in normal aging.

Three experiments have demonstrated that age-related increases in both probability and speed of false recognitions for word lists depended on the use of a gist-based memory strategy. When test conditions promoted a gist strategy, both younger and older participants were as likely to falsely recognize a thematically associated lure as to correctly recognize a studied item, and both groups were equally fast in making these decisions. However, when test conditions deemphasized a gist-based strategy, older adults were more likely than younger adults, and faster, to falsely recognize both strong and weakly associated lures. These findings suggest an age-related increase in reliance on gist-based processing that may underlie age differences in false memory.

Frequent Cognitive Activity Compensates for Education Differences in Episodic Memory

OBJECTIVES To test the hypothesis that frequent participation in cognitive activities can moderate the effects of limited education on cognitive functioning. DESIGN A national study of adult development and aging, Midlife in the United States, with assessments conducted at the second wave of measurement in 2004-2006. SETTING Assessments were made over the telephone (cognitive measures) and in a mail questionnaire (demographic variables, measures of cognitive and physical activity, and self-rated health). PARTICIPANTS A total of 3,343 men and women between the ages of 32 and 84 with a mean age of 55.99 years. MEASUREMENTS The dependent variables were Episodic Memory (Immediate and Delayed Word List Recall) and Executive Functioning (Category Fluency, Backward Digit Span, Backward Counting Speed, Reasoning, and Attention Switching Speed). The independent variables were years of education and frequency of cognitive activity (reading, writing, doing word games or puzzles, and attending lectures). The covariates were age, sex, self-rated health, income, and frequency of physical activity. RESULTS The two cognitive measures were regressed on education, cognitive activity frequency, and their interaction, while controlling for the covariates. Education and cognitive activity were significantly correlated with both cognitive abilities. The interaction of education and cognitive activity was significant for episodic memory but not for executive functioning. CONCLUSION Those with lower education had lower cognitive functioning, but this was qualified by level of cognitive activity. For those with lower education, engaging frequently in cognitive activities showed significant compensatory benefits for episodic memory, which has promise for reducing social disparities in cognitive aging.

Fast noisy speech: Age differences in processing rapid speech with background noise.

In order to investigate the effects of age on the ability to process speech under conditions of background noise, younger and older adults listened to and reported time-compressed spoken sentences presented with varying levels of background babble. Although the two age groups did not differ significantly in terms of either pure tone averages or in the ability to accurately report the sentences when they were presented in quiet, the older participants showed less tolerance for background noise than younger adults. This age difference in performance was further magnified by increased speech rates, suggesting that both age-related slowing of processing and reduced inhibition of distracting sounds may produce age deficits in speech processing.

Age Differences in Reaction Time and Attention in a National Telephone Sample of Adults: Education, Sex, and Task Complexity Matter

This study demonstrated effects of age, education, and sex on complex reaction time in a large national sample (N = 3,616) with a wide range in age (32-85) and education. Participants completed speeded auditory tasks (from the MIDUS [Midlife in the U.S.] Stop and Go Switch Task) by telephone. Complexity ranged from a simple repeated task to an alternating task that involved central executive processes including attention switching and inhibitory control. Increased complexity was associated with slower responses in older adults, those with lower education, and women, even after controlling for differences in health status. Higher levels of education were associated with greater central executive efficiency across adulthood: Overall, adults with college degrees performed on complex tasks like less educated individuals who were 10 years younger, up to age 75. These findings suggest that advanced education can moderate age differences on complex speeded tasks that require central executive processes, at least up to the point in old age at which biological declines predominate. The approach demonstrates the utility of combining laboratory paradigms with survey methods to enable the study of larger, more diverse and representative samples across the lifespan.

Histories of Social Engagement and Adult Cognition: Midlife in the U.S. Study

OBJECTIVES To evaluate whether social contacts, support, and social strain/conflict are related to executive function and memory abilities in middle-age and older adults. METHODS Longitudinal data on social contacts, support, and strain/conflict were examined in relation to executive function and memory at ages 35-85 years using data from the national Midlife in the U.S. (MIDUS) study. Age-related differences in patterns of association were also examined. RESULTS Regression analyses, controlling for age, sex, race, education, chronic health conditions, and health behaviors, revealed significant positive associations between histories of greater social contacts and support and both executive function and episodic memory, whereas declines in social contacts were negatively associated with both outcomes. Greater average reported frequency of social exchanges characterized by strain or conflict was negatively associated with executive function but not episodic memory. Patterns were generally consistent across different age groups; where differences were seen, associations were stronger in younger age group. DISCUSSION Positive and negative aspects of social relationships are related to cognition throughout adulthood, consistent with the hypothesis that social factors have life-long influences on cognition. Positive and negative aspects of social engagement may thus be important factors to consider in relation to efforts to promote optimal cognitive development and cognitive aging.

Word recognition within a linguistic context: effects of age, hearing acuity, verbal ability, and cognitive function.

Objective: Participants in traditional studies of the effects of context on spoken word recognition have been university undergraduates. When older adults have been included, they have typically been matched with these young adults for verbal ability or years of education. Although this may be a good strategy for eliminating confounding variables, it is not clear how results of these studies may extend to the general population of young and older adults. The objective of this study was to examine the effects of adult age, hearing acuity, verbal ability, and cognitive function on the use of linguistic context in spoken word recognition. Design: Fifty-three adults, aged 19 to 89 yr, heard short sentences in which the final word was masked by multitalker babble. The level of babble was progressively reduced in 2 dB steps until the sentence-final word could be correctly identified. Published norms were used to construct sets of sentences in which the same word could be heard with three levels of predictability (low, medium, and high) based on the linguistic context. In a fourth condition (no context), the words were preceded by a neutral carrier phrase. Participants received tests of verbal ability, with an emphasis on vocabulary knowledge, a brief test battery to assess cognitive function, and an assessment of hearing acuity based on puretone thresholds. Participants’ hearing acuity ranged from normal acuity to moderate hearing loss. Results: Results showed that the signal to noise ratio necessary for correct word recognition varied inversely with the probability of that word occurring in the sentence context. Hearing loss had a significant effect on word recognition for words heard in a neutral context, but the effect of hearing acuity diminished progressively with increasing contextual probability of the target word. Hierarchical multiple regressions showed that hearing acuity accounted for a significant amount of the variance at the lowest three levels of contextual probability but not at the highest probability level tested. Cognitive function contributed significantly to the obtained variance in word recognition performance at all levels of contextual probability tested. Moreover, participant age accounted for a significant amount of variance even after hearing acuity and cognitive function were taken into account. Verbal ability in the range represented by the test participants did not contribute significantly to recognition performance in any of the context conditions. Conclusions: Peripheral hearing acuity accounted for only a part of the variance in word recognition accuracy, with significant variance also contributed by individual differences in cognitive function and participant age. Results showed the ability to use linguistic context to aid spoken word recognition is sufficiently robust that a relatively wide range in verbal ability among native English speakers had no effect on recognition performance.

Age and diabetes related changes in verbal fluency

Non-insulin-dependent diabetes mellitus is present in 7-10% of the aged. This disease appears to be associated with an acceleration of the aging process and results in compromised performance on learning and memory tasks. The present study used a verbal fluency test to examine semantic memory performance in two age groups (55-64 and 65-74 years) of diabetic subjects and controls. In addition, immediate and secondary memory were also examined using the digit symbol and digit span tests and a serial learning task. Results showed that digit symbol performance was poorer for older subjects and diabetics while serial learning was poorer only for diabetic subjects. However, the number of words generated on the verbal fluency test was similar for all groups. Qualitative analyses of the verbal output revealed that older subjects and diabetics produced the greatest number of previously recited words (repetitions). Repetitions may signal a failure to adequately monitor behavior which in turn could contribute to cognitive decline.