David F. Hultsch

Use It or Lose It: Engaged Lifestyle as a Buffer of Cognitive Decline in Aging?

Data from the Victoria Longitudinal Study were used to examine the hypothesis that maintaining intellectual engagement through participation in everyday activities buffers individuals against cognitive decline in later life. The sample consisted of 250 middle-aged and older adults tested 3 times over 6 years. Structural equation modeling techniques were used to examine the relationships among changes in lifestyle variables and an array of cognitive variables. There was a relationship between changes in intellectually related activities and changes in cognitive functioning. These results are consistent with the hypothesis that intellectually engaging activities serve to buffer individuals against decline. However, an alternative model suggested the findings were also consistent with the hypothesis that high-ability individuals lead intellectually active lives until cognitive decline in old age limits their activities.

Measurement properties of the center for epidemiological studies depression scale (CES−D) in older populations

Two cross-sectional samples of adults were administered the 20-item Center for Epidemiological Studies-Depression Scale (CES-D). The results support the measurement validity of the CES-D for depression screening in older adult populations

Intraindividual variability in cognitive performance in older adults: comparison of adults with mild dementia, adults with arthritis, and healthy adults.

Intraindividual variability in latency and accuracy of cognitive performance across both trials and occasions was examined in 3 groups of older adults: healthy adults, adults with arthritis, and adults diagnosed with mild dementia. Participants completed 2 reaction-time and 2 episodic-memory tasks on 4 occasions. Results indicated that intraindividual variability in latency was greater in individuals diagnosed with mild dementia than in adults who were neurologically intact, regardless of their health status. Individual differences in variability were stable over time and across cognitive domains. Intraindividual variability was also related to level of performance and was uniquely predictive of neurological status, independent of level of performance. Results suggest that intraindividual variability may be a behavioral indicator of compromised neurological mechanisms.

Relationships between metamemory, memory predictions, and memory task performance in adults.

A cross-sectional sample of adults recalled categorized word lists and narrative texts. Subjects gave performance predictions before each of 3 recall trials for each task. Older subjects had poorer memory performance and also predicted lower performance levels than did younger subjects. The LISREL models suggested (a) direct effects of memory self-efficacy (MSE) on initial predictions; (b) upgrading of prediction-performance correlations across trials, determined by direct effects of performance on subsequent predictions; (c) significant effects of a higher order verbal memory factor on MSE; and (d) an independent relationship of text recall ability to initial text recall performance predictions. These results lend support to the theoretical treatment of predictions as task-specific MSE judgments.

Performance variability is related to change in cognition: evidence from the Victoria Longitudinal Study.

Performance variability across repeated task administrations may be an important indicator of age-related cognitive functioning. In the present investigation, the authors examined whether age differences and change in inconsistency were related to 6-year (3 occasion) cognitive change. Inconsistency scores were computed from 4 reaction time tasks performed by 446 older adults (54-89 years). Replicating previous cross-sectional results, greater inconsistency was observed for older participants even after controlling for differences in response speed. New longitudinal results demonstrated (a) associations between inconsistency at baseline measurement and 6-year change in cognitive performance; (b) longitudinal change in inconsistency; and (c) intraindividual covariation between 6-year change in inconsistency and 6-year change in level of cognitive function. These findings support the view that performance variability serves as a marker of cognitive aging.

Short-term longitudinal change in cognitive performance in later life

Changes in mean performance on memory, information processing, and intellectual ability tasks over a 3-year period were examined. The sample consisted of 328 community-dwelling men and women (from an original sample of 484 individuals) aged 55-86 years. Ss completed tasks yielding measures of verbal processing time, working memory, implicit memory, vocabulary, verbal fluency, world knowledge, reading comprehension, word recall, and text recall. The results showed significant average decline on working memory, verbal fluency, and world knowledge. There were also interactions for 2 processing time measures and working memory, showing greater decline in the earlier-born cohort group than in the later-born cohort group. A step-down analysis revealed that covarying declines in other variables, including processing time, did not eliminate significant declines in working memory, verbal fluency, and world knowledge.

Latent Change Models of Adult Cognition: Are Changes in Processing Speed and Working Memory Associated With Changes in Episodic Memory?

The authors used 6-year longitudinal data from the Victoria Longitudinal Study (VLS) to investigate individual differences in amount of episodic memory change. Latent change models revealed reliable individual differences in cognitive change. Changes in episodic memory were significantly correlated with changes in other cognitive variables, including speed and working memory. A structural equation model for the latent change scores showed that changes in speed and working memory predicted changes in episodic memory, as expected by processing resource theory. However, these effects were best modeled as being mediated by changes in induction and fact retrieval. Dissociations were detected between cross-sectional ability correlations and longitudinal changes. Shuffling the tasks used to define the Working Memory latent variable altered patterns of change correlations.

Ability correlates of memory performance in adulthood and aging.

The predictive relationships between an array of cognitive process and intellectual ability variables and text- and word-recall performance were examined. A sample of 584 men and women from 3 age groups (19-36, 55-69, and 70-86 years) completed a battery of 23 tasks marking 2 latent criterion variables and 10 latent predictor variables. The results indicated that (a) individual differences in process and ability variables predict performance on text and word recall, accounting for approximately half of the variance; (b) the pattern of predictors is quite similar for text and word recall; (c) age-related differences in text and word recall can be substantially accounted for by individual differences in constituent abilities, particularly indicators of verbal speed and working memory; and (d) there is some evidence to suggest that the pattern of ability-performance relationships varies across age, but such interactions appear to be relatively small.

Neurocognitive markers of cognitive impairment: exploring the roles of speed and inconsistency.

A well-known challenge for research in the cognitive neuropsychology of aging is to distinguish between the deficits and changes associated with normal aging and those indicative of early cognitive impairment. In a series of 2 studies, the authors explored whether 2 neurocognitive markers, speed (mean level) and inconsistency (intraindividual variability), distinguished between age groups (64-73 and 74-90+ years) and cognitive status groups (nonimpaired, mildly impaired, and moderately impaired). Study 1 (n = 416) showed that both level and inconsistency distinguished between the age and 2 cognitive status (not impaired, mildly impaired) groups, with a modest tendency for inconsistency to predict group membership over and above mean level. Study 2 (n = 304) replicated these results but extended them because of the qualifying effects associated with the unique moderately impaired oldest group. Specifically, not only were the groups more firmly distinguished by both indicators of speed, but evidence for the differential contribution of performance inconsistency was stronger. Neurocognitive markers of speed and inconsistency may be leading indicators of emerging cognitive impairment.Supervisory Committee Dr. Kimberly Kerns, Department of Psychology Supervisor Dr. Mauricio Garcia-Barrera, Department of Psychology Departmental Member – Revision Supervisor Dr. John Walsh, Department of Educational Psychology and Leadership Studies External Member Dr. Leslie Saxon, Department of Linguistics Additional Member Abstract The purpose of the current study was to examine the impact of working memory on speech monitoring processes in the primary language of school-age children using the framework of Levelt’s Perceptual Loop Theory of speech production (1983). A community sample of eight children aged 6-8 and fourteen children aged 10-12 completed 4 verbal description tasks under different conditions; control, working memory load, white noise and combined working memory load and white noise. Participants also completed measures of listening span, digit span and spatial span. The results indicate that with increasing working memory load, children make significantly more speech errors, silent pauses and repetitions. No relationship was found between working memory and total repairs per errors or between working memory and total number of editing terms used. Group differences across the conditions were not significant; however, age-related trends were notable. Younger children had greater difficulty monitoring their speech with the introduction of working memory load; whereas, older children had greater difficulty with the introduction of white noise. A revised speech production model incorporating aspects of working memory is recommended and implications for clinical populations are discussed.The purpose of the current study was to examine the impact of working memory on speech monitoring processes in the primary language of school-age children using the framework of Levelt’s Perceptual Loop Theory of speech production (1983). A community sample of eight children aged 6-8 and fourteen children aged 10-12 completed 4 verbal description tasks under different conditions; control, working memory load, white noise and combined working memory load and white noise. Participants also completed measures of listening span, digit span and spatial span. The results indicate that with increasing working memory load, children make significantly more speech errors, silent pauses and repetitions. No relationship was found between working memory and total repairs per errors or between working memory and total number of editing terms used. Group differences across the conditions were not significant; however, age-related trends were notable. Younger children had greater difficulty monitoring their speech with the introduction of working memory load; whereas, older children had greater difficulty with the introduction of white noise. A revised speech production model incorporating aspects of working memory is recommended and implications for clinical populations are discussed.

How'd They Do It? Malingering Strategies on Symptom Validity Tests

Twenty-five undergraduate students were instructed to feign believable impairment following a brain injury from a car accident and 27 students were told to perform like they had recovered from such an injury. Three forced-choice tests, the Test of Memory Malingering (TOMM), Victoria Symptom Validity Test (VSVT), and Word Memory Test (WMT) were given. Test-taking strategies were evaluated by means of a questionnaire given at the end of the test session. The results revealed that all the tasks differentiated between groups. Using conventional cut-scores, the WMT proved most efficient while the VSVT captured the most participants in the definitive below-chance category. Individuals instructed to feign injury were more likely to prepare prior to the experiment, with feigning of memory loss as the most frequently reported strategy. Regardless, preparation effort did not translate into believable performance on the tests.