The secure base script and the task of caring for elderly parents: implications for attachment theory and clinical practice.

This study explores links between adults' attachment representations and the task of caring for elderly parents with dementia. Participants were 87 adults serving as primary caregivers of a parent or parent-in-law with dementia. Waters and Waters' ( 2006 ) Attachment Script Assessment was adapted to assess script-like attachment representation in the context of caring for their elderly parent. The quality of adult-elderly parent interactions was assessed using the Level of Expressed Emotions Scale (Cole & Kazarian, 1988 ) and self-report measures of caregivers' perception of caregiving as difficult. Caregivers' secure base script knowledge predicted lower levels of negative expressed emotion. This effect was moderated by the extent to which participants experienced caring for elderly parents as difficult. Attachment representations played a greater role in caregiving when caregiving tasks were perceived as more difficult. These results support the hypothesis that attachment representations influence the quality of care that adults provide their elderly parents. Clinical implications are discussed.

Cerebral oxygenation in wake and during sleep and its relationship to cognitive function in community-dwelling older adults without sleep disordered breathing.

BACKGROUND: This descriptive cross-sectional study investigated the relationships between cerebral oxygen reserve and cognitive function in community-dwelling older adults. METHODS: Participants (72 women and 40 men) underwent standard polysomnography, including regional measures of percent oxyhemoglobin saturation (rcSO(2)) determined by cerebral oximetry. Two variables were used to calculate cerebral oxygen reserve: (a) awake rcSO(2) (mean presleep rcSO(2)) and (b) the change in rcSO(2) from before sleep to the end of the first non-rapid-eye movement cycle. General linear models, adjusted for the effects of education and occupation, tested differences in performance on standard tests of memory, attention, and speed of mental processing. RESULTS: Awake rcSO(2) values were normal (60%-79.9%) in 64 participants, marginal (50%-59.9%) in 41, and low (43%-49.9%) in 7. Participants with normal awake levels had higher cognitive function than those with low levels (p < .05). Changes in rcSO(2) were greatest in participants with marginal awake rcSO(2) values; among whom, those who increased rcSO(2) during sleep (n = 17) had better memory function than the 24 who did not (p < .05). CONCLUSIONS: Low awake rcSO(2) values mark individuals with low cerebral oxygen reserves and generally lower cognitive function; marginal awake rcSO(2) values that fall during sleep may indicate loss of cerebral oxygen reserve and an increased risk for cognitive decline. Further studies may clarify the significance of and mechanisms underlying individual differences in awake rcSO(2) and the changes that occur in rcSO(2) while asleep.

Aging and visual short-term memory: effects of object type and information load.

Previous research has observed that the size of age differences in short-term memory (STM) depends on the type of material to be remembered, but has not identified the mechanism underlying this pattern. The current study focused on visual STM and examined the contribution of information load, as estimated by the rate of visual search, to STM for two types of stimuli - meaningful and abstract objects. Results demonstrated higher information load and lower STM for abstract objects. Age differences were greater for abstract than meaningful objects in visual search, but not in STM. Nevertheless, older adults demonstrated a decreased capacity in visual STM for meaningful objects. Furthermore, in support of Salthouse's processing speed theory, controlling for search rates eliminated all differences in STM related to object type and age. The overall pattern of findings suggests that STM for visual objects is dependent upon processing rate, regardless of age or object type.

The effect of an exercise-based balance intervention on physical and cognitive performance for older adults: a pilot study.

BACKGROUND: Several exercise-based falls prevention interventions produced significant long-term reductions in fall rate, but few demonstrate long-term improvements in falls risk factors. A strong body of evidence supports a protective effect of aerobic or strength-training exercise on cognition. Individuals participating in an exercise-based balance improvement program may also experience this protective effect. This may contribute to the decreased rate of falls reported in the literature. PURPOSE: To determine if individuals participating in an evidence-based exercise program to reduce falls would demonstrate improvements in both physical and cognitive performance. METHODS: In this nonexperimental, pretest, posttest design study, 76 adults (65-93 years) participated in a scripted 12-week, 24 session exercise-based balance improvement program. Each 60 minute class incorporated balance, strength, endurance, and flexibility exercises. Participants completed baseline assessments of physical and cognitive performance measures 1 week prior and 1 week following the intervention. RESULTS: Fifty-two participants completed posttest measures. There were significant improvements in 3 physical performance measures (chair rise time, 360 degree turn, and 4 square step test). There also was similar improvement in the Symbol Digit Modality Test, a measure of processing speed and mental flexibility. When participants were dichotomized into 2 groups based on achieving/not achieving, a baseline walking speed of at least 1.0 meters/second, secondary analysis revealed greater improvements in cognitive performance measures of Trails A and Trails B tests by faster walkers compared to slower walkers. CONCLUSIONS: Participation in balance programs can have a positive impact on cognition and physical outcomes. This may provide insight about how exercise influences fall risk. Therapists can utilize this information clinically by educating patients about the potential positive effect of balance exercises on cognition.

Perceived stress and everyday memory complaints among older adult women.

Memory complaints among older adults are often influenced by depression and anxiety, but the association of stress to memory complaints has received little attention. We examined the associations of perceived stress, life events, and activity level to everyday memory complaints among healthy older women, while controlling for the influence of depression and anxiety. Participants (N=54) completed self-report questionnaires on memory complaints, perceived stress, recent life events, activity level, depression, and anxiety. Partial correlation analyses indicated that higher levels of perceived stress were associated with higher levels of memory complaints when controlling for the influence of depression and anxiety, but that life events and activity level were not related to memory complaints. This study highlights that perceived stress, like depression and anxiety, is a psychological factor that influences the appraisal of cognitive ability; however, larger and more heterogeneous samples will be needed to better understand the multifactorial nature of memory complaints in older adulthood.

Cerebrovascular disease and patterns of cerebral oxygenation during sleep in elders.

PURPOSE: The aim of this descriptive exploratory study was to describe patterns of cerebral oxygen reserves during sleep and their association with cerebrovascular risk factors in elders. METHOD: Participants--115 elders, age 70+ years--were monitored overnight using standard polysomnography. Measures included arterial oxyhemoglobin (SaO2) and regional measures of percentage of cerebral oxyhemoglobin saturation (rcSO2) via cerebral oximetry. Participants were classified based on the magnitude of change in rcSO2 from resting baseline to the end of the first nonrapid-eye-movement (NREM) period. One-way ANOVA and Chi-square were used to test group differences in SaO2 and the prevalence of cerebrovascular risk factors. FINDINGS: 20 participants (Group 1) experienced an increase in rcSO2 during sleep along with sleeping rcSO2 levels >or= 55%; 95 participants experienced a decline in rcSO2; 72 participants (Group 2) had sleeping rcSO2 levels >or= 55%; and 23 participants had sleeping rcSO2 levels <55% (Group 3). Although all three groups had equivalent declines in SaO2 levels during sleep, Group 3 had more cardiovascular comorbidity than Groups 1 and 2. CONCLUSIONS: Although SaO2 levels decline in most people during sleep, compensatory vascular responses to these drops in SaO2 are important for preventing rcSO2 from falling during sleep. Those entering sleep with lower baseline rcSO2 levels and those with greater declines in cerebral oxygenation during sleep may have greater cardiovascular burden and be at greater risk for stroke and other forms of disabling cerebrovascular disease.

An analysis of age differences in perceptual speed.

Tests of the generalized slowing hypothesis have demonstrated the strong predictive power of tests of perceptual comparison speed in accounting for age differences across a range of cognitive domains. The goals of this study were to determine whether short-term memory (STM) and perceptual demands contribute to age differences on two commonly used tests of perceptual comparison speed, the letter and pattern comparison tests, and to test whether these task components account for unique variance in predicting age differences in working memory and reasoning. Results showed that, after controlling for visual contrast sensitivity and a general slowing factor, age differences increased with increases in both STM load and perceptual degradation. Only STM load, however, accounted for a significant portion of the relationship of age with higher level cognition. We concluded that perceptual comparison tests are dependent on multiple age-sensitive abilities, not all of which are related to age differences in higher level cognition.

Aging and working memory inside and outside the focus of attention: dissociations of availability and accessibility.

Two experiments used the N-Back task to test for age differences in working memory inside and outside the focus of attention. Manipulations of the difficulty of item-context binding (Experiment 1) and of stimulus feature binding (Experiment 2) were used to create conditions that varied in their demand on working memory, with the expectation that greater demand might increase age differences in focus-switching costs and the search rate outside the focus of attention. Results showed, however, that although age differences were evident in measures of overall speed and accuracy, and the manipulations significantly affected response times and accuracy in the expected direction, the experimental manipulations had no impact on age differences. Findings instead pointed to age-related reductions in accuracy but not speed of focus-switching and search outside the focus of attention. Thus, age-related deficits appear to involve the availability of representations in working memory, but not their accessibility.

Working memory for item and temporal information in younger and older adults.

Two experiments examined age differences in mechanisms hypothesized to affect activation of item and temporal information in working memory. Activation levels were inferred from the ability to reject n-back lures matching items in different temporal positions. Information with the least decay had a performance advantage over less recent information, but was susceptible to the same temporal context errors found in all adjacent-to-target lure positions. Lures most distant from the current item showed a performance rebound. The pattern of increased magnitudes of age effects at adjacent-to-target positions indicated a reduction in older adults' working memory for temporal context information above and beyond item memory declines. Results overall support the emphasis on context information as a critical factor in working memory and cognitive aging.

Exploratory analysis of cerebral oxygen reserves during sleep onset in older and younger adults.

OBJECTIVES: To explore differences in cerebral oxygen reserves during sleep in old and young adults. DESIGN: Descriptive cross-sectional study. SETTING: General clinical research center. PARTICIPANTS: Nine old (aged 65-84) and 10 young (aged 21-39) adults. MEASUREMENTS: Subjects were monitored during the first nightly sleep cycle using standard polysomnography, including measures of arterial oxyhemoglobin saturation (SaO(2)). Changes in regional cerebral oxyhemoglobin saturation (rcSO(2)) were used to estimate cerebral oxygen reserves. General linear models were used to test group differences in the change in SaO(2) and rcSO(2) during sleep. RESULTS: Older subjects had lower SaO(2) than young subjects before sleep (baseline) (F((1,18))=5.1, P=.04) and during sleep (F((1,18))=10.7, P=.01). During sleep, half of the older subjects and none of the younger ones had SaO(2) values below 95%. In addition, the older subjects had more periods of oxygen desaturation (drops in SaO(2) > or = 4%) (chi-square=24.3, P=.01) and lower SaO(2) levels during desaturation (F((1,18))=11.1, P<.01). Although baseline values were similar, rcSO(2) decreased during sleep 2.1% in older subjects (F((1,8))=3.8, P=.05) but increased 2.1% during sleep in younger subjects (F((1,9))=4.6, P=.04). When the older subjects awakened from sleep, rcSO(2), but not SaO(2), returned to baseline; both returned to baseline in younger subjects. CONCLUSION: This exploratory analysis generated the hypothesis that lower SaO(2), combined with declines in regional blood flow, contributes to decline in cerebral oxygen reserves during sleep in older subjects. Further study will assess the effects of factors (e.g., medical conditions, subclinical disorders, and sleep architecture) that might account for these differences.

Adult age differences in the access and deletion functions of inhibition.

This study examined age differences in working memory using a delayed-matching-to-sample (DMTS) task. Based on the inhibitory decline hypothesis, which posits that older adults are more susceptible to interference, age differences were expected to be greater for older adults when irrelevant information was present during encoding. Two experiments tested both the access and deletion functions of inhibition. In both experiments, performance was equated for older and younger participants on a no-interference version of the DMTS task to control for age differences in encoding information into working memory. Results consistently showed equivalent effects of distraction for older and younger adults regardless of the difficulty of the perceptual discrimination of targets and distractors, the degree of processing of the distractors, or the semantic relationship between targets and distractors. These results support theories that propose age differences in encoding to explain age differences in working memory, and are inconsistent with theories that propose that older adults are more susceptible to interference than younger adults.

Tailoring protocols to successfully recruit and retain older adults in a longitudinal study of sleep and cognition.

Many studies attest to the challenges of recruiting and retaining older adults in longitudinal studies. This article presents the methods used by the Physiological Research to Improve Sleep and Memory project to recruit and retain 115 adults (age 70 and older) in a 2-year study that involved annual administrations of two neurocognitive test batteries and two nights of polysomnography. Strategies built on knowledge obtained from participant informants and the use of tailored, individualized protocols are described. Together, these strategies enabled participants to become vested in the research process and to fully participate in all aspects of the study.

Respiratory periodicity and electroencephalogram arousals during sleep in older adults.

The aim of this exploratory study was to examine the relationship of electroencephalogram (EEG) arousals to breathing patterns and the relationship of both arousals and breathing patterns to arterial oxygenation during sleep in older adults. Five older adults were monitored using standard polysomnography. Records were divided into 5-min segments and breathing patterns identified based on the level of respiratory periodicity and the variability in the frequency of breathing cycles. Standard criteria were used to determine sleep states and occurrence of EEG arousals. High respiratory periodicity was seen in 23% of the segments, whereas 24% had low respiratory periodicity with minimal variability in the frequency of breathing (Type A low respiratory periodicity) and 53% had low respiratory periodicity with high variability in the frequency of breathing (Type B low respiratory periodicity). Nearly all (97%) segments with high respiratory periodicity had EEG arousals, whereas fewer segments (33%) with low respiratory periodicity had arousals, regardless of the stage of sleep. Desaturations occurred more often in segments with high respiratory periodicity, F((2,4)) = 57.3, p < .001, but overall, the mean SaO(2) of segments with high respiratory periodicity did not differ from levels seen in segments with low respiratory periodicity, F((2,4)) = 0.77, ns. Our findings suggest that high respiratory periodicity is a common feature of EEG arousals and, in older adults, may be important for maintaining oxygen levels during desaturations during sleep.

Age differences in concept formation.

In order to identify the source of age-related deficits in concept formation, older and younger adults completed a new Concept Matching Test, tests of selective attention, and the Sorting Test, a standardized test of concept formation (Delis, Kaplan, & Kramer, 2001). Older adults showed intact concept identification, the ability to generate abstract concepts from stimulus features, but age differences were observed when irrelevant features were present. In addition, selective attention, but not concept identification ability, predicted age-related declines on the Sorting Test. Thus, reduced concept formation in older adults may stem from declines in abilities other than the capacity for abstraction.

Response inhibition and everyday memory complaints in older adult women.

OBJECTIVE: To explore the association of executive functions to the everyday memory complaints of healthy older adults. METHODS: Ninety-nine community-dwelling women aged 60 and above were administered a battery that included neuropsychological tests of executive functions and memory, along with self-report measures of everyday memory complaints, depression, and anxiety. RESULTS: Multivariate regression analyses revealed that a measure of response inhibition (Stroop Color-Word) accounted for unique variance in predicting memory complaints above and beyond measures of episodic memory, depression, and anxiety. Depression, however, accounted for the largest variance in memory complaints. CONCLUSIONS: Higher frequency of everyday memory complaints among older adults was associated with decreased response inhibition independent of episodic memory and affective state. Further research is needed to understand the interrelationships among these and other predictors of everyday memory complaints.

Explaining age differences in temporal working memory.

To determine the cognitive mechanisms underlying age differences in temporal working memory (WM), the authors examined the contributions of item memory, associative memory, simple order memory, and multiple item memory, using parallel versions of the delayed-matching-to-sample task. Older adults performed more poorly than younger adults on tests of temporal memory, but there were no age differences in nonassociative item memory, regardless of the amount of information to be learned. In contrast, a combination of associative and simple order memory, both of which were reduced in older adults, completely accounted for age-related declines in temporal memory. The authors conclude that 2 mechanisms may underlie age differences in temporal WM, namely, a generalized decline in associative ability and a specific difficulty with order information.

The contributions of attention and working memory to age differences in concept identification.

The contributions of attention and working memory to adult age differences in concept identification were examined in two experiments using the standard version of the California Card Sorting Test plus two modified versions. Older adults demonstrated global reductions in their ability to identify concepts whether sorting stimuli, identifying concepts used by the examiner, or generating concepts from abstract cues. Although age differences in selective attention and interference control did not contribute to these deficits, reduced working memory accounted for the age-related increase in perseverative errors. Our conclusions focus on whether impairments in working memory might fully account for age differences in concept identification.

Characteristics of stepping over an obstacle in community dwelling older adults under dual-task conditions.

Previous research suggests that older adults may have difficulty attending to simultaneous tasks. This study was conducted to determine how concurrent performance of a secondary cognitive task influences walking and stepping over an obstacle in community dwelling older adults. Twenty-one men and women with a mean age of 73.4 years (S.D.=5.3) participated in the study. Subjects performed a gait task both alone (single-task condition) and in combination with a cognitive task that involved reciting numbers (dual-task condition). In the gait task, each subject walked at his/her fastest speed along a 10-m walkway and stepped over an obstacle designed to simulate a door threshold. Paired t-tests were used to compare gait parameters (10 m gait speed, gait speed during obstacle approach and negotiation, medial-lateral center of pressure excursion and velocity during obstacle negotiation, foot clearance over the obstacle, step length and foot position relative to the obstacle) and cognitive task performance under single and dual-task conditions. Toe-obstacle distance was greater and obstacle-heel distance was reduced under dual-task conditions. Performance of the remaining gait parameters did not change with the addition of a secondary cognitive task. Cognitive task performance decreased under dual-task conditions. These community dwelling older adults demonstrated minimal or no change in measured gait parameters during simultaneous performance of a cognitive task. The observed decrement in cognitive task performance suggests that subjects may have placed a higher priority on gait performance.

Examining the locus of age effects on complex span tasks.

To investigate the locus of age effects on complex span tasks, the authors evaluated the contributions of working memory functions and processing speed. Age differences were found in measures of storage capacity, language processing speed, and lower level speed. Statistically controlling for each of these in hierarchical regressions substantially reduced, but did not eliminate, the complex span age effect. Accounting for lower level speed and storage, however, removed essentially the entire age effect, suggesting that both functions play important and independent roles. Additional evidence for the role of storage capacity was the absence of complex span age differences with span size calibrated to individual word span performance. Explanations for age differences based on inhibition and concurrent task performamce were not supported.

Adult age differences in temporal and item memory.

Three experiments tested whether the relationship between age differences in temporal and item memory depends on the degree to which the item memory measure relies on memory for context. The authors predicted a stronger relationship of temporal memory to free recall than to recognition memory. Results showed that age differences in temporal memory could be eliminated after controlling for free recall but not recognition memory performance. Under some conditions recognition memory accounted for a significant portion of age-related variance in temporal memory. These results challenge past research that has interpreted age differences in temporal and item memory as independent and suggest that a generalized decline in context memory may underlie reduced performance in older adults on all types of memory tests.