Visuomotor adaptation in normal aging

Visuomotor adaptation to a gradual or sudden screen cursor rotation was investigated in healthy young and elderly subjects. Both age groups were equally divided into two subgroups; one subgroup was exposed to 11.25° step increments of visual feedback rotation, every 45 trials (up to a total of 90°), whereas a second subgroup was subjected to 90° rotation from the onset of exposure. Participants performed discrete, horizontal hand movements to virtual targets in four randomized directions. Targets appeared on a computer screen in front of them, and a board prevented vision of the hand at all times. Differential effects of aging on visuomotor adaptation were found, depending on the time course of the visual distortion. In both age groups, early exposure to the sudden visual feedback distortion resulted in typical spiral-like trajectories, which became straighter by late exposure. However, the final adaptation level was reduced in the aged group, although the aftereffects were similar. When subjects were exposed to the gradual distortion, no statistically significant differences in measures of adaptation with advancing age were found. In this case, both age groups appeared to adapt equally. However, after removal of the distortion, elderly subjects showed reduced aftereffects as compared with the young group. These findings suggest differential effects of aging on adaptation to gradual versus sudden visual feedback distortions, and may help to explain the conflicting results obtained in previous visuomotor adaptation studies.     

Frontal amnesia and the dysexecutive syndrome

This study analyzes the memory deficits shown by an amnesic patient with bilateral frontal damage and a dysexecutive syndrome. He resembles a classic amnesic patient in showing grossly impaired episodic memory for both verbal and nonverbal material, together with normal digit span, and on occasion normal recency in free recall. He differs from the classic amnesic pattern however in showing an impairment in both the speed and accuracy of performance on tests of semantic memory, and in clear evidence for impaired performance on some though not all procedural learning tasks. Finally, his autobiographical memory was poor and subject to substantial confabulation. It is suggested that the pattern of deficits is consistent with a combination of a classic amnesic syndrome with the additional problems associated with the frontal dysexecutive syndrome, rather than exhibiting a qualitatively different form of amnesia.     

Picture priming in normal aging and Alzheimer's disease

The present study investigated age invariance for naming pictures and whether implicit memory is spared in Alzheimer's disease (AD). During the study phase, young adults, AD patients, and older controls were shown outlines of familiar pictures. After a distracter task, implicit memory was assessed incidentally. The results showed similar visual priming for the three groups, although young adults responded faster than the two older groups. Moreover, the number of errors was smaller for studied than for non-studied pictures. This pattern of results was repeated across the three groups, although AD patients produced more errors than young adults and older controls, and there were no differences between these latter groups. These results confirmed previous visual and haptic findings showing unimpaired perceptual priming in normal aging and AD patients when implicit memory is assessed using identification tasks. These results are interpreted from a cognitive neuroscience perspective.     

Number-Stroop performance in normal aging and Alzheimer's-type dementia

The number-Stroop paradigm was used to investigate changes in the inhibitory system and in numerical processing in healthy elderly and individuals with dementia of Alzheimer's type (DAT). The size-congruity effect (i.e., relative to neutral trials, incongruent pairs interfere and/or congruent pairs facilitate either numerical or physical comparison) was found in all groups, though the pattern of interference and facilitation varied across them. Overall, the selective attention breakdown was reflected by the increase in interference shown by the older group and the DAT group. On the other hand, the observation of a standard laterality effect andof automatic numerical processing in all groups suggests that access and retrieval of numerical information is relatively resistant to cognitive deterioration.     

Neuronal changes in normal human aging and Alzheimer's disease

This article discusses age-related changes in brain weight, total number of cortical neurons, cortical dendrites, spine, and synapse density. The conclusion is that the present outlook is less grim than it was 30 years ago. Age-related reduction appears to be specific to brain region and cortical layer rather than a general feature. In addition, we describe a different pattern of changes that occur in Alzheimer's disease patients. This review concludes that the association cortices in particular are affected in aging and Alzheimer's disease and that the primary visual and somatosensory cortices are relatively spared.     

Neuropsychological correlates of recollection and familiarity in normal aging

The dual-process model of recognition memory proposed by Jacoby (1991; see also Mandler, 1980) postulates the existence of two independent components of recognition memory: a conscious retrieval process (recollection) and an automatic component ( familiarity). Older adults appear to be impaired in recollection, but findings with respect to familiarity have been mixed. Studies of the brain bases of these components, using neurological patients, have also been inconclusive. We examined recollection and familiarity, using the process dissociation procedure, in older adults characterized on the basis of both their frontal and their medial temporal lobe function. Findings suggest that only some older adults, depending on their neuropsychological status, are impaired in recollection and/or familiarity: Recollection seems to involve both frontal and medial temporal lobe function, whereas familiarity appears to be dependent only on function associated with the medial temporal lobes.     

A cognitive-based model of tool use in normal aging

While several cognitive domains have been widely investigated in the field of aging, the age-related effects on tool use are still an open issue and hardly any studies on tool use and aging is available. A significant body of literature has indicated that tool use skills might be supported by at least two different types of knowledge, namely, mechanical knowledge and semantic knowledge. However, neither the contribution of these kinds of knowledge to familiar tool use, nor the effects of aging on mechanical and semantic knowledge have been explored in normal aging. The aim of the present study was to fill this gap. To do so, 98 healthy elderly adults were presented with three tasks: a classical, familiar tool use task, a novel tool use task assessing mechanical knowledge, and a picture matching task assessing semantic knowledge. The results showed that aging has a negative impact on tool use tasks and on knowledge supporting tool use skills. We also found that aging did not impact mechanical and semantic knowledge in the same way, confirming the distinct nature of those forms of knowledge. Finally, our results stressed that mechanical and semantic knowledge are both involved in the ability to use familiar tools.     

Stimulus modality and verbal learning performance in normal aging

The present study investigated the effects of modality presentation on the verbal learning performance of 26 older adults and 26 younger cohorts. A multitrial free-recall paradigm was implemented incorporating three modalities: Auditory, Visual, and simultaneous Auditory plus Visual. Older subjects learned fewer words than younger subjects but their rate of learning was similar to that of the younger group. The visual presentation of objects (with or without the simultaneous auditory presentation of names) resulted in better learning, recall, and retrieval of information than the auditory presentation alone.     

Positive explorers: modeling dynamic control in normal aging

Situations in which there are multiple changes occurring all at once and which demand complex decisions to be made are common throughout life, but little is known about how normal aging influences performance on these types of scenarios. To determine performance differences associated with normal aging, we test older and younger adults in a dynamic control task. The task involves the control of a single output variable over time via multiple and uncertain input controls. The Single Limited Input, Dynamic Exploratory Responses (SLIDER) computational model, is implemented to determine the behavioral characteristics associated with normal aging in a dynamic control task. Model-based analysis demonstrates a unique performance signature profile associated with normal aging. Specifically, older adults exhibit a positivity effect in which they are more influenced by positively valenced feedback, congruent with previous research, as well as enhanced exploratory behavior.     

Monitoring processes and metamemory experience in patients with dysexecutive syndrome

The aim of the present study was to determine whether monitoring measures are differentially disturbed in dysexecutive patients after frontal lesions. Twelve dysexecutive patients and 12 healthy controls were administered a paired-associates learning task. Their performances on recall prediction, judgment-of-learning (JOL), and feeling-of-knowing judgment (FOK) were then compared. The results revealed that the two groups differed only on accuracy measures of the FOK paradigm. The study of the overall correlations between the three measures of metamemory revealed a significant relation between recall prediction and accuracy measures of the JOL. We failed to find any significant correlation with the accuracy measures of the FOK. Taken together, our data confirm that metamemory experience is not a unitary construct but rather a group of distinct and quite independent mechanisms.     

Impact of symptoms and aging attribution on emotions and coping

Two experimental studies and a large field study were designed to examine how symptom severity, symptom duration, symptom ambiguity, and the association of symptoms with aging affected emotional responses and coping with illness threats. In Study 1, 280 respondents from the surrounding community reported the emotional and coping responses they would manifest to scenarios that varied the severity, duration, and ambiguity (i.e., labeled vs. unlabeled) of a common set of symptoms. Severity had more of an impact on coping strategies than did duration or illness label; severe symptoms elicited stronger emotional upset and a higher incidence of both self-care behaviors and seeking of medical care. Symptoms of longer duration also resulted in increased seeking of medical care. Responses of the 334 adults participating in Study 2 replicated and extended these findings: A closed-ended item asking participants whether the symptoms could be attributed to aging showed that attribution of symptoms to aging increased with age, was more frequent for mild symptoms, and was associated with reduced emotional response to symptoms and a tendency to delay seeking treatment. Participants in the field study (168 patients seeking medical care for a variety of symptoms) completed interviews tracing symptom processing and emotional and coping reactions. The results provided evidence for the external validity of the scenario studies, as the attribution of symptoms to aging was greater for older than younger patients and resulted in a significant tendency to delay seeking medical care. Results of these studies suggest that symptom experience and symptom interpretation must be considered in the study of coping responses to illness threats.     

The applied value of collaborative memory research in aging: Behavioral and neural considerations

Our aim in this paper is to bring attention to the applied value of collaborative memory research in aging. At this time, much collaborative memory research focuses on the negative effects of collaboration in younger adults, and is primarily basic in nature. Here, we highlight the positive effects of collaboration that have received less attention, with a particular emphasis on the applied value of these effects in older adults. We first review studies to show that recalling in a group improves later individual recall and reduces memory errors in older adults. We then outline a four-step approach towards bridging laboratory and applied collaborative memory research, which involves: (1) complementing traditional paradigms with more ecologically valid paradigms, (2) evaluating these paradigms in applied settings, (3) adapting these paradigms for use with cognitively intact and cognitively impaired populations, and (4) modifying these paradigms to examine the neural systems that operate during collaborative recall.     

Thought-action fusion and anxiety disorders symptoms in normal adolescents.

The present study examined thought-action fusion (TAF) in a large sample of normal adolescents (n=427). Participants completed the Thought-Action Fusion Questionnaire for Adolescents (TAFQ-A) and scales measuring trait anxiety, symptoms of obsessive-compulsive disorder, other anxiety disorders, and depression. Results showed that the TAFQ-A is a reliable instrument assessing two dimensions of TAF, viz. Morality (i.e., the belief that unacceptable thoughts are morally equivalent to overt actions) and Likelihood (i.e., the belief that thinking of an unacceptable or disturbing situation will increase the probability that that situation actually occurs). Furthermore, TAF was not only associated with symptoms of OCD, but also with symptoms of other anxiety disorders and depression. However, when controlling for levels of trait anxiety, most connections between TAF and anxiety disorders symptoms disappeared. Symptoms of OCD and generalised anxiety remained significantly related to TAF. Altogether, the data are supportive of the notion that TAF is involved in a broad range of anxiety disorders and in particular OCD.     

Depressive symptoms, cortisol, and cognition during human aging: the role of negative aging perceptions

Depressive symptoms and memory impairments are associated with heightened stress hormone levels during aging. A factor that is related to memory deficits during aging is internalized negative aging stereotypes; the idea people have about the process of aging. In this study, we assessed the associations between internalized negative aging stereotypes, depressive symptoms, subjective and objective memory assessments, and cortisol concentration among older adults. Forty older adults aged between 58 and 85 years (18 females and 22 males; mean age?±?SD: 71.25?±?8.80 years) were assessed in this study. Measures of internalized negative aging stereotypes, depressive symptoms, and both subjective and objective memory performance were assessed. Salivary samples were obtained for measurement of cortisol concentration. Stepwise linear regressions were executed in our main analyses. Internalized negative aging stereotypes were associated with increased depressive symptoms and subjective memory complaints. No significant differences were observed for objective memory performance, or cortisol concentration. Internalized negative aging stereotypes are associated with increased depressive symptomatology and subjective complaints of memory; however, they do not predict increased cortisol concentration nor objective memory performance during aging. These results indicate that the mechanism underlying the association between internalized negative aging stereotypes and cognitive impairments may not be related to dysregulations of cortisol secretion among older adults.     

Residual effects of cigarette smoking on cognitive performance in normal aging

The present study examined the residual effects of smoking status on cognitive function in 76 nondemented older adults. Current smokers, ex-smokers, and nonsmokers who were screened for health and intellectual impairments were administered a battery of standardized neuropsychological tests to measure problem solving, psychomotor speed, memory, attention span, perception, and language production. Performance decrements were found for smokers on measures of psychomotor speed. No between-group differences were noted on any of the nonspeeded tests. There were no differences between nonsmokers and ex-smokers on any measures. The results suggest that the residual effects of current cigarette smoking negatively influence speeded cognitive capabilities in older adults.     

Primed word-fragment completion and successive memory test performance in normal aging

Young and old subjects were investigated to examine whether: the effects of priming are influenced by aging; there is independence between primed word-fragment completion and recognition performances; and the dependence between different tests is influenced by aging. A successive test paradigm was employed involving repeated assessment of to-be-remembered words by means of recognition and primed word-fragment completion. The results show that implicit memory declines with increasing age, and that correlations between different memory tests decrease with age. The outcome suggests that age-related memory decline involves several forms of memory, including primed word-fragment completion, and is reflected in correlations between measures of implicit and explicit memory.     

Differential course of executive control changes during normal aging

Normal aging has been associated with executive control deficits, but it is as yet unclear whether different executive subprocesses are differentially affected during the course of aging. The present study aimed to investigate age effects on a range of executive control subcomponents. Four consecutive age groups (20-30 years, 31-45 years, 46-60 years, 61-75 years), matched on present state IQ and mood, were compared on tasks of strategic memory processing, verbal fluency, reasoning, inhibition, task management, and self-rating of executive abilities. Deficits concerning the suppression of habitual and experimentally induced prepotent response tendencies and the ability to efficiently divide attention were observed in subjects over 60 years of age compared to the younger groups, while memory, verbal fluency, and reasoning were largely unaffected. Results suggest a sharp decline of executive function after age 60 and a differential course of different executive subcomponents across aging, adding further support to a multi-dimensional model of executive function.     

Achievement attributions and depressive symptoms in attention deficit-disordered and normal children

Depressive symptoms and achievement attributions were examined in attention deficit-disordered (ADD) and normal schoolchildren. The findings indicate that the ADD children acknowledged having more depressive symptoms and displayed more external attributions both for positive and for negative achievement. In addition, correlations reveal that the normal children's achievement attributions became more internal with age, whereas the ADD children became more external for negative events. The patterns of the relationships among measures are discussed.