Showing papers by "Kenneth M. Heilman published in 2019"

Regional leukoaraiosis and cognition in non-demented older adults

Abstract: Frontal lobe-executive functions are heavily dependent on distal white matter connectivity. Even with healthy aging there is an increase in leukoaraiosis that might interrupt this connectivity. The goal of this study is to learn 1) the location, depth, and percentage of leukoaraiosis in white matter among a sample of non-demented older adults and 2) associations between these leukoarioasis metrics and composites of cognitive efficiency (processing speed, working memory, and inhibitory function), and episodic memory. Participants were 154 non-demented older adults (age range 60-85) who completed a brain MRI and neuropsychological testing on the same day. Brain MRIs were segmented via Freesurfer and white matter leukoaraiosis depth segmentations was based on published criteria. On average, leukoaraiosis occupied 1 % of total white matter. There was no difference in LA distribution in the frontal (1.12%), parietal (1.10%), and occipital (0.95%) lobes; there was less LA load within the temporal lobe (0.23%). For cortical depth, leukoaraiosis was predominantly in the periventricular region (3.39%; deep 1.46%, infracortical 0.15%). Only increasing frontal lobe and periventricular leukoaraiosis were associated with a reduction in processing speed, working memory, and inhibitory function. Despite the general presence of LA throughout the brain, only frontal and periventricular LA contributed to the speeded and mental manipulation of executive functioning. This study provides a normative description of LA for non-demented adults to use as a comparison to more disease samples.

Chronological Effects of Emotional Valence on the Self-selected Retrieval of Autobiographical Memories.

Abstract: BACKGROUND AND OBJECTIVE Salience of emotional autobiographical memories may have temporal patterns associated with valence. Recall of negative emotional memories is often important in survival and well-being. Based on the possible survival value of negative memories, we posited that when given an open-ended request to recall either a sad or a happy memory, people are more likely to recall an older sad memory than a happy one. METHODS We asked 20 healthy participants, aged 18-63 years, to freely recall happy and sad emotional memories and estimate the length of time that had passed since the recalled event had occurred. We analyzed the age of each memory based on valence. RESULTS Sixteen of 20 participants volunteered a more remote sad than happy memory (P<0.05). Older participants' sad memories were more remote (P<0.05), but the ratio of happy to sad memories was not affected by age. CONCLUSIONS Self-selected free retrieval of autobiographical happy and sad emotional memories reveals a time bias. Although the reason for this temporal dichotomy is unknown, it may be that engaging systems involved in defense and survival alters the encoding and/or retrieval characteristics of the memory that modify salience.

Vertical and Radial Attentional Neglect in Corticobasal Syndrome.

Abstract: Corticobasal degeneration (CBD), a tau-related neurodegenerative disease, is characterized by limb rigidity, dystonia, myoclonus, apraxia, and cognitive deficits. We report a patient with probable corticobasal syndrome, a major phenotype of CBD, who revealed both lower vertical and proximal radial a

Novel associative processing and aging: effect on creative production.

Abstract: Creative production has been reported to decline with age. This study investigated age-related differences in creative verbal production. Participants were 30 younger and 30 older adults. Study testing included language and cognitive assessments and the experimental task wherein participants created short stories incorporating words that are not commonly related, semantically or associatively. The resulting stories were rated by independent blinded judges for originality, cohesion, appropriateness, and organization. Younger adults' stories were rated as being significantly more original and more appropriate. Integrating unrelated words to create original stories requires activating widely distributed lexical-semantic networks to develop novel associations. Potential decreased neural network connectivity due to white matter degradation, commonly seen in normal aging, as well as decrements in front-executive disengagement may have affected older adults' performance on this story creation task. Future research using neuroimaging may elucidate possible neuroanatomic correlates of age-related changes in associative creative production..

The Influence of Focused and Sustained Spatial Attention on the Allocation of Spatial Attention.

Abstract: Objective The objective of this study was to evaluate the impact of directed and sustained attention on the allocation of visuospatial attention. Healthy people often have left lateral and upward vertical spatial attentional biases. However, it is not known whether there will be an increase in bias toward the attended portion of the stimulus when volitional spatial attention is allocated to a portion of a stimulus, whether there are asymmetrical spatial alterations of these biases, and how sustained attention influences these biases. Methods We assessed spatial bias in 36 healthy, right-handed participants using a variant of horizontal and vertical line bisections. Participants were asked to focus on one or the other end of vertical or horizontal lines or entire vertical or horizontal lines, and then to bisect the line either immediately or after a 20 second delay. Results We found a significant main effect of attentional focus and an interaction between attentional focus and prolonged viewing with delayed bisection. Focusing on a certain portion of the line resulting in a significant deviation toward the attended portion and prolonged viewing of the line prior to bisection significantly enhanced the degree of deviation toward the attended portion. Conclusions The enhanced bias with directed and sustained attention may be useful modifications of the line bisection test, particularly in clinical populations. Thus, future studies should determine whether prolonged viewing with delayed bisection and spatially focused attention reveals attentional biases in patients with hemispheric lesions who perform normally on the traditional line bisection test. (JINS, 2019, 25, 65-71).

Hand asymmetries of tactile attention in younger and older adults.

Abstract: Background/Objectives: The allocation of attention can alter the perception of magnitude. When performing line bisections, young adults deviate leftward (pseudoneglect), a bias thought to be induced by right hemisphere dominance for allocating spatial attention. However, when performing body bisections young adults deviate rightward, suggesting left hemisphere dominance for allocating body-centered attention. With aging, there is a reduction of pseudoneglect thought to result from either an age-related decrease in right hemispheric functions (right hemi-aging) or from hemispheric asymmetry reduction in older adults (HAROLD). The goal of this study was to learn if there are tactile body-centered perceptual-attentional right-left asymmetries in that change with aging. Methods: The participants were younger and older healthy adults. Semmes-Weinstein Monofilaments were used to test for differences in the perceived magnitude of pressure differences between a reference stimulus and test stimuli applied to the right and left palmar thenar eminence. Results: Young adults perceived the magnitude of difference in the lightest pressure stimuli applied to the right hand as being greater than the older adults. Young adults perceived the magnitude of difference between the lightest pressure and reference applied to the right hand to be greater than the left hand, but older adults perceived a lighter stimulus greater on the left compared to the right. Conclusions: Whereas the right hemisphere appears to be dominant in mediating spatial attention, the left hemisphere may play a dominant role in the allocation of body-centered attention. Like the aging-related reduction of the visual perception of the magnitude (length) of the left side of a line, this tactile reduction in magnitude (pressure) perception in older adults suggests that with aging, there is a reduction of left-hemispheric mediated allocation of tactile attention, and this result is not fully consistent with either the HAROLD or hemi-aging models.