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Backward digit span test pdf3/23/2023 DB additionally recruited bilateral DLPFC, left IPL, and Broca’s area. The degree of activation increased linearly with increasing task difficulty in DF. Combined data from both experiments demonstrate that DF and DB rely upon a largely overlapping functional neural system associated with working memory, most notably right dorsolateral prefrontal cortex (DLPFC) and bilateral inferior parietal lobule (IPL) as well as the anterior cingulate, a region associated with attentional effort. No differences in activation were found between the two experimental groups. To eliminate possible visuospatial confounds, Experiment 2 replicated the first experiment in six additional healthy participants who were blindfolded during the study. DF and DB each activated frontal, parietal, and cerebellar regions as well as prominently activating medial occipital cortex. In Experiment 1, eight healthy participants performed verbal DF, DB, and a sensorimotor control task during measurement of regional cerebral blood flow (rCBF). We therefore examined the shared and separate neural systems of these tasks in two positron emission tomography (PET) experiments. Studies of focal brain lesions have partially elucidated the brain regions essential for these tasks however relatively little information exists on the underlying functional neuroanatomy in the intact brain. The digits forward (DF) and backward (DB) tasks are widely used neuropsychological measures believed to tap overlapping systems of phonological processing and working memory. More broadly, our results demonstrate that task analysis is a vital partner of neuroimaging in the cognitive neuroscience enterprise. These results call into question conclusions that have been drawn about the neural basis of working memory. A fourth experiment suggested that the location n-back task may recruit verbal processes in addition to spatial processes. We report three behavioral experiments demonstrating that the letter n-back task additionally recruits spatial processes. Neuroimaging researchers have assumed that the letter n-back task only engages processes involved in the short-term maintenance and manipulation of verbal information. We demonstrate the danger in making such assumptions using, as an example, the n-back task, which has been widely used in neuroimaging studies of working memory. When functional neuroimaging researchers draw conclusions about the sensory, cognitive, or motor processes that are associated with changes in brain activity, they are making assumptions about the component processes involved in performing a complex behavioral task. These findings are consistent with an emerging construct of consent capacity in which discrete decisional abilities are differentially associated with cognitive processes and indicate that the sensitivity and accuracy of consent capacity assessments can be improved by evaluating decisional abilities separately. Prevalence of incapacity was greater than expected in participants with and without significant cognitive impairment when decisional abilities were considered separately. Neuropsychological performance and within-person variability were independently associated with continuous and dichotomous measures of capacity, and within-person neuropsychological variability was significantly associated with within-person decisional ability variability. Participants completed the MacArthur Competence Assessment Tool-Treatment and 11 neuropsychological tests commonly used in the cognitive assessment of older individuals. Participants were recruited from the community with fliers and advertisements and consisted of men (N = 79) and women (N = 80) with (N = 83) or without (N = 76) significant cognitive impairment. Assessments were performed in the participant's preferred location (e.g., outpatient clinic office, senior center, or home). Standard scores were used to compute mean neuropsychological performance and within-person across-test variability. Participants completed a neuropsychological test battery and a standardized capacity assessment. This study examined the relationship of within-person across-test neuropsychological performance variability to a current construct of treatment decision (consent) capacity. Within-person across-test neuropsychological performance variability has been shown to predict future dementia. The capacity of older adults to make healthcare decisions is often impaired in dementia and has been linked to performance on specific neuropsychological tasks.
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