| 1. |
- Kalpouzos, Gregoria, et al.
(författare)
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Local brain atrophy accounts for functional activity differences in normal aging
- 2012
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580 .- 1558-1497. ; 33:3, s. 623.e1-
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Tidskriftsartikel (refereegranskat)abstract
- Functional brain imaging studies of normal aging typically show age-related under-and overactivations during episodic memory tasks. Older individuals also undergo nonuniform gray matter volume (GMv) loss. Thus, age differences in functional brain activity could at least in part result from local atrophy. We conducted a series of voxel-based blood oxygen level-dependent (BOLD)-GMv analyses to highlight whether age-related under-and overrecruitment was accounted for by GMv changes. Occipital GMv loss accounted for underrecruitment at encoding. Efficiency reduction of sensory-perceptual mechanisms underpinned by these areas may partly be due to local atrophy. At retrieval, local GMv loss accounted for age-related overactivation of left dorsolateral prefrontal cortex, but not of left dorsomedial prefrontal cortex. Local atrophy also accounted for age-related overactivation in left lateral parietal cortex. Activity in these frontoparietal regions correlated with performance in the older group. Atrophy in the overrecruited regions was modest in comparison with other regions as shown by a between-group voxel-based morphometry comparison. Collectively, these findings link age-related structural differences to age-related functional under-as well as overrecruitment.
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| 2. |
- Han, Xiaolei, et al.
(författare)
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Accelerometer-measured sedentary behavior patterns, brain structure, and cognitive function in dementia-free older adults : a population-based study
- 2023
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Ingår i: Journal of Alzheimer's Disease. - : IOS Press. - 1387-2877 .- 1875-8908. ; 96:2, s. 657-668
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Tidskriftsartikel (refereegranskat)abstract
- Background: Sedentary behavior is associated with cognitive impairment, but the neuropathological mechanisms underlying their associations are poorly understood.Objective: To investigate the associations of accelerometer-measured sedentary behavior patterns with brain structure and cognition, and further to explore the potential mechanisms.Methods: This community-based study included 2,019 older adults (age≥60 years, 59% women) without dementia derived from participants in the baseline examination of MIND-China (2018-2020). We assessed sedentary parameters using an accelerometer and cognitive function using a neuropsychological test battery. Structural brain markers were assessed on the structural brain MRI scans in a subsample (n = 1,009). Data were analyzed using the general linear, isotemporal substitution, and mediation models.Results: In the total sample (n = 2,019), adjusting for multiple covariates and moderate-to-vigorous-intensity physical activity, longer mean sedentary bout duration was linearly related with lower z-scores of global cognition, verbal fluency, and memory (ptrend < 0.05), whereas greater total sedentary time was linearly associated with lower z-scores of global cognition, verbal fluency, and memory only among individuals with long sedentary time (>10 h/day) (ptrend < 0.05); Breaking up sedentary time with same amount of light-intensity physical activity was significantly associated with higher verbal fluency and memory z-scores (p < 0.05). In the MRI subsample (n = 1,009), separately entering structural brain MRI markers into the mediation models substantially attenuated the associations of mean sedentary bout duration with global cognition, verbal fluency, and memory z-scores.Conclusion: Prolonged uninterrupted sedentary time is associated with poor global cognition, memory, and verbal fluency among rural older adults, and structural brain markers could partially mediate the association.
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| 3. |
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| 4. |
- Lundström, Maria, et al.
(författare)
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Postoperative delirium in old patients with femoral neck fracture : a randomized intervention study.
- 2007
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Ingår i: Aging Clinical and Experimental Research. - 1594-0667 .- 1720-8319. ; 19:3, s. 178-186
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND AND AIMS: Delirium is a common postoperative complication in elderly patients which has a serious impact on outcome in terms of morbidity and costs. We examined whether a postoperative multi-factorial intervention program can reduce delirium and improve outcome in patients with femoral neck fractures.METHODS: One hundred and ninety-nine patients, aged 70 years and over (mean age+/-SD, 82+/-6, 74% women), were randomly assigned to postoperative care in a specialized geriatric ward or a conventional orthopedic ward. The intervention consisted of staff education focusing on the assessment, prevention and treatment of delirium and associated complications. The staff worked as a team, applying comprehensive geriatric assessment, management and rehabilitation. Patients were assessed using the Mini Mental State Examination and the Organic Brain Syndrome Scale, and delirium was diagnosed according to DSM-IV criteria.RESULTS: The number of days of postoperative delirium among intervention patients was fewer (5.0+/-7.1 days vs 10.2+/-13.3 days, p=0.009) compared with controls. A lower proportion of intervention patients were delirious postoperatively than controls (56/102, 54.9% vs 73/97, 75.3%, p=0.003). Eighteen percent in the intervention ward and 52% of controls were delirious after the seventh postoperative day (p<0.001). Intervention patients suffered from fewer complications, such as decubitus ulcers, urinary tract infections, nutritional complications, sleeping problems and falls, than controls. Total postoperative hospitalization was shorter in the intervention ward (28.0+/-17.9 days vs 38.0+/-40.6 days, p=0.028).CONCLUSIONS: Patients with postoperative delirium can be successfully treated, resulting in fewer days of delirium, fewer other complications, and shorter length of hospitalization.
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| 5. |
- Persson, Jonas, et al.
(författare)
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Longitudinal assessment of default-mode brain function in aging
- 2014
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580 .- 1558-1497. ; 35:9, s. 2107-2117
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Tidskriftsartikel (refereegranskat)abstract
- Age-related changes in the default-mode network (DMN) have been identified in prior cross-sectional functional magnetic resonance imaging studies. Here, we investigated longitudinal change in DMN activity and connectivity. Cognitively intact participants (aged 49-79 years at baseline) were scanned twice, with a 6-year interval, while performing an episodic memory task interleaved with a passive control condition. Longitudinal analyses showed that the DMN (control condition > memory task) could be reliably identified at both baseline and follow-up. Differences in the magnitude of task-induced deactivation in posterior DMN regions were observed between baseline and follow-up indicating reduced deactivation in these regions with increasing age. Although no overall longitudinal changes in within-network connectivity were found across the whole sample, individual differences in memory change correlated with change in connectivity. Thus, our results show stability of whole-brain DMN topology and functional connectivity over time in healthy older adults, whereas within-region DMN analyses show reduced deactivation between baseline and follow-up. The current findings provide novel insights into DMN functioning that may assist in identifying brain changes in patient populations, as well as characterizing factors that distinguish between normal and pathologic aging.
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| 6. |
- Pudas, Sara, et al.
(författare)
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Midlife memory ability accounts for brain activity differences in healthy aging
- 2014
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Ingår i: Neurobiology of Aging. - : Elsevier BV. - 0197-4580 .- 1558-1497. ; 35:11, s. 2495-2503
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Tidskriftsartikel (refereegranskat)abstract
- Cross-sectional neuroimaging studies suggest that hippocampal and prefrontal cortex functions underlie individual differences in memory ability in older individuals, but it is unclear how individual differences in cognitive ability in youth contribute to cognitive and neuroimaging measures in older age. Here, we investigated the relative influences of midlife memory ability and age-related memory change on memory-related BOLD-signal variability at one time point, using a sample from a longitudinal population-based aging study (N = 203, aged 55–80 years). Hierarchical regression analyses showed that midlife memory ability, assessed 15–20 years earlier, explained at least as much variance as memory change in clusters in the left inferior prefrontal cortex and the bilateral hippocampus, during memory encoding. Furthermore, memory change estimates demonstrated higher sensitivity than current memory levels in identifying distinct frontal regions where activity was selectively related to age-related memory change, as opposed to midlife memory. These findings highlight challenges in interpreting individual differences in neurocognitive measures as age-related changes in the absence of longitudinal data and also demonstrate the improved sensitivity of longitudinal measures.
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| 7. |
- Hansson, Patrik, et al.
(författare)
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Relationship between natural teeth and memory in a healthy elderly population
- 2013
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Ingår i: European Journal of Oral Sciences. - : Wiley. - 0909-8836 .- 1600-0722. ; 121:4, s. 333-340
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Tidskriftsartikel (refereegranskat)abstract
- The relationship between mastication and cognitive function remains unclear, but both animal and experimental human studies suggest a possible causal relationship. In the present study it was hypothesized that natural teeth are of importance for hippocampus-based cognitive processes, such as episodic long-term memory. A population-based sample of 273 participants (55-80yr of age; 145 women) was investigated in a cross-sectional study. The participants underwent health assessment, completed a battery of cognitive tests, and took part in an extensive clinical oral examination. The number of natural teeth contributed uniquely and significantly to explaining variance (3-4%) in performance on measures of episodic memory and semantic memory over and above individual differences in age, years of education, gender, occupation, living conditions, and medical history. The number of natural teeth did not have an influence on the performance of measures of working memory, visuospatial ability, or processing speed. Within the limitations of the current study, a small, but significant, relationship between episodic memory and number of natural teeth is evident.
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| 8. |
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| 9. |
- Köhncke, Ylva, et al.
(författare)
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Self-rated intensity of habitual physical activities is positively associated with dopamine D-2/3 receptor availability and cognition
- 2018
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Ingår i: NeuroImage. - : Elsevier BV. - 1053-8119 .- 1095-9572. ; 181, s. 605-616
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Tidskriftsartikel (refereegranskat)abstract
- Between-person differences in cognitive performance in older age are associated with variations in physical activity. The neurotransmitter dopamine (DA) contributes to cognitive performance, and the DA system deteriorates with advancing age. Animal data and a patient study suggest that physical activity modulates DA receptor availability, but data from healthy humans are lacking. In a cross-sectional study with 178 adults aged 64-68 years, we investigated links among self-reported physical activity, D(2/3)DA receptor (D2/3DR) availability, and cognitive performance. D2/3DR availability was measured with [C-11]raclopride positron emission tomography at rest. We used structural equation modeling to obtain latent factors for processing speed, episodic memory, working memory, physical activity, and D2/3DR availability in caudate, putamen, and hippocampus. Physical activity intensity was positively associated with D2/3DR availability in caudate, but not putamen and hippocampus. Frequency of physical activity was not related to D2/3DR availability. Physical activity intensity was positively related to episodic memory and working memory. D2/3DR availability in caudate and hippocampus was positively related to episodic memory. Taken together, our results suggest that striatal DA availability might be a neurochemical correlate of episodic memory that is also associated with physical activity.
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| 10. |
- Lilja-Lund, Otto, et al.
(författare)
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Dual-Task Performance in Older Adults With and Without Idiopathic Normal Pressure Hydrocephalus
- 2022
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Ingår i: Frontiers in Aging Neuroscience. - : Frontiers Media S.A.. - 1663-4365. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- Two of the main features of idiopathic normal pressure hydrocephalus (iNPH) are disturbed gait and cognition. These features are typically investigated separately, but here we combined walking with a cognitive task to investigate if older adults with iNPH were more susceptible to dual-task interference on walking than those without iNPH. In total, 95 individuals from the general population participated in our study. Of these, 20 were classified as Possible iNPH (median [interquartile range, IQR] 80 years [75–82.5]) and 75 as Unlikely iNPH (74 years [72–78]). Conversation, 10-m walking, semantic and phonemic verbal fluency were performed either combined or independently. “Stopping walking while talking” was noted. Pairwise comparisons and multiple logistic regression analyses were used. We found that the Possible iNPH group was older, stopped walking more frequently during the conversation, and had a slower single-task pace. The dual-task pace was slower for both groups. Only single-task walking pace could predict Possible iNPH when adjusted for age. We could establish a dual-task cost on gait performance in this sample of older adults from the general population, but the cost was not exclusive for individuals with Possible iNPH. To further assess the value of dual-task testing in iNPH, including observations of stopping walking while talking, a study of a clinical iNPH material with more severe symptoms would be valuable.
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