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- Blennow, Kaj, 1958, et al.
(author)
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Traumatic brain injuries.
- 2016
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In: Nature reviews. Disease primers. - : Springer Science and Business Media LLC. - 2056-676X. ; 2
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Journal article (peer-reviewed)abstract
- Traumatic brain injuries (TBIs) are clinically grouped by severity: mild, moderate and severe. Mild TBI (the least severe form) is synonymous with concussion and is typically caused by blunt non-penetrating head trauma. The trauma causes stretching and tearing of axons, which leads to diffuse axonal injury - the best-studied pathogenetic mechanism of this disorder. However, mild TBI is defined on clinical grounds and no well-validated imaging or fluid biomarkers to determine the presence of neuronal damage in patients with mild TBI is available. Most patients with mild TBI will recover quickly, but others report persistent symptoms, called post-concussive syndrome, the underlying pathophysiology of which is largely unknown. Repeated concussive and subconcussive head injuries have been linked to the neurodegenerative condition chronic traumatic encephalopathy (CTE), which has been reported post-mortem in contact sports athletes and soldiers exposed to blasts. Insights from severe injuries and CTE plausibly shed light on the underlying cellular and molecular processes involved in mild TBI. MRI techniques and blood tests for axonal proteins to identify and grade axonal injury, in addition to PET for tau pathology, show promise as tools to explore CTE pathophysiology in longitudinal clinical studies, and might be developed into diagnostic tools for CTE. Given that CTE is attributed to repeated head trauma, prevention might be possible through rule changes by sports organizations and legislators.
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| 3. |
- Tian, Qu, et al.
(author)
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Association of Dual Decline in Memory and Gait Speed With Risk for Dementia Among Adults Older Than 60 Years A Multicohort Individual-Level Meta-analysis
- 2020
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In: JAMA Network Open. - : American Medical Association (AMA). - 2574-3805. ; 3:2
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Journal article (peer-reviewed)abstract
- Question Is a decline in both memory and gait speed with aging associated with a higher risk of dementia than no decline or a decline in memory or gait only in older adults? Findings In this meta-analysis of 6 studies including 8699 participants from the United States and Europe, a decline in both memory and gait was associated with 6.28 times higher risk of developing dementia than no decline. Meaning Older adults without dementia with parallel declines in memory and gait are associated with high risk of developing dementia and may be a group to target for prevention. This meta-analysis assesses whether parallel declines in memory and gait speed among older adults, compared with those who experience no decline or decline in either memory or gait speed only, are associated with risk of developing dementia. Importance Dual decline in both memory and gait speed may characterize a group of older individuals at high risk for future dementia. Objective To assess the risk of dementia in older persons who experience parallel declines in memory and gait speed compared with those who experience no decline or decline in either memory or gait speed only. Design, Setting, and Participants A multicohort meta-analysis was performed of 6 prospective cohort studies conducted between 1997 and 2018 in the United States and Europe. Participants were 60 years or older, had an initial gait speed of more than 0.6 m/s (ie, free of overt dismobility), with repeated measures of memory and gait speed before dementia diagnosis during a mean follow-up of 6.6 to 14.5 years. Within each study, participants were divided into 4 groups: memory decline only, gait speed decline only, dual decline, or no decline (hereafter referred to as usual agers). Gait decline was defined as a loss of 0.05 m/s or more per year; memory decline was defined as being in the cohort-specific lowest tertile of annualized change. Main Outcomes and Measures Risk of incident dementia according to group membership was examined by Cox proportional hazards regression with usual agers as the reference, adjusted for baseline age, sex, race/ethnicity, educational level, study site, and baseline gait speed and memory. Results Across the 6 studies of 8699 participants, mean age ranged between 70 and 74 years and mean gait speed ranged between 1.05 and 1.26 m/s. Incident dementia ranged from 5 to 21 per 1000 person-years. Compared with usual agers, participants with only memory decline had 2.2 to 4.6 times higher risk for developing dementia (pooled hazard ratio, 3.45 [95% CI, 2.45-4.86]). Those with only gait decline had 2.1 to 3.6 times higher risk (pooled hazard ratio, 2.24 [95% CI, 1.62-3.09]). Those with dual decline had 5.2 to 11.7 times the risk (pooled hazard ratio, 6.28 [95% CI, 4.56-8.64]). Conclusions and Relevance In this study, dual decline of memory and gait speed was associated with increased risk of developing dementia among older individuals, which might be a potentially valuable group for preventive or therapeutic interventions. Why dual decline is associated with an elevated risk of dementia and whether these individuals progress to dementia through specific mechanisms should be investigated by future studies.
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