Associate Editor Tom McBride discusses the contents of the Dementia Special Issue’s first two weeks.
This month, PLOS Medicine is proud to present our third Special Issue: Dementia across the Lifespan and around the Globe. Guest Editors Carol Brayne (Director, Cambridge Institute of Public Health, University of Cambridge) and Bruce Miller (Director, University of California, San Francisco Memory and Aging Center), have advised us on the selection of the research papers and commissioning of discussion pieces that appear in the Special Issue. The articles cover a broad range of research, including pathophysiology, prevention, treatment, and societal impact of dementia.
Here’s what has published in the first two weeks:
Trends in dementia incidence over the recent decades
Using data from Dutch general practitioner networks between 1992 and 2014, Emma van Bussel and colleagues examine trends in dementia incidence, finding that age-specific incidence of dementia has not declined in the Netherlands over the past two decades. In a linked perspective, Eric Larson and Kenneth Langa discuss the findings from van Bussel and colleagues in relation to evidence from their own and other studies in Europe and North America that found decreasing prevalence or incidence from 1982 to 1999. Larson and Langa consider the many factors that may differ between countries and affect dementia incidence and prevalence, noting that keeping track of these factors could inform public health campaigns aimed at reducing dementia risk throughout populations.
Protective and risk factors for developing dementia
Previous studies have found that a history of traumatic brain injury (TBI) is associated with an increased risk of developing dementia later in life, but it is unclear whether a history of TBI is linked to cognitive function among older adults without dementia. Using data from the Health and Retirement Study, a large nationally representative study of older adults, Raquel Gardner and colleagues compared subjective memory impairment and measures of objective cognitive function among adults with TBI history to those without TBI. While they did not find any differences in the objective measures of cognitive function, (attention, working memory, short-term memory, calculation, and verbal fluency), they did find that adults who had experienced more severe TBI (ie resulting in loss of consciousness), reported more subjective memory impairment. Factors like education, occupation, and stimulating leisure activities may increase cognitive reserve and are thought to help delay or reduce risk of dementia. In a community-based cohort study, Serhiy Dekhtyar and colleagues examine the association between engagement in various cognitive reserve-enhancing factors at early, mid, and late life and risk of dementia concurrence after 75. They find that engagement in stimulating activities at all life stages were on their own associated with a reduced risk of dementia, and that increased engagement over the entire life course was associated with progressively reduced risk of dementia. So while it is important to engage in stimulating mental activities all throughout life, late-life interventions aimed at reducing risk through cognitively stimulating activities.
Improving early diagnosis of dementia
In one research article, Elise Cornelis and colleagues describe the development of a new evaluation tool that uses basic and instrumental activities of daily living to diagnose of mild cognitive impairment and mild dementia, which could be a useful addition to the common diagnostic process using cognitive and mood measures and biomarkers. In a cluster randomized trial, Gill Livingston and colleagues investigated whether a letter mailed to patients encouraging them to consult their primary care physician with potential memory problems led to an increase in early diagnosis of dementia in the United Kingdom.
Complications diagnosing and treating dementia alongside comorbid conditions
Thomas Jackson and colleagues discuss the difficulty of diagnosing dementia in patients admitted to acute hospitals, especially when it is complicated with delirium. Difficulties with diagnosis, and with care, of dementia and delirium can negatively influence the trajectory of dementia disease trajectories, and Jackson and colleagues call for hospitals to focus on early and accurate diagnosis of dementia and delirium, and researchers to work on improving diagnostics and management. In a large retrospective cohort study, Luke Mondor and colleagues examine multimorbidity and healthcare utilization among home care clients with dementia in Ontario, Canada, and find that a high level of multimorbidity (two or more conditions in addition to dementia) is associated with increased risk of hospitalization and emergency department visits, but that continuity of physician care did not modify this association.
Strategies for treatment
Two Perspective articles consider interventions– one theoretical– that are alternatives to the to date frustrating approach of developing pharmaceuticals that target the neuropathologies associated with dementias. Linda Clare proposes using a cognitive rehabilitation approach for people living with dementia. Cognitive rehabilitation provides people with a non-pharmaceutical intervention that can be tailored to the individual and severity of disease, and can help people with dementia engage in meaningful activities, reduce disability, and delay institutionalization. In a separate piece, David Bennett makes a case for targeting cognitive (neural) reserve, rather than one of the specific neuropathologies (eg amyloid-β or neurofibrillary tangles) as a therapeutic endpoint. Identifying a treatment that targets neural reserve, he argues, would be effective for any number of brain pathologies affecting cognition.
New Dementia Special Issue papers will appear throughout the March 2017 issue of PLOS Medicine. To view new papers as they publish, go to the Special Issue collection.
Featured Image Credit: dierk schaefer, Flickr
This post has been edited to correct Thomas Jackson’s name.