Summary: A new study reports delirium can accelerate cognitive decline in people undergoing pathological changes associated with dementia.
When hospitalised, people can become acutely confused and disorientated. This condition, known as delirium, affects a quarter of older patients and new research by UCL and University of Cambridge shows it may have long-lasting consequences, including accelerating the dementia process.
The study, published today in the journal JAMA Psychiatry, is the first to show the multiplying effects of delirium and dementia in these patients.
Episodes of delirium in people who are not known to have dementia, might also reveal dementia at its earliest stages, the research found.
While both delirium and dementia are important factors in cognitive decline among the elderly, delirium is preventable and treatable through dedicated geriatric care.
Further research is needed to understand exactly how delirium interacts with dementia, and how this could be blocked.
“If delirium is causing brain injury in the short and long-term, then we must increase our efforts to diagnose, prevent and treat delirium. Ultimately, targeting delirium could be a chance to delay or reduce dementia” said Dr. Daniel Davis (MRC Unit for Lifelong Health and Ageing at UCL), who led the research while at the University of Cambridge.
Scientists looked at three European populations – in Finland, Cambridge and UK-wide – and examined brain specimens in 987 people aged 65 and older. Each person’s memory, thinking and experience of delirium had been recorded over 10 years towards the end of their life.
When these were linked with pathology abnormalities due to Alzheimer’s and other dementias, those with both delirium and dementia-changes had the most severe change in memory.
Dr Davis added: “Unfortunately, most delirium goes unrecognised. In busy hospitals, a sudden change in confusion not be noticed by hospital staff. Patients can be transferred several times and staff often switch over – it requires everyone to ‘think delirium’ and identify that a patient’s brain function has changed.”
About this neuroscience research article
Funding: The research was funded by the Wellcome Trust.
Source: Margaret-Anne Orgill – UCL Image Source: NeuroscienceNews.com image is credited to Odra Noel. Original Research: Full open access research for “Association of Delirium With Cognitive Decline in Late Life: A Neuropathologic Study of 3 Population-Based Cohort Studies” by Daniel H. J. Davis, PhD, MRCP; Graciela Muniz-Terrera, PhD; Hannah A. D. Keage, PhD; Blossom C. M. Stephan, PhD; Jane Fleming, PhD; Paul G. Ince, MD, FRCPath; Fiona E. Matthews, PhD; Colm Cunningham, PhD; E. Wesley Ely, MD, MPH; Alasdair M. J. MacLullich, PhD, MRCP; Carol Brayne, MD; for the Epidemiological Clinicopathological Studies in Europe (EClipSE) Collaborative Members in JAMA Psychiatry. Published online January 18 2017 doi:10.1001/jamapsychiatry.2016.3423
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[cbtabs][cbtab title=”MLA”]UCL “Delirium Could Accelerate Dementia Related Mental Decline.” NeuroscienceNews. NeuroscienceNews, 18 January 2017. <https://neurosciencenews.com/delirium-dementia-decline-5964/>.[/cbtab][cbtab title=”APA”]UCL (2017, January 18). Delirium Could Accelerate Dementia Related Mental Decline. NeuroscienceNew. Retrieved January 18, 2017 from https://neurosciencenews.com/delirium-dementia-decline-5964/[/cbtab][cbtab title=”Chicago”]UCL “Delirium Could Accelerate Dementia Related Mental Decline.” https://neurosciencenews.com/delirium-dementia-decline-5964/ (accessed January 18, 2017).[/cbtab][/cbtabs]
Association of Delirium With Cognitive Decline in Late Life: A Neuropathologic Study of 3 Population-Based Cohort Studies
Importance Delirium is associated with accelerated cognitive decline. The pathologic substrates of this association are not yet known, that is, whether they are the same as those associated with dementia, are independent, or are interrelated.
Objective To examine whether the accelerated cognitive decline observed after delirium is independent of the pathologic processes of classic dementia.
Design, Setting, and Participants Harmonized data from 987 individual brain donors from 3 observational cohort studies with population-based sampling (Vantaa 85+, Cambridge City Over-75s Cohort, Cognitive Function and Ageing Study) performed from January 1, 1985, through December 31, 2011, with a median follow-up of 5.2 years until death, were used in this study. Neuropathologic assessments were performed with investigators masked to clinical data. Data analysis was performed from January 1, 2012, through December 31, 2013. Clinical characteristics of brain donors were not different from the rest of the cohort. Outcome ascertainment was complete given that the participants were brain donors.
Exposures Delirium (never vs ever) and pathologic burden of neurofibrillary tangles, amyloid plaques, vascular lesions, and Lewy bodies. Effects modeled using random-effects linear regression and interactions between delirium and pathologic burden were assessed.
Outcomes Change in Mini-Mental State Examination (MMSE) scores during the 6 years before death.
Results There were 987 participants (290 from Vantaa 85+, 241 from the Cambridge City Over-75s Cohort, and 456 from the Cognitive Function and Ageing Study) with neuropathologic data; mean (SD) age at death was 90 (6.4) years, including 682 women (69%). The mean MMSE score 6 years before death was 24.7 points. The 279 individuals with delirium (75% women) had worse initial scores (−2.8 points; 95% CI, −4.5 to −1.0; P < .001). Cognitive decline attributable to delirium was −0.37 MMSE points per year (95% CI, −0.60 to −0.13; P < .001). Decline attributable to the pathologic processes of dementia was −0.39 MMSE points per year (95% CI, −0.57 to −0.22; P < .001). However, the combination of delirium and the pathologic processes of dementia resulted in the greatest decline, in which the interaction contributed an additional −0.16 MMSE points per year (95% CI, −0.29 to −0.03; P = .01). The multiplicative nature of these variables resulted in individuals with delirium and the pathologic processes of dementia declining 0.72 MMSE points per year faster than age-, sex-, and educational level–matched controls.
Conclusions and Relevance Delirium in the presence of the pathologic processes of dementia is associated with accelerated cognitive decline beyond that expected for delirium or the pathologic process itself. These findings suggest that additional unmeasured pathologic processes specifically relate to delirium. Age-related cognitive decline has many contributors, and these findings at the population level support a role for delirium acting independently and multiplicatively to the pathologic processes of classic dementia.
“Association of Delirium With Cognitive Decline in Late Life: A Neuropathologic Study of 3 Population-Based Cohort Studies” by Daniel H. J. Davis, PhD, MRCP; Graciela Muniz-Terrera, PhD; Hannah A. D. Keage, PhD; Blossom C. M. Stephan, PhD; Jane Fleming, PhD; Paul G. Ince, MD, FRCPath; Fiona E. Matthews, PhD; Colm Cunningham, PhD; E. Wesley Ely, MD, MPH; Alasdair M. J. MacLullich, PhD, MRCP; Carol Brayne, MD; for the Epidemiological Clinicopathological Studies in Europe (EClipSE) Collaborative Members in JAMA Psychiatry. Published online January 18 2017 doi:10.1001/jamapsychiatry.2016.3423