Delirium and long-term cognitive impairment. Int Rev Psychiatry

Department of Geriatric Medicine, University of Edinburgh, Royal Infirmary of Edinburgh, Edinburgh, Scotland, UK.
International Review of Psychiatry (Impact Factor: 1.8). 02/2009; 21(1):30-42. DOI: 10.1080/09540260802675031
Source: PubMed


Delirium is a severe, acute neuropsychiatric syndrome that is highly prevalent in acute hospital populations. Delirium has noticeable effects on length of hospitalization, cost of care, mortality and morbidity. In addition to these well-established adverse consequences, there is increasing evidence linking delirium and a higher risk of long-term cognitive impairment (LTCI), including dementia. A prior review (Jackson, Gordon, Hart, Hopkins, & Ely, 2004), in which nine studies (total N = 1,885, years 1989-2003) were considered, concluded that there was evidence for an association between delirium and LTCI. Here we provide a review of studies published since Jackson's review. We included nine reports, with a total of 2,025 patients. The studies show diverse sample sizes, methodologies, designs and patient populations. However, taken together, the results of these new studies broadly confirm that there is a link between delirium and LTCI. We go on to discuss putative mechanisms and explanations. These include (1) delirium as a marker of chronic progressive pathology, but unrelated to any progression, (2) delirium as a consequence of acute brain damage which is also responsible for a 'single hit' or triggering of active processes causing LTCI, (3) delirium itself as a cause of LTCI, and (4) drug treatment of delirium or other conditions as a cause of LTCI. We conclude with suggestions for future research.

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    • "In addition to delirium, an earlier dementia diagnosis tended to be significantly associated with poorer cognitive performance in the current study, whereas a delirium previous to hospital admission did not have significant negative effects. Few studies (MacLullich et al., 2009) have comprehensively assessed the contribution of baseline clinical and demographic variables on cognitive outcome measures in elderly , previously delirious, populations. Cognitive performance was worse in the delirium group so soon after the delirium had cleared and just before the patients were sent home, and this is concerning. "
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    ABSTRACT: The aim of this study was to examine early cognitive performance after a delirium in elderly general hospital patients. Patients were divided into a delirium (n = 47) and a control (n = 25) group. One week before discharge and after delirium had cleared in the first group, all patients completed a neuropsychological test battery (The Cambridge Cognitive Examination-Revised [CAMCOG-R]). Group differences in cognitive performance were analyzed adjusting for differences in baseline sociodemographic and clinical variables. Adjusting for group differences in baseline variables, the delirium group performed significantly worse than the control group on CAMCOG-R; its subdomains language, praxis, and executive functioning; and on Mini Mental State Examination derived from CAMCOG-R. The occurrence of delirium in hospital thus detrimentally affects early cognitive performance.
    Full-text · Article · Sep 2014 · The Journal of nervous and mental disease
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    • "Delirium impacts adversely upon a variety of healthcare outcomes that include more prolonged hospitalisation, reduced likelihood of subsequent socio-adaptive independence, persistent or 'long-term' cognitive impairments in older persons and elevated mortality rates [4] [5]. Delirium is thus a major health care concern [6]. "
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    ABSTRACT: Delirium is a serious neuropsychiatric syndrome of acute onset that occurs in approximately one in five general hospital patients and is associated with serious adverse outcomes that include loss of adaptive function, persistent cognitive problems and increased mortality. Recent studies indicate a three-domain model for delirium that includes generalised cognitive impairment, disturbed executive cognition, and disruption of behaviours that are under circadian control such as sleep-wake cycle and motor activity levels. As a consequence, attention has focused upon the possible role of the circadian timing system (CTS) in the pathophysiology of delirium. We explored this possibility by reviewing evidence that (1) many symptoms that occur in delirium are influenced by circadian rhythms, (2) many features of recognised circadian rhythm disorders are similar to characteristic features of delirium, (3) common risk factors for delirium are known to disrupt circadian systems, (4) physiological disturbances of circadian systems have been noted in delirious patients, and (5) positive effects in the treatment of delirium have been demonstrated for melatonin and related agents that influence the circadian timing system. A programme of future studies that can help to clarify the relevance of circadian integrity to delirium is described. Such work can provide a better understanding of the pathophysiology of delirium while also identifying opportunities for more targeted therapeutic efforts.
    Full-text · Article · Jul 2013 · Medical Hypotheses
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    • "Yet, most studies that examined the association of delirium with cognitive impairment merely used screening instruments which are inappropriate for fully characterizing and quantifying defects in specific cognitive domains (Jackson et al., 2004). Therefore, the precise nature of the cognitive impairments and the extent to which particular cognitive domains are affected after delirium remain uncertain (MacLullich et al., 2009). A better understanding of the nature of the cognitive impairments following delirium might help to ascertain the value of different hypotheses that have been proposed to explain the relationship between delirium and cognitive impairment at follow-up. "
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    ABSTRACT: Background: Delirium is a risk factor for long-term cognitive impairment and dementia. Yet, the nature of these cognitive deficits is unknown as is the extent to which the persistence of delirium symptoms and presence of depression at follow-up may account for the association between delirium and cognitive impairment at follow-up. We hypothesized that inattention, as an important sign of persistent delirium and/or depression, is an important feature of the cognitive profile three months after hospital discharge of patients who experienced in-hospital delirium. Methods: This was a prospective cohort study. Fifty-three patients aged 75 years and older were admitted for surgical repair of acute hip fracture. Before the surgery, baseline characteristics, depressive symptomatology, and global cognitive performance were documented. The presence of delirium was assessed daily during hospital admission and three months after hospital discharge when patients underwent neuropsychological assessment. Results: Of 27 patients with in-hospital delirium, 5 were still delirious after three months. Patients with in-hospital delirium (but free of delirium at follow-up) showed poorer performance than patients without in-hospital delirium on tests of global cognition and episodic memory, even after adjustment for age, gender, and baseline cognitive impairment. In contrast, no differences were found on tests of attention. Patients with in-hospital delirium showed an increase of depressive symptoms after three months. However, delirium remained associated with poor performance on a range of neuropsychological tests among patients with few or no signs of depression at follow-up. Conclusion: Elderly hip fracture patients with in-hospital delirium experience impairments in global cognition and episodic memory three months after hospital discharge. Our results suggest that inattention, as a cardinal sign of persistent delirium or depressive symptomatology at follow-up, cannot fully account for the poor cognitive outcome associated with delirium.
    Full-text · Article · May 2013 · International Psychogeriatrics
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