Person:

Fong, Tamara

Background: Difficulties with performance of functional activities may result from cognitive and/or physical impairments. To date, there has not been a clear delineation of the physical and cognitive demands of activities of daily living. Objectives: To quantify the relative physical and cognitive demands required to complete typical functional activities in older adults. Design: Expert panel survey. Setting: Web-based platform. Participants: Eleven experts from eight academic medical centers and 300 community dwelling elderly adults age 70 and older scheduled for elective non-cardiac surgery from two academic medical centers. Methods: Sum scores of expert ratings were calculated and then validated against objective data collected from a prospective longitudinal study. Main Outcome Measurements Correlation between expert ratings and objective neuropsychological tests (memory, language, complex attention) and physical measures (gait speed and grip strength) for performance-based tasks. Results: Managing money, self-administering medications, using the telephone, and preparing meals were rated as requiring significantly more cognitive demand, while walking and transferring, moderately strenuous activities, and climbing stairs were assessed as more physically demanding. Largely cognitive activities correlated with objective neuropsychological performance (r=0.13–0.23, p<.05) and largely physical activities correlated with physical performance (r=0.15–0.46, p<.05). Conclusions: Quantifying the degree of cognitive and/or physical demand for completing a specific task adds an additional dimension to standard measures of functional assessment. This additional information may significantly influence decisions about rehabilitation, post-acute care needs, treatment plans, and caregiver education.

Deficits in cholinergic function have been postulated to cause delirium and cognitive decline. This review examines current understanding of the cholinergic deficiency hypothesis in delirium by synthesizing evidence on potential pathophysiological pathways. Acetylcholine synthesis involves various precursors, enzymes, and receptors, and dysfunction in these components can lead to delirium. Insults to the brain, like ischemia and immunological stressors, can precipitously alter acetylcholine levels. Imbalances between cholinergic and other neurotransmitter pathways may result in delirium. Furthermore, genetic, enzymatic, and immunological overlaps exist between delirium and dementia related to the cholinergic pathway. Important areas for future research include identifying biomarkers, determining genetic contributions, and evaluating response to cholinergic drugs in delirium. Understanding how the cholinergic pathway relates to delirium may yield innovative approaches in the diagnosis, prevention, and treatment of this common, costly, and morbid condition.

OBJECTIVES: To identify barriers and motivators to participation in long-term clinical research by high-risk elderly people and to develop procedures to maximize recruitment and retention. DESIGN: Quantitative and qualitative survey. SETTING: Academic primary care medicine and pre-anesthesia testing clinics. PARTICIPANTS: Fifty patients aged 70 and older, including 25 medical patients at high risk of hospitalization and 25 patients with planned major surgery. MEASUREMENTS: Fifteen- to 20-minute interviews involved open- and closed-ended questions guided by an in-depth script. Two planned study protocols were presented to each participant. Both involved serial neuropsychological assessments, blood testing, and magnetic resonance brain imaging (MRI); one added lumbar puncture (LP). Participants were asked whether they would be willing to participate in these protocols, rated barriers and incentives to participation, and were probed with open-ended questions. RESULTS: Of 50 participants (average age 78, 44% male, 40% nonwhite), 32 (64%) expressed willingness to participate in the LP-containing protocol, with LP cited as the strongest disincentive. Thirty-eight (76%) expressed willingness to participate in the protocol without LP, with phlebotomy and long interviews cited as the strongest disincentives. Altruism was a strong motivator for participation, whereas transportation was a major barrier. Study visits at home, flexible appointment times, assessments shorter than 75 minutes, and providing transportation and free parking were strategies developed to maximize study participation. CONCLUSION: Vulnerable elderly people expressed a high rate of willingness to participate in an 18-month prospective study. Participants identified incentives and barriers that enabled investigators to develop procedures to maximize recruitment and retention.

Background Brief cognitive screening measures are valuable tools for both research and clinical applications. The most widely used instrument, the Mini-Mental State Examination (MMSE), is limited in that it must be administered face-to-face, cannot be used in participants with visual or motor impairments, and is protected by copyright. Screening instruments such as the Telephone Interview for Cognitive Status (TICS) were developed to provide a valid alternative, with comparable cut-point scores to rate global cognitive function.

Methods The MMSE, TICS-30, and TICS-40 scores from 746 community-dwelling elders who participated in the Aging, Demographics, and Memory Study (ADAMS) were analyzed with equipercentile equating, a statistical process of determining comparable scores based on percentile equivalents for different forms of an examination.

Results Scores from the MMSE and TICS-30 and TICS-40 corresponded well, and clinically relevant cut-point scores were determined. For example, an MMSE score of 23 is equivalent to 17 and 20 on the TICS-30 and TICS-40, respectively.

Conclusions These findings indicate that TICS and MMSE scores can be linked directly. Clinically relevant and important MMSE cut points and the respective ADAMS TICS-30 and TICS-40 cut-point scores are included, to identify the degree of cognitive impairment among respondents with any type of cognitive disorder. These results will help in the widespread application of TICS in both research and clinical practice.

Cognitive and brain reserve are well studied in the context of age-associated cognitive impairment and dementia. However, there is a paucity of research that examines the role of cognitive or brain reserve in delirium. Indicators (or proxy measures) of cognitive or brain reserve (such as brain size, education, and activities) pose challenges in the context of the long prodromal phase of Alzheimer disease but are diminished in the context of delirium, which is of acute onset. This article provides a review of original articles on cognitive and brain reserve across many conditions affecting the central nervous system, with a focus on delirium. The authors review current definitions of reserve. The authors identify indicators for reserve used in earlier studies and discuss these indicators in the context of delirium. The authors highlight future research directions to move the field ahead. Reserve may be a potentially modifiable characteristic. Studying the role of reserve in delirium can advance prevention strategies for delirium and may advance knowledge of reserve and its role in aging and neuropsychiatric disease generally.

The objective of this analysis was to develop a measure of neuropsychological performance for cardiac surgery and to assess its psychometric properties. Older patients (n = 210) underwent a neuropsychological battery using nine assessments. The number of factors was identified with variable reduction methods. Factor analysis methods based on item response theory were used to evaluate the measure. Modified parallel analysis supported a single factor, and the battery formed an internally consistent set (coefficient alpha = .82). The developed measure provided a reliable, continuous measure (reliability > .90) across a broad range of performance (–1.5 SDs to +1.0 SDs) with minimal ceiling and floor effects.

OBJECTIVES: To determine whether patients who developed delirium after cardiac surgery were at risk of functional decline.

DESIGN: Prospective cohort study.

SETTING: Two academic hospitals and a Veterans Affairs Medical Center.

PARTICIPANTS: One hundred ninety patients aged 60 and older undergoing elective or urgent cardiac surgery.

MEASUREMENTS: Delirium was assessed daily and was diagnosed according to the Confusion Assessment Method. Before surgery and 1 and 12 months postoperatively, patients were assessed for function using the instrumental activities of daily living (IADL) scale. Functional decline was defined as a decrease in ability to perform one IADL at follow-up.

RESULTS: Delirium occurred in 43.1% (n=82) of the patients (mean age 73.7±6.7). Functional decline occurred in 36.3% (n=65/179) at 1 month and in 14.6% (n=26/178) at 12 months. Delirium was associated with greater risk of functional decline at 1 month (relative risk (RR)=1.9, 95% confidence interval (CI)=1.3–2.8) and tended toward greater risk at 12 months (RR=1.9, 95% CI=0.9–3.8). After adjustment for age, cognition, comorbidity, and baseline function, delirium remained significantly associated with functional decline at 1 month (adjusted RR=1.8, 95% CI=1.2–2.6) but not at 12 months (adjusted RR=1.5, 95% CI=0.6–3.3).

CONCLUSION: Delirium was independently associated with functional decline at 1 month and had a trend toward association at 12 months. These findings provide justification for intervention trials to evaluate whether delirium prevention or treatment strategies might improve postoperative functional recovery.

Dementia with Lewy bodies (DLB) is often associated with occipital hypometabolism or hypoperfusion, as well as deficits in cholinergic neurotransmission. In this study, 11 mild DLB, 16 mild AD and 16 age-matched controls underwent arterial spin-labeled perfusion MRI (ASL-pMRI) and neuropsychological testing. Patterns of cerebral blood flow (CBF) and cognitive performance were compared. In addition, combined ASL-pMRI and ChEI drug challenge (pharmacologic MRI) was tested as a probe of cholinergic function in 4 of the DLB participants. Frontal and parieto-occipital hypoperfusion was observed in both DLB and AD but was more pronounced in DLB. Following ChEI treatment, perfusion increased in temporal and parieto-occipital cortex, and cognitive performance improved on a verbal fluency task. If confirmed in a larger study, these results provide further evidence for brain cholinergic dysfunction in DLB pathophysiology, and use of pharmacologic MRI as an in vivo measure of cholinergic function.

OBJECTIVES: To use an expert consensus process to identify indicators of delirium features to help enhance bedside recognition of delirium. DESIGN: Modified Delphi consensus process to assign existing cognitive and delirium assessment items to delirium features in the Confusion Assessment Method (CAM) diagnostic algorithm. SETTING: Meetings of expert panel. PARTICIPANTS: Panel of seven interdisciplinary clinical experts. MEASUREMENTS: Panelists' assignments of each assessment item to indicate CAM features. RESULTS: From an initial pool of 119 assessment items, the panel assigned 66 items to at least one CAM feature, and many items were assigned to more than one feature. Experts achieved a high level of consensus, with a postmeeting kappa for agreement of 0.98. The study staff compiled the assignment results to create a comprehensive list of CAM feature indicators, consisting of 107 patient interview questions, cognitive tasks, and interviewer observations, with some items assigned to multiple features. A subpanel shortened this list to 28 indicators of important delirium features. CONCLUSION: A systematic, well-described qualitative methodology was used to create a list of indicators for delirium based on the features of the CAM diagnostic algorithm. This indicator list may be useful as a clinical tool for enhancing delirium recognition at the bedside and for aiding in the development of a brief delirium screening instrument.

Background Delirium is common after cardiac surgery and may be associated with long-term changes in cognitive function. We examined postoperative delirium and the cognitive trajectory during the first year after cardiac surgery.

Methods We enrolled 225 patients 60 years of age or older who were planning to undergo coronary-artery bypass grafting or valve replacement. Patients were assessed preoperatively, daily during hospitalization beginning on postoperative day 2, and at 1, 6, and 12 months after surgery. Cognitive function was assessed with the use of the Mini–Mental State Examination (MMSE; score range, 0 to 30, with lower scores indicating poorer performance). Delirium was diagnosed with the use of the Confusion Assessment Method. We examined performance on the MMSE in the first year after surgery, controlling for demographic characteristics, coexisting conditions, hospital, and surgery type.

Results The 103 participants (46%) in whom delirium developed postoperatively had lower preoperative mean MMSE scores than those in whom delirium did not develop (25.8 vs. 26.9, P<0.001). In adjusted models, those with delirium had a larger drop in cognitive function (as measured by the MMSE score) 2 days after surgery than did those without delirium (7.7 points vs. 2.1, P<0.001) and had significantly lower postoperative cognitive function than those without delirium, both at 1 month (mean MMSE score, 24.1 vs. 27.4; P<0.001) and at 1 year (25.2 vs. 27.2, P<0.001) after surgery. With adjustment for baseline differences, the between-group difference in mean MMSE scores was significant 30 days after surgery (P<0.001) but not at 6 or 12 months (P=0.056 for both). A higher percentage of patients with delirium than those without delirium had not returned to their preoperative baseline level at 6 months (40% vs. 24%, P=0.01), but the difference was not significant at 12 months (31% vs. 20%, P=0.055).

Conclusions Delirium is associated with a significant decline in cognitive ability during the first year after cardiac surgery, with a trajectory characterized by an initial decline and prolonged impairment.