JAMDA
Volume 10, Issue 3 , Pages 181-188, March 2009

Detecting Delirium and Subsyndromal Delirium Using Different Diagnostic Criteria among Demented Long-Term Care Residents

  • Philippe Voyer, RN, PhD

      Affiliations

    • Faculty of Nursing, Laval University, and Laval University Geriatric Research Unit of St-Sacrement Hospital Centre, Quebec City, Canada
    • Corresponding Author InformationAddress correspondence to Philippe Voyer, RN, PhD, Faculty of Nursing, Laval University, 2425 rue de l'agriculture, bureau 4106, Pavillon Paul-Comtois, Quebec City (QC), Canada G1V 0A6
    • ,
  • Sylvie Richard, OT, MSc

      Affiliations

    • Center for Excellence in Aging – Research Unit, Quebec City, Canada
    • ,
  • Lise Doucet, RN, MSc

      Affiliations

    • Nursing Administration, Centre de Santé et de services sociaux de la Vieille-Capitale, Quebec City, Canada
    • ,
  • Pierre-Hugues Carmichael, BSc, MSc

      Affiliations

    • Center for Excellence in Aging, Quebec City, Canada

published online 09 January 2009.

Article Outline

Objectives

To evaluate the impact of using different diagnostic criteria on prevalence rates of delirium and subsyndromal delirium (SSD) among demented long-term care (LTC) residents.

Design

Descriptive study.

Setting

LTC settings in Quebec City, Canada.

Participants

Participants were 155 individuals aged 65 and older, with dementia.

Measurements

(1) Prevalence rates of delirium according to: (a) the Diagnostic and Statistical Manual of Mental Disorders (DSM-III, DSM-III-R, and DSM-IV) and (b) the Confusion Assessment Method (CAM) algorithms for definite and probable delirium; and (2) prevalence rates of SSD employing 2 definitions described in previous studies.

Results

Prevalence rates of delirium according to each set of criteria were 26.5% for DSM-III; 29% for DSM-IV-TR; 41.3% for DSM-III-R; 45.8% for CAM algorithm for definite delirium; and 70.3% for CAM algorithm for probable delirium. A total of 109 subjects (70.3%) were identified as delirious consistent with at least one classification and 37 (23.9%) met all the sets of criteria considered. Prevalence rates for SSD were 75 (48.4%) and 78 (50.3%) depending on the definition employed.

Conclusion

Prevalence rates for delirium are much affected by the diagnostic formulations used. The use of DSM-IV-TR among this population could result in fewer cases being identified as delirious and thus compromise proper care for those individuals. Considering that SSD was prevalent among this population, a systematic implementation of protocols targeting risk factors of delirium might be beneficial among demented LTC residents.

Keywords: Delirium, subsyndromal delirium, long-term care setting, dementia, diagnostics

 

Delirium is defined as a mental disorder of acute onset with a fluctuating course, characterized by disturbances in consciousness, attention, orientation, memory, thought, perception and behavior.1 It is a serious problem among elderly patients in hospital and post-acute settings because it has been associated with numerous negative outcomes, such as decline in functional and cognitive status, as well as increased morbidity and mortality rates.2, 3, 4, 5 Consequences of delirium are not limited to patient outcomes; it also represents an important source of distress for family members and nursing staff.6 Delirium also leads to greater hospital costs related to longer hospital stays and an increased demand on nursing time.7, 8

Prevalence of delirium among elderly patients varies from 9.6% to 89%.9, 10, 11 It is highest among vulnerable elderly patients with preexisting cognitive impairment.12 The wide variation in prevalence is due not only to methodological issues, such as differences in the population under study or the type of clinical settings under consideration, but also to the criteria selected for its diagnosis and the diagnostic instruments used.13, 14, 15

Although delirium has been documented in medical literature for more than 2000 years (using different terminology),16 it was first described as a diagnostic entity by the American Psychiatric Association in the third edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM) in 1980.17 Since then, there have been 3 revisions of the DSM18, 19, 20 that have led to 2 comprehensive changes in the delirium-defining criteria: DSM-III-R (1987)19 and DSM-IV (1994).20 These modifications were based on extensive clinical experience as well as the identification of difficulties with regard to interpretation of some of the criteria contained in the earlier editions21 (these criteria are detailed in the method section). It should be borne in mind that DSM-IV and DMS-IV-TR criteria for delirium are similar. Although the DSM set of criteria has not changed in recent years, researchers continue to study the different versions of the DSM criteria for delirium, comparing it with each version or with detection instruments or even contributing to the evolution of the concept of delirium with new terms such as subsyndromal delirium. These studies are very important for clinical practice. It is not mere theoretical questioning; for individual patients it can mean the difference between life and death. To receive care related to delirium, the individual has first to be diagnosed with the condition and the criteria used to make that diagnosis can make a difference.

Studies on delirium, whether they were addressing prevalence,19, 22 detection,9, 10 treatment or prevention,7, 23 have not only relied on diagnostic criteria to determine the presence of delirium but also on different delirium diagnostic instruments. Indeed, many instruments have been developed to enable nonphysician caregivers to detect the presence of delirium.24 The Confusion Assessment Method (CAM), developed by Inouye et al,25 is certainly the best known and the most commonly used delirium diagnostic instrument.9, 26, 27

Besides well-established sets of criteria such as the DSM-IV, or a validated instrument such as the CAM, there has recently emerged a new concept known as subsyndromal delirium (SSD). SSD refers to a condition in which patients have one or more symptoms of delirium without displaying its full clinical presentation. Some researchers have studied the prognostic significance of SSD among elderly individuals. Cole et al28 found that elderly medical patients (n = 164) with prevalent SSD at admission had longer acute-care hospital stay, increased postdischarge mortality, more symptoms of delirium, and a lower cognitive and functional level at follow-up (2, 6, and 12 months) than patients with no SSD. Marcantonio and colleagues29 compared the clinical outcomes of elderly patients admitted to post-acute facilities with delirium, subsyndromal delirium, and no delirium. Subjects with SSD were found to have outcomes that fall between those of subjects with and without delirium. For example, a 6-month mortality rate of 25% was reported for subjects with delirium, compared with 18% for the SSD group and 5.7% for subjects without delirium or SSD.

As far as the present authors are aware, no study has examined the performance of different sets of diagnostic criteria on the prevalence of delirium and subsyndromal delirium among long-term care (LTC) residents with dementia. Residents in LTC facilities constitute a unique population where risk factors for delirium such as dementia, are very prevalent. To offer quality care to this very frail population, there needs to be a better understanding of the frequency of this syndrome and its subclinical manifestation. Early recognition of delirium is essential in order to deal promptly with the underlying medical causes as well as to enable the rapid implementation of interventions targeting the individual predisposing and precipitating delirium risk factors and in so doing, reduce its severity, duration, and consequences.10, 30, 31, 32

Since delirium recognition is based on the use of sets of specific criteria from the DSM or the use of certain diagnostic tools, prevalence rates of delirium in this population could well differ according to the definition used. Given this, providing empirical evidence of the effect of these alternative definitions on delirium prevalence is crucial for future revision of the criteria with regard to this particular clinical setting and population. Moreover, clinicians working with this population can select the diagnostic tool most adapted to their patients.

The aim of this study was to compare the prevalence rates of delirium among demented long-term care residents as indicated by the following diagnostic criteria: DSM-III, DSM-III-R, and DSM-IV, as well as CAM algorithms for definite and probable delirium. In addition, prevalence rates of SSD according to both Cole's and Marcantonio's definitions of SSD were assessed.

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Methods 

Study Settings and Selection of Participants 

Subjects were recruited in 3 LTC facilities and 1 LTC unit of a large regional hospital, all located within the Quebec City region of Canada. A convenience sampling procedure was used. All patients aged 65 years and older with dementia and no history of psychiatric illness were eligible for this study. Following clearances from all appropriate institutional ethics committees, a study nurse met with the head nurse of every unit in each participating facility to identify eligible patients. Specifically, the unit head nurse was asked to identify demented residents based on the presence of a medical diagnosis of dementia in their medical chart.

Once the eligible residents had been identified, there was an informative letter about the study sent to their families, inviting them to contact the study nurse to obtain further information, if so desired. After their questions had been answered satisfactorily, those contacting the study nurse were invited to sign proxy consent forms. Assent for participation was also obtained from the residents whose cognitive impairment was judged to be mild or moderate.

In all, 293 families of demented residents were solicited. Of these, 122 did not respond (41.6%), 11 refused to take part (3.8%), and 160 agreed to give their consent (54.6%). After the enrollment period, 3 residents died before evaluation, 1 was transferred, and 1 was hospitalized, leaving a total of 155 participants in the study.

Data Collection 

The study nurses involved in this study each completed 15 hours of instruction on delirium and dementia, given by a research team member. Instructions on the research procedures plus direct supervision in the data collection from 15 participants were also provided. All observational measures were completed based on patient monitoring over a 7-hour period. One study nurse focused on the completion of measures of delirium, subsyndromal delirium, and dementia severity. A second study nurse collected baseline characteristics of patients (education level, length of stay in their current LTC facility, comorbidity level, number of drugs taken, and degree of functional autonomy).

Measures 

Measures of Delirium and Subsyndromal Delirium 

The different classification systems for diagnosis of delirium or subsyndromal delirium are based on the presence of a variety of symptoms and conditions, which are combined in different ways according to each classification system. Figure 1 presents the criteria required for each classification (delirium and SSD) looked at in this study. In order to operationalize these symptoms and conditions, we used the CAM, which is a structured and validated33 instrument that operationalizes 9 symptoms of delirium (acute onset and fluctuating course, inattention, disorganized thinking, altered level of consciousness, disorientation, memory impairment, perceptual disturbances, psychomotor agitation or retardation, and altered sleep-wake cycle). In addition to the information gathered during the course of the 7-hour observation period, the study nurse had to conduct 3 structured interviews with the resident over the course of the day in order to complete the CAM. To assess “acute onset of symptoms,” the study nurse gathered information from all available sources (staff, family member, medical chart). A baseline assessment of the resident's cognitive status using the Hierarchic Dementia Scale (HDS) performed 7 days before the evaluation was also used to appraise the criterion “acute onset” of symptoms. Any evidence of new delirium symptoms would result in a positive score for this criterion. To assess “fluctuation,” the study nurse had to observe a fluctuation in at least one of the previously mentioned delirium symptoms during the course of the 7-hour observation period.

According to the study by Cole et al28 built on the DSM-III-R, subsyndromal delirium is defined as individuals not meeting DSM-III-R criteria for delirium and having at least 2 of the following symptoms: clouding of consciousness, inattention, disorientation, perceptual disturbances.

On the basis of the Marcantonio et al study,29 which is built on the CAM, subsyndromal delirium is defined as individuals not meeting the CAM algorithm of definite delirium but displaying at least one criterion of this latter.

Within the context of the present study, inter-rater agreement was satisfactory: kappa of 0.53 (95% CI: 0.03–1.00) for CAM definitive delirium and kappa of 0.71 (95% CI: 0.21–1.00) for CAM probable delirium.

Other Measures 

Subjects were classified into 4 different subtypes according to Meagher et al's criteria34: (1) Hypoactive (presence of 4 or more of the following: unawareness, decreased alertness, sparse or slow speech, lethargy, decreased motor activity, staring and apathy), (2) Hyperactive (presence of 3 or more of the following: hypervigilance, restlessness, fast or loud speech, anger or irritability, combativeness, impatience, uncooperativeness, swearing, singing, laughing, euphoria, wandering, easy startling, distractibility, nightmares, persistent thoughts), (3) Mixed: must have satisfied both hypoactive and hyperactive conditions, and (4) Without a motoric component: subjects meeting neither hyper nor hypoactive criteria as defined above.

Dementia severity was gauged using the Hierarchic Dementia Scale (HDS),35 consisting of 20 subscales assessing a broad spectrum of cognitive abilities. The subscales in turn, comprise either 5 or 10 items in decreasing order of difficulty. The maximum score for the entire scale is 200 points. Cognitively intact older adults generally achieve the maximum number of points, or close to it.36 The validity and reliability of the HDS is well established.37, 38 For example, Ronnberg and Ericsson37 reported a test-retest reliability of .96 and a concurrent validity coefficient between the HDS and the Mini Mental Status Examination of .86. More recently, Engelborghs et al39 demonstrated a significant correlation between HDS and biological markers of Alzheimer's disease.

Comorbidity was assessed by chart review with the validated and reliable Charlson Comorbidity Index (CCI).40 The overall score ranges from 0 to 37 with higher scores indicating greater comorbidity. A value of 8 and higher was the cut-off point.

Functional autonomy of the resident was measured by the Functional Autonomy Measurement System (SMAF).41 This 29-item scale measures functional ability in 5 areas: activities of daily living (ADL: 7 items), mobility (6 items), communication (3 items), mental functions (5 items), and instrumental activities of daily living (IADL: 8 items). For institutionalized subjects, a modified 21-item version (excluding the 8 IADL items) has been developed. The degree of disability for each item is scored on a 5-point scale: 0 = independent, −0.5 = with difficulty, −1 = with supervision, −2 = with help, and −3 = dependent. The total score of the SMAF ranges from 0 to −63. The absolute value of the total score was used; therefore a higher score is indicative of severe autonomy impairment. This original version of this scale has shown good test-retest and inter-rater reliability (intraclass correlations of 0.95 and 0.96 respectively).42

Statistical Analyses 

The authors used simple descriptive statistics to describe the study population and evaluate the prevalence of delirium and subsyndromal delirium according to the different classification systems: DSM-III, DSM-III-R, DSM-IV, and CAM algorithm (definite and probable) for delirium and both Marcantonio's and Cole's definitions for subsyndromal delirium. All analyses were carried out using SAS for Windows, version 9.1 (SAS Institute Inc., Cary, NC).

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Results 

Baseline characteristics of the 155 residents are presented in Table 1. The mean age of the participants was 86.3 ± 6.9 (mean ± SD) and most of them were female (73.6%). The mean time since admission to their LTC facility was 2.6 years (SD: 2.3). The degree of cognitive impairment in this population was important, with a mean score of 91.0 (SD: 49.0) on the HDS Scale. About 41% of participants had a high level of comorbidity (score ≥8 on the Charlson Comorbidity Index) and the mean number of prescribed medications was 9.1 (SD: 4.3). More than two thirds of the residents were showing substantial deterioration of their functional autonomy (score ≥ 29 on the SMAF).

Table 1. Baseline Characteristics of Residents (n = 155)
Variables [Missing Values]Mean (SD)n (%)
Age86.3(6.9)
65–74 8(5.2)
75–84 48(31.0)
≥85 99(63.9)
Sex
Female 114(73.6)
Marital status
Married-living as married 43(27.7)
Level of education (years) [4]7.8(3.5)
Ethnicity
Caucasian 150(96.8)
Days since admission942.0(839.2)
Comorbidity (CCI-range: 0–37)
Moderate to severe (≥8) 64(41.3)
Number of drugs taken9.1(4.3)
Severity of dementia (HDS-range: 0–200)91.0(49.0)
Functional autonomy (SMAF-range: 0–63)34.0(11.2)
0–29 50(32.2)
29.1–40 50(32.2)
≥41 55(35.5)

CCI, Charlson Comorbidity Index; HDS, Hierarchic Dementia Scale; SMAF, Functional Autonomy Measurement System.

Table 2 shows prevalence rates of delirium according to each classification system. Of the 155 residents in the study, 41 (26.5%) met DSM-III criteria for delirium, 45 (29.0%) met DSM-IV criteria, 64 (41.3%) met DSM-III-R criteria, 71 (45.8%) met the CAM algorithm for definite delirium, and last, 109 (70.3%) met the CAM algorithm for probable delirium. A total of 109 subjects (70.3%) were identified as delirious according to at least one classification and 37 (23.9%) met all the sets of criteria considered (Figure 2). The CAM algorithm for probable delirium was the most inclusive set of criteria as it incorporated all delirium cases. The DSM-III-R identified 27 cases of delirium not identified by the DSM-III and 25 cases not identified by the DSM-IV. All but one subject identified by the CAM algorithm for definite delirium were also identified by the three versions of the DSM combined (n = 70). The classification system for delirium was found to have slight to no influence on the type of delirium forms that we observed.

Table 2. Prevalence of Delirium and Forms of Delirium According to Each Classification System (n = 155)
DSM-IIIDSM-III-RDSM-IVCAM DefiniteCAM Probable
n (%)n (%)n (%)n (%)n (%)
[Missing][Missing][Missing][Missing][Missing]
Prevalence of delirium41(26.5)64(41.3)45(29.0)71(45.8)109(70.3)
Forms of delirium:
(Meaghers's criteria)[8][10][8][8][14]
Hypoactive3(9.1)3(5.6)5(13.5)5(8.8)7(7.6)
Hyperactive13(39.4)28(51.8)14(37.8)28(49.1)46(50.0)
Mixed16(48.5)17(31.5)16(43.2)18(31.6)30(32.6)
Normal1(3.0)6(11.1)2(5.4)6(10.5)9(9.8)

DSM, Diagnostic and Statistical Manual of Mental Disorders; CAM, Confusion Assessment Method.

  • View full-size image.
  • Fig. 2. 

    Prevalence and overlap of the different criteria sets for delirium (Diagnostic Manual of Mental Disorders: DSM-III, DSM-III-R, and DSM-IV and Confusion Assessment Method – CAM algorithms for probable and definite delirium) and subsyndromal delirium (SSD) (Marcantonio's and Cole's operationalization of SSD) n = 155.

Figure 2 presents prevalence rates of subsyndromal delirium among the study population. Of the 155 residents, 75 (48.4%) were identified with SSD according to Cole's definition and 78 (50.3%) according to Marcantonio's definition. Eighty-five residents (54.8%) met at least one definition of subsyndromal delirium and 68 (43.9%) met both definitions.

Figure 3 indicates the total number of cases identified at risk of experiencing deleterious consequences when SSD is considered in addition to delirium. Using Marcantonio's definition for SSD, 96.1% of the cases were identified as being at risk compared to 89.7% when Cole's definition was applied.

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Discussion 

This study investigated the effect that using different classification systems had on prevalence rates (detection rates) of delirium among demented elderly residents in LTC settings. It also aimed at describing the frequency of subsyndromal delirium among this same population according to 2 different definitions.28, 29 As far as the authors are aware, the present study is the first to address these particular issues among this distinctive population.

The first observation that can be made from the results of the present study is that regardless of the diagnostic criteria used to define delirium, the number of delirious individuals in our sample was important. This result may be explained by the fact that all the subjects were demented and dementia is one of the leading risk factors for delirium.43, 44, 45, 46 The prevalence rates obtained in the present study are in line with those reported in a systematic review conducted by Fick et al11 on delirium superimposed on dementia (prevalence rates ranging from 22% to 89%).

Our results indicate that prevalence rates for delirium are very much affected by the set of diagnostic criteria used. In fact, prevalence rates among the study population varied from 26.4% to 70.3%. Of all the DSM editions, DSM-III-R was found to be the most inclusive set of criteria, followed by the DSM-IV and DSM-III. Previous studies that looked at prevalence rates according to the various DSM editions were mainly carried out in medical settings. Liptzin et al15 compared the application of DSM-III and DSM-III-R criteria for delirium among 325 elderly patients admitted for acute medical problems to a general hospital. Contrary to our results, they found that DSM-III criteria were the most inclusive identifying 125 cases of delirium (38.4%) compared with 106 cases (32.6%) for the DSM-III-R. Although Liptzin et al did not exclude patients with dementia from their study, the prevalence of dementia among their study population was not reported.

In another study, by Laurila et al,13 the impact of different diagnostic criteria on prevalence rates for delirium among geriatric acute care hospital patients (n = 230) and nursing home residents (n = 195) was examined. Sixty-four percent of both their populations together (n = 425) were demented. For the whole sample, the most inclusive set of criteria was the DSM-IV (24.9%), followed by the DSM-III-R (19.5%), and DSM-III (18.8%). However, their results were different when they analyzed the hospital patient and nursing home resident groups separately. Indeed they found the DSM-IV criteria set was the most inclusive among geriatric acute-care hospital patients (34.8%), whereas the DSM-III-R criteria set was the most inclusive among nursing home residents (14.4%). These results corroborate the findings of the present study where DSM-III-R was also found to be the most inclusive DSM set of criteria among LTC residents.

Although one of the main objectives of the DSM-IV Work Group was to create criteria more sensitive to delirium in different settings,21 the findings of the present study indicate that among demented elderly residents, use of DSM-IV results in fewer cases being identified as delirious. These results support the argument that it may be advisable to adapt the criteria used for the diagnosis of delirium to the particular population under study.

It is important to mention that being the most inclusive criteria set does not imply that this set is the most valid for identifying delirious individuals. It could well be that some additional cases detected using the DSM-III-R compared with the DSM-IV were false positives. Diagnostic accuracy is a complex issue because there is no gold standard for delirium. A review of the history of delirium highlights the complex nature of this mental disorder and therefore the difficulty to define it.16 A better understanding of the physiopathology of delirium and dementia, as well as the identification of specific biomarkers for delirium superimposed on dementia, would help clarify the diagnostic accuracy of criteria for delirium among demented individuals. Meanwhile, it would seem more prudent to favor sensitivity over specificity to encourage clinicians to look for any underlying illness causing the delirium, such as pneumonia or the adverse effect of medication. Another argument supporting the use of the most inclusive diagnostic classification is that the literature reveals that the prognosis of delirium is poor, irrespective of the diagnostic criteria used.47

With regard to the prevalence of subsyndromal delirium, the results of the present study indicate that, no matter the definition of SSD used, the prevalence of SSD was important among the studied population. Of the 155 residents, 68 (43.9%) met both of the SSD definitions; 78 (50.3%) met Marcantonio's definition, and 75 (48.4%) met Cole's definition. Considering that the vast majority of our study population was identified as having delirium or SSD and that both delirium and SSD have been associated with deleterious consequences in previous studies, the present results suggest that the development of preventive interventions aimed at reducing the risk of both delirium or SSD is quite relevant in LTC settings. It is important to mention that although full recovery is generally expected after an episode of delirium, this is not always the case.16 In fact, little is known about delirium recovery among older patients with dementia.11 It would therefore appear desirable, for now, to favor preventive measures such as the Hospital Elder Life Program23, 48 even though their effectiveness among demented residents remains to be assessed. Nonetheless, the present results lend support to the view that elderly residents with dementia in LTC facilities constitute a very frail population that requires special attention from all caregivers.49

The strengths of the present study include: (1) the use of an instrument to identify symptoms of delirium (CAM) that is recognized for its psychometric properties; (2) ratings of delirium or SSD based on a 7-hour observation period; and (3) information collected by trained research nurses. This study has several limitations that should be noted. One of them concerns the exclusion of one criterion required by the DSM: the presence of an alleged medical cause of delirium (eg, dehydration, physical restraint, drug side effects, infectious diseases). This decision was based on the difficulty of identifying a specific medical cause of delirium in LTC settings, given the high level of comorbidity among the LTC population.50 It should be recalled, however, that most studies in this field use the CAM, which does not include this particular criterion.23, 51 Another limitation of the study involves potential misclassification bias with regard to subsyndromal delirium measurement. Because of the fluctuating nature of delirium, it is possible that an individual classified as suffering from SSD was in fact delirious. It is important to mention however that because our evaluation of SSD was based not only on information gathered over the 7-hour observation period but also from other sources of information (medical staff, family members, chart review), this potential error is probably negligible. Another potential source of misclassification bias relates to the criteria used to define SSD. These definitions were not developed specifically for a demented elderly population. It is therefore possible that some symptoms related to dementia such as disorientation and perceptual disorders (eg, delusion) found in Marcantonio's definition could have been falsely attributed to SSD. The effect of these classification biases would have been to overestimate the prevalence rates of SSD in our population. Although future studies are needed to address the validity of the criteria for SSD among demented residents, the findings of this study may serve as a starting point for understanding this phenomenon.

Clinical Implications 

These findings have important implications for clinical practice in LTC settings. Among elderly LTC residents with dementia, DSM-III-R criteria appeared to be the most inclusive set of criteria of all the DSM editions proposed to date. Use of DSM-IV among this very frail population could result in fewer individuals being identified as delirious and thus would prevent the implementation of measures designed to minimize the negative consequences of delirium for these individuals, not to mention the risk of overlooking an underlying medical illness necessitating immediate attention. The present findings also support the use of the CAM algorithm for definite delirium among this population as it was found to identify all delirious patients in accordance with the DSM-III-R set of criteria.

In addition, given the high prevalence of SSD, systematic application of protocols targeting modifiable risk factors of delirium in order to prevent its full-blown presentation could turn out to be beneficial among this population.

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Acknowledgment 

The authors would thank Dr Martin G. Cole and Dr Jane McCusker for their constructive comments on an earlier version of the manuscript and Christine Danjou, Sophie Dufort, Christine Noebert, and Marie-Pierre Poulin for their dedicated work.

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 Funding for this work was through an Investigator Award to Philippe Voyer from the Quebec Health Research Funds (Fonds de la recherche en santé du Québec) and the Quebec Nursing Research Funds (Fonds de la recherche en sciences infirmières du Québec). Financial support also came from the Saint-Sacrement Hospital Foundation.

PII: S1525-8610(08)00363-0

doi:10.1016/j.jamda.2008.09.006

JAMDA
Volume 10, Issue 3 , Pages 181-188, March 2009

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