Review of research instruments and techniques used to detect delirium

Delirium detection in clinical practice and research: critique of current tools and suggestions for future development

Delirium is underrecognized clinically. Many tools have been developed to assist with the diagnosis of delirium, and they vary greatly in purpose, quality, and administration time. It is suggested that future development of delirium assessment instruments be guided by a dichotomization of raters into expert and nonexpert groups. Careful consideration of the needs of the two groups suggests that assessment instruments designed for nonexperts should be entirely objective, whereas those instruments developed for experts should include the full range of constructs associated with the syndrome. This conceptualization is explored in detail, and existing assessment instruments are considered briefly in light of this position.

Recognition of delirium in ICU patients: a diagnostic study of the NEECHAM confusion scale in ICU patients

Background

A delirium, is a serious, high-frequency complication in intensive care unit (ICU) patients. The consequences of this complication range from high morbidity and mortality to greater need for nursing care. Despite these, delirium is often not recognized and there for not treated. In this study a nursing screening instrument, the NEECHAM confusion scale, was studied for early recognition of delirium ICU patients. This scale proved valid and reliable in several studies in the general hospital population.

Methods

In this study validity and reliability were tested in a prospective cohort of 105 patients. Gold standard for delirium was an independent DSM-IV diagnosis. User friendliness was tested by structured evaluation of nurses' experiences working with the scale.

Results

The NEECHAM confusion scale showed high internal consistency (Cronbach's alpha 0.88) and an interrater reliability of Cohen's Kappa 0.60. The concurrent validity with the DSM-IVcriteria showed a strong link (chi-square 67.52, p [less than or equal to] 0.001). Sensitivity was high, 97% and specificity was good 83%. ICU nurses completed the NEECHAM confusion rating in 3.69, ± 1.21 minutes average. In general the nurses were positive about the NEECHAM confusion scale. They were able to collect data during regular care, but experienced problems in rating the scale in intubated patients. The items in themselves were clear, the content validity, measured by the language used was rated good.

Conclusion

The psychometric characteristics of the NEECHAM confusion scale of this ICU study are generally consistent with validity research previously reported for the general hospital population. The psychometric characteristics and the ease of use of the NEECHAM confusion scale enables ICU nurses to early recognize delirium. Further study, especially in intubed patients is recommended.

The measurement of delirium: review of scales

This review describes the characteristics and evaluates the psychometric qualities (process of testing and the results) of thirteen delirium instruments. Delirium instruments differ in goal (diagnosis, screening symptoms severity), type of data on which the rating is based (observation, interview or test of patients), the rater qualities required, the number of items and the rating time needed. Most instruments are based on the Diagnostic Statistical Manual criteria and measure signs and symptoms as described by these criteria. Reliability of delirium instruments shows good to excellent results. Validity of the delirium instruments is overall fair to good. Differences exist, however, in the degree to which reliability and validity were tested and the quality of the testing procedures. Most instruments are not further developed and tested after the initial study. Conclusion of this review is that most delirium instruments show promising results but need further testing. Testing is needed in different samples and on a broader range of aspects with regard to reliability and validity. Much emphasis should be given to the procedures used in future studies. Ease of use is an aspect of testing that is so far not taken into account, however, is important for use of instruments in clinical practice. A minority of instruments can be seen as "ready to use" instruments meaning well tested in more than one sample with good results. For screening high-risk, elderly hospitalized patients, the NEECHAM Confusion Scale and the Delirium Observation Screening Scale are recommended. The Confusion Assessment Method is the best diagnostic tool and the Delirium Rating Scale shows best results in screening symptom severity. For ICU patients the CAM-ICU is recommended. The MDAS is well tested in cancer patients. Nurses, however, have not yet tested the DRS and MDAS in practice.

The Delirium Observation Screening Scale: a screening instrument for delirium

The Delirium Observation Screening (DOS) scale, a 25-item scale, was developed to facilitate early recognition of delirium, according to the Diagnostic and Statistical Manual-IV criteria, based on nurses' observations during regular care. The scale was tested for content validity by a group of seven experts in the field of delirium. Internal consistency, predictive validity, and concurrent and construct validity were tested in two prospective studies with high risk groups of patients: geriatric medicine patients and elderly hip fracture patients. Among the patients admitted to a geriatric department (N = 82), 4 became delirious; among the elderly hip fracture patients (N = 92), 18 became delirious. The DOS scale was determined to be content valid and showed high internal consistency, alpha = 0.93 and alpha = 0.96. Predictive validity against the Diagnostic and Statistical Manual-IV diagnosis of delirium made by a geriatrician was good in both studies. Correlations of the DOS scale with the Mini Mental State Examination (MMSE) were Rs -0.79 (p < or = 0.001) in the hip fracture patients and Rs -0.66 (p < or = 0.001) in the geriatric medicine patients. Concurrent validity, as tested by comparison of the research nurse's ratings of the DOS scale and the Confusion Assessment Method (CAM), for the group of hip fracture patients was 0.63 (p < or = 0.001). Construct validity of the DOS was tested against the Informant Questionnaire of Cognitive Decline in Elderly (IQCODE), a preexisting psychiatric diagnosis and the Barthel Index. Correlation with the IQCODE was 0.74 (p < or = 0.001) in the study with the hip fracture patients and 0.33 (p < or = 0.05) in the study with the geriatric medicine patients. Correlation with the Barthel Index was -0.26 (p < or = 0.05) in the geriatric medicine patients and -0.55 (p < or = 0.001) in the hip fracture patients. The overall conclusion of these studies is that the DOS scale shows satisfactory validity and reliability, to guide early recognition of delirium by nurses' observation.

Delirium among newly admitted postacute facility patients: prevalence, symptoms, and severity

BACKGROUND

Delirium may persist for weeks or months, and discharging elderly patients quickly from acute care facilities is not uncommon. Therefore, the adverse impact of delirium on loss of independence may occur in the postacute setting rather than in the hospital. The purpose of this study is to describe the prevalence of delirium, delirium symptoms, and severity assessed at admission to postacute facilities.

METHODS

Subjects were recruited from seven Boston-area skilled nursing facilities specializing in postacute care. Assessment instruments included the Mini-Mental Status Exam, Delirium Symptom Interview, Memorial Delirium Assessment Scale, and Confusion Assessment Method (CAM) Diagnostic Algorithm. Delirium status was categorized into four groups: full, two or more symptoms, one symptom, and no delirium. Descriptive statistics were calculated and chi-square analyses and an analysis-of-variance were used to examine delirium characteristics by delirium group.

RESULTS

Among 2158 subjects, approximately 16% had full CAM-defined delirium at admission to the postacute facility. In addition, nearly 13% of the subjects had two or more symptoms of delirium, approximately 40% had one delirium symptom, and 32% had no symptoms of delirium. In a comparison of the group with no symptoms of delirium with that with CAM-defined delirium, there was a significant trend toward (a) older age, (b) lower scores on the Mini-Mental Status Exam, (c) more Delirium Symptom Interview symptoms, and (d) higher Memorial Delirium Assessment Scale Scores.

CONCLUSIONS

Results indicate that 16% of admissions to postacute facilities have CAM-defined delirium, and over two thirds had at least one delirium symptom. It is not known whether or not postacute staff have the training necessary to detect or manage delirium. Managing delirium may require different strategies and techniques in a postacute setting, thereby requiring further research.

Delirium in patients with advanced cancer

Managing delirium is of major importance in end-of-life care and frequently gives rise to controversies and to clinical and ethical dilemmas. These problems arise from a number of causes, including the sometimes-poor recognition or misdiagnosis of delirium despite its frequent occurrence. Delirium generates major symptomatic of distress for the patient, consequent stress for the patient's family, the potential to misinterpret delirium symptomatology, and behavioral management challenges for health care professionals. Paradoxically, delirium is potentially reversible in some episodes, but in many patients delirium presents a nonreversible terminal episode. Greater educational efforts are required to improve the recognition of delirium and lead to a better understanding of its impact in end-of-life care. Future research might focus on phenomenology, the development of low-burden instruments for assessment, communication strategies, and the family education regarding the manifestations of delirium. Further research is needed among patients with advanced cancer to establish a predictive model for reversibility that recognizes both baseline vulnerability factors and superimposed precipitating factors. Evidence-based guidelines should be developed to assist physicians in more appropriate use of sedation in the symptomatic management of delirium.

Four acute confusion assessment instruments: reliability and validity for use in long-term care facilities

Frail older adults in long-term care (LTC) facilities are at high risk for acute confusion. This study evaluated the reliability and validity of four acute confusion instruments for use in LTC: the Clinical Assessment of Confusion-A (CAC-A), the Clinical Assessment of Confusion-B (CAC-B), the NEECHAM Confusion Scale (NEECHAM), and the Visual Analog Scale for Acute Confusion (VASAC). Seventy-four residents from two LTC facilities were evaluated for acute confusion using the four instruments as well as the Mini-Mental Status Examination (MMSE), the Geriatric Depression Scale (GDS), and Diagnostic and Statistical Manual for Mental Disorders (DSM IV) criteria for delirium. Coefficient alphas were .82 for the CAC-A, .86 for the CAC-B, and .80 for the NEECHAM. Interrater reliability on 30 paired evaluations was .90 for the CAC-B, .87 for the NEECHAM, and .80 for the VAS-AC. All instruments were correlated with the MMSE and the DSM IV criteria for delirium at the p < .001 level. Predictive validity was supported for the CAC-B, the NEECHAM, and the VAS-AC. Discriminant validity using the GDS was supported for the VAS-AC. Construct validity using confirmatory factor analysis was supported for the NEECHAM, with a two-factor structure. Based on this study, the VAS-AC is recommended for use as a general screening instrument and when it is positive for acute confusion, the NEECHAM should be used for a more indepth assessment.

Early recognition of delirium: review of the literature

This review focuses on delirium and early recognition of symptoms by nurses. Delirium is a transient organic mental syndrome characterized by disturbances in consciousness, thinking and memory. The incidence in older hospitalized patients is about 25%. The causes of delirium are multi-factorial; risk factors include high age, cognitive impairment and severity of illness. The consequences of delirium include high morbidity and mortality, lengthened hospital stay and nursing home placement. Delirium develops in a short period and symptoms fluctuate, therefore nurses are in a key position to recognize symptoms. Delirium is often overlooked or misdiagnosed due to lack of knowledge and awareness in nurses and doctors. To improve early recognition of delirium, emphasis should be given to terminology, vision and knowledge regarding health in ageing and delirium as a potential medical emergency, and to instruments for systematic screening of symptoms.

Validity and reliability of the Portuguese version of the Confusion Assessment Method (CAM) for the detection of delirium in the elderly

This study has tested the validity and reliability of the Portuguese version of the Confusion Assessment Method (CAM), a diagnostic assessment instrument for delirium developed by Inouye et al. (1990). The sample was formed by 100 patients with 60 and more years of age, admitted at the emergency service of Santa Casa de São Paulo, in the time periods between July and August, 1996, November and December, 1996 and February and March, 1997. The sensibility was 94.1% and specificity 96.4%. The assessors reliability in a sample of the 24 patients resulted in a kappa = 0.70. We have concluded that CAM is an adequate instrument to assess the presence of delirium, reliable to assess elderly patients at the emergency services.

Delirium in the terminally-ill cancer patient: aetiology, symptoms and management

Delirium is a frequent and serious clinical problem in the terminally ill cancer patient. Multiple dimensions of delirium make definition, measurement, and assessment of it challenging in clinical nursing practice. Assessment and management of delirium requires knowledge of the diagnostic criteria for it, aetiology, signs and symptoms, and nursing interventions. Four delirium assessment scales determined to be useful in assessing patients with terminal illness are reviewed. The use of a delirium assessment instrument in routine nursing assessments would be important for the nurse's early detection of delirium so that interventions to reverse the causes of delirium could immediately be implemented.

Delirium in the terminally ill

Delirium is highly prevalent in terminally ill patients, especially in the last weeks of life, when some cognitive impairment develops in as many as 85% of patients. Delirium is associated with increased morbidity in terminally ill patients and can interfere with pain and symptom control. The cause of delirium is usually multifactorial and often cannot be found or reversed in dying patients. Nonpharmacologic and pharmacologic interventions are effective in controlling the symptoms of delirium in terminally ill patients. Haloperidol and other newer neuroleptics are safe and effective in eliminating delirium for some patients. In approximately one third of patients, delirium can be managed successfully only by providing sedation.

[Confusion syndromes in hospitalized aged patients: polymorphism of symptoms and course. Prospective study of 183 patients]

Using explicit criteria contained in the DSM III R, we collected in a prospective cohort study clinical features, outcome and risk factors from two cohorts of delirium in hospitalized elderly patients: 138 hospitalized in geriatric department and 45 patients admitted to an acute and comprehensive care hospital. The clinical features were assessed using a quantitative scale (developed by Derouesné). Delirium was unrecognized or misdiagnosed by physicians in 34% of the cases. The onset was known only two thirds of cases. The incidence of hyperactive type, prolonged hospital stay, poor outcomes (persistent delirium leading up to dementia) were highest in subjects admitted in comprehensive hospital. The etiology of delirium is complex and multifactorial. An underlying cause was identified in 80% of patients. The length or the worsening of delirium was significantly higher in patients with psychiatric or dementia comorbidity (OR: 0.2; IC 95%: 0.1-0.5). The prognosis was better in patients without psychoactive medications (OR: 0.2; IC 95%: 0.1-0.4) or with metabolic abnormalities or acute diseases and disorders (OR: 3.3; IC 95%: 1.5-7.6). The predisposing factors to the development of dementia were prior use of psychoactive medications and signs of prior cognitive impairment. This article suggests delirium in elderly patients is associated with several outcomes. The prognosis should be improved at admission by specific scale and an evaluation of predisposing and precipitating factors.

Subsyndromal Delirium

The authors sought to determine whether subsyndromal delirium is a qualitatively distinct clinical entity or a spectrum of cognitive and behavioral abnormalities. They conducted a prospective, longitudinal study on 325 patients in an acute care hospital with 3- and 6-month follow-ups. Patients were classified into one of three groups: those meeting full DSM criteria for delirium, those with subsyndromal delirium, and those with no symptoms of delirium. There were no differences in risk factors between those developing DSM-defined delirium or subsyndromal delirium. Number of independent risk factors was a significant predictor of delirium. Patients with subsyndromal delirium fall on a continuum between those with DSM-defined delirium and those with no symptoms of delirium. These data suggest that delirium does represent a spectrum of neurobehavioral impairment. Patients with symptoms of subsyndromal delirium are at risk for considerable morbidity; therefore clinicians should attempt to reduce and treat the onset of occurrence of subsyndromal delirium.

Problems associated with underrecognition of delirium in critical care: a case study

Delirium, a syndrome that results in high morbidity and mortality rates in the elderly, continues to be underrecognized by physicians and nurses. Factors influencing the underrecognition of delirium are specific to individual institutions and their health care providers. The factors leading to the underrecognition of delirium must be identified so that changes can be made to increase early recognition. A case study conducted in a critical care unit in a midwestern hospital from interviews of nurses, chart audit, and patient observation, identified two major problems associated with the lack of recognition of delirium in that institution: (1) lack of knowledge on the part of nurses about the criteria and methods of detecting delirium, and (2) ineffective communication between all staff members in relaying symptoms of onset of the disorder. As a result of this study, staff education, assessment protocols, and improved communication and documentation techniques are indicated as targeted methods for improving recognition and treatment of delirium in this setting. Similar case studies can be performed to evaluate institutional practice, and thereby identify barriers to early recognition of delirium.

Delirium in elderly patients: evaluation and management

OBJECTIVE

To review the evaluation and management of delirium in elderly patients for primary-care providers.

DESIGN

We summarize the clinical features, course, pathophysiologic aspects, predisposing factors, causes, and differential diagnosis of delirium and discuss approaches to affected patients and various management strategies.

RESULTS

Delirium, an altered mental state, occurs more frequently in elderly than in younger patients. The pathophysiologic changes associated with aging and the higher occurrence of multiple medical problems and need for medications contribute to the higher frequency of delirium in elderly patients. Evaluation should begin with a consideration of the most common causes, such as a change in or addition to prescribed medications, a withdrawal from alcohol or other sedative-hypnotic drugs, an infection, or a sudden change in neurologic, cardiac, pulmonary, or metabolic state. Finally, management of delirium is threefold: (1) identifying and treating underlying causes, (2) nonpharmacologic interventions, and (3) pharmacologic therapies to manage symptoms of delirium.

CONCLUSION

Elderly patients frequently experience delirium. Delirious symptoms can produce devastating consequences if they are not recognized and appropriately treated.

Neuropsychiatric syndromes and psychological symptoms in patients with advanced cancer

This article represents the contributions of the panel on "Neuropsychiatric Syndromes and Psychological Symptoms" of the National Cancer Institute of Canada Workshop on Symptom Control and Supportive Care in Patients with Advanced Cancer. The panel's presentations focused on mood disorders and cognitive disorders, and described the current state of knowledge regarding prevalence, assessment, and intervention. Recommendations for future research are presented based on a consensus of the panel as to the need to fill glaring gaps in our current state of knowledge, and a desire to improve the quality of research in this area of palliative medicine. Recommendations for future research on neuropsychiatric symptoms and syndromes in palliative care include (1) adoption of uniform terminology (taxonomy of disorders) and diagnostic classification systems, (2) utilization of existing validated tools and measures in prevalence and intervention research, (3) development of new tools and measures that are more applicable and relevant to the palliative care setting, (4) encouragement for studies of the prevalence of neuropsychiatric symptoms and syndromes, (5) promotion of intervention studies utilizing pharmacologic and nonpharmacologic treatments for depressive disorders and cognitive disorders in advanced cancer patients, and (6) expansion of the focus of such research to other neuropsychiatric disorders (for example, anxiety disorders, posttraumatic stress disorders, and sleep disorders), symptoms (fatigue and tension) and related issues (suicidal ideation and desire for hastened death).

A critique of instruments and methods to detect, diagnose, and rate delirium

This document reviews existing instruments for evaluation of delirium. Instruments have been grouped into four categories: tests that screen for cognitive impairment, delirium diagnostic instruments, delirium-specific numerical rating scales, and laboratory and paraclinical exams. Analysis of instruments was based on comparison of their psychometric properties as well as subjective judgment. Guidelines are suggested for choosing the appropriate instrument according to the type of clinical evaluation or delirium research envisaged. Important factors in choosing an instrument, besides the appropriateness of its psychometric characteristics, include administration time constraints, level of rater expertise, and patient capabilities. By familiarizing investigators with the variety of evaluation instruments available, this work should permit more appropriate instrument selection in future studies on delirium.

A review of delirium assessment instruments

This paper reviews various types of assessment instruments for delirium, including nursing screening scales, symptom checklists, an analog scale, an interview schedule, and symptom rating scales. Their structures and applicability to the clinical and research assessment of delirium are described. Despite the seeming plethora of assessment methods, only a few are suitable for use by researchers.

Progression and Resolution of Delirium in Elderly Patients Hospitalized for Acute Care

The authors describe the clinical course of delirium in 325 elderly patients hospitalized for acute care. Of those patients who developed DSM-III delirium (n = 91), over two-thirds of patients (69.2%) experienced a prodromal period of at least 1 day prior to meeting full DSM-III criteria. Clinical evidence of delirium frequently persisted after hospital discharge although there was evidence of lessening of the extent of symptoms over time. These findings have implications for discharge planners concerned with providing appropriate supports for those still experiencing delirium symptoms at the time of hospital discharge.

An empirical study of delirium subtypes

Using a structured instrument, 325 elderly patients admitted to a general hospital for an acute medical problem were evaluated daily in order to detect symptoms of delirium. Patients were scored for 'hyperactive' or 'hypoactive' symptoms, and then the 125 patients with DSM-III delirium were rated as 'hyperactive type' (15%), 'hypoactive type' (19%), 'mixed type' (52%), or 'neither' (14%). There were no statistically significant differences between the groups with respect to age, sex, place of residence, or presence of dementia. These definitions of subtypes should be studied further.