Introduction
Background
Psychopathology and cognitive alterations in delirium
ICD-10—F05 Delirium not induced by alcohol and other psychoactive substances | ICD-11—6D70 Neurocognitive disorders: delirium |
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An etiologically nonspecific organic cerebral syndrome characterized by concurrent disturbances of consciousness and at least two of the following domains: attention, perception, thinking, memory, psychomotor behavior, emotion, or sleep-wake schedule. The duration is variable and the degree of severity ranges from mild to very severe | Delirium is characterized by: 1. disturbed attention (i.e., reduced ability to direct, focus, sustain, and shift attention) and 2. awareness (i.e., reduced orientation to the environment) that develops over a short period of time and tends to fluctuate during the course of a day, accompanied by other cognitive impairment such as: memory deficit, disorientation, or impairment in language, visuospatial ability, or perception. Disturbance of the sleep-wake cycle (reduced arousal of acute onset or total sleep loss with reversal of the sleep-wake cycle) may also be present. The symptoms are attributable to a disorder or disease not classified under mental and behavioral disorders or to substance intoxication or withdrawal or to a medication |
Development of the confusion assessment method (CAM)
Methods
Results
Delirium detection tools | ||||||||||
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Abbreviation (full name) | Target patient group/investigator (I) | Screening vs. monitoring Items | Scoring | Average duration | Psychometric properties | Reference | Critical appraisal | |||
Sens | Spec | Others | RS | |||||||
Confusion assessment method (CAM) Family | ||||||||||
3D-CAM (3-minute diagnostic CAM) | General medicine patients ≥ 75 years (n = 201) (+ collateral history) I: trained physician/nurse | Screening 20 items (10 for patient interview, 10 observational) + 2 optional questions for collateral history All items referring to 4 core features 1. Acute onset and/or fluctuating course 2. Inattention 3. Disorganized thinking 4. Altered level of consciousness | CAM algorithm: 1 + 2 + (3 or 4) positive = suspected delirium | 3 min | Total sample: | – | DSM-IV criteria | [38] | Good structure as guidance; operationalization of core features; less interviewer training required | |
0.95 | 0.94 | |||||||||
Patients with dementia: | ||||||||||
0.96 | 0.86 | |||||||||
Patients without dementia: | ||||||||||
0.93 | 0.96 | |||||||||
CAM (short form) | Older patients ≥ 65 years (n = 56) + collateral history I: trained lay rater or clinician | Screening 4 items on core features (see 3D-CAM) | CAM algorithm: 1 + 2 + (3 or 4) positive = suspected delirium | 5–10 min | 0.94–1.00 | 0.90–0.95 | IRR: presence/absence of delirium 100%, k = 1.0; assessing 4 core features 93%, k = 0.81 | Geriatric psychiatrist rating after comprehensive assessment | [29] | Professional training required; poor sensitivity when CAM is conducted by untrained/insufficiently trained rater |
CAM-ICU (CAM for the intensive care unit) | Adult ICU patients (n = 38) + collateral history I: trained lay rater or clinician | Screening 8 items on core features (see 3D-CAM) | CAM algorithm: 1 + 2 + (3 or 4) positive = suspected delirium | < 5 min | Total sample: | IRR: k = 0.95 | DSM-IV criteria | [11] | Eligible for intubated ICU patients; operationalization of core features | |
0.95–1.00 | 0.89–0.93 | |||||||||
Patients ≥ 65 years: | ||||||||||
0.90–1.00 | 0.83–1.00 | |||||||||
Patients with dementia: | ||||||||||
1.00 | 1.00 | |||||||||
FAM-CAM (Family CAM) | Community-dwelling older people ≥ 65 years with dementia (n = 52) Collateral history (caregiver/informant) I: trained rater/clinician | Screening 11 items | CAM algorithm: 1 + 2 + (3 or 4) positive = suspected delirium | 5–10 min | 0.88 | 0.98 | Overall agreement with CAM 96% | CAM | [51] | Collateral history only |
mCAM-ED (modified CAM for the emergency department) | ED patients ≥ 65 years (n = 286) (+ collateral history if available) I: trained clinician | Screening Two-step-rating: 1. MOTYB to identify inattention 2. If inattention present → MSQ for identifying cognitive impairment, Comprehension subtest of CTD for identifying disorganized thinking | Modified CAM algorithm: 1a (acute onset) AND 1b (fluctuating course) + 2 + (3 or 4) positive = diagnosed delirium, 1a OR 1b + 2 + (3 or 4) positive = suspected delirium | < 5 min | Total sample: | – | DSM-IV criteria | Two-step approach; operationalization of core features | ||
0.90 | 0.98 | |||||||||
Patients with dementia: | ||||||||||
0.91 | 0.87 | |||||||||
Patients without dementia: | ||||||||||
0.89 | 0.99 | |||||||||
UB-CAM (Ultra-brief-CAM) | General medicine patients ≥ 75 years (n = 201) (+ collateral history) I: trained physician/nurse | Screening 2–15 items UB‑2, in the case of an incorrect answer followed by a modified 3D-CAM (assessment of each CAM feature is stopped after one incorrect answer or positive observation item of that feature) | CAM algorithm: 1 + 2 + (3 or 4) positive = suspected delirium | 2 min | 0.93 | 0.95 | – | 3D-CAM | Retrospective simulation based on 3D-CAM and UB‑2 data of two studies | |
Other tools than CAM | ||||||||||
4AT (4 As test) | Acute care and rehabilitation patients ≥ 70 years (n = 234) + collateral history I: untrained geriatrician | Screening 4 items: alertness AMT‑4 Attention (MOTYB) Acute change or fluctuation | Score 0–12 0 = no CI or delirium 1–3 = possible CI ≥ 4 = possible delirium | < 5 min | 0.90 | 0.84 | AUC 0.89–0.93 | DSM-IV criteria | [5] | Information on acute change/fluctuation not mandatory for delirium diagnosis; no special training required; includes MOTYB |
BCS (bedside confusion scale) | Palliative patients (n = 31) I: rater (no requirements) | Screening Tool 2 items: psychomotor activity + MOTYB | Score 0–5 Cut-off: ≥ 2 = suspected delirium | 2 min | 1.0 | 0.85 | – | CAM | [52] | Includes MOTYB |
DOS/DOSS (delirium observation screening scale) | Van Gemert: older patients ≥ 70 years (n = 87) Koster: cardiac surgery patients ≥ 45 years (n = 112) + collateral history (25-items version) I: nurse | Screening + Monitoring Severity scoring included Original version: 25 items Revised version: 13 items | Score 0–13 Final score = (score shift 1 + score shift 2 + score shift 3) / 3 Cut-off: ≥ 3 = suspected delirium | 5 min (13-items version) | Van Gemert: | – | DSM-IV criteria | Suitable tool for periodical (once per shift) delirium screening by nurses | ||
0.89 | 0.88 | |||||||||
Koster: | ||||||||||
1.00 | 0.97 | |||||||||
DTS (delirium triage screen) | Adult patients (n = 406) I: trained clinician or lay rater | Screening 2 items | Scoring: First item (altered level of consciousness) positive = screening positive, specific delirium assessment required (recommended tool: bCAM). Negative first item is followed by second item (spelling “LUNCH” backwards), > 1 error = screening positive, specific delirium assessment required | < 1 min | DTS alone: | IRR: k = 0.79 | DSM-IV-TR criteria | [20] | Two-step approach (combination with specific delirium assessment recommended) | |
0.98 | 0.55 | |||||||||
DTS + bCAM: | ||||||||||
0.78–0.84 | 0.96–0.97 | |||||||||
MOTYB (months of the year backwards) | Adult patients, median age 69 years (n = 265) I: trained medical staff/nurse | Screening Months of the year forward, starting with January, followed by MOTYB, starting with December | At least “July” has to be reached without any error (omission or wrong month), error before July = suspected delirium | < 2 min | All participants (17–95 years): | – | DSM-IV criteria | [44] | Suitable as a quick and easy screening test for delirium Two-step approach recommended: positive result should be followed by specific delirium assessment | |
0.83 | 0.91 | |||||||||
Participants > 69 years: | ||||||||||
0.84 | 0.90 | |||||||||
ED patients ≥ 65 years (n = 286) | Screening MOTYB, starting with December, ending with January | 1 point for each error; ≥ 8 points = suspected delirium | 0.95 | 0.94 | – | DSM-IV criteria | [23] | |||
MOTYB, starting with December | All months named correctly at least from December to September September is not reached without error = suspected delirium | 0.90 | 0.89 | |||||||
mRASS (modified Richmond agitation sedation scale) | Older patients ≥ 65 years (n = 95) I: trained nurse | Screening + Monitoring Modified version of the RASS: Step 1: question “Describe how you are feeling today” Step 2: scoring the mRASS containing the additional aspect of attention | Screening: Any abnormal score (≠ 0) = suspected delirium Monitoring: any change to prior score | < 1 min | Used as a single instrument for delirium screening: | – | DSM-IV criteria | [7] | Suitable instrument to identify incident delirium (daily administration) | |
0.64 | 0.93 | |||||||||
Used as a monitoring instrument to detect change: | ||||||||||
0.74 | 0.92 | |||||||||
Nu-DESC (nursing delirium screening scale) | Adult patients (n = 146) /nurse (who observed patient) I: trained clinician/nurse or lay rater | Screening + Monitoring Severity scoring included 5 items | Each item scored 0–2 (0 = absent, 1 = mild, 2 = severe) Total score 0–10 Cut-off: ≥ 2 = suspected delirium | < 2 min | 0.86 | 0.87 | – | CAM | Suitable tool for periodical (once per day) delirium screening by nurses Subjective component of scoring a symptom “mild” or “severe” | |
SQiD (single question in delirium) | Patients with cancer, age 30–79 years (n = 21) Collateral history (friend/relative/caregiver) I: trained clinician or lay rater | One question: “Do you feel that … (patient’s name) has been more confused lately?” | Answer “yes” or “no” “Yes” = suspected delirium | < 1 min | Vs. psychiatrist interview | [48] | Suitable as a quick and easy delirium screening question for caregiver interview Two-step approach recommended: positive result should be followed by specific delirium assessment of patient | |||
0.80 | 0.71 | – | – | |||||||
Vs. CAM: | ||||||||||
0.67 | 0.67 | – | – | |||||||
Vs. MMSE: | ||||||||||
0.50 | 0.59 | – | – | |||||||
Patients ≥ 75 years (n = 100) | 0.77 | 0.51 | – | DSM-IV criteria | [36] | |||||
UB‑2 (ultra-brief 2‑item screener) | Patients ≥ 75 years (n = 201) I: trained clinician | Screening 2 items: naming the current day of the week + MOTYB | Any incorrect answer, omission of one or more months or no answer/answer “I do not know” = suspected delirium | < 2 min | Sens 0.93 | Spec 0.64 | – | DSM-IV criteria | [13] | Suitable as a quick and easy screening test for delirium Two-step approach recommended: positive result should be followed by specific delirium assessment |