Delirium Severity Measures Summary Table

The Delirium Severity Measures Summary Table was developed by Dr. Rich Jones, leader of the NIDUS Measurement and Harmonization Core. The table includes summary information on 14 delirium severity assessment tools, including number of items, approximate time to administer, and notes on the background and development of each tool.

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AbbreviationInstrumentCitationNumber of itemsTime to adminsterTraining or certification requirementsPrimary use of toolBackgroundNotes
CAM-S Long Form

CAM-S Short Form
Confusion Assessment Method - Severity Scale, Long Form

Confusion Assessment Method - Severity Scale, Short Form
Inouye, S. K., Kosar, C. M., Tommet, D., Schmitt, E. M., Puelle, M. R., Saczynski, J. S., . . . Jones, R. N. (2014). The CAM-S: development and validation of a new scoring system for delirium severity in 2 cohorts: the CAM-S score for delirium severity. Annals of Internal Medicine, 160(8), 526-533. doi:10.7326/M13-1927.
Long form: 10
Short form: 4
Long form: 10-15 min
Short form: < 5 mins inclusive
Trained lay interviewers or cliniciansThe instrument is suggested for clinical and research purposes, to track the level of severity of delirium symptomsThe CAM-S is a severity scale based on the additive scoring of symptoms rated in the CAM (Confusion Assessment Method). Inouye et al (2014) describe psychometric properties and validation analyses supportive of the use of the CAM-S as a measure of delirium severity. Two versions are described, a long form and a short form.CAM-S is scored based on a brief cognitive screen to rate the core features of the Confusion Assessment Method. The severity score is created by an additive summary of the ratings ranging from 0-7 (short form) and 0-19 (long form).
CRSConfusion Rating ScaleWilliams, M. A., Ward, S. E., & Campbell, E. B. (1988). Confusion: testing versus observation. Journal of Gerontological Nursing, 14(1), 25-30.
PMID: 3335761
4Behaviors are rated on an 8hr shiftTrained nursesRating confusion among hospitalized patients.Included disorientation, communication abnormality, inappropriate behaviors, illusions or hallucinationsBehaviors or symptoms are rated as 0 = not present at any time during shift, 1 = present at some time during shift, 2 = present at some time during the shift in marked form.
CRSConfusion Rating ScaleWilliams, M. A. (1991). Delirium/acute confusional states: evaluation devices in nursing. International Psychogeriatrics, 3(02), 301-308.
PMID: 1811781
4Behaviors are rated on an 8hr shift. Takes < 5 minutes to administerTrained nursesThis instrument is suggested for clinical and research purposes to help idenify the presence of delirium in a patient. Development of the CRS was based on the results of exploration of delirium in elderly hip fracture patients (Williams et al., Nurs. Res. 1979:1(28):25-35).Authors write: "Overall, the CRS should be regarded as an immature scale. Its strength is its reflection of clinical reality, but for research purposes the behaviors need to be
operationalized more specifically, perhaps weighted, and additional dimensions added."
CSEConfusional State Evaluation Robertsson, B., Karlsson, I., Styrud, E., & Gottfries, C. G. (1997). Confusional State Evaluation (CSE): an instrument for measuring severity of delirium in the elderly. British Journal of Psychiatry, 170(6), 565-570.
PMID: 9330025
12+1030 minutesTrained nurse, psychologist or physician.This instrument is suggested for clinicial and research purposes to track severity of delirium.Developed specifically as an observer-rated scale for delirium severity assessment, based on literature review and neurologist and psychiatrist expert opion and the GBS, CPRS, and DRS for inspiration.12 items used to generate confusion score, 10 items evaluated individually, and address associated features (7 items) and duration and intensity (3 items). Ratings based on clinical patient interview and informant interview.
DASDelirium Assessment ScaleO'Keeffe, S. T. (1994). Rating the severity of delirium: the Delirium Assessment Scale. International Journal of Geriatric Psychiatry, 9(7), 551-556.
DOI: 10.1002/gps
9"several minutes" Unclear; in O'Keeffe (1994) all raters were physiciansThe instrument is to use the operationalized criteria to determine the
severity of delirium symptoms
An testing of an operalization of DSM-3 criteria for rating the presence and severity of delirium as origianlly proposed by Gottlieb et al. (1991) Johnson et al. (1990).
DI, DIDXDelirium IndexMcCusker, J., Cole, M., Bellavance, F., & Primeau, F. (1998). Reliability and validity of a new measure of severity of delirium. International Psychogeriatrics, 10(4), 421-433.
PMID: 9924835
75-10minAdministered by a trained research assistant based only on observation of the patient and the administration of at least the
first five questions of the MMSE
The DI is intended for use in monitoring changes in severity over time among
patients previously diagnosed with delirium.
Based upon seven of the nine items included in the CAM.The instrument can be found in the Appendix of this paper. Ratings are based solely upon observation of the individual patient, without additional information from family members, nursing staff, or the patient medical chart
DOMDelirium-O-Meterde Jonghe, J. F. M., Kalisvaart, K. J., Timmers, J. F. M., Kat, M. G., & Jackson, J. C. (2005). Delirium‐O‐Meter: a nurses' rating scale for monitoring delirium severity in geriatric patients. International Journal of Geriatric Psychiatry, 20(12), 1158-1166. 
PMID: 16315151
13<5 minNurses without specific training in geriatric care It is used for nurses to screen for the presence of delirium originally. it is also able to measure severity of delirium.Developed on the basis of the DSM-IV criteriaThe instrument can be found in the Appendix of this paper
DOSDelirium Observation Screening ScaleSchuurmans, M. J., Shortridge-Baggett, L. M., & Duursma, S. A. (2003). The Delirium Observation Screening Scale: A screening instrument for delirium. Research and theory for nursing practice, 17(1), 31-50.
DOI: 10.1891/rtnp.17.1.31.
25<5 minNurse with a basic knowledge of geriatrics or caregiver; minimal training is requiredDesigned to capture early symptoms of delirium that nurses can observe during regular nursing care. Can be used in routine daily clinical practice to measure and monitor severity of delirium by nurses. Developed on the basis of the DSM-IV criteria, and to specifically overcome percieved limitations of the Clinical Assessment of Confusion - A, the CRS, and NEECHAM. See also Schuurmans, M. J. (1996). Vroegtijdige signalering van het delier door verpleegkundigen [Early recognition of delirium by nurses]. In Onderzoek in de verpleging en verzorging in relatie tot de praktijk (pp. 55-60) De Tijdstroom/LCVV, Maastricht.
DRSDelirium Rating ScaleTrzepacz PT, Baker RW, Greenhouse J. A symptom rating scale for delirium. Psychiatry Res. 1988;23(1):89-97.
DOI: 10.1016/0165-
10NR; rating must be based on observations reflecting at least a 24-hour periodPsychiatrist or trained clinicianTo identify and quantitate the severity of delirium; for use in research and treatment evaluation.At the time developed, the authors report the state of art in delirium severity measurement was clinician global impairment ratings. This instrument was designed as a observer rating scale with symptoms informed by DSM criteria.Rated by the clinician using all available information from the patient interview, mental status examination, medical history and tests, nursing observations, family reports, etc. This is the old version and the DRS-R-98 is the more recent version.
DRS-R-98Delirium Rating Scale-Revised-98Trzepacz, P. T., Mittal, D., Torres, R., Kanary, K., Norton, J., & Jimerson, N. (2001). Validation of the Delirium Rating Scale-Revised-98: comparison with the Delirium Rating Scale and the Cognitive Test for Delirium. The Journal of neuropsychiatry and clinical neurosciences, 13(2), 229-242.
DOI: 10.1176/jnp.13.2.229
(13 for severity)
20-30 minutes for scoring; >2 hours for gathering information needed to rate itemsPsychiatrists, other physicians, nurses, and psychologists can use it if they have had appropriate clinical training in evaluating psychiatric phenomenology in medically ill patients. Rater must be clinically trained.Initial assessment and repeated measurements of delirium; can be used in research or comprehensive clinical evaluations symptom severityRevised version of DRSAll available sources of information are used to rate the items (nurses, family, chart) in addition to examination of the patient. Timeframe >2 hours is advised.
MDASMemorial Delirium Rating ScaleBreitbart, W., Rosenfeld, B., Roth, A., Smith, M. J., Cohen, K., & Passik, S. (1997). The Memorial Delirium Assessment Scale. Journal of Pain Symptom Management, 13(3), 128-137. 
DOI: 10.1016-S0885-
10>10 min
Plus additional 15-30 minutes to establish rapport, review chart
records, and speak to staff/family members.
Trained clinicians.A measure of delirium severity among medically ill patients. Designed to be used repeatedly within a 24-hr period and without the use of additional adjunctive measures (such as mental status tests). The authors note that the tool might also be useful for "establishing a diagnosis of delirium."Developed to address perceived shortcomings of CAM (screening, not severity rating) and DRS (includes items not expected to vary). Designed to be consistent with DSM-III+, DSM-IV, and ICD-9 classification systems.Authors provide specific instructions for handling missing item responses (prorating).
NEECHAMNEECHAM Confusion Scale Neelon, V. J., Champagne, M. T., Carlson, J. R., & Funk, S. G. (1996). The NEECHAM Confusion Scale: construction, validation, and clinical testing. Nursing Research, 45(6), 324. 
DOI: 10.1097/00006199-
910 minNursesDesigned as a rapid assessment of "acute confusional state or delirium"; intended for routine systematic monitoring of patients.Desiged based on literature review, expert research team and consultant opinion. 3 subscales (processing, behavior, physiologic control).Commonly criticized for including risk factors or cause indicators (vital signs, oxygen saturation, urinary continence)
Nu-DESCNursing Delirium Screening ScaleGaudreau, J. D., Gagnon, P., Harel, F., & Roy, M. A. (2005). Impact on delirium detection of using a sensitive instrument integrated into clinical practice. General Hospital Psychiatry, 27(3), 194-199. 
DOI: 10.1016/j.genhosppsych
5NRNursesDesigned for routine use in busy inpatient settings and without patient participation.

Gadreau et al (2005) validate in terms of concurrent criterion validity.
Derived from the CRS but with modifications to maintain consistency with DSM-IV. The Nu-DESC adds a fifth psychomotor retardation item to the CRS.It is interesting that the Nu-DESC is described as a screening scale and evaluated in terms of concurrent criterion validity in Gaudreau et al (2005), but Williams et al (1991; Int Psychogeriatr 2(3):301-8) imply the CRS is useful for grading severity.
RCDSReversible Cognitive Dysfunction ScaleTreloar, A. J., & Macdonald, A. (1997). Outcome of delirium, part 1. Outcome of delirium diagnosed by DSM‐III‐R, ICD‐10 and CAMDEX and derivation of the Reversible Cognitive Dysfunction Scale among acute geriatric inpatients. International Journal of Geriatric Psychiatry, 12(6), 609-613. 
PMID: 9215940
UnclearNRUnclearTo identify feature of acute cognitive impairment that predict likelihood of recovery.Inspired by the observation that standard defitions of delirium are poor predictors of recovery, and proposed
reversible cognitive dysfunction as an alternative concept.
Despite the title, this manuscript does not describe the "scale" in a useful way.
This table summarizes 14 measures of delirium severity, with information on number of items, administration time, required training and notes on the instrument background.

This table was developed by Richard N. Jones, ScD.