4-DSD: 4-Delirium Superimposed on Dementia

2021

A four-item assessment developed specifically for delirium superimposed on moderate-to-severe dementia. Its multicentre derivation and validation cohort included acute and rehabilitation wards; at a cut-off of 5 or more, reported sensitivity and specificity were both 80%, with lower specificity in the small severe-dementia subgroup. Despite its name and developer-site location, 4-DSD is a separate instrument and is not a version or adaptation of 4AT.

At a glance

Purpose: Episodic assessment
Population: Adult
Setting: General / acute hospital, Rehabilitation / post-acute
Time: ~3 min
Items: 4
Score or threshold: ≥5 of 12

Format: A four-item clinician assessment developed for delirium superimposed on moderate-to-severe dementia and evaluated in acute and rehabilitation wards. Scores range from 0 to 12; the study evaluated a threshold of 5 or more.

Strengths: Designed specifically for moderate-to-severe dementia; includes acute change/fluctuation and function
Limitations: One principal validation cohort; specificity was 56% in the small severe-dementia subgroup (n=26)

Training and instructions

4-DSD form. Public instrument material checked on 5 September 2026. Follow the source’s version and permission conditions.

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Tool and original sources

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Original paper

Original paperMorandi A, Grossi E, Lucchi E, Zambon A, Faraci B, Severgnini J, et al. The 4-DSD: A New Tool to Assess Delirium Superimposed on Moderate to Severe Dementia. Journal of the American Medical Directors Association. 2021;22(7):1535-1542.e3. doi: 10.1016/j.jamda.2021.02.029. PMID: 33823162.
This is the original published source for 4-DSD. It reported sensitivity of 80% and specificity of 80% against an independent DSM-5 clinical assessment.
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One DTA study identifiedCore instrument family

Classification

Episodic assessment

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Evidence

Diagnostic-accuracy evidenceOne DTA study identified

Reported sensitivity and specificity

Headline metric source

Original/source study · 2021; pmid:33823162

Denominator: Reported source unit: 134 (analysis unit not fully reconciled)
Reference standard: Independently completed DSM-5 delirium assessment

80%

Sensitivity

80%

Specificity

Cut-off ≥5 vs DSM-5 (n=134). The cohort comprised 80 acute-ward participants (60%) and 54 rehabilitation-ward participants (40%); in severe dementia (n=26), sensitivity was 82% and specificity 56%.

More evidence and citation details

Full name: 4-Delirium Superimposed on Dementia
Also known as: 4-DSD, 4 Delirium Superimposed on Dementia
Evidence summary: single
Diagnostic-accuracy evaluations: 1
Reference standard: DSM-5
Reliability: ;
Citation: Morandi A, Grossi E, Lucchi E, Zambon A, Faraci B, Severgnini J, MacLullich A, Smith H, Pandharipande P, Rizzini A, Galeazzi M, Massariello F, Corradi S, Raccichini A, Scrimieri A, Morichi V, Gentile S, Lucchini F, Pecorella L, Mossello E, Cherubini A, Bellelli G The 4-DSD: A New Tool to Assess Delirium Superimposed on Moderate to Severe Dementia Journal of the American Medical Directors Association. 2021;22(7):1535-1542.e3. PMID 33823162

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Primary validation studies

Distinct primary publications from the current diagnostic-accuracy audit. Reviews and repeated evaluations within one paper are not counted again. Overlapping cohorts have not all been reconciled. Read the counting rules and limitations.

Open 1 identified paper

Morandi A, Grossi E, Lucchi E, Zambon A, Faraci B, Severgnini J, MacLullich A, Smith H, Pandharipande P, Rizzini A, Galeazzi M, Massariello F, Corradi S, Raccichini A, Scrimieri A, Morichi V, Gentile S, Lucchini F, Pecorella L, Mossello E, Cherubini A, Bellelli G (2021). The 4-DSD: A New Tool to Assess Delirium Superimposed on Moderate to Severe Dementia. Journal of the American Medical Directors Association.
Reference category: independent clinical reference.

Version: Use the current version supplied by the developer page
Information checked: 2026-07-19

Instrument-specific terms apply. See the access and copyright policy or send a correction.

Base clinical review: 2026-07-29. Instrument description source check: 2026-09-05. Scope and limitations.

4-DSD: 4-Delirium Superimposed on Dementia

At a glance

Primary validation papers

Large-scale clinical implementation