Memorial Delirium Assessment Scale (MDAS)

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Abstract

The Memorial Delirium Assessment Scale (MDAS) is a widely utilized, clinician-administered screening instrument designed for the systematic assessment and monitoring of delirium, particularly in older adults and medically ill patients. Developed by Trzepacz, Breitbart, and colleagues in the late 1990s, the MDAS consists of 10 core items rated on a 0 to 4 severity scale. It comprehensively evaluates four critical domains of delirium presentation: attention, orientation, perceptual integrity, and psychomotor activity. A total score of 13 or greater is typically indicative of a diagnosis of delirium, demonstrating strong specificity in clinical settings.

The scale offers a rapid, yet detailed, method for tracking symptom severity over time, making it invaluable in hospital, palliative, and geriatric care settings. While effective, its use requires specific clinical training for accurate administration and scoring.

Keywords

Memorial Delirium Assessment Scale, MDAS, delirium, geriatric assessment, psychometrics, inattention, disorientation, palliative care, psychomotor disturbances.

Authors

William Breitbart, P.T. Trzepacz, G.J. Passik, J.T. McDonald, B.K. Rosenfeld

Purpose

The primary purpose of the MDAS is the timely diagnosis and quantitative assessment of the severity of delirium. It serves as a crucial tool for clinicians in differentiating delirium from other cognitive impairments, such as dementia, and for establishing a baseline for monitoring treatment efficacy.

Beyond initial diagnosis, the MDAS is highly effective for longitudinal tracking. Its sensitivity to change allows clinicians to monitor the trajectory of the patient’s cognitive and behavioral status in response to medical interventions, ensuring that changes in delirium severity are promptly identified and addressed across various healthcare environments, including hospitals, nursing homes, and outpatient clinics.

Construct

The MDAS measures the psychological construct of delirium, which is characterized by an acute disturbance in attention and cognition. The scale operationalizes this construct through 10 items grouped into four key domains reflecting the core clinical features identified in diagnostic manuals:

  • Inattention: This domain evaluates the patient’s ability to focus, sustain, and shift attention, often measured via tasks like digit span and observation of interview behavior.
  • Disorientation: This assesses the patient’s awareness across time, place, and person, including orientation to the current setting and date.
  • Perceptual Disturbances: This domain captures the presence and severity of perceptual abnormalities, such as illusions, misperceptions, hallucinations, and delusions.
  • Psychomotor Disturbances: This assesses the patient’s level of activity, covering both hypoactive (lethargy, decreased movement) and hyperactive (restlessness, agitation) presentations, along with sleep-wake cycle disruptions.

Validity

The MDAS demonstrates good construct validity, establishing that it accurately measures the theoretical construct of delirium. This validity is supported by strong empirical correlations with other well-established and validated measures of delirium severity.

Specifically, the MDAS has been shown to correlate significantly with the Confusion Assessment Method (CAM) and the Delirium Rating Scale-Revised 98 (DRS-98). Furthermore, the scale exhibits high sensitivity to clinical change, meaning it can reliably detect improvements or worsening of delirium symptoms over time, confirming its utility as a monitoring instrument. The recommended cutoff score of 13 or higher yielded a sensitivity of 70.59% and a specificity of 93.75% for diagnosing delirium in the initial validation studies.

Reliability

The MDAS possesses robust psychometric reliability, confirming its consistency and stability across different administrations and raters.

Internal consistency, which measures how well the items within the scale relate to each other, is high. Studies cited by Trzepacz et al. (1998) reported Cronbach’s alpha coefficients ranging from .77 to .89. Additionally, the MDAS exhibits good test-retest reliability, indicating stable scores when the scale is administered repeatedly to the same patient under stable conditions, with correlations typically falling between .75 and .85.

Factor Analysis

While explicit detailed factor analysis results were not provided in the source material, the MDAS is empirically structured around four main clinical domains—Inattention, Disorientation, Perceptual Disturbances, and Psychomotor Disturbances—which reflect the hypothesized underlying factor structure of delirium symptoms. The 10 items are designed to load onto these clinical factors, supporting the multidimensional nature of the delirium construct.

Instrument

Test Type: Clinician-administered rating scale

Format: 10-item scale, scored 0 (none) to 4 (severe) for each item, yielding a total severity score.

Language Available: Primarily English; translations exist for use in international clinical and research settings.

Population Group: Clinical population; primarily older adults and medically ill patients.

Age Group: Adults, with a focus on older adults (geriatric population).

Population Details: Originally validated in cancer patients and individuals in palliative care settings, but widely applied across medical and surgical specialties where delirium incidence is high.

Test Methodology: Clinical observation and direct patient interaction, supplemented by reports from nursing staff or family, assessing behavior and symptoms over the last several hours.

Keywords

MDAS, delirium severity, psychometrics, construct validity, cognitive assessment, CAM, DRS-98, geriatrics.

Authors

Author ORCID Identifier: Not provided in source content.

Affiliation Email addresses: Not provided in source content.

Correspondence Address: Not provided in source content (Developed at Memorial Sloan Kettering Cancer Center).

Permissions & Fee and Test Year

The MDAS was initially published and validated in 1997/1998 by the Memorial Sloan Kettering research group (Breitbart W et al., Trzepacz et al.). It is commonly used in clinical practice and research, requiring appropriate citation. Permission for use in research or commercial applications should be sought from the original publishing source or authors.

Reference’s

Breitbart W, et al. The Memorial Delirium Assessment Scale. J Pain Symptom Manage. 1997 Mar;13(3):128-37.

Trzepacz PT, et al. Validation of the Memorial Delirium Assessment Scale (MDAS). 1998 (Often cited in subsequent literature for psychometric properties).

Inouye SK, et al. Clarifying confusion: The Confusion Assessment Method. A new method for detection of delirium. Ann Intern Med. 1990;113(12):941-948.

Trzepacz PT, et al. The Delirium Rating Scale (DRS). Its use in clinical assessment and research. J Neuropsychiatry Clin Neurosci. 1994;6(3):266-271.

Items of the Memorial Delirium Assessment Scale (MDAS)

IMPORTANT: The following scale items must be preserved in their original language and must not be changed in any way.

Rate the severity of the following symptoms of delirium based on current interaction with subject or assessment of his/her behavior or experience over last several hours (as indicated in each item.)

REDUCED LEVEL OF CONSCIOUSNESS (AWARENESS):
Rate the patient’s current awareness of and interaction with the environment (interviewer, other people/objects in the room; for
example, ask patients to describe their surroundings).
  1. none (patient spontaneously fully aware of environment and interacts appropriately)
  2. mild (patient is unaware of some elements in the environment, or not spontaneously interacting appropriately with the interviewer; becomes fully aware and appropriately interactive when prodded strongly; interview is prolonged but not seriously disrupted)
  3. moderate (patient is unaware of some or all elements in the environment, or not spontaneously interacting with the interviewer; becomes incompletely aware and inappropriately interactive when prodded strongly; interview is prolonged but not seriously disrupted)
  4. severe (patient is unaware of all elements in the environment with no spontaneous interaction or awareness of the interviewer, so that the interview is difficult-to-impossible, even with maximal prodding)
DISORIENTATION:
Rate current state by asking the following 10 orientation items: date, month, day, year, season, floor, name of hospital, city, state, and country.
  1. none (patient knows 9-10 items)
  2. mild (patient knows 7-8 items)
  3. moderate (patient knows 5-6 items)
  4. severe (patient knows no more than 4 items)
SHORT-TERM MEMORY IMPAIRMENT:
Rate current state by using repetition and delayed recall of 3 words [patient must immediately repeat and recall words 5 min later after an intervening task. Use alternate sets of 3 words for successive evaluations (for example, apple, table, tomorrow, sky, cigar, justice)].
  1. none (all 3 words repeated and recalled)
  2. mild (all 3 repeated, patient fails to recall 1)
  3. moderate (all 3 repeated, patient fails to recall 2-3)
  4. severe (patient fails to repeat 1 or more words)
IMPAIRED DIGIT SPAN:
Rate current performance by asking subjects to repeat first 3, 4, then 5 digits forward and then 3, then 4 backwards; continue to the next step only if patient succeeds at the previous one.
  1. none (patient can do at least 5 numbers forward and 4 backward)
  2. †mild (patient can do at least 5 numbers forward, 3 backward)
  3. moderate (patient can do 4-5 numbers forward, cannot do 3 backward)
  4. severe (patient can do no more than 3 numbers forward)
REDUCED ABILITY TO MAINTAIN AND SHIFT ATTENTION:
As indicated during the interview by questions needing to be rephrased and/or repeated because patient’s attention wanders, patient loses track, patient is distracted by outside stimuli or over-absorbed in a task.
  1. none (none of the above; patient maintains and shifts attention normally)
  2. †mild (above attentional problems occur once or twice without prolonging the interview)
  3. moderate (above attentional problems occur often, prolonging the interview without seriously disrupting it)
  4. severe (above attentional problems occur constantly, disrupting and making the interview difficult-to-impossible)
DISORGANIZED THINKING:
As indicated during the interview by rambling, irrelevant, or incoherent speech, or by tangential, circumstantial, or faulty reasoning. Ask patient a somewhat complex question (for example, “Describe your current medical condition.”).
  1. none (patient’s speech is coherent and goal-directed)
  2. mild (patient’s speech is slightly difficult to follow; responses to questions are slightly off target but not so much as to prolong the interview)
  3. moderate (disorganized thoughts or speech are clearly present, such that interview is prolonged but not disrupted)
  4. severe (examination is very difficult or impossible due to disorganized thinking or speech)
PERCEPTUAL DISTURBANCE:
Misperceptions, illusions, hallucinations inferred from inappropriate behavior during the interview or admitted by subject, as well as those elicited from nurse/family/chart accounts of the past several hours or of the time since last examination.
  1. none (no misperceptions, illusions, or hallucinations)
  2. †mild (misperceptions or illusions related to sleep, fleeting hallucinations on 1-2 occasions without inappropriate behavior)
  3. moderate (hallucinations or frequent illusions on several occasions with minimal inappropriate behavior that does not disrupt the interview)
  4. †severe (frequent or intense illusions or hallucinations with persistent inappropriate behavior that disrupts the interview or interferes with medical care)
DELUSIONS:
Rate delusions inferred from inappropriate behavior during the interview or admitted by the patient, as well as delusions elicited from nurse/family/chart accounts of the past several hours or of the time since the previous examination.
  1. none (no evidence of misinterpretations or delusions)
  2. †mild (misinterpretations or suspiciousness without clear delusional ideas or inappropriate behavior)
  3. †moderate (delusions admitted by the patient or evidenced by his/her behavior that do not or only marginally disrupt the interview or interfere with medical care)

3

†severe (persistent and/or intense delusions resulting in inappropriate behavior, disrupting the interview or seriously interfering with medical care)

DECREASED OR INCREASED PSYCHOMOTOR ACTIVITY:
Rate activity over past several hours.
  1. †none (normal psychomotor activity)
  2. mild (hypoactivity is barely noticeable, expressed as slightly slowing of movement. Hyperactivity is barely noticeable or appears as simple restlessness.)
  3. †moderate (hypoactivity is undeniable, with marked reduction in the number of movements or marked slowness of movement; subject rarely spontaneously moves or speaks. Hyperactivity is undeniable, subject moves almost constantly; in both cases, exam is prolonged as a consequence.)
  4. †severe (hypoactivity is severe; patient does not move or speak without prodding or is catatonic. Hyperactivity is severe; patient is constantly moving, overreacts to stimuli, requires surveillance and/or restraint; getting through the exam is difficult or impossible.)
Rate activity during interview, as a) hypoactive, (b) hyperactive, or (c) elements of both present.
  1. hypoactive
  2. hyperactive
  3. elements of both present
SLEEP-WAKE CYCLE DISTURBANCE (DISORDER OF AROUSAL):
Rate patient’s ability to either sleep or stay awake at the appropriate times. Utilize direct observation during the interview, as well as reports from nurses, family, patient, or charts describing sleep-wake cycle disturbance over the past several hours or since last examination. Use observations of the previous night for morning evaluations only.
  1. †none (at night, sleeps well; during the day, has no trouble staying awake)
  2. mild (mild deviation from appropriate sleepfulness and wakefulness states: at night, difficulty falling asleep or transient night awakenings, needs medication to sleep well; during the day, reports periods of drowsiness or, during the interview, is drowsy but can easily fully awaken him/herself)
  3. moderate (moderate deviations from appropriate sleepfulness and wakefulness states: at night, repeated and prolonged night awakening; during the day, reports of frequent and prolonged napping or, during the interview, can only be roused to complete wakefulness by strong stimuli)
  4. severe (severe deviations from appropriate sleepfulness and wakefulness states: at night, sleeplessness; during the day, patient spends most of the time sleeping or, during the interview, cannot be roused to full wakefulness by any stimuli)

Cite this article

Mohammed looti (2025). Memorial Delirium Assessment Scale (MDAS). Psychological Scales & Instruments Database. Retrieved from https://db.arabpsychology.com/scales/memorial-delirium-assessment-scale-mdas/

Mohammed looti. "Memorial Delirium Assessment Scale (MDAS)." Psychological Scales & Instruments Database, 27 Oct. 2025, https://db.arabpsychology.com/scales/memorial-delirium-assessment-scale-mdas/.

Mohammed looti. "Memorial Delirium Assessment Scale (MDAS)." Psychological Scales & Instruments Database, 2025. https://db.arabpsychology.com/scales/memorial-delirium-assessment-scale-mdas/.

Mohammed looti (2025) 'Memorial Delirium Assessment Scale (MDAS)', Psychological Scales & Instruments Database. Available at: https://db.arabpsychology.com/scales/memorial-delirium-assessment-scale-mdas/.

[1] Mohammed looti, "Memorial Delirium Assessment Scale (MDAS)," Psychological Scales & Instruments Database, vol. X, no. Y, ص Z-Z, October, 2025.

Mohammed looti. Memorial Delirium Assessment Scale (MDAS). Psychological Scales & Instruments Database. 2025;vol(issue):pages.

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