Dementia scales
Mini Mental State Examination (MMSE)
Main reference: Folstein MF, Folstein SE, McHugh PR: "Mini-mental State". A practical method for grading the cognitive state of patients for the clinician. Journal of Psychiatric Research 12:189–198, 1975.
Type: Structured clinician-rated interview scale incorporating pencil-and-paper tasks.
Main indications: Used to screen for the presence of cognitive impairment caused by dementia.
Rating performed by: Trained health professionals.
Time period covered by scale: The present.
Time required to complete rating: 5–10 minutes.
Remarks: Probably the most widely used tool for assessing cognitive impairment in the elderly. Easy to perform at the bedside or on an out-patient basis. The MMSE assesses nine items:
- Memory
- Orientation
- Attention
- Verbal fluency
- Nominal aphasia
- Receptive aphasia plus receptive apraxia
- Alexia
- Agraphia
- Constructional apraxia
Normative data for populations of different ages are available.
Although initially thought to be a rather limited instrument and insensitive to change over time, it has proven to be a useful assessment tool in clinical drug trials. Nevertheless, it is inadequately sensitive to change to be a good choice as an outcome variable in clinical trials. It may give misleading results in the context of poor education or language/sensory difficulties or poor motivation (e.g. depression).
It may fail to detect mild/moderate cognitive impairment in people of high educational level or premorbid intelligence ("ceiling" effect). It also has "floor" effects in terms of its inability to detect change in established severe dementia.
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Clock drawing test
Main reference: Sunderland T, Hill JL, Mellow AM, et al.: Clock drawing in Alzheimer's disease. A novel measure of dementia severity. Journal of the American Geriatrics Society 37:725–729, 1989.
Type: Clinician-rated patient activity.
Main indications: Used to screen for cognitive impairment and dementia, and as a measure of spatial dysfunction and neglect. Useful in patients with a normal Mini Mental State Examination in whom a degree of cognitive impairment is nevertheless still suspected; may detect executive cognitive dysfunction in such patients.
Rating performed by: Trained health professional.
Time period covered by scale: The present.
Time required to complete rating: Usually 5 minutes, but there is no time limit set for the patient to complete the test.
Remarks: Simple and reasonably quick to perform but poorly standardised. The patient is either asked to draw a clock on a blank piece of paper or else is presented with a circle and ask to draw in the numbers on the face of the clock. The patient may also be asked to draw in the hour and minute hands of the clock, sometimes to a specific time (often 10 minutes past 11 o'clock).
A third method is to ask the patient to draw in the hour and minute hands to a set time on a pre-drawn clock. Scoring systems vary. For example, the Watson system is based on dividing the clock into quadrants, and determining the score from the number of digits in each quadrant; the Sunderland method also takes into account the positioning of the clock hands. The process whereby the patient failing in putting in 12, 6, 9 and 3, and ensuring correct spacing may be clinically informative.
The presence of an abnormal MMSE score alerts clinicians to the possibility of cognitive impairment. For patients referred for geriatric assessment who have a normal MMSE score, a clock-drawing test, scored by either the Watson or the Sunderland method, is a moderately sensitive and specific adjunct for detecting executive cognitive dysfunction.
An overview is available at McMaster University's Neurosurvival website.
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Checklist differentiating pseudodementia from dementia
Main reference: Wells CE. Pseudodementia. American Journal of Psychiatry 136:895–900, 1979.
Type: Semi-structured interview
Main indications: Designed to differentiate pseudodementia from true dementia.
Rating performed by: Experienced rater.
Time period covered by scale: The duration of the present problem.
Time required to complete rating: 15 minutes
Remarks: This checklist is a 22-item interview that focuses on the patient's clinical course and history, the complaints and clinical behaviour, and the patient's mental capacity. It has been well validated using a psychometric test battery, computed tomography and electroencephalography. It is designed for clinical use.
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Neuropsychiatry Inventory (NPI)
Main reference: Cummings JL, Mega M, K Gray, et al.: The Neuropsychiatric Inventory: comprehensive assessment of psychopathology in dementia. Neurology 44:2308–2314, 1994; Cummings JL.: The Neuropsychiatric Inventory: assessing psychopathology in dementia patients. Neurology 48(Suppl 6):S10–S16, 1997.
Type: Clinician-rated scale.
Main indications: Designed to assess behavioural and neuropsychological disturbances (including abnormalities of mood and psychotic phenomena) in patients with dementia.
Rating performed by: Trained health professionals in consultation with a carer who is familiar with the patient's behaviour.
Time period covered by scale: Previous week
Time required to complete rating: 30 minutes
Remarks: Assesses 12 behavioural disturbances that are common in dementia:
- Delusions
- Hallucinations
- Agitation
- Dysphoria
- Anxiety
- Apathy
- Irritability
- Euphoria
- Disinhibition
- Aberrant motor activity
- Night-time behavioural disturbances
- Eating disturbances
Assesses both the severity and the frequency of the abnormal behaviours as well as the distress each symptom causes the carer. Uses a screening strategy so that only those behaviours with a positive response to the screening questions are examined and scored, thereby minimising the time needed to conduct the test.
Clinical Dementia Rating (CDR)
Main reference: Morris JC. The Clinical Dementia Rating (CDR): Current version and scoring rules. Neurology 43:2412–2414, 1993.
Type: Semi-structured interview with patient with dementia and informant.
Main indications: Designed to rate the severity of dementia.
Rating performed by: Trained health professional.
Time period covered by scale: Previous week.
Time required to complete rating: 60–90 minutes.
Remarks: Involves separate structured interviews with the patient and a carer. Scores are determined for six independent categories: memory, orientation, judgement and problem-solving, community affairs, home and hobbies, and personal care.
Scores are allocated by comparing the patient's characteristics with a descriptive guideline for each score. Various algorithms have been developed to compute the global rating score. Scores in each domain and the total score range from 0 (absent) through 0.5 (questionable), mild (2), and moderate (3) to severe (4).
The global rating scores gleaned from interviews with a carer have been found to be similar enough to those gleaned from interviews with both a carer and the patient for a carer-only interview to be used if necessary.
Training in using this scale is available at Washington University's Alzheimer's Disease Research Center website.
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Disability Assessment for Dementia (DAD)
Main reference: Gelinas I, Gauthier L, McIntyre M, Gauthier S: Development of a functional measure for persons with Alzheimer's disease: the disability assessment for dementia. American Journal of Occupational Therapy 53:471–481, 1999.
Type: Structured interview or questionnaire for the patient's carer.
Main indications: Designed to quantify functional abilities in activities of daily living in patients with dementia and other cognitive impairments.
Rating performed by: Clinician.
Time period covered by scale: Clinical condition at the time of the interview.
Time required to complete rating: 20 minutes.
Remarks: Originally developed to assess patients with Alzheimer's disease living in care institutions. Contains 40 items relating to basic self-care and instrumental aspects of activities of daily living. Scored from 0 (most impairment) to 100 (least impairment).
Generally, the decline in the total scores in mild-to-moderate Alzheimer's disease, for example, averages about one point per month, which equates to the loss of one item on the DAD scale every 2 months.
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GBS Scale
Main reference: Gottfries CG, Bråne G, Gullberg B, Steen G: A new rating scale for dementia syndromes. Arch Gerontol Geriatr 1: 311-330, 1982.
Type: Clinician-rated scale.
Main indications: Designed to give a quantitative measure of dementia, independent of etiology, and a dementia profile.
Rating performed by: Trained mental health professional, on the basis of observation during interview. In case the patient is severely demented information must be obtained from relatives and health care staff.
Time period covered by scale: Condition of the patient during the most recent period (can be specified).
Time required to complete rating: Approx. 30 minutes.
Remarks: Divided into four subscales. The first three estimate the motor, intellectual and emotional impairments. The fourth part measures six symptoms common in dementia. Can also be used for repeated ratings of patients participating in drug trials or for studying the course of illness. Is not meant to be a diagnostic scale.
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Cambridge Cognitive Examination (CAMCOG)
Main reference: Grevett C, O'Brien J. A new database for CAMCOG. Old Age Psychiatrist 28:9, 2002. Comprehensive information about CAMCOG can also be found as a pdf-file at the INTRAS website.
Type: Structured interview
Main indications: Designed to assess cognition in elderly patients, including those with dementia.
Rating performed by: Trained interviewer.
Time period covered by scale: Duration of interview itself.
Time required to complete rating: 20 minutes.
Remarks: CAMCOG is a component of the Cambridge Examination for Mental Disorders in the Elderly (CAMDEX), and generates scores in eight domains (orientation, language, memory, attention, praxis, calculation, abstract thinking, perception) as well as a total score.
CAMDEX provides a computer program for analysing results, but the program is no longer easily compatible with computer operating systems in ordinary use. A CAMCOG database has been developed as a tool to allow users to score, record, collate and analyse cognitive assessments using modern computer systems.
CAMCOG scores are more normally distributed than those on MMSE; the problem of "ceiling effects" is also less than with MMSE. It is possible to calculate MMSE scores since all the relevant items are embedded in the CAMCOG.
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Published on CNSforum 19 Aug 2004