A New Screening Test for Alzheimer's

Summarized by Robert W. Griffith, MD
December 18, 2006

Summary

A new test, called SLUMS, has been developed, which is more efficient than the MMSE in diagnosing mild neurocognitive disorder.

Introduction

The routine test that physicians give to people they suspect may have Alzheimer's disease is the Mini-Mental State Examination (MMSE), also known as the Folstein test. It's been in widespread use since it was first published in 1975, and it's well accepted by experts. Apart from helping in diagnosis, it's used to follow the progress of the disease, especially in clinical trials of new treatments. However, the MMSE is not very good at identifying people with what is known as mild neurocognitive disorder (MNCD), especially in more educated patients. MNCD is also known as Mild Cognitive Impairment (MCI). In various studies, 12% to 28% of subjects progress to Alzheimer's disease within 2 to 4 years, at an average rate of 14 per year.

A more sensitive test that would disclose MNCD would help the physician identify patients on their first visit, so that they may start treatment as early as possible. Research physicians at St Louis University, led by Drs John Morley and Syed Tariq, decided to tackle this problem. They developed and tested a 30-point screening test, called The Saint Louis University Mental Status (SLUMS) examination, comparing its results with those from the MMSE in the same patients.

What was done

Geriatric hospitals in the Saint Louis area provided 705 volunteers for the study. At baseline a complete physical and mental status examination was done, with Diagnostic Statistical Manual of Mental Disorder criteria used to diagnose MCND or dementia. The participants were then given the MMSE and SLUMS examinations.

The MMSE is a series of questions and tests, each of which scores points if answered correctly. If every answer is correct, a maximum score of 30 points is possible. It covers orientation, memory, attention, calculation, language, writing, and drawing-copying skills¹. The SLUMS is similar in format, but it supplements the MMSE with enhanced tasks in the attention, calculation, recall, digit span, clock- drawing, and immediate recall areas. The clock-drawing test assesses executive function, one of the earliest forms of cognition affected in MNCD. The test is reproduced at the first related link below.

The analyses of the results included evaluation of the sensitivity, specificity, and predictive values for various cut-off scores for the diagnosis of MCND and dementia, based on the results from the participants diagnosed with these conditions.2 The subjects were classified according to whether they had received high school education or not.

Results of the comparison

The average age of the participants was 75 years; 31% had less than a high school education, while 69% had a high school education or above. They were predominantly white males. There were 180 subjects (25.5%) with MCND, 82 (11.5%) with dementia, and 440 (63%) with normal brain function.

The optimal cut-off MMSE and SLUMS scores for the two groups of participants are given in the table:

	High School Education	Less Than High School
MMSE
MCND	28.5	29.5
Dementia	26.5	27.5
SLUMS
MCND	23.5	25.5
Dementia	19.5	21.5

Statistical analyses showed that the sensitivity and specificity were similar for both SLUMS and MMSE in detecting dementia, but the SLUMS appeared to be better in differentiating MNCD from normal cognitive function.

What SLUMS can do

Both SLUMS and MMSE can identify dementia, but SLUMS clearly has an advantage: it can help physicians diagnose MNCD on a first visit; using the MMSE for this requires follow-up screening to detect a decline in scores. One may hope that there will soon be effective treatment for MNCD, making its early diagnosis an important step.

In using the SLUMS, one can see the clear differentiation between the scores for both conditions:

	High School Education	Less Than High School
Normal functioning	27 to 30	25 to 30
MNCD	21 to 26	20 to 24
Dementia	1 to 20	1 to 19

The test is already in use at many Veterans Administration Hospitals. It seems a useful addition to the toolbox of primary care physicians who are trying to detect MNCD as early as possible. Let us hope there will soon be new medications availability that can help treat, or at least slow, this disorder.

Source

• Comparison of the Saint Louis University Mental Status Examination and the Mini-mental State Examination for dementia and mild neurocognitive disorder - a pilot study. SH. Tariq, N. Tumosa, JT. Chibnal,  et al. , Am J Geriatr Psychiatry , 2006, vol. 14, pp. 900--910

Footnotes
1. Folstein M, Folstein S, McHugh P. Mini-Mental State. A practical method for grading the cognitive state of patients for the clinician. J Psych Res 1975;12:189-198
2. The sensitivity of a test is the proportion of those people who actually have the condition who have a positive test result. When a test has a high sensitivity, a negative result can help rule out the diagnosis. The specificity of a test is the proportion of people without the disease who have a negative test result. When a test has a high specificity, a positive result 'rules in' the diagnosis.

Related Links
The SLUMS Examination
The Mini-Mental State Exam
The Instrumental Activities of Daily Living Test

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