Comparison of Clinical Performance of AQT-CF, MMSE, and ADAS-cog:

Preliminary ResultsNiels Peter Nielsen, M.D.

Siegbert Warkentin, Ph.D.

James Jacobson, M.D.

Lennart Minthon, M.D., Ph.D.

Elisabeth H. Wiig, Ph.D.

Copyright 2002 @ RAN Diagnostics, Inc.

Objectives

1. Compare the diagnostic utility of three measures of cognition (AQT-CF, MMSE, and ADAS-cog), used alone, for differentiating patients with Alzheimer’s Disease from normal patients.

2. Determine if a combination of tests provides better diagnostic utility than a single test.

3. Suggest a testing strategy for clinical application of these cognitive measures.

Sample Population

Normal AD P valuen 46 33

Language Swedish Swedish

Education > 11 yrs > 11 yrs

Age 70.85+/- 8.94

75.3 +/- 7.04 P<0.02

Cognitive Measures

AQT MMSE ADASProbe Temporo-

parietal dysfunction

Cognitive impairment

Comprehensive testing for AD

Test Color-form naming

Measure Time (sec) Point score Behavior rating

Normal < 60 27-30 <10

AD >70 <27 10 - 70

Test time 3-5 min 10 min 45 min

Color-Form Naming Tests

Test Plates (40 items each)

General Results

Normal AD P ValueAQT-CF 51.21+/- 9.17 96.88 +/-

21.78< 0.001

MMSE 29.07 +/- 1.44

23.03 +/- 3.64

< 0.001

ADAS-cog 7.4 +/- 3.51 23.38 +/- 9.14

< 0.001

Sensitivity Analysis

Sensitivity

(%)

Specificity

(%)

Predictive Value

(%)

AQT-CF 88 100 95

MMSE 82 94 87

ADAS-cog

95 98 97

Receiver Operator Curve

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1

f alse alarm

aqt-cf

random

mmse

adas-cog

False Alarm

Diagnosis

Stepwise Discriminant Analysis

Y(0,1) = B0 + B1X1 + B2X2 +B3X3 …+BiXi

Variables = age, gender, AQT-CF, MMSE, ADAS-cog

Y(0,1) = -3.720 + .122(ADAS-cog) + .030(AQT-CF)

Best discrimination by ADAS-cog & AQT-CF

AGE, gender, MMSE not included

Sensitivity Analysis:AQT-CF and ADAS-cog

Normal

AD

Normal

21 0 Spec= 100%

AD 1 44 Sens= 98%

Predicted

Actual

AQT-CF and ADAS-cog: Predictive Value = 98.5%

Measure CharacteristicsAQT-CF MMSE ADAS-

cogTime 3-5 min 10 min 45 min

Monitor Nonmedical

Professional

Professional

Cost Low Moderate High

Conflicts Factors

None Age, education, culture, literacy

Judgment, experience

PV(alone/ combo)

95/98.5 87/NA 97/98.5

Screening Yes Yes No

Diagnosis Yes Yes

Summary

1. Used alone, AQT-CF and ADAS-cog have comparable predictive value, superior to MMSE.

2. Used in combination, the best PV value is obtained by using AQT-CF and ADAS-cog.

3. For screening, AQT-CF is preferred because of short test time, independence from a medical professional, and high predictive value.

4. For final diagnosis, the combination of AQT-CF and ADAS-cog provides the highest predictive value.

Conclusions

1. AQT-CF is a powerful clinical tool to assess cognitive functions associated with temporo-parietal activation.

2. Test characteristics of AQT-CF make it especially valuable as an initial screening test for both normal individuals and suspected AD patients.

3. For final diagnosis, the best predictive value is provided by use of both the AQT-CF and ADAS-cog.