Classification Accuracy and Predictive Ability of The Medical Symptom Validity Test's Dementia Profile and General Memory Impairment Profile

Abstract

When assessing symptom validity in patients with dementia, traditional approaches may be inappropriate because neurological factors may cause altered performance. The Medical Symptom Validity Test has a Dementia Profile that explicitly recognizes this fact. We prospectively evaluated classification accuracy of the Dementia Profile for 52 referrals to a memory disorders clinic. The Dementia Profile correctly classified 36/52 patients. Sensitivity was 54.8%, specificity was 90.5%, positive predictive value was 89.5%, negative predictive value was 60.0%, and the likelihood ratio was 5.77. Of 31 patients with dementia, 11 did not fail symptom validity indices. When only considering patients who failed symptom validity indices, sensitivity of the Dementia Profile was 85%. Classification accuracy statistics are also provided for the Genuine Memory Impairment Profile.

Keywords:

• Symptom validity
• Dementia
• Medical Symptom Validity Test
• Neuropsychological assessment
• Forensic neuropsychology.

Acknowledgments

The authors thank Scott R. Millis for his thoughtful review and helpful comments on a draft of the manuscript. The authors also thank John C. Courtney for access to data from his Brazilian study.