Sensitivity and specificity of ventromedial prefrontal cortex tests in behavioral variant frontotemporal dementia

Abstract

Background: Behavioral variant frontotemporal dementia (bvFTD) is characterized by early and substantial ventromedial prefrontal cortex (VMPFC) dysfunction. To date, however, there is no consensus regarding which tests are most sensitive and specific to assess VMPFC dysfunction in this condition.

Methods: In this study we compared the sensitivity and specificity of four common VMPFC specific tests (Mini-SEA, Go/No-Go Subtest of the Frontal Assessment Battery, Reversal-Learning Test, and Iowa Gambling Task) at first clinic presentation in two neurodegenerative cohorts (bvFTD, Alzheimer's disease) and age-matched, healthy controls.

Results: We found that the Mini-SEA, evaluating theory of mind and emotion processes, emerged as the most sensitive and specific of the VMPFC tests employed. The Mini-SEA alone successfully distinguished bvFTD and Alzheimer's disease (AD) in >82% of subjects at first presentation. Similarly, the FAB Go/No-Go and Reversal-Learning Tests also showed very good discrimination power, but to a lesser degree. The Iowa Gambling Task, one of the most common measures of VMPFC function, was the least specific of these tests.

Conclusion: Sensitivity to detect VMPFC dysfunction was high across all test employed, but specificity varied considerably. The Mini-SEA emerged as the most promising of the VMPFC-specific diagnostic tests. Clinicians should take into account the variable specificity of currently available VMPFC tests, which can complement current carer-based questionnaires and clinical evaluation to improve the diagnosis of behavioral dysfunctions due to VMPFC dysfunction.

Keywords: Alzheimer’s disease; Frontotemporal dementia; Social cognition; Ventromedial prefrontal cortex; bvFTD.