Utility of Behavioral versus Cognitive Measures in Differentiating between Subtypes of Frontotemporal Lobar Degeneration and Alzheimer’s Disease

Abstract

We hypothesized that a modified version of the Frontal Behavioral Inventory (FBI-mod), along with a few cognitive tests, would be clinically useful in distinguishing between clinically defined Alzheimer’s disease (AD) and subtypes of frontotemporal lobar degeneration (FTLD): frontotemporal dementia (dysexecutive type), progressive nonfluent aphasia, and semantic dementia. We studied 80 patients who were diagnosed with AD (n = 30) or FTLD (n = 50), on the basis of a comprehensive neuropsychological battery, imaging, neurological examination, and history. We found significant between-group differences on the FBI-mod, two subtests of the Rey Auditory Verbal Learning Test (verbal learning and delayed recall), and the Trail Making Test Part B (one measure of ‘executive functioning’). AD was characterized by relatively severe impairment in verbal learning, delayed recall, and executive functioning, with relatively normal scores on the FBI-mod. Frontotemporal dementia was characterized by relatively severe impairment on the FBI-mod and executive functioning in the absence of severe impairment in verbal learning and recall. Progressive nonfluent aphasia was characterized by severe impairment in executive functioning with relatively normal scores on verbal learning and recall and FBI-mod. Finally, semantic dementia was characterized by relatively severe deficits in delayed recall, but relatively normal performance on new learning, executive functioning, and on FBI-mod. Discriminant function analysis confirmed that the FBI-mod, in conjunction with the Rey Auditory Verbal Learning Test, and the Trail Making Test Part B categorized the majority of patients as subtypes of FTLD or AD in the same way as a full neuropsychological battery, neurological examination, complete history, and imaging. These tests may be useful for efficient clinical diagnosis, although progressive nonfluent aphasia and semantic dementia are likely to be best distinguished by language tests not included in standard neuropsychological test batteries.

Rate of Cognitive Change Measured by Neuropsychologic Test Performance in 3 Distinct Dementia Syndromes

“…Performance on Trail Making Part B requires cognitive flexibility and set shifting, faculties thought to be impaired in FTD. 32 PPA subjects also declined on Trail Making, which again, may reflect the verbal nature of the test, or executive function deficits which may conceivably also emerge in this group given the overlap between these 2 syndromes over time.…”

Evaluating Behavior in Mouse Models of the Behavioral Variant of Frontotemporal Dementia: Which Test for Which Symptom?

“…The test consists in ordering cards following one criterion; then the criterion changes and the patient must adapt to order the cards following the new criterion. The Trail Making Test, which consists in ordering one succession of numbers and one succession of letters and alternating numbers and letters, is also commonly used for the diagnosis of FTD [70,71]. …”

Language, executive function and social cognition in the diagnosis of frontotemporal dementia syndromes

“…In contrast, a number of other studies have reported severe executive deficits in nfvPPA as measured by the WCST or Trail Making Test Part B (Knibb et al, 2009; Nestor et al, 2003). Further, the executive problems in subjects with nfvPPA have been sometimes shown to be of a greater magnitude than in bvFTD (Heidler-Gary et al, 2007). Variable disease severity is certain to contribute to the discrepancy across studies, and it is also likely that cognitive profiles differ on a case by case basis.…”