Clinical and MRI predictors of conversion from mild behavioural impairment to dementia

Abstract Objective As an analogy with mild cognitive impairment (MCI), the mild behavioural impairment (MBI) construct has been proposed as a diagnostic label for those presenting late-onset behavioural symptoms. To date, however, the clinical, cognitive and structural imaging features associated with an increased risk of conversion from MBI to dementia are poorly understood. Methods We retrospectively analysed the cognitive performance and structural brain MRI of 113 subjects, with a clinical follow-up of at least 4 years available. Subjects were randomly assigned to a Group A (56 subjects; age: 65.4±7.9 years, 15 females, MMSE score: 28.4±2.3)) or to a Group B (57 subjects, age: 66.6±6.4, 17 females, MMSE score: 28.0±1.4). In the Group A, cognitive and structural variables were compared between converters (at 4 years) and non-converters and then verified in the Group B group. Results In the Group A, 14 patients converted to bv-FTD and 4 to Alzheimer's Disease (AD). Converters presented at baseline lower executive function scores and total Theory of Mind (ToM scores), as well as more severe focal frontal atrophy. In the Group B, 13 subjects converted to bv-FTD and none to AD. The combination of the variables identified in the Group A significantly (p Conclusion The combined presence of executive deficit, impaired ToM, and presence of isolated frontal atrophy was associated with risk of progression from MBI to a clinically evident neurodegenerative condition, mainly bv-FTD, over a 4-year period.