Progression of frontal lobe symptoms in FTD, LBD and AD

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Background: To study the progression of frontal lobe symptoms within and across diagnostic dementia categories, a cross-sectional analysis of baseline behavioral data that are part of a large, prospective and longitudinal Belgian study, was performed. Methods: Diagnosed according to strictly applied clinical diagnostic criteria, patients with probable Alzheimer's disease (AD) (n=456), frontotemporal dementia (FTD) (n=55), and dementia with Lewy bodies (DLB) (n=48) were included. All patients underwent a neuropsychological examination and behavioral assessment by means of a battery of scales. Staging of dementia severity was assessed by means of the Global Deterioration Scale (GDS). Based on GDS scores, patients were recategorized in three subgroups according to dementia severity: mild (GDS stages 2 and 3, n=62), moderate (GDS stages 4 and 5, n=252) and severe (GDS stages 6 and 7, n=245) dementia. Frontal lobe symptoms were assessed by means of the Middelheim Frontality Score (MFS). Results: In FTD patients, no significant difference in MFS total score between FTD patients belonging to the mild and severe dementia stages was found (p=0.828, n=28). In both AD and DLB groups, the MFS total score increased significantly when disease progressed as demonstrated by significantly higher MFS total scores in severe dementia stages compared to mild stages (AD: p 0.001, n=254; DLB: p 0.001, n=25). Comparing the evolution of the MFS total scores in function of disease progression between FTD and AD patients, significantly higher MFS total scores were achieved in FTD patients, irrespective of dementia severity (p <0.001 for mild, moderate and severe dementia subgroups). At no stage of disease severity, significant differences in MFS total scores comparing DLB and AD groups were achieved. The MFS items ‘disinhibition' and ‘aspontaneity' were present in a significantly higher proportion of severely affected DLB patients compared to severely affected AD patients (p=0.005 and p=0.009 respectively). Conclusions: In FTD, mean MFS scores were high at dementia onset and remain as such during the disease evolution. Compared to AD, FTD patients displayed significantly more frontal lobe symptoms, allowing discrimination between both diseases, especially in the earliest disease stages. With disease progression, AD and DLB patients gradually displayed more frontal lobe symptoms.

S. Engelborghs, M. Aries, N. Le Bastard, H. Debruyne, M. Van Buggenhout, G. Nagels, P. De Deyn. O3-06-05: Progression of frontal lobe symptoms in frontotemporal dementia and dementia with Lewy bodies as compared with Alzheimer's disease. Alzheimer's and Dementia, Volume 4, Issue 4, Pages T171-T172 (2008)