Belgian researchers gave 456 probable AD patients, 55 probable FTD patients, and 48 probable DLB patients exams that measured dementia severity and frontal lobe symptoms.

"In FTD patients, frontal lobe symptoms were severe in the mild, moderate and severe dementia stages although the nature of frontal lobe symptoms depended on disease severity. AD and DLB patients displayed more frontal lobe symptoms in the advanced disease stages as compared to disease onset, suggesting gradual frontal lobe involvement as the disease progresses."

The authors suggest that "behavioural observation of frontal lobe symptoms," particularly in those in the earliest disease stage, may be useful in a differential diagnosis (between different dementia types). In order to conduct clinical trials for disease-modifying treatments, it's critical to properly diagnose participants.

The abstract is copied below.

Robin



International Journal of Geriatric Psychiatry. 2010 Nov;25(11):1186-95.

Relation between frontal lobe symptoms and dementia severity within and across diagnostic dementia categories.

Aries MJ, Le Bastard N, Debruyne H, Van Buggenhout M, Nagels G, De Deyn PP, Engelborghs S.
Department of Neurology and Memory Clinic, Middelheim and Hoge Beuken General Hospitals (ZNA), University of Antwerp, Antwerp, Belgium.

Abstract
BACKGROUND: To study frontal lobe symptoms in relation to dementia severity within and across diagnostic dementia categories, a cross-sectional analysis of behavioural data was performed.

METHODS: Patients with probable Alzheimer's disease (AD) (n=456), frontotemporal dementia (FTD) (n=55) and dementia with Lewy bodies (DLB) (n=48) were included. Dementia severity and frontal lobe symptoms were assessed by means of the global deterioration scale and the Middelheim frontality score (MFS).

RESULTS: In FTD, no difference in MFS total scores between patients belonging to the mild and severe dementia stages was found (p=0.828). In AD and DLB groups, significantly higher MFS total scores were found in severe dementia stages compared to mild dementia stages (p<0.001). Comparing MFS total scores between FTD and AD patients, significantly higher scores were achieved in FTD patients, irrespective of dementia severity (p<0.001).

CONCLUSIONS: In FTD patients, frontal lobe symptoms were severe in the mild, moderate and severe dementia stages although the nature of frontal lobe symptoms depended on disease severity. AD and DLB patients displayed more frontal lobe symptoms in the advanced disease stages as compared to disease onset, suggesting gradual frontal lobe involvement as the disease progresses. The nature of frontal lobe symptoms related to dementia severity differed between AD, DLB and FTD patients, suggesting different patterns of frontal lobe involvement. Last but not the least, these data point to the potential diagnostic value of behavioural observation of frontal lobe symptoms for (differential) dementia diagnosis, especially at the earliest disease stages. These findings await confirmation through a prospective, longitudinal study.

Copyright © 2010 John Wiley & Sons, Ltd.

PubMed ID#: 20957694 (see pubmed.gov for this abstract only)

It would be interesting to know how the LBD patients were rated on global deterioration correcting for PD symptoms. How many of our LOs lost control of bladder and maybe even bowel, ability to dress themselves or even speak due to autonomic and neuromuscular deficits. Even people with pure PD lost their ability to speak. I often have no idea whether some of my husband's 'late stage' behaviors are due to neuromuscular or frontal lobe. Robin, if you have a link or access to the full report I would love to see it and would also like your input on this. Thanks.

Typically dementia rating scales take into account cognitive function and ability to perform ADLs. In this study, I don't believe cognitive function and ADLs were assessed. The focus was on frontal lobe symptoms. So I don't think motor symptoms played any role at all.

As I read it, they were correlating dementia severity with behavioral symptoms, the former assessed using the global deterioration scale and the latter using the Middelheim frontality score. I guess what I was interested to know, as with any of these assessments, how they determine where PD leaves off and dementia begins [in LBD] when it comes to certain tools on the global deterioration scale.