Daniela Galimberti (Italy)
University of Milan Department of Neurological SciencesAuthor Of 2 Presentations
THE ITALIAN DEMENTIA WITH LEWY BODIES STUDY GROUP (DLB-SINDEM): A MULTICENTER SURVEY ON THE ACCURACY AND THE PREVALENCE OF DLB DIAGNOSIS
- Mirella Russo (Italy)
Abstract
Background and Aims:
Dementia with Lewy bodies (DLB) is the second most common neurodegenerative cause of dementia. However, clinical diagnosis can be challenging. Two toolkits have been deverloped to aid the clinical diagnosis of DLB: the Lewy Body Composite Risk Score (LBCRS) and the Assessment Toolkit for DLB (AT-DLB). The aim of the present study is to evaluate the diagnostic accuracy of these two questionnaires, as well as their capacity to enhance application and interpretation of the Consensus Criteria.
Methods:
In this study, LBCRS and AT-DLB were distributed to 135 Cognitive Decline and Dementia Centers (CDCD). We asked to administer the two questionnaires to all patients referred within the following three months, independently from the clinical diagnosis, and also to apply Consensus Criteria for DLB diagnosis, according to the results of each of the two toolkits, to all subjects.
Results:
A total of 23 Centers participated to the survey, and 2006 patients were enrolled. Diagnosis of dementia was not concordant in 152 (7.58%) subjects, who were excluded from the cohort. Of the 1854 remaining patients, 56.53% were female; the mean age was 75.06±14.58 years. LBCRS toolkit showed a good reliability (Cronbach-alpha=0.77), even when removing variables from the construct Conversely, AT-DLB toolkit Cronbach-alpha was 0.52 and, after the subtraction of the “cognitive fluctuation” criterion, was only 0.31.
Conclusions:
In a clinical setting, LBCRS questionnaire shows a better diagnostic accuracy for DLB diagnosis than AT-DLB questionnaire. Further investigations should focus on the assessment of LBCRS capacity to identify DLB patients at prodromal stages.
UNRAVELLING THE ASSOCIATION BETWEEN AMYLOID-PET AND CSF BIOMARKERS: WHO REALLY DESERVES AN A+?
- Luca Sacchi (Italy)
Abstract
Background and Aims:
Correlation between CSF-Aβ42 and amyloid-PET is inconstant across the AD spectrum. However, they are considered interchangeable, along with Aβ42/40 ratio, for defining ‘Alzheimer’s Disease pathologic change’ (A+). We aimed at further unravelling the association between amyloid-PET and CSF biomarkers of AD in patients with low CSF-Aβ42.
Methods:
We included 23 patients who underwent 18F-Florbetaben-PET scan, MRI and CSF analysis showing reduced levels of Aβ42 within a 365 days interval. Thresholds used for dichotomization were: Aβ42<640 pg/mL (A+); pTau>61 pg/mL (T+); Aβ42/40<0.069 (ADratio). Amyloid-PET scans were visually classified as positive/negative and processed by four pipelines (SPMCL, SPMAAL, FSGM, FSWC). Transformation to Centiloid units was performed, setting threshold for PET-positivity to 20.1.
Results:
Different pipelines gave highly intercorrelated SUVRs (rho 0.93-0.99). The most significant findings were: pTau positive correlation with SPMCL and SPMAAL SUVRs (rho 0.56, p 0.0063; rho 0.51, p 0.0148 respectively) and Aβ42/40 negative correlation with SPMCL and SPMAAL SUVRs (rho -0.56, p 0.0058; rho -0.52, p 0.0117 respectively). In subregion analysis, SUVRs of precuneus, posterior cingulate and anterior cingulate cortices showed the highest correlation with pTau, while Aβ42/40 ratio best correlated with posterior cingulate SUVR. SUVRs were significantly higher in A+/T+ than in A+/T- (p 0.0018-0.0059) and in ADratio versus non ADratio subjects (p 0.0002). Combining either pTau or Aβ40 with Aβ42 significantly increased concordance with PET-status.
Conclusions:
Our data confirm that correlation between Aβ42 and PET SUVR does not hold after CSF-Aβ42 positivity has been reached and that PET measures show a stronger association with pTau and Aβ42/40 at this stage.