| 1. |
- Cousins, Katheryn A Q, et al.
(author)
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ATN incorporating cerebrospinal fluid neurofilament light chain detects frontotemporal lobar degeneration.
- 2021
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In: Alzheimer's & dementia : the journal of the Alzheimer's Association. - : Wiley. - 1552-5279. ; 17:5, s. 822-830
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Journal article (peer-reviewed)abstract
- The ATN framework provides an in vivo diagnosis of Alzheimer's disease (AD) using cerebrospinal fluid (CSF) biomarkers of pathologic amyloid plaques (A), tangles (T), and neurodegeneration (N). ATN is rarely evaluated in pathologically confirmed patients and its poor sensitivity to suspected non-Alzheimer's pathophysiologies (SNAP), including frontotemporal lobar degeneration (FTLD), leads to misdiagnoses. We compared accuracy of ATN (ATNTAU ) using CSF total tau (t-tau) to a modified strategy (ATNNfL ) using CSF neurofilament light chain (NfL) in an autopsy cohort.ATNTAU and ATNNfL were trained in an independent sample and validated in autopsy-confirmed AD (n=67) and FTLD (n=27).ATNNfL more accurately identified FTLD as SNAP (sensitivity=0.93, specificity=0.94) than ATNTAU (sensitivity=0.44, specificity=0.97), even in cases with co-occurring AD and FTLD. ATNNfL misclassified fewer AD and FTLD as "Normal" (2%) than ATNTAU (14%).ATNNfL is a promising diagnostic strategy that may accurately identify both AD and FTLD, even when pathologies co-occur.
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| 2. |
- Dominguez Perez, Sophia, et al.
(author)
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Neuropsychological and Neuroanatomical Features of Patients with Behavioral/Dysexecutive Variant Alzheimer's Disease (AD) : A Comparison to Behavioral Variant Frontotemporal Dementia and Amnestic AD Groups
- 2022
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In: Journal of Alzheimer's Disease. - 1387-2877. ; 89:2, s. 641-658
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Journal article (peer-reviewed)abstract
- Background: An understudied variant of Alzheimer's disease (AD), the behavioral/dysexecutive variant of AD (bvAD), is associated with progressive personality, behavior, and/or executive dysfunction and frontal atrophy. Objective: This study characterizes the neuropsychological and neuroanatomical features associated with bvAD by comparing it to behavioral variant frontotemporal dementia (bvFTD), amnestic AD (aAD), and subjects with normal cognition. Methods: Subjects included 16 bvAD, 67 bvFTD, 18 aAD patients, and 26 healthy controls. Neuropsychological assessment and MRI data were compared between these groups. Results: Compared to bvFTD, bvAD showed more significant visuospatial impairments (Rey Figure copy and recall), more irritability (Neuropsychological Inventory), and equivalent verbal memory (Philadelphia Verbal Learning Test). Compared to aAD, bvAD indicated more executive dysfunction (F-letter fluency) and better visuospatial performance. Neuroimaging analysis found that bvAD showed cortical thinning relative to bvFTD posteriorly in left temporal-occipital regions; bvFTD had cortical thinning relative to bvAD in left inferior frontal cortex. bvAD had cortical thinning relative to aAD in prefrontal and anterior temporal regions. All patient groups had lower volumes than controls in both anterior and posterior hippocampus. However, bvAD patients had higher average volume than aAD patients in posterior hippocampus and higher volume than bvFTD patients in anterior hippocampus after adjustment for age and intracranial volume. Conclusion: Findings demonstrated that underlying pathology mediates disease presentation in bvAD and bvFTD.
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| 3. |
- Quilico Cousins, Katheryn Alexandra, et al.
(author)
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CSF Biomarkers of Alzheimer Disease in Patients With Concomitant alpha-Synuclein Pathology
- 2022
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In: Neurology. - : Ovid Technologies (Wolters Kluwer Health). - 0028-3878 .- 1526-632X. ; 99:20
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Journal article (peer-reviewed)abstract
- Background and Objectives CSF biomarkers beta-amyloid 1-42 (A beta(42)) phosphorylated tau 181 (p-tau(181)), total tau (t-tau), and neurogranin (Ng) can diagnose Alzheimer disease (AD) in life. However, it is unknown whether CSF concentrations, and thus their accuracies, are affected by concomitant pathologies common in AD, such as alpha-synuclein (alpha Syn). Our primary goal was to test whether biomarkers in patients with AD are altered by concomitant alpha Syn. We compared CSF A beta(42), p-tau(181), t-tau, and Ng levels across autopsy-confirmed AD and concomitant AD and alpha Syn (AD + alpha Syn). Antemortem CSF levels were related to postmortem accumulations of alpha Syn. Finally, we tested how concommitant AD + alpha Syn affected the diagnostic accuracy of 2 CSF-based strategies: the amyloid/tau/neurodegeneration (ATN) framework and the t-tau/A beta(42) ratio. Methods Inclusion criteria were neuropathologic diagnoses of AD, mixed AD + alpha Syn, and alpha Syn. A convenience sample of nonimpaired controls was selected with available CSF and a Mini-Mental State Examination (MMSE) >= 27. alpha Syn without AD and controls were included as reference groups. Analyses of covariance (ANCOVAs) tested planned comparisons were CSF A beta(42), t-tau, and Ng differences across AD and AD + alpha Syn. Linear models tested how biomarkers were altered by alpha Syn accumulation in AD, accounting for pathologic beta-amyloid and tau. Receiver operating characteristic and area under the curve (AUC), including 95% CI, evaluated diagnostic accuracy. Results Participants were 61 patients with AD, 39 patients with mixed AD + alpha Syn, 20 patients with alpha Syn, and 61 controls. AD had similar median age (73 [interquartile range {IQR} = 12] years), MMSE (23 [IQR = 9]), and sex distribution (male = 49%) compared with AD + alpha Syn age (70 [IQR = 13] years; p = 0.3), MMSE (25 [IQR = 9.5]; p = 0.19), and sex distribution (male = 69%; p = 0.077). ANCOVAs showed that AD + alpha Syn had lower p-tau(181) (F(1,94) = 17, p < 2.6e-16), t-tau (F(1,93) = 11, p = 0.0004), and Ng levels (F(1,50) = 12, p = 0.0004) than AD; there was no difference in A beta(42) = 0.44). Models showed increasing alpha Syn related to lower (beta = -0.26, SE = 0.092, p = 0.0065), t-tau (beta = -0.19, SE = 0.092, p = 0.041), and Ng levels (beta = -0.2, SE = 0.066, p = 0.0046); alpha Syn was not a significant factor for A beta(42) (p = 1). T-tau/A beta(42) had the highest accuracy when detecting AD, including mixed AD + alpha Syn cases (AUC = 0.95; CI 0.92-0.98). Discussion Findings demonstrate that concomitant alpha Syn pathology in AD is associated with lower CSF p-tau(181), t-tau, and Ng levels and can affect diagnostic accuracy in patients with AD.
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