Browsing by Author "Jack, Clifford, Jr."

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Late Life Depression is Associated with Reduced Cortical Amyloid Burden: Findings from the ADNI Depression Project
    (Elsevier, 2021) Mackin, R. Scott; Insel, Philip S.; Landau, Susan; Bickford, David; Morin, Ruth; Rhodes, Emma; Tosun, Duygu; Rosen, Howie J.; Butters, Meryl; Aisen, Paul; Raman, Rema; Saykin, Andrew; Toga, Arthur; Jack, Clifford, Jr.; Koeppe, Robert; Weiner, Michael W.; Nelson, Craig; Alzheimer’s Disease Neuroimaging Initiative & the ADNI Depression Project; Radiology and Imaging Sciences, School of Medicine
    Background: We evaluated the role of cortical amyloid deposition as a factor contributing to memory dysfunction and increased risk of dementia associated with late-life depression (LLD). Methods: A total of 119 older adult participants with a current diagnosis of major depression (LLD) from the Alzheimer's Disease Neuroimaging Initiative (ADNI) Depression Project study and 119 nondepressed (ND) cognitively unimpaired participants matched on age, sex, and APOE genotype were obtained from the ADNI database. Results: Thirty-three percent of LLD participants met ADNI criteria for mild cognitive impairment. Compared with ND individuals, the LLD group exhibited less global amyloid beta (Aβ) accumulation (p = .05). The proportion of amyloid positivity in the LLD group was 19.3% compared with 31.1% for the ND participants (p = .02). Among LLD participants, global Aβ was not associated with lifetime number of depressive episodes, lifetime length of depression, length of lifetime selective serotonin reuptake inhibitor use, or lifetime length of untreated depression (p > .21 for all). Global Aβ was associated with worse memory performance (p = .05). Similar results were found in secondary analyses restricting comparisons to the cognitively unimpaired LLD participants as well as when comparing the LLD group with an ND group that included participants with mild cognitive impairment. Conclusions: Contrary to expectation, the LLD group showed less Aβ deposition than the ND group and Aβ deposition was not associated with depression history characteristics. Aβ was associated with memory, but this relationship did not differ between LLD and ND. Our results suggest that memory deficits and accelerated cognitive decline reported in previous studies of LLD are not due to greater cortical Aβ accumulation.
  • Thumbnail Image
    Item
    Resting-State Functional Connectivity Disruption as a Pathological Biomarker in Autosomal Dominant Alzheimer Disease
    (Mary Ann Liebert, 2021) Smith, Robert X.; Strain, Jeremy F.; Tanenbaum, Aaron; Fagan, Anne M.; Hassenstab, Jason; McDade, Eric; Schindler, Suzanne E.; Gordon, Brian A.; Xiong, Chengjie; Chhatwal, Jasmeer; Jack, Clifford, Jr.; Karch, Celeste; Berman, Sarah; Brosch, Jared R.; Lah, James J.; Brickman, Adam M.; Cash, David M.; Fox, Nick C.; Graff-Radford, Neill R.; Levin, Johannes; Noble, James; Holtzman, David M.; Masters, Colin L.; Farlow, Martin R.; Laske, Christoph; Schofield, Peter R.; Marcus, Daniel S.; Morris, John C.; Benzinger, Tammie L. S.; Bateman, Randall J.; Ances, Beau M.; Neurology, School of Medicine
    Aim: Identify a global resting-state functional connectivity (gFC) signature in mutation carriers (MC) from the Dominantly Inherited Alzheimer Network (DIAN). Assess the gFC with regard to amyloid (A), tau (T), and neurodegeneration (N) biomarkers, and estimated years to symptom onset (EYO). Introduction: Cross-sectional measures were assessed in MC (n = 171) and mutation noncarrier (NC) (n = 70) participants. A functional connectivity (FC) matrix that encompassed multiple resting-state networks was computed for each participant. Methods: A global FC was compiled as a single index indicating FC strength. The gFC signature was modeled as a nonlinear function of EYO. The gFC was linearly associated with other biomarkers used for assessing the AT(N) framework, including cerebrospinal fluid (CSF), positron emission tomography (PET) molecular biomarkers, and structural magnetic resonance imaging. Results: The gFC was reduced in MC compared with NC participants. When MC participants were differentiated by clinical dementia rating (CDR), the gFC was significantly decreased in MC CDR >0 (demented) compared with either MC CDR 0 (cognitively normal) or NC participants. The gFC varied nonlinearly with EYO and initially decreased at EYO = −24 years, followed by a stable period followed by a further decline near EYO = 0 years. Irrespective of EYO, a lower gFC associated with values of amyloid PET, CSF Aβ1–42, CSF p-tau, CSF t-tau, 18F-fluorodeoxyglucose, and hippocampal volume. Conclusions: The gFC correlated with biomarkers used for defining the AT(N) framework. A biphasic change in the gFC suggested early changes associated with CSF amyloid and later changes associated with hippocampal volume.