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Amyloid negativity in patients with clinically diagnosed Alzheimer disease and MCI
Landau SM, Horng A, Fero A, Jagust WJ, Alzheimer's Disease Neuroimaging Initiative.. Neurology, 2016-03-11
Topic: Amyloid, tau and blood-test diagnosis
Objective To examine the clinical and biomarker characteristics of patients with amyloid-negative Alzheimer disease (AD) and mild cognitive impairment (MCI) from the Alzheimer's Disease Neuroimaging Initiative (ADNI), a prospective cohort study. Methods We first investigated the reliability of florbetapir- PET in patients with AD and patients with MCI using CSF-Aβ1-42 as a comparison amyloid measurement. We then compared florbetapir- vs florbetapir+ patients with respect to several AD-specific biomarkers, baseline and longitudinal cognitive measurements, and demographic and clinician report data. Results Florbetapir and CSF-Aβ1-42 +/- status agreed for 98% of ADs (89% of MCIs), indicating that most florbetapir- scans were a reliable representation of amyloid status. Florbetapir- AD (n = 27/177; 15%) and MCI (n = 74/217, 34%) were more likely to be APOE4-negative (MCI 83%, AD 96%) than their florbetapir+ counterparts (MCI 30%, AD 24%). Florbetapir- patients also had less AD-specific hypometabolism, lower CSF p-tau and t-tau, and better longitudinal cognitive performance, and were more likely to be taking medication for depression. In MCI only, florbetapir- participants had less hippocampal atrophy and hypometabolism and lower functional activity questionnaire scores compared to florbetapir+ participants. Conclusions Overall, image analysis problems do not appear to be a primary explanation of amyloid negativity. Florbetapir- ADNI patients have a variety of clinical and biomarker features that differ from their florbetapir+ counterparts, suggesting that one or more non-AD etiologies (which may include vascular disease and depression) account for their AD-like phenotype.
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APA 7th
Landau, S. M., Horng, A., Fero, A., Jagust, W. J., & Alzheimer's Disease Neuroimaging Initiative. (2016). Amyloid negativity in patients with clinically diagnosed Alzheimer disease and MCI. Neurology. https://doi.org/10.1212/wnl.0000000000002576
Vancouver
Landau SM, Horng A, Fero A, Jagust WJ, Alzheimer's Disease Neuroimaging Initiative. Amyloid negativity in patients with clinically diagnosed Alzheimer disease and MCI. Neurology. 2016. doi:10.1212/wnl.0000000000002576. PMID: 26968515.
BibTeX
@article{landau2016-26968515,
author = {Landau, S. M. and Horng, A. and Fero, A. and Jagust, W. J. and {Alzheimer's Disease Neuroimaging Initiative}},
title = {{Amyloid negativity in patients with clinically diagnosed Alzheimer disease and MCI}},
journal = {Neurology},
year = {2016},
doi = {10.1212/wnl.0000000000002576},
pmid = {26968515},
url = {https://doi.org/10.1212/wnl.0000000000002576}
}
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Key findings
- Results Florbetapir and CSF-Aβ1-42 +/- status agreed for 98% of ADs (89% of MCIs), indicating that most florbetapir- scans were a reliable representation of amyloid status.
- In MCI only, florbetapir- participants had less hippocampal atrophy and hypometabolism and lower functional activity questionnaire scores compared to florbetapir+ participants.
- Conclusions Overall, image analysis problems do not appear to be a primary explanation of amyloid negativity.
- Florbetapir- ADNI patients have a variety of clinical and biomarker features that differ from their florbetapir+ counterparts, suggesting that one or more non-AD etiologies (which may include vascular disease and depression) account for their AD-like phenotype.
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Study details
- Study designcohort study
- Participants27
- Evidence strengthModerate
How this study scored 62/100
Published in a leading specialty journal, and it is a cohort study following people over time. Scored zero for effect reported and randomised / blinded because the record does not state it. We have no data on journal's citation record, times cited, citations per year, impact for its field and year, cited by studies here, still being cited, senior author's track record and institution's track record, so those were left out: it earned 38 of the 61 points we could judge it on, which is 62 out of 100.
| Component | Points | Why |
|---|---|---|
| Journal tier | 9 / 10 | Tier 2 — leading specialty journal (Neurology) |
| Journal's citation record | — / 4 | No journal record from OpenAlex — left out of this score |
| Study design | 7 / 12 | A cohort study following people over time |
| Strength of evidence | 3 / 5 | Rated “moderate” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 1 / 5 | 2016 — within 20 year(s) of the newest study here |
| Sample size | 1 / 4 | 27 participants |
| Effect reported | 0 / 3 | No effect size reported — scores zero (not stated in the record — scored 0) |
| Studied in people | 3 / 3 | Studied in people (participant count stated) |
| Randomised / blinded | 0 / 2 | No randomisation or blinding stated — scores zero (not stated in the record — scored 0) |
| Times cited | — / 7 | No citation count (not found in OpenAlex) — left out of this score |
| Citations per year | — / 5 | No citation count or no year — left out of this score |
| Impact for its field and year | — / 6 | No field-weighted citation impact (OpenAlex has none yet) — left out of this score |
| Cited by studies here | — / 6 | Not yet checked against this library's citation graph — left out of this score |
| Still being cited | — / 4 | No yearly citation counts — left out of this score |
| Senior author's track record | — / 4 | Senior author's record not available — left out of this score |
| Institution's track record | — / 3 | No institution listed in OpenAlex — left out of this score |
| Multi-centre collaboration | 2 / 3 | PubMed indexes it as a multicentre study |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 26968515) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Points | 38 / 61 | Scored on 12 of 20 parts. We have no data for the rest, so they are left out: 38 of the 61 points we could judge it on is 62 out of 100. |
| Total | 62 / 100 | — |
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