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Frontal-hippocampal double dissociation between normal aging and Alzheimer's disease
Head D, Snyder AZ, Girton LE, Morris JC, Buckner RL.. Cerebral cortex (New York, N.Y. : 1991), 2004-09-15
Topic: Amyloid, tau and blood-test diagnosis
Controversy persists regarding whether Alzheimer's disease (AD) is a distinct entity or instead exists on a continuum with nondemented aging. To explore this issue, volumetric analyses of callosal and hippocampal regions were performed on 150 participants aged 18-93 years. Group-level analyses revealed that nondemented age-related differences were greater in anterior than posterior callosal regions and were not augmented by early-stage AD. In contrast, early-stage AD was associated with substantial reduction in hippocampal volume. Examination of the 100 older adults using regression analyses demonstrated age-associated differences in callosal volume that were similar in demented and nondemented individuals. Early-stage AD was again characterized by a marked reduction in hippocampal volume while age alone induced only mild differences in hippocampal volume. As a final analysis, the formal double dissociation was confirmed by comparing the effects of age directly against the effects of dementia. These results suggest a multiple-component model of aging. One process, associated with AD, manifests early and prominently in the medial temporal lobe. A separate process, ubiquitous in aging, affects brain white matter with an anterior-to-posterior gradient and may underlie the executive difficulties common in aging.
Key findings
- Group-level analyses revealed that nondemented age-related differences were greater in anterior than posterior callosal regions and were not augmented by early-stage AD.
- In contrast, early-stage AD was associated with substantial reduction in hippocampal volume.
- Examination of the 100 older adults using regression analyses demonstrated age-associated differences in callosal volume that were similar in demented and nondemented individuals.
- These results suggest a multiple-component model of aging.
- One process, associated with AD, manifests early and prominently in the medial temporal lobe.
Study details
- Participants150
- Evidence strengthLow
How this study scored 45/100
Published in a peer-reviewed journal. Scored zero for study design, 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, institution's track record and multi-centre collaboration, so those were left out: it earned 26 of the 58 points we could judge it on, which is 45 out of 100.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (Cerebral cortex (New York, N.Y. : 1991)) |
| Journal's citation record | — / 4 | No journal record from OpenAlex — left out of this score |
| Study design | 0 / 12 | No study design recorded — scores zero, not guessed (not stated in the record — scored 0) |
| Strength of evidence | 1 / 5 | Rated “low” in our summary |
| Peer-review validation | 10 / 10 | Peer-reviewed. Published as an article in a named peer-reviewed journal. |
| How recent | 1 / 5 | 2005 — older than 20 years, still counted |
| Sample size | 2 / 4 | 150 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 | — / 3 | Institutions not listed — left out of this score |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 15371293) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Points | 26 / 58 | Scored on 11 of 20 parts. We have no data for the rest, so they are left out: 26 of the 58 points we could judge it on is 45 out of 100. |
| Total | 45 / 100 | — |
What each of these 20 components measures, and what this score is not →
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Cite this study APA, Vancouver, BibTeX · download .bib or .ris
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APA 7th
Head, D., Snyder, A. Z., Girton, L. E., Morris, J. C., & Buckner, R. L. (2005). Frontal-hippocampal double dissociation between normal aging and Alzheimer's disease. Cerebral cortex (New York, N.Y. : 1991). https://doi.org/10.1093/cercor/bhh174
Vancouver
Head D, Snyder AZ, Girton LE, Morris JC, Buckner RL. Frontal-hippocampal double dissociation between normal aging and Alzheimer's disease. Cerebral cortex (New York, N.Y. : 1991). 2005. doi:10.1093/cercor/bhh174. PMID: 15371293.
BibTeX
@article{head2005-15371293,
author = {Head, D. and Snyder, A. Z. and Girton, L. E. and Morris, J. C. and Buckner, R. L.},
title = {{Frontal-hippocampal double dissociation between normal aging and Alzheimer's disease}},
journal = {Cerebral cortex (New York, N.Y. : 1991)},
year = {2005},
doi = {10.1093/cercor/bhh174},
pmid = {15371293},
url = {https://doi.org/10.1093/cercor/bhh174}
}
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