Home › Research › Brain scans and imaging
Declarative memory impairments in Alzheimer's disease and semantic dementia
Nestor PJ, Fryer TD, Hodges JR.. NeuroImage, 2005-11-21
Topic: Risk, prevention and care in population studies
Semantic dementia (SD) and Alzheimer's disease (AD) are both disorders in which early pathology affects the temporal lobe yet they produce distinct syndromes of declarative memory impairment-loss of established semantic knowledge with relatively preserved episodic memory in the former and the converse in the latter. Groups with mild SD and mild AD who showed a double dissociation in these two aspects of declarative memory were studied-the SD group's episodic memory and the AD group's semantic knowledge each being comparable to controls. Positron emission tomography and volumetric magnetic resonance imaging were used to map deficits in regional cerebral metabolic rate and mesial temporal lobe (MTL) atrophy, respectively. Episodic memory impairment in AD was associated with dysfunction of an integrated network (mesial temporal lobe, mamillary bodies, dorso-mesial thalamus and posterior cingulate). Semantic memory impairment in SD was associated with bilateral rostral temporal lobe hypometabolism. The SD group had comparable MTL atrophy and hypometabolism to that found in AD but the remainder of their limbic-diencephalic network was preserved suggesting that the latter explains their ability to acquire new episodic memories. The results challenge the view that amnesia in early AD can be explained by the degree of MTL damage alone while showing that semantic impairment can occur with damage restricted to the rostral temporal lobes.
Cite this study APA, Vancouver, BibTeX · download .bib or .ris
APA 7th
Nestor, P. J., Fryer, T. D., & Hodges, JR. (2006). Declarative memory impairments in Alzheimer's disease and semantic dementia. NeuroImage. https://doi.org/10.1016/j.neuroimage.2005.10.008
Vancouver
Nestor PJ, Fryer TD, Hodges JR. Declarative memory impairments in Alzheimer's disease and semantic dementia. NeuroImage. 2006. doi:10.1016/j.neuroimage.2005.10.008. PMID: 16300967.
BibTeX
@article{nestor2006-16300967,
author = {Nestor, P. J. and Fryer, T. D. and Hodges, JR.},
title = {{Declarative memory impairments in Alzheimer's disease and semantic dementia}},
journal = {NeuroImage},
year = {2006},
doi = {10.1016/j.neuroimage.2005.10.008},
pmid = {16300967},
url = {https://doi.org/10.1016/j.neuroimage.2005.10.008}
}
Built from the record alzhub holds for this paper, not looked up. Volume, issue and page numbers are not held in the record. Check the citation against the original before you use it.
Key findings
- Episodic memory impairment in AD was associated with dysfunction of an integrated network (mesial temporal lobe, mamillary bodies, dorso-mesial thalamus and posterior cingulate).
- Semantic memory impairment in SD was associated with bilateral rostral temporal lobe hypometabolism.
- The SD group had comparable MTL atrophy and hypometabolism to that found in AD but the remainder of their limbic-diencephalic network was preserved suggesting that the latter explains their ability to acquire new episodic memories.
- The results challenge the view that amnesia in early AD can be explained by the degree of MTL damage alone while showing that semantic impairment can occur with damage restricted to the rostral temporal lobes.
New to this subject? Start with our plain-English guide: Brain scans & tests →
Study details
- Evidence strengthLow
How this study scored 36/100
Published in a peer-reviewed journal. Scored zero for study design, sample size, effect reported, studied in people 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 21 of the 58 points we could judge it on, which is 36 out of 100.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (NeuroImage) |
| 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 | 2006 — older than 20 years, still counted |
| Sample size | 0 / 4 | Participant count not stated — scores zero (not stated in the record — scored 0) |
| Effect reported | 0 / 3 | No effect size reported — scores zero (not stated in the record — scored 0) |
| Studied in people | 0 / 3 | Not stated whether this was studied in people — scores zero (not stated in the record — scored 0) |
| 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 16300967) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Points | 21 / 58 | Scored on 11 of 20 parts. We have no data for the rest, so they are left out: 21 of the 58 points we could judge it on is 36 out of 100. |
| Total | 36 / 100 | — |
What each of these 20 components measures, and what this score is not →
Read the original
Free copy unknown: no free-copy check has an answer for this record yet. That does not mean it is paywalled.
Related studies in Brain scans and imaging
Also tagged “declarative-memory”
2 studies in the library carry the topic tag “declarative-memory”; these are this study's neighbours in a fixed, alphabetical-by-hash tour of them, not the closest in content. All 2 tagged studies.