Definition and research guide
This page combines a MeSH definition, publication statistics and selected research abstracts. It is a starting point for reading the literature, not a medical textbook or a systematic evidence review.
Content available: 3 complete abstracts (490 words), 9 references. Full article text is not stored or reproduced here; follow the PMID, DOI or PMC links to read the original sources and their access terms.
Definition
An acquired organic mental disorder with loss of intellectual abilities of sufficient severity to interfere with social or occupational functioning. The dysfunction is multifaceted and involves memory, behavior, personality, judgment, attention, spatial relations, language, abstract thought, and other executive functions. The intellectual decline is usually progressive, and initially spares the level of consciousness.
Definition: NLM Medical Subject Headings (MeSH) scope note (Public domain (U.S. National Library of Medicine); attribution requested). View the MeSH record.
Also known as: Dementias; Amentia; Amentias; Senile Paranoid Dementia; Dementias, Senile Paranoid; Paranoid Dementia, Senile; Paranoid Dementias, Senile; Senile Paranoid Dementias.
Where it fits in the MeSH classification
- Broader topics
- Brain Diseases; Neurocognitive Disorders
- Narrower topics
- AIDS Dementia Complex; Alzheimer Disease; Aphasia, Primary Progressive; Creutzfeldt-Jakob Syndrome; Dementia, Vascular; Diffuse Neurofibrillary Tangles with Calcification; Frontotemporal Lobar Degeneration; Huntington Disease; Kluver-Bucy Syndrome; Lewy Body Disease; Mixed Dementias
- See also
- Tauopathies
Research landscape
PubMed indexes 245,116 records tagged with the MeSH heading “Dementia” (counts retrieved 2026-10-29). 78,408 of them (32.0%) were published from 2020 onward, and the busiest period so far is 2020 onward with 78,408 records.
Reviews account for 47,736 records (19.5%) and meta-analyses for 3,480. Randomized controlled trials number 5,041 (2.1%) as a share of all records on the topic.
Show the data
| Period | Records |
|---|---|
| through 1999 | 41,350 |
| 2000-2009 | 47,883 |
| 2010-2019 | 77,475 |
| 2020 onward | 78,408 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 47,736 | 19.5% |
| Meta-analyses | 3,480 | 1.4% |
| Randomized controlled trials | 5,041 | 2.1% |
Method: PubMed query "Dementia"[MeSH Terms] with publication-type and date filters, retrieved 2026-10-29.
Reading the evidence in neuroscience
Neuroscience draws on tools with different strengths: cellular and animal work can manipulate circuits directly, while human imaging and electrophysiology observe the living brain at lower resolution. Small imaging studies are prone to false positives, and findings in animals do not always carry over to people. Clinical neurology and psychiatry rely on trials and cohort studies whose outcomes are often symptom scales. Check the species, the sample size, how the outcome was measured and whether results were replicated.
Evidence from open-access studies
These open-access studies come from PubMed’s best-match results for this heading (papers whose main topic it is), ranked here by citation count, with one recent addition. Each abstract is reproduced in full under its recorded open licence so that you can read the authors’ own words. They illustrate the literature; they are not a systematic summary of it. Citation counts measure attention, not reliability or clinical benefit.
| Study / authors | Year | Source label / design | Europe PMC citations | Licence / source |
|---|---|---|---|---|
| Speech clocks decode dementia phenotypes, social exposome, and biological aging | 2026 | Research article Design not recorded in structured metadata | 1 | cc by PMID 42814823 · DOI · PMC13626050 |
| Definitions of Person-Centeredness for Persons With Dementia in the United States: A Scoping Review | 2026 | Research article Design not recorded in structured metadata | 1 | cc by PMID 42708495 · DOI · PMC13556327 |
| Alterations of gut microbiota in Down syndrome and their association with Alzheimer's disease | 2026 | Research article Design not recorded in structured metadata | 1 | cc by PMID 42712102 · DOI · PMC13554992 |
Speech clocks decode dementia phenotypes, social exposome, and biological aging [1]
Abstract reading summary — source excerpts
- Opening excerpt
- Biological aging clocks offer estimations of aging and dementia, yet scalability is limited.
- Closing excerpt
- These results indicate that SAGs capture cross-sectional multilevel aging-related variation and may offer a scalable, culturally adaptable, low-cost biomarker candidate for research in underrepresented global settings.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (178 words)
Biological aging clocks offer estimations of aging and dementia, yet scalability is limited. We introduce a large-scale, cross-national speech clock derived from 2928 individuals across five Latin American countries, spanning healthy controls (HCs), mild cognitive impairment (MCI), Alzheimer's disease (AD), and non-language/language-dominant frontotemporal dementia (nldFTD/ldFTD). Multimodal acoustic and linguistic features were trained with supervised models to estimate chronological age, generating speech age gaps (SAGs) as cross-sectional markers of deviations from chronological age, with positive values interpreted as relatively older-appearing speech profiles. SAGs differentiated diagnostic groups (HCs < patient groups, with AD < nldFTD < ldFTD). This pattern was associated with clinical/cognitive domains. SAGs correlated with phosphorylated tau (p-Tau217) in AD and social exposome in HCs and AD. Brain clocks (structural/functional/combined) were associated with SAG in AD, nldFTD, and ldFTD. Epigenetic age correlated with SAGs in HCs and AD across Hannum, Retroclock, and OMICmAge, whereas ldFTD associations were limited to Retroclock and OMICmAge. These results indicate that SAGs capture cross-sectional multilevel aging-related variation and may offer a scalable, culturally adaptable, low-cost biomarker candidate for research in underrepresented global settings.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 42814823 · DOI · PMC13626050
Definitions of Person-Centeredness for Persons With Dementia in the United States: A Scoping Review [2]
Abstract reading summary — source excerpts
- Opening excerpt
- Person-centeredness first emerged as a concept in dementia care in the 1980s.
- Closing excerpt
- , organizations and systems), is recommended.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (150 words)
Person-centeredness first emerged as a concept in dementia care in the 1980s. Nearly 40 years later, it has no universal definition, which limits operationalization and implementation of care and supportive services, measures, interventions, policy, and regulation for people with dementia. Thus, a scoping review of the current definitions of person-centeredness in US dementia care was conducted. Of the 71 included studies, there was considerable variability in elements/themes, complexity, and cited theories; the most common themes were needs and preferences, relationships, and personhood, all of which were present in at least half of the studies' definitions. Importantly, more than 150 articles that were reviewed did not contain a definition, despite including the term in their titles or abstracts. Further investigation in pursuit of a more nuanced conceptualization of person-centeredness that includes these key themes, while also addressing concerns about applicability to diverse cultures and contexts (e.g., organizations and systems), is recommended.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 42708495 · DOI · PMC13556327
Alterations of gut microbiota in Down syndrome and their association with Alzheimer's disease [3]
Abstract reading summary — source excerpts
- Opening excerpt
- IntroductionAdults with Down syndrome (DS) have a higher risk of Alzheimer's disease (AD).
- Closing excerpt
- DiscussionAdults with DS display AD-associated changes in GM partially resembling those reported previously in euploid AD patients.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (162 words)
IntroductionAdults with Down syndrome (DS) have a higher risk of Alzheimer's disease (AD). As gut microbiota (GM) alterations have been reported in AD, we investigated their association with cognitive decline and plasma AD biomarkers in DS.MethodsFecal and plasma samples were collected from 58 adults with DS (21-75 years) and 30 euploid controls (CTRL; 25-83 years). GM was profiled using 16S rRNA sequencing, filtering low prevalent taxa. Major neurocognitive disorder (NcD) was diagnosed with Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) criteria. Plasma levels of phosphorylated tau 181 (p-tau181), neurofilament light chain (NfL), and glial fibrillary acidic protein (GFAP) were measured using Simoa.ResultsDS showed no changes in overall microbial diversity compared to CTRL, but genera including UBA1819 and Intestinibacter were altered. Specific genera showed changes in DS with NcD, like Alistipes (increased) and Roseburia (decreased), with the latter negatively associated with plasma AD biomarkers.DiscussionAdults with DS display AD-associated changes in GM partially resembling those reported previously in euploid AD patients.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 42712102 · DOI · PMC13554992
Key reviews and meta-analyses
The most cited review-type papers among PubMed’s best-match results for this heading, listed with bibliographic details only. Follow the links for the full text and access terms.
- Research article Cardioprotective Glucose-Lowering Agents and Dementia Risk: A Systematic Review and Meta-Analysis [4]
- Research article Blood phosphorylated tau for the diagnosis of Alzheimer's disease: a systematic review and meta-analysis [5]
- Research article Sleep disorders increase the risk of dementia, Alzheimer's disease, and cognitive decline: a meta-analysis [6]
- Research article Amyloid-beta-targeting monoclonal antibodies for people with mild cognitive impairment or mild dementia due to Alzheimer's disease [7]
- Research article Time to Diagnosis in Dementia: A Systematic Review With Meta-Analysis [8]
- Research article Environmental risk factors for all-cause dementia, Alzheimer's disease dementia, vascular dementia, and mild cognitive impairment: An umbrella review and meta-analysis [9]
References
- Hernandez H, Pedraza LK, Santamaria-Garcia H, Moguilner S, Legaz A, Prado P, et al.. Speech clocks decode dementia phenotypes, social exposome, and biological aging. . 2026. PMID 42814823 · DOI · PMC13626050
- Efird-Green L, Jones LB, Fazio S, Zimmerman S. Definitions of Person-Centeredness for Persons With Dementia in the United States: A Scoping Review. . 2026. PMID 42708495 · DOI · PMC13556327
- Pellegrini C, Ravaioli F, De Fanti S, Siliquini A, Sala C, Rochat M, et al.. Alterations of gut microbiota in Down syndrome and their association with Alzheimer's disease. . 2026. PMID 42712102 · DOI · PMC13554992
- Seminer A, Mulihano A, O'Brien C, Krewer F, Costello M, Judge C, et al.. Cardioprotective Glucose-Lowering Agents and Dementia Risk: A Systematic Review and Meta-Analysis. JAMA Neurol. 2025. PMID 40193122 · DOI · PMC11976645
- Therriault J, Brum WS, Trudel L, Macedo AC, Bitencourt FV, Martins-Pfeifer CC, et al.. Blood phosphorylated tau for the diagnosis of Alzheimer's disease: a systematic review and meta-analysis. Lancet Neurol. 2025. PMID 40818474 · DOI
- Ungvari Z, Fekete M, Lehoczki A, Munkácsy G, Fekete JT, Zábó V, et al.. Sleep disorders increase the risk of dementia, Alzheimer's disease, and cognitive decline: a meta-analysis. Geroscience. 2025. PMID 40214959 · DOI · PMC12181552
- Nonino F, Minozzi S, Sambati L, Del Giovane C, Baldin E, Bassi MC, et al.. Amyloid-beta-targeting monoclonal antibodies for people with mild cognitive impairment or mild dementia due to Alzheimer's disease. Cochrane Database Syst Rev. 2026. PMID 41985900 · DOI · PMC13082890
- Kusoro O, Roche M, Del-Pino-Casado R, Leung P, Orgeta V. Time to Diagnosis in Dementia: A Systematic Review With Meta-Analysis. Int J Geriatr Psychiatry. 2025. PMID 40716451 · DOI · PMC12300619
- Jones A, Ali MU, Mayhew A, Aryal K, Correia RH, Dash D, et al.. Environmental risk factors for all-cause dementia, Alzheimer's disease dementia, vascular dementia, and mild cognitive impairment: An umbrella review and meta-analysis. Environ Res. 2025. PMID 39889875 · DOI
About this article
- Sources
- NLM Medical Subject Headings (definition, synonyms); NCBI PubMed (counts, identifiers); Europe PMC (open-access abstracts and citation counts).
- Verification
- Every reference was resolved against PubMed on 2026-10-31; title, year and DOI matched.
- Review state
- automated source verified; no human expert review has been recorded yet.
- Version
- 1, last updated 2026-10-29.
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Evidence strength
EvidenceHelix's computed view of the study designs behind this topic: how common meta-analyses, randomized trials and reviews are, how recent the literature is, and a plain-language reading. It describes the design mix of the literature. It is not a quality appraisal of any study, and it is not medical advice.