Cited by 386Dementia and Cognitive Impairment ResearchAlzheimer's disease research and treatmentsNeuroinflammation and Neurodegeneration Mechanisms

Clinical, imaging, and pathological heterogeneity of the Alzheimer's disease syndrome

Open access
Lam, Benjamin, Masellis, Mario, Freedman, Morris, Stuss, Donald T, Black, Sandra E·2013·Alzheimer's Research & Therapy

Abstract

With increasing knowledge of clinical in vivo biomarkers and the pathological intricacies of Alzheimer's disease (AD), nosology is evolving. Harmonized consensus criteria that emphasize prototypic illness continue to develop to achieve diagnostic clarity for treatment decisions and clinical trials. However, it is clear that AD is clinically heterogeneous in presentation and progression, demonstrating variable topographic distributions of atrophy and hypometabolism/hypoperfusion. AD furthermore often keeps company with other conditions that may further nuance clinical expression, such as synucleinopathy exacerbating executive and visuospatial dysfunction and vascular pathologies (particularly small vessel disease that is increasingly ubiquitous with human aging) accentuating frontal-dysexecutive symptomatology. That some of these atypical clinical patterns recur may imply the existence of distinct AD variants. For example, focal temporal lobe dysfunction is associated with a pure amnestic syndrome, very slow decline, with atrophy and neurofibrillary tangles limited largely to the medial temporal region including the entorhinal cortex. Left parietal atrophy and/or hypometabolism/hypoperfusion are associated with language symptoms, younger age of onset, and faster rate of decline - a potential 'language variant' of AD. Conversely, the same pattern but predominantly affecting the right parietal lobe is associated with a similar syndrome but with visuospatial symptoms replacing impaired language function. Finally, the extremely rare frontal variant is associated with executive dysfunction out of keeping with degree of memory decline and may have prominent behavioural symptoms. Genotypic differences may underlie some of these subtypes; for example, absence of apolipoprotein E e4 is often associated with atypicality in younger onset AD. Understanding the mechanisms behind this variability merits further investigation, informed by recent advances in imaging techniques, biomarker assays, and quantitative pathological methods, in conjunction with standardized clinical, functional, neuropsychological and neurobehavioral evaluations. Such an understanding is needed to facilitate 'personalized AD medicine', and eventually allow for clinical trials targeting specific AD subtypes. Although the focus legitimately remains on prototypic illness, continuing efforts to develop disease-modifying therapies should not exclude the rarer AD subtypes and common comorbid presentations, as is currently often the case. Only by treating them as well can we address the full burden of this devastating dementia syndrome.

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Integrity signals

Registry

Crossref · 10.1186/alzrt155

Cites

97 of 97 references verified0 citation errors · 0 not checkable

Statistics

Claims the paper makes

The claims and statistics of this paper haven’t been checked yet.

Run the check — free, no account needed. It reads the open-access text and checks the sources it cites.

A few free checks a day · papers already verified open instantly · results are public

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • CNS diseases often present with a wide range of symptoms that vary among individuals, making it challenging to develop standardized diagnostic criteria and treatment approaches.

    “CNS diseases often present with a wide range of symptoms that vary among individuals. This heterogeneity makes it challenging to develop standardized diagnostic criteria and treatment approaches [21, 22].”

    From Extracellular vesicles as nanotheranostic platforms for targeted neurological disorder interventions (2024) · cites this paper as [22]

    The Introduction describes variation in symptoms and progression among Alzheimer’s disease subtypes. In Future directions (Translational implications: diagnosis and therapy), the paper says phenotypic variation may affect treatment response and that unclear diagnostic criteria for early-onset subtypes hamper clinical-trial implementation. These passages support the point for Alzheimer’s disease, but not the broader claim about CNS diseases generally. (LLM, conf=0.86)

    Experimental — accuracy not yet measured
  • fvAD accounts for approximately 2-3% of AD.

    “Some studies have suggested that fvAD accounts for approximately 2–3% of AD, [1, 2]”

    From Diagnosing the frontal variant of Alzheimer’s disease: a clinician’s yellow brick road (2017) · cites this paper as [2]

    The ‘Frontal (executive) variant’ section reports 2 cases among 100 AD cases in one series, consistent with the lower end of the claimed range. It also reports 3 among 63 in another series—about 5%—and does not establish that fvAD accounts for 2–3% of AD overall. (LLM, conf=0.84)

    Experimental — accuracy not yet measured
  • At 15 months, intense pathology is present in the TG mice, including Aβ plaques, tau, myelin damage, axonal degeneration, axonal loss, and an inflammatory reaction with reactive microglia and astrocytes.

    “At 15 months, intense pathology is present in the TG mice, which includes not only Aβ plaques and tau, but also confounding factors, such as, myelin damage, axonal degeneration, axonal loss, and an inflammatory reaction with reactive microglia and astrocytes [29, 30].”

    From Brain microstructure abnormalities in the 3xTg-AD mouse – A diffusion MRI and morphology correlation study (2022) · cites this paper as [29]

    The Disease topography section discusses plaques and tau-related pathology in human Alzheimer’s disease, while the white matter hyperintensities section discusses human imaging findings. Searches for 15-month-old TG mice, myelin and axonal damage, and reactive microglia and astrocytes found no passage addressing the claimed mouse pathology. (LLM, conf=0.76)

    Experimental — accuracy not yet measured

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

The self-check needs the paper’s full text.

Cites

Flagged first, then by citations

1 of the 98 references couldn’t be matched to a known paper.

Cited by

Sorted by citations

Authors
Lam, B., Masellis, M., Freedman, M., Stuss, D. T., & Black, S. E.
Affiliations
  • Sunnybrook Health Science Centre (CA)
  • Mount Sinai Hospital (CA)
Corresponding author
Lam, Benjamin
Venue
Alzheimer's Research & Therapy
Published
2013
Volume
5
Issue
1
Pages
1
ISSN
1758-9193 (ISSN-L)
OpenAlex
W2165612785
Cited by
386
References
98
Citations by year
2026: 25 · 2025: 37 · 2024: 35 · 2023: 41 · 2022: 38 · 2021: 40 · 2020: 42 · 2019: 34 · 2018: 23 · 2017: 27 · 2016: 20 · 2015: 15 · 2014: 4 · 2013: 4
FWCI
1.96
Type
journal article
Language
en
Open access
Locations
  • Alzheimer s Research & Therapy (publishedVersion)
  • Europe PMC (PubMed Central) (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
Funders
  • Sunnybrook Foundation
  • University of Toronto
  • Morris Kerzner Memorial Fund
  • Canadian Institutes of Health Research (13129, MT13129)
Topics
  • Health Sciences › Medicine › Psychiatry and Mental health › Dementia and Cognitive Impairment Research
  • Health Sciences › Medicine › Physiology › Alzheimer's disease research and treatments
  • Life Sciences › Neuroscience › Neurology › Neuroinflammation and Neurodegeneration Mechanisms
Keywords
Alzheimer's disease, clinical heterogeneity, disease classification, parietal lobe atrophy, synucleinopathies, cerebral small vessel disease, executive dysfunction, apolipoprotein E e4, neuroimaging biomarkers, neurofibrillary tangles, entorhinal cortex, personalized medicine, disease-modifying therapy

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

Are you an author, or do you see a problem with this page? Request a review