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68/100

✓ Peer-reviewed alzhub usefulness score 68 out of 100. Getting a diagnosis

Topic: Risk, prevention and care in population studies

Plain-language summary

Background Parkinson's disease is associated with an increased incidence of cognitive impairment and dementia. We evaluated cognitive performance (Montreal Cognitive Assessment [MoCA] scores), demographic and clinical data, APOE status, and biomarkers (CSF and dopamine transporter [DAT] imaging results). In multivariate analyses, baseline age, University of Pennsylvania Smell Inventory Test (UPSIT) scores, CSF amyloid - (Aβ 42 ) to t-tau ratio, and APOE status were associated with change in MoCA scores over time. Baseline age, MoCA and UPSIT scores, and CSF Aβ 42 to t-tau ratio were associated with MoCA score at 2 years (using a backwards p-removal threshold of 0·1). Accuracy of prediction of cognitive impairment using age alone (area under the curve 0·68, 95% CI 0·60-0·76) significantly improved by addition of clinical scores (UPSIT, Rapid Eye Movement Sleep Behaviour Disorder Screening Questionnaire [RBDSQ], Geriatric Depression Scale, and Movement Disorder Society Unified Parkinson's Disease Rating Scale motor scores; 0·76, 0·68-0·83), CSF variables (0·74, 0·68-0·81), or DAT imaging results (0·76, 0·68-0·83). In combination, the five variables showing the most significant associations with cognitive impairment (age, UPSIT, RBDSQ, CSF Aβ 42 , and caudate uptake on DAT imaging) allowed prediction of cognitive impairment at 2 years (0·80, 0·74-0·87; p=0·0003 compared to age alone).

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APA 7th

Schrag, A., Siddiqui, U. F., Anastasiou, Z., Weintraub, D., & Schott, J. M. (2017). Clinical variables and biomarkers in prediction of cognitive impairment in patients with newly diagnosed Parkinson's disease: a cohort study. The Lancet. Neurology. https://doi.org/10.1016/s1474-4422(16)30328-3

Vancouver

Schrag A, Siddiqui UF, Anastasiou Z, Weintraub D, Schott JM. Clinical variables and biomarkers in prediction of cognitive impairment in patients with newly diagnosed Parkinson's disease: a cohort study. The Lancet. Neurology. 2017. doi:10.1016/s1474-4422(16)30328-3. PMID: 27866858.

BibTeX

@article{schrag2017-27866858,
  author  = {Schrag, A. and Siddiqui, U. F. and Anastasiou, Z. and Weintraub, D. and Schott, J. M.},
  title   = {{Clinical variables and biomarkers in prediction of cognitive impairment in patients with newly diagnosed Parkinson's disease: a cohort study}},
  journal = {The Lancet. Neurology},
  year    = {2017},
  doi     = {10.1016/s1474-4422(16)30328-3},
  pmid    = {27866858},
  url     = {https://doi.org/10.1016/s1474-4422(16)30328-3}
}

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.

How to read this study

Design: this is a follow-up (cohort) study. People are observed over time and not assigned to anything, so an association can reflect other differences between groups. Look at how long follow-up lasted, how many dropped out, and whether the authors adjusted for age, education and other health conditions.
Size: the record lists 390 participants. Ask whether that is enough for the question, and who they were.
Effect: the record gives no effect size, so the summary above cannot say how large any difference was.

What the evidence grade means here

This page is graded moderate. alzhub.org assigns the grade automatically from keywords in the abstract, not from reading the paper. Moderate means the abstract mentions a cohort, case-control or longitudinal design. It can add at most 5 of the 100 points in the study score, and it is a label about design, not a verdict on whether the findings are true.

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Key findings

Background Parkinson's disease is associated with an increased incidence of cognitive impairment and dementia.
We evaluated cognitive performance (Montreal Cognitive Assessment [MoCA] scores), demographic and clinical data, APOE status, and biomarkers (CSF and dopamine transporter [DAT] imaging results).
In multivariate analyses, baseline age, University of Pennsylvania Smell Inventory Test (UPSIT) scores, CSF amyloid - (Aβ 42 ) to t-tau ratio, and APOE status were associated with change in MoCA scores over time.
Baseline age, MoCA and UPSIT scores, and CSF Aβ 42 to t-tau ratio were associated with MoCA score at 2 years (using a backwards p-removal threshold of 0·1).
Accuracy of prediction of cognitive impairment using age alone (area under the curve 0·68, 95% CI 0·60-0·76) significantly improved by addition of clinical scores (UPSIT, Rapid Eye Movement Sleep Behaviour Disorder Screening Questionnaire [RBDSQ], Geriatric Depression Scale, and Movement Disorder Society Unified Parkinson's Disease Rating Scale motor scores; 0·76, 0·68-0·83), CSF variables (0·74, 0·68-0·81), or DAT imaging results (0·76, 0·68-0·83).

Why it matters

In people newly diagnosed with Parkinson's disease, age, smell test scores, CSF amyloid to t-tau ratio, and APOE status were associated with later change in cognitive test scores. Combining five variables improved prediction of cognitive impairment at 2 years compared with using age alone, but this is about predicting cognitive impairment, not treating, curing, or preventing Alzheimer's disease.

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Study details

Study designcohort study
Participants390
Evidence strengthModerate

How this study scored 68/100

Published in a leading specialty journal, and it is a cohort study following people over time. Scored zero for effect reported and randomized / blinded because the record does not state it.

Component	Points	Why
Journal tier	9 / 10	Tier 2 — leading specialty journal (The Lancet. Neurology)
Journal's citation record	3 / 4	The Lancet Neurology: journal h-index 457 (OpenAlex, 2026-10-29)
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	2 / 5	2017 — within 10 year(s) of the newest study here
Sample size	2 / 4	390 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)
Randomized / blinded	0 / 2	No randomization or blinding stated — scores zero (not stated in the record — scored 0)
Times cited	6 / 7	Cited 429 times (OpenAlex, 2026-10-10)
Citations per year	4 / 5	39.0 citations a year over 11 year(s) since 2017
Impact for its field and year	5 / 6	Cited 20.4× the average for papers of its field and year (OpenAlex FWCI)
Cited by studies here	2 / 6	Cited by 6 other studies in this library
Still being cited	3 / 4	Cited 122 times in 2024–2026 (2026 still in progress; OpenAlex)
Senior author's track record	3 / 4	Last-listed author Jonathan M. Schott: h-index 96 (OpenAlex, whole career)
Institution's track record	2 / 3	University College London: institution h-index 2,029 (OpenAlex)
Multicenter collaboration	2 / 3	OpenAlex lists 5 institution(s) in 2 countries
Indexed in PubMed	2 / 2	Indexed in PubMed (PMID 27866858)
Free to read	0 / 2	Behind a paywall — scores zero
Total	68 / 100	—

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