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Cognitive impairment in incident, untreated Parkinson disease: the Norwegian ParkWest study
Aarsland D, Brønnick K, Larsen JP, Tysnes OB, Alves G, Norwegian ParkWest Study Group.. Neurology, 2008-11-19
Topic: Brain imaging, connectivity and assessment
Plain-language summary
Background Little is known regarding the cognitive impairment in subjects with early, drug-naïve Parkinson disease (PD). The aim of this study was to explore the proportion with mild cognitive impairment (MCI) and subtypes in an incidence cohort of untreated PD in Southern and Western Norway. Methods A total of 196 non-demented, drug-naive patients who were recruited after an extensive search of all new cases of PD in the area and 201 healthy control subjects completed a battery of neuropsychological tests of verbal memory, visuospatial, and attentional-executive functioning. Subjects were classified as MCI if the age- and education-corrected z-score was falling 1.5 standard deviations below the mean for at least one of the cognitive domains. Results The PD group was more impaired on all neuropsychological tests than controls, but the effect sizes were small. The largest effect size was found for verbal memory. A total of 18.9% of the patients with PD were classified as MCI, with a relative risk of 2.1 (1.2-3.6) in PD compared to the control group. Patients with PD with and without MCI did not differ significantly regarding demographic and motor features. Among PD-MCI patients, nearly two-thirds had a non-amnestic MCI subtype, and one third had an amnestic MCI subtype. Conclusions The findings demonstrate a twofold increase in the proportion with cognitive impairment in subjects with early, untreated Parkinson disease (PD) compared to controls. This has implications for diagnosis and management of PD. AD = Alzheimer disease; aMCI-MD = amnestic multiple-domain MCI; aMCI-SD = amnestic single-domain MCI; CVLT-2 = California Verbal Learning Test II; IQCode = Informant Questionnaire on Cognitive decline in the elderly; MADRS = Montgomery and Aasberg Depression Rating Scale; MCI = mild cognitive impairment; MMSE = Mini-Mental State Examination; naMCI-MD = non-amnestic multiple-domain MCI; naMCI-SD = non-amnestic single-domain MCI; PD = Parkinson disease; RR = relative risks; UPDRS = Unified Parkinson's Disease Rating Scale; VOSP = Visual Object and Space Perception Battery.
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APA 7th
Aarsland, D., Brønnick, K., Larsen, J. P., Tysnes, O. B., Alves, G., & Norwegian ParkWest Study Group. (2009). Cognitive impairment in incident, untreated Parkinson disease: the Norwegian ParkWest study. Neurology. https://doi.org/10.1212/01.wnl.0000338632.00552.cb
Vancouver
Aarsland D, Brønnick K, Larsen JP, Tysnes OB, Alves G, Norwegian ParkWest Study Group. Cognitive impairment in incident, untreated Parkinson disease: the Norwegian ParkWest study. Neurology. 2009. doi:10.1212/01.wnl.0000338632.00552.cb. PMID: 19020293.
BibTeX
@article{aarsland2009-19020293,
author = {Aarsland, D. and Brønnick, K. and Larsen, J. P. and Tysnes, O. B. and Alves, G. and {Norwegian ParkWest Study Group}},
title = {{Cognitive impairment in incident, untreated Parkinson disease: the Norwegian ParkWest study}},
journal = {Neurology},
year = {2009},
doi = {10.1212/01.wnl.0000338632.00552.cb},
pmid = {19020293},
url = {https://doi.org/10.1212/01.wnl.0000338632.00552.cb}
}
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Key findings
- Results The PD group was more impaired on all neuropsychological tests than controls, but the effect sizes were small.
- A total of 18.9% of the patients with PD were classified as MCI, with a relative risk of 2.1 (1.2-3.6) in PD compared to the control group.
- Patients with PD with and without MCI did not differ significantly regarding demographic and motor features.
- Conclusions The findings demonstrate a twofold increase in the proportion with cognitive impairment in subjects with early, untreated Parkinson disease (PD) compared to controls.
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Study details
- Participants196
- Effect size18.9%
- Evidence strengthModerate
How this study scored 55/100
Published in a leading specialty journal. Scored zero for study design and randomized / 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 multicenter collaboration, so those were left out: it earned 32 of the 58 points we could judge it on, which is 55 out of 100.
| Component | Points | Why |
|---|---|---|
| Journal tier | 9 / 10 | Tier 2 — leading specialty journal (Neurology) |
| 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 | 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 | 1 / 5 | 2009 — within 20 year(s) of the newest study here |
| Sample size | 2 / 4 | 196 participants |
| Effect reported | 2 / 3 | Effect reported as a number, without an interval or test |
| 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 | — / 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 |
| Multicenter collaboration | — / 3 | Institutions not listed — left out of this score |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 19020293) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Points | 32 / 58 | Scored on 11 of 20 parts. We have no data for the rest, so they are left out: 32 of the 58 points we could judge it on is 55 out of 100. |
| Total | 55 / 100 | — |
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