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Cognitive function in early Parkinson's disease: a population-based study
Elgh E, Domellöf M, Linder J, Edström M, Stenlund H, Forsgren L.. European journal of neurology, 2009-06-15
Topic: Risk, prevention and care in population studies
Background and purpose The study aims to describe the frequency, pattern and determinants of cognitive function in patients with newly diagnosed Parkinson's disease (PD); to compare patients with impaired cognition to patients with intact cognition; and to compare to matched healthy controls. Methods Patients were identified in a longitudinal population based study of idiopathic non-drug induced parkinsonism. Eighty-eight newly diagnosed patients with PD and no dementia were included during a four year period. The patients and 30 age- and sex-matched healthy control subjects underwent a comprehensive neuropsychological assessment. Results Patients performed significantly worse than healthy controls in a majority of neuropsychological tests. Test results in attention, psychomotor function, episodic memory (free recall), executive function and category fluency were significantly lower in the patient group. Comparison with normative data revealed that 30% of the patients had deficits in > or =1 cognitive domain (episodic memory, executive function and verbal function). Seventy per cent of the patients had normal performance. Unified Parkinson's Disease Rating Scale (UPDRS) III sub scores; speech, facial expression, rigidity and bradykinesia were significantly higher, and disease duration shorter amongst the cognitively impaired than amongst the cognitively intact patients. Tremor showed no difference. Education level was an independent predictor of dysfunction in patients with > or =2 cognitive domains affected. Conclusion Cognitive dysfunction is common in untreated patients in early PD, affecting attention, psychomotor function, episodic memory, executive function and category fluency. Education level was an independent predictor of severe cognitive dysfunction.
Key findings
- Results Patients performed significantly worse than healthy controls in a majority of neuropsychological tests.
- Test results in attention, psychomotor function, episodic memory (free recall), executive function and category fluency were significantly lower in the patient group.
- Comparison with normative data revealed that 30% of the patients had deficits in > or =1 cognitive domain (episodic memory, executive function and verbal function).
- Unified Parkinson's Disease Rating Scale (UPDRS) III sub scores; speech, facial expression, rigidity and bradykinesia were significantly higher, and disease duration shorter amongst the cognitively impaired than amongst the cognitively intact patients.
Why it matters
This population-based study found that 30% of newly diagnosed Parkinson's disease patients had deficits in at least one cognitive domain, while 70% performed normally. It is about cognitive function in early Parkinson's disease, not about treating, curing or preventing Alzheimer's disease.
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Study details
- Study designlongitudinal study
- Evidence strengthModerate
How this study scored 50/100
Published in a peer-reviewed journal, and it is a longitudinal study following the same people over time. Scored zero for sample size, effect reported, studied in people and randomised / blinded because the record does not state it.
| Component | Points | Why |
|---|---|---|
| Journal tier | 7 / 10 | Tier 3 — peer-reviewed journal (European journal of neurology) |
| Journal's citation record | 2 / 4 | European Journal of Neurology: journal h-index 181 (OpenAlex, 2026-10-29) |
| Study design | 7 / 12 | A longitudinal study following the same 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 | 1 / 5 | 2009 — within 20 year(s) of the newest study here |
| 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 | 5 / 7 | Cited 248 times (OpenAlex, 2026-10-10) |
| Citations per year | 3 / 5 | 13.1 citations a year over 19 year(s) since 2009 |
| Impact for its field and year | 4 / 6 | Cited 10.5× the average for papers of its field and year (OpenAlex FWCI) |
| Cited by studies here | 2 / 6 | Cited by 3 other studies in this library |
| Still being cited | 2 / 4 | Cited 21 times in 2024–2026 (2026 still in progress; OpenAlex) |
| Senior author's track record | 1 / 4 | Last-listed author Lillemor Forsgren: h-index 8 (OpenAlex, whole career) |
| Institution's track record | 1 / 3 | Umeå University: institution h-index 813 (OpenAlex) |
| Multi-centre collaboration | 0 / 3 | OpenAlex lists 1 institution(s) in 1 country — scores zero (affiliation lists can be incomplete) |
| Indexed in PubMed | 2 / 2 | Indexed in PubMed (PMID 19538208) |
| Free to read | 0 / 2 | Behind a paywall — scores zero |
| Total | 50 / 100 | — |
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Read the original
May need a subscription OpenAlex found no free copy of the full text (checked 6 Feb 1020), so the publisher may charge for it. The PubMed abstract is free.
Cite this study APA, Vancouver, BibTeX · download .bib or .ris
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.
APA 7th
Elgh, E., Domellöf, M., Linder, J., Edström, M., Stenlund, H., & Forsgren, L. (2009). Cognitive function in early Parkinson's disease: a population-based study. European journal of neurology. https://doi.org/10.1111/j.1468-1331.2009.02707.x
Vancouver
Elgh E, Domellöf M, Linder J, Edström M, Stenlund H, Forsgren L. Cognitive function in early Parkinson's disease: a population-based study. European journal of neurology. 2009. doi:10.1111/j.1468-1331.2009.02707.x. PMID: 19538208.
BibTeX
@article{elgh2009-19538208,
author = {Elgh, E. and Domellöf, M. and Linder, J. and Edström, M. and Stenlund, H. and Forsgren, L.},
title = {{Cognitive function in early Parkinson's disease: a population-based study}},
journal = {European journal of neurology},
year = {2009},
doi = {10.1111/j.1468-1331.2009.02707.x},
pmid = {19538208},
url = {https://doi.org/10.1111/j.1468-1331.2009.02707.x}
}
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