Alison Yarnall

Alison Yarnall


Research Focus & Metrics

Academic Career Length

16Years (2011-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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28 January 2014 in Neurology
Verified
Journal Article
Open access
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AYAlison Yarnall
Alison Yarnall
DBDavid P. Breen
David P. Breen
GDGordon W. Duncan
Gordon W. Duncan
TKTien K. Khoo
Tien K. Khoo
SCShirley Y. Coleman
Shirley Y. Coleman
DBDavid J. Burn
David J. Burn
Objective: To describe the frequency of mild cognitive impairment (MCI) in Parkinson disease (PD) in a cohort of newly diagnosed incident PD cases and the associations with a panel of biomarkers. Methods: Between June 2009 and December 2011, 219 subjects with PD and 99 age-matched controls participated in clinical and neuropsychological assessments as part of a longitudinal observational study. Consenting individuals underwent structural MRI, lumbar puncture, and genotyping for common variants of COMT, MAPT, SNCA, BuChE, EGF, and APOE. PD-MCI was defined with reference to the new Movement Disorder Society criteria. Results: The frequency of PD-MCI was 42.5% using level 2 criteria at 1.5 SDs below normative values. Memory impairment was the most common domain affected, with 15.1% impaired at 1.5 SDs. Depression scores were significantly higher in those with PD-MCI than the cognitively normal PD group. A significant correlation was found between visual Pattern Recognition Memory and cerebrospinal β-amyloid 1–42 levels (β standardized coefficient = 0.350; p = 0.008) after controlling for age and education in a linear regression model, with lower β-amyloid 1–42 and 1–40 levels observed in those with PD-MCI. Voxel-based morphometry did not reveal any areas of significant gray matter loss in participants with PD-MCI compared with controls, and no specific genotype was associated with PD-MCI at the 1.5-SD threshold. Conclusions: In a large cohort of newly diagnosed PD participants, PD-MCI is common and significantly correlates with lower cerebrospinal β-amyloid 1–42 and 1–40 levels. Future longitudinal studies should enable us to determine those measures predictive of cognitive decline.

15 January 2013 in Neurology
Verified
Journal Article
Closed access
PDF file
TKTien K Khoo
Tien K Khoo
AYAlison Yarnall
Alison Yarnall
GDGordon W Duncan
Gordon W Duncan
SCShirley Coleman
Shirley Coleman
JOJohn O'Brien
John O'Brien
DBDavid J Burn
David J Burn
Objective: Nonmotor symptoms (NMS) are common in patients with established Parkinson disease (PD) but their frequency in early PD has not been extensively studied. Our aim was to determine the frequency of NMS in a cohort of patients with newly diagnosed PD. Methods: A total of 159 patients with early PD and 99 healthy controls participated in this study. NMS were screened for using the Nonmotor Symptom Questionnaire. Other assessments included measures of motor disability (Movement Disorders Society–revised Unified Parkinson9s Disease Rating Scale [MDS-UPDRS]), disease severity (Hoehn & Yahr staging), depression (Geriatric Depression Scale), and global cognitive function (Mini-Mental State Examination and Montreal Cognitive Assessment). Results: The PD group reported a significantly greater number of NMS compared with controls (8.4 [4.3] vs 2.8 [2.6]). In the PD group, the most commonly experienced NMS were excessive saliva, forgetfulness, urinary urgency, hyposmia, and constipation. Patients with higher MDS-UPDRS III scores and those with the postural instability gait subtype experienced a greater number of NMS. Conclusion: NMS are common in early PD and reflect the multisystem nature of the disorder. Even in the earliest stages of PD, NMS may be detrimental to patients9 functional status and sense of well-being.

7 October 2013 in Movement Disorders
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Journal Article
Closed access
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GDGordon W Duncan
Gordon W Duncan
TKTien K Khoo
Tien K Khoo
AYAlison Yarnall
Alison Yarnall
JOJohn O'Brien
John O'Brien
SCShirley Y Coleman
Shirley Y Coleman
DBDavid J Burn
David J Burn

21 March 2016 in Movement Disorders
Verified
Journal Article
Open access
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CWCaroline H. Williams‐Gray
Caroline H. Williams‐Gray
RWRuwani Wijeyekoon
Ruwani Wijeyekoon
AYAlison Yarnall
Alison Yarnall
RLRachael A. Lawson
Rachael A. Lawson
DBDavid P. Breen
David P. Breen
OGon behalf of the ICICLE‐PD study group
on behalf of the ICICLE‐PD study group
Background: The immune system is a promising therapeutic target for disease modification in Parkinson's disease (PD), but appropriate immune‐related biomarkers must be identified to allow patient stratification for trials and tracking of therapeutic effects. The objective of this study was to investigate whether immune markers in peripheral blood are candidate prognostic biomarkers through determining their relationship with disease progression in PD.Methods: Serum samples were collected in incident PD cases and age‐matched controls. Subjects were clinically evaluated at baseline and 18 and 36 months. Ten cytokines and C‐reactive protein were measured, with data reduction using principal‐component analysis, and relationships between component scores and motor (MDS Unified Parkinson's Disease Rating Scale — part 3) and cognitive (Mini Mental State Examination [MMSE]) measures of disease severity/progression were investigated.Results: TNF‐α, IL1‐β, IL‐2, and IL‐10 were higher in PD (n = 230) than in controls (n = 93), P ≤ 0.001). Principal‐component analysis of log‐transformed data resulted in a 3‐component solution explaining 51% of the variance. Higher “proinflammatory” and lower “anti‐inflammatory” component scores were associated with more rapid motor progression over 36 months (P < 0.05), and higher “proinflammatory” component scores were associated with lower MMSE at all times (P < 0.05). Multiple linear regression analysis with adjustment for covariates confirmed “anti‐inflammatory” component score was the strongest predictor of slower motor progression (β = −0.22, P = 0.002), whereas proinflammatory cytokines were associated with lower baseline MMSE (β = −0.175, P = 0.007).Conclusions: Serum immune marker profile is predictive of disease progression in PD and hence a potential prognostic biomarker. However, interventional trials are needed to clarify whether peripheral immune changes causally contribute to the progression of PD. © 2016 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society

4 September 2017 in Age and Ageing
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Journal Article
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AYAlison Yarnall
Alison Yarnall
ASAvan A. Sayer
Avan A. Sayer
ACAndrew Clegg
Andrew Clegg
KRKenneth Rockwood
Kenneth Rockwood
SPStuart Parker
Stuart Parker
JHJohn V Hindle
John V Hindle
The concept of multimorbidity has attracted growing interest over recent years, and more latterly with the publication of specific guidelines on multimorbidity by the National Institute for Health and Care Excellence (NICE). Increasingly it is recognised that this is of particular relevance to practitioners caring for older adults, where multimorbidity may be more complex due to the overlap of physical and mental health disorders, frailty and polypharmacy. The overlap of frailty and multimorbidity in particular is likely to be due to the widespread health deficit accumulation, leading in some cases to functional impairment. The NICE guidelines identify ‘target groups’ who may benefit from a tailored approach to care that takes their multimorbidity into account, and make a number of research recommendations. Management includes a proactive individualised assessment and care plan, which improves quality of life by reducing treatment burden, adverse events, and unplanned or uncoordinated care.

14 July 2015 in Brain
Verified
Journal Article
Open access
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EMElijah Mak
Elijah Mak
LSLi Su
Li Su
GWGuy B Williams
Guy B Williams
MFMichael J Firbank
Michael J Firbank
RLRachael A Lawson
Rachael A Lawson
JOJohn O'Brien
John O'Brien
Mild cognitive impairment in Parkinson’s disease is associated with progression to dementia (Parkinson’s disease dementia) in a majority of patients. Determining structural imaging biomarkers associated with prodromal Parkinson’s disease dementia may allow for the earlier identification of those at risk, and allow for targeted disease modifying therapies. One hundred and five non-demented subjects with newly diagnosed idiopathic Parkinson’s disease and 37 healthy matched controls had serial 3 T structural magnetic resonance imaging scans with clinical and neuropsychological assessments at baseline, which were repeated after 18 months. The Movement Disorder Society Task Force criteria were used to classify the Parkinson’s disease subjects into Parkinson’s disease with mild cognitive impairment (n = 39) and Parkinson’s disease with no cognitive impairment (n = 66). Freesurfer image processing software was used to measure cortical thickness and subcortical volumes at baseline and follow-up. We compared regional percentage change of cortical thinning and subcortical atrophy over 18 months. At baseline, cases with Parkinson’s disease with mild cognitive impairment demonstrated widespread cortical thinning relative to controls and atrophy of the nucleus accumbens compared to both controls and subjects with Parkinson’s disease with no cognitive impairment. Regional cortical thickness at baseline was correlated with global cognition in the combined Parkinson’s disease cohort. Over 18 months, patients with Parkinson’s disease with mild cognitive impairment demonstrated more severe cortical thinning in frontal and temporo-parietal cortices, including hippocampal atrophy, relative to those with Parkinson’s disease and no cognitive impairment and healthy controls, whereas subjects with Parkinson’s disease and no cognitive impairment showed more severe frontal cortical thinning compared to healthy controls. At baseline, Parkinson’s disease with no cognitive impairment converters showed bilateral temporal cortex thinning relative to the Parkinson’s disease with no cognitive impairment stable subjects. Although loss of both cortical and subcortical volume occurs in non-demented Parkinson’s disease, our longitudinal analyses revealed that Parkinson’s disease with mild cognitive impairment shows more extensive atrophy and greater percentage of cortical thinning compared to Parkinson’s disease with no cognitive impairment. In particular, an extension of cortical thinning in the temporo-parietal regions in addition to frontal atrophy could be a biomarker in therapeutic studies of mild cognitive impairment in Parkinson’s disease for progression towards dementia.