Samuel Stuart1,2, Rachael A Lawson1, Alison J Yarnall1, Jeremy Nell1,3, Lisa Alcock1, Gordon W Duncan1,4, Tien K Khoo5,6, Roger A Barker7, Lynn Rochester1,3, David J Burn8. 1. Institute of Neuroscience/Newcastle University Institute for Ageing, Clinical Ageing Research Unit, Newcastle University, Newcastle Upon Tyne, UK. 2. Department of Neurology, Balance Disorders Laboratory, Oregon Health & Science University, Portland, Oregon, USA. 3. Newcastle Upon Tyne Hospitals NHS Foundation Trust, Newcastle Upon Tyne, UK. 4. Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK. 5. School of Medicine & Menzies Health Institute Queensland, Griffith University, Australia. 6. School of Medicine, University of Wollongong, Wallongong, New South Wales, Australia. 7. Cambridge University, John van Geest Centre for Brain Repair and Department of Neurology, E.D. Adrian Building, Cambridge, UK. 8. Faculty of Medical Science, Newcastle University, Newcastle Upon Tyne, UK.
Abstract
BACKGROUND: Cumulative dementia incidence in Parkinson's disease (PD) is significant, with major personal and socioeconomic impacts on individuals with PD and their carers. Early identification of dementia risk is vital to ensuring optimal intervention. Saccadic deficits often distinguish neurodegenerative disorders and cognitive impairment, but their ability to predict cognitive decline in PD has yet to be determined. The aims of this study were to (1) evaluate baseline (6.4 ± 6.1 months since PD diagnosis) differences in pro-saccadic metrics between those with early PD and healthy age-matched adults; and (2) assess the ability of baseline pro-saccades to predict subsequent cognitive decline over 4.5 years. METHODS: One hundred and forty-one PD and 90 age-matched participants recruited at diagnosis underwent saccadometric assessment of pro-saccades at baseline and had cognition assessed at baseline, 18, 36, and 54 months. Pro-saccadic characteristics included latency, duration, amplitude, peak, and average velocity. Cognitive assessment included executive function, attention, fluctuating attention, and memory. Linear mixed-effects models examined pro-saccadic metrics as predictors of cognitive decline over 54 months. RESULTS: Pro-saccades were significantly impaired at baseline in PD compared with controls. Pro-saccadic characteristics of latency, duration, peak, and average velocity predicted decline in global cognition, executive function, attention, and memory over 54 months in PD. In addition, only reduction in global cognition and attention were predicted by pro-saccadic metrics in age-matched adults, indicating that PD findings were not purely age related. CONCLUSIONS: Saccadic characteristics are impaired in early PD and are predictive of cognitive decline in several domains. Assessment of saccades may provide a useful non-invasive biomarker for long-term PD cognitive decline in early disease.
BACKGROUND: Cumulative dementia incidence in Parkinson's disease (PD) is significant, with major personal and socioeconomic impacts on individuals with PD and their carers. Early identification of dementia risk is vital to ensuring optimal intervention. Saccadic deficits often distinguish neurodegenerative disorders and cognitive impairment, but their ability to predict cognitive decline in PD has yet to be determined. The aims of this study were to (1) evaluate baseline (6.4 ± 6.1 months since PD diagnosis) differences in pro-saccadic metrics between those with early PD and healthy age-matched adults; and (2) assess the ability of baseline pro-saccades to predict subsequent cognitive decline over 4.5 years. METHODS: One hundred and forty-one PD and 90 age-matched participants recruited at diagnosis underwent saccadometric assessment of pro-saccades at baseline and had cognition assessed at baseline, 18, 36, and 54 months. Pro-saccadic characteristics included latency, duration, amplitude, peak, and average velocity. Cognitive assessment included executive function, attention, fluctuating attention, and memory. Linear mixed-effects models examined pro-saccadic metrics as predictors of cognitive decline over 54 months. RESULTS: Pro-saccades were significantly impaired at baseline in PD compared with controls. Pro-saccadic characteristics of latency, duration, peak, and average velocity predicted decline in global cognition, executive function, attention, and memory over 54 months in PD. In addition, only reduction in global cognition and attention were predicted by pro-saccadic metrics in age-matched adults, indicating that PD findings were not purely age related. CONCLUSIONS: Saccadic characteristics are impaired in early PD and are predictive of cognitive decline in several domains. Assessment of saccades may provide a useful non-invasive biomarker for long-term PD cognitive decline in early disease.
Authors: Carmen Martin-Ruiz; Caroline H Williams-Gray; Alison J Yarnall; John J Boucher; Rachael A Lawson; Ruwani S Wijeyekoon; Roger A Barker; Claire Kolenda; Craig Parker; David J Burn; Thomas Von Zglinicki; Gabriele Saretzki Journal: J Parkinsons Dis Date: 2020 Impact factor: 5.568