1. Brain reserve as predictor of stroke outcome

The concept of brain reserve is well established in neurodegeneration. In this project, we aim to adapt the concept of brain reserve for stroke to improve prediction of post-stroke outcome. Brain reserve is represented by quantitative brain characteristics at the time stroke occurs (e.g. brain volume, hippocampus volume), it is reduced by brain pathology (e.g. white matter hyperintensities, brain atrophy). We investigate the impact of proxies of brain reserve and its pathology on post-stroke cognition and outcome.

2. Impact of cognitive reserve on stroke outcome

The concept of cognitive reserve has been developed to explain the inter-individual variability in response to neurodegenerative pathology. We suggested that this concept might be a valuable framework to predict post-stroke cognitive deficits and functional outcome. ‘Cognitive reserve’ is defined as the function of lifetime intellectual activities, which serve to shape network efficiency, processing capacity and flexibility (Barulli & Stern, 2013). We propose that post-stroke cognition and stroke outcome can be defined as a result of an interaction between brain reserve (e.g. brain volume), cognitive reserve (e.g. level of education) and lesion load. 

The projected is supported by Synapsis-Foundation and Heidi Seiler-Foundation. 

3. Post-stroke cognitive trajectories

Post-stroke cognitive deficits demonstrate high inter-individual variability, which is expected to increase further due to the increasing life expectancy and number of patients with pre-stroke brain pathology and cognitive deficits.

There exist different types and patterns of post-stroke cognitive decline:

1. the deficits in one or several cognitive domains meaning the variability in neuropsychological profiles;
2. the decline might vary from mild to manifested dementia comprising a wide spectrum in severity;
3. with occurrence immediately after stroke or with delayed manifestation several months later without obvious reasons.

Patients at risk for post-stroke cognitive decline cannot be reliably identified now. In the project, we track the cognitive functioning in stroke patients. Our aim is to understand the inter-individual variability in post-stroke cognitive trajectories and to improve its prediction.

4. Neuroimaging of post-stroke cognition

In this project, we aim to apply the methods of advanced neuroimaging (e.g. functional MRI, diffusion q-imaging) to understand the underlying mechanisms of inter-individual variability in post-stroke cognitive trajectories. 

Umarova RM, Schumacher LV, Schmidt CSM, et al. Interaction between cognitive reserve and age moderates effect of lesion load on stroke outcome. Sci Rep. 2021; 4478.

Umarova RM. Adapting the concepts of brain and cognitive reserve to post-stroke cognitive deficits: Implications for understanding neglect. Cortex 2017; 97: 327–338. Adapting the concepts of brain and cognitive reserve to post-stroke cognitive deficits: Implications for understanding neglect - ScienceDirect

Umarova R, Beume L, Reisert M, et al. Distinct white matter alterations following severe stroke: Longitudinal DTI-study in neglect. Neurology. 2017; 88: 1546–1555. Distinct white matter alterations following severe stroke | Neurology

Umarova R, Nitschke K, Kaller Ch, et al. Predictors and signatures of recovery from neglect in acute stroke. Annals of Neurology 2016; 79: 673-86. Predictors and signatures of recovery from neglect in acute stroke - Umarova - 2016 - Annals of Neurology - Wiley Online Library

Umarova R, Saur D, Kaller C, et al.  Acute neglect and extinction: different functional state of attention system. Brain. 2011: 134(11): 3310-25. Acute visual neglect and extinction: distinct functional state of the visuospatial attention system | Brain | Oxford Academic (oup.com)

Team

• Laura Gallucci, PhD-student
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• Franziska Westphalen, Master student
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• Florian Rudaz, Master student
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• Moritz Hürlimann, Master student
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Collaborators

• Dr. Marco Reisert, Dr. Elias Kellner, Research Group «Microstructure Imaging» University of Freiburg, Germany
• Prof. Matthias Wilhelm, Head of Center for Preventive cardiology and Center for Sport Medicine, University hospital Bern
• Dr. med. Arsany Hakim, Department of Neuroradiology, University Hospital Bern, University of Bern