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This was my first serious research interest and it continues to be an area that is in need of advocacy and development. I and others have shown that fatigue is a very real and disabling symptom, even though it is subjective and difficult to measure.


Despite significant advances, we will have a long way to go before fatigue reaches the same level of acceptance as other subjective symptoms such as pain and depression. Until that happens, I believe that progress toward treatments and a deeper understanding of the causes of this disabling symptom will be slow and piecemeal.



Key Publications: Fatigue

Here is some of my past research if you’d like to learn more about fatigue.

Fatigue and Fatigability in Neurologic Illnesses: Proposal for a Unified Taxonomy

This paper addresses key issues regarding terminology and phenomenology to allow for more consistent definitions and measurements of fatigue for clinical research and care.

Parkinson’s Disease-Related Fatigue: A Case Definition and Recommendations for Clinical Research

This is the report of an international working group proposing case definition criteria for Parkinson’s disease (PD)-related fatigue. 

Structural Brain Correlates of Fatigue in Older Adults With and Without Parkinson’s Disease

Neuroimaging study showing that fatigue in Parkinson’s disease (PD) is associated with changes in the brain that are different than depression or sleep and also different from older adults without Parkinson’s who had fatigue. These results suggest that PD-related fatigue is a unique neurobiologic syndrome.

Compensatory Neural Activity in Response to Cognitive Fatigue

The brain engages unique networks to maintain cognitive performance under fatiguing conditions. When these compensatory networks fail the rate of performance decline increases steeply.

Change in Intraindividual Variability Over Time as a Key Metric for Defining Performance-Based Cognitive Fatigability

Working with colleagues at the University of Florida we asked the question of how fatigue affects performance on a cognitive task. Although people had slower reaction times this wasn’t the whole story. Looking at how the distribution of responses changed over time we found that the fastest responses actually improved, likely due to learning and that the slowing of average reaction times was largely driven by an increase in variability, possibly due to attentional lapses.

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