A Case of Primary Post-Stroke Fatigue: Origins in Abnormal Sensorimotor Neural Network Activity

In this chapter we present a case of severe primary post-stroke fatigue in a young stroke survivor (<60 years). In the 2½ years of follow-up, we show that her fatigue as measured by the Fatigue Severity Scale-7 remained stable, and consistently severe for the entire duration. Detailed investigations of the sensorimotor system revealed neurophysiological changes that were indicative of maladaptive plasticity within the sensorimotor networks which explained the core features of post-stroke fatigue. Elevated effort perception for a muscle contraction, despite comparable motor power to those without fatigue. Reduced motor cortex excitability in the affected hemisphere suggests elevated effort perception could arise from altered processing of sensory information from contracting muscles. Over-processing of distractor stimuli in a laboratory task explained high fatigue and reported sensory overload. We also show that a transient increase in motor cortical excitability using non-invasive brain stimulation reduced fatigue significantly for a week and remained so a month later. In summary, we have presented a young female stroke survivor with no overt physical and mental deficits, or mood disorders, manifest severe primary post-stroke fatigue, whose origins lie in maladaptive sensorimotor plasticity.