The neural correlates of cognitive fatigue in traumatic brain injury using functional MRI

Brain Inj. 2009 May;23(5):420-32. doi: 10.1080/02699050902788519.


Primary objective: The present study used fMRI (functional magnetic resonance imaging) to objectively assess cognitive fatigue in persons with traumatic brain injury (TBI). It was hypothesized that while performing a cognitive task, TBI participants would show increased brain activity over time, indicative of increased cerebral 'effort' which might manifest as the subjective feeling of cognitive fatigue.

Methods and procedures: Functional MRI was used to track brain activity across time while 11 TBI patients with moderate-severe injury and 11 age-matched healthy controls (HCs) performed a modified Symbol Digit Modalities Task (mSDMT). Cognitive fatigue was operationally defined as a relative increase in cerebral activation across time compared to that seen in HCs. ROIs were derived from the Chauduri and Behan model of cognitive fatigue.

Main outcomes and results: While performing the mSDMT, participants with a TBI showed increased activity, while HCs subsequently showed decreased activity in several regions including the middle frontal gyrus, superior parietal cortex, basal ganglia and anterior cingulate.

Conclusions: Increased brain activity exhibited by participants with a TBI might represent increased cerebral effort which may be manifested as cognitive fatigue. Functional MRI appears to be a potentially useful tool for understanding the neural mechanisms associated with cognitive fatigue in TBI.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Basal Ganglia / physiopathology
  • Brain Injuries / physiopathology*
  • Brain Mapping / methods
  • Case-Control Studies
  • Cognition Disorders / diagnosis*
  • Female
  • Frontal Lobe / physiopathology
  • Gyrus Cinguli / physiopathology
  • Humans
  • Magnetic Resonance Imaging / methods
  • Male
  • Mental Fatigue / physiopathology*
  • Middle Aged
  • Neuropsychological Tests
  • Thalamus / physiopathology
  • Young Adult