Neural correlates of cognitive fatigue in multiple sclerosis using functional MRI

Ventromedial prefrontal cortex modulates fatigue after penetrating traumatic brain injury

“…Other limitations of the study include the different numbers of the experimental groups and the possible confounds due to prescription and over-the-counter medications; we tried to reduce the effect of the latter confound, however, through a detailed pharmacologic history. Nevertheless, the consistency of our findings with other recent studies described above 2,3,4,22 strengthens the validity of the results and suggests that treatments aimed at regulating vmPFC function and reward mechanisms might restore energy to those patients who complain of fatigue following brain damage.…”

“…2 While a host of different mechanisms have been related to fatigue, 2 recent theories have implicated frontal cortex structures and deep gray matter as the possible neural substrate of fatigue in neurologic disorders. 2,3 Moreover, recent evidence links medial prefrontal structures to fatigue in neurologic conditions such as multiple sclerosis 4 as well as to social withdrawal and apathy 5 -i.e., clinical presentations that present with some overlap with the construct of fatigue. Finally, in different experimental paradigms, ventromedial prefrontal cortex (vmPFC) territories have been linked with cognitive tasks, such as effort-evaluation, that could help to explain the cognitive underpinnings of fatigue.…”

“…1,4,9 These factors enabled us to account for the impact of different cognitive, demographic, and psychosocial factors that might play a role in fatigue perception. One limitation on the interpretation of our study is its reliance only on male subjects with PBI; further studies are needed to expand these observations to females and subjects with other neurologic disorders.…”

Voxelwise Assessment of the Regional Distribution of Damage in the Brains of Patients with Multiple Sclerosis and Fatigue

“…Seminal studies failed to find a relationship between the presence and severity of fatigue in patients with MS and several MR imagingϪderived quantities, such as the presence and number of gadolinium-enhancing lesions, 4 T2-visible lesion burden, 5 the severity of brain atrophy, 5 and microscopic damage to the normal-appearing WM 6 and GM, as a whole. 7 Conversely, the application of functional imaging techniques, including positron-emission tomography 8 and functional MR imaging, [9][10][11][12] has demonstrated abnormalities of functions in several cortical and subcortical areas, mainly located in the frontal lobes and basal ganglia in patients with fatigued MS compared with HC and those with nonfatigued MS, suggesting that fatigue in MS might be related to a dysfunction of distinct corticosubcortical circuits. Voxel-wise assessment of the topographic distribution of damage in the different compartments of the central nervous system is an appealing strategy for defining whether such functional changes might be associated with structural changes in critical brain regions or pathways of patients with fatigued MS.…”

A wireless body measurement system to study fatigue in multiple sclerosis

“…They do not permit long-term monitoring (e.g., 24 h) and the subject under scanning is not free to move. Due to these limitations, none of the previous studies with MRI or fMRI (White et al 2004, Rocca et al 2007, Tartaglia et al 2008, DeLuca et al 2008, Rocca et al 2009 involved any complex task assigned to the subjects, especially complex physical tasks. Only a few studies evaluated fatigue-related physiological and functional parameters among MS patients.…”