Less efficient and costly processes of frontal cortex in childhood chronic fatigue syndrome

Abstract

The ability to divide one's attention deteriorates in patients with childhood chronic fatigue syndrome (CCFS). We conducted a study using a dual verbal task to assess allocation of attentional resources to two simultaneous activities (picking out vowels and reading for story comprehension) and functional magnetic resonance imaging. Patients exhibited a much larger area of activation, recruiting additional frontal areas. The right middle frontal gyrus (MFG), which is included in the dorsolateral prefrontal cortex, of CCFS patients was specifically activated in both the single and dual tasks; this activation level was positively correlated with motivation scores for the tasks and accuracy of story comprehension. In addition, in patients, the dorsal anterior cingulate gyrus (dACC) and left MFG were activated only in the dual task, and activation levels of the dACC and left MFG were positively associated with the motivation and fatigue scores, respectively. Patients with CCFS exhibited a wider area of activated frontal regions related to attentional resources in order to increase their poorer task performance with massive mental effort. This is likely to be less efficient and costly in terms of energy requirements. It seems to be related to the pathophysiology of patients with CCFS and to cause a vicious cycle of further increases in fatigue.

Decreased Connectivity and Increased Blood Oxygenation Level Dependent Complexity in the Default Mode Network in Individuals with Chronic Fatigue Syndrome

“…Thus, DMN synchronization in CFS was weaker than NC during the task, which more generally may be expected to increase the energy consumption required to perform tasks. Our observation of increased BOLD activation in CFS not balanced by increased BOLD inhibition elsewhere in the brain, together with similar observations in previous reports (Lange et al, 2005;Mizuno et al, 2015), provide support for this notion. It appears that CFS patients demand more BOLD activation to compensate for the more complex and unsynchronized brain activity/connectivity in and between different components of their central nervous system.…”

Altered right anterior insular connectivity and loss of associated functions in adolescent chronic fatigue syndrome

“…Decreases in motivational neural circuitry were associated with increases in mental and general fatigue and reductions in physical activity in adult CFS [ 81 ]. Previous fMRI studies with children and adolescents with CFS found changes in activities of the prefrontal and parietal regions during attentional control [ 82 ] and decreases in striatal activity involved in reward sensitivity and motivation [ 83 ].…”

Extension of recovery time from fatigue by repeated rest with short‐term sleep during continuous fatigue load: Development of chronic fatigue model

“…On the other hand, mental fatigue is known to be related to decreased motivation (Kitani, ; Mizuno et al, ) and is assessed by a reduction in voluntary activities (Yamato et al, ). For example, mental fatigue represents a failure to initiate and/or sustain mental tasks requiring self‐motivation (Chaudhuri and Behan, ), and in childhood chronic fatigue syndrome patients, the neuronal activity in the left dorsal inferior frontal gyrus was negatively correlated with motivation in which the neuronal activity had been shown to be positively correlated with the Chalder fatigue scale score in healthy volunteers (Mizuno et al, ). The present study demonstrates that, in the WLFST, nighttime spontaneous activity but not swimming time is decreased for a longer period after the 5‐min‐rest IWI procedure.…”