Background/Purpose: Patient with Chronic Fatigue Syndrome (CFS) frequently report cognitive complaints, including lack of concentration and forgetfulness. Previous neuropsychological studies reported attentional and memory dysfunction in CFS patients. We wanted to determine the association between mental fatigue and brain activity as measured by arterial spin labeling (ASL). The perception of mental fatigue was induced with the Paced Auditory Serial Attention test (PASAT) that involves attention, working memory and executive function. We measured cerebral blood flow (CBF) changes in CFS patients and compared them to healthy controls (HC).

Methods: CFS was determined using the CDC Criteria. 15 CFS patients (age = 50.5±13.0)) and 12 HC (age = 49.2±12.2) underwent a 3 Tesla Achieva MRI during rest using a pseudo-continuous arterial spin labeling (pCASL) sequence. pCASL can quantify CBF without using exogenous contrast agents by magnetically labeling inflowing blood. Individual scans were corrected for motion and spatially smoothed, then label and control pairs were subtracted to create a perfusion image. The perfusion image was used to calculate a quantified CBF map, which was then normalized to standardized space. After practice trials, participants were placed in the MRI scanner where they viewed a computer screen and listened to PASAT stimuli. Subjects continuously rated their level of exhaustion on a VAS. Groups were compared using voxel-wise independent samples t-tests. Statistical parametric maps were thresholded using a cluster forming t-statistic greater than 4.0 (p < 0.00025) and a spatial extent of 20 contiguous voxels (160 mm³) to control for multiple comparisons.

Results: Fatigue ratings were 0.4 (0.6) and 3.9 (2.1) for HC and CFS patients, respectively (p < 0. 01).  Overall cerebral blood flow was similar between groups (p > .05). CFS patients showed reduced blood flow in the right hemisphere superior frontal gyrus.  In the significant cluster, HC participants had a mean (SD) CBF of 66.12 (7.89) compared to 63.24 (6.22) (ml/100g/min) in CFS patients (t(25) = 4.73, p = 0.007, Cohen’s d = 1.80).  

Conclusion: More reduced cerebral perfusion was observed in the right superior frontal gyrus of CFS patients compared to HC during PASAT. The superior frontal gyrus plays a major role in the Attention Network. Reduced blood flow of this area may be a cause or consequence of chronic fatigue as well as impaired attention and cognition often observed in CFS.

---

« Back to 2014 ACR/ARHP Annual Meeting

ACR Meeting Abstracts - https://acrabstracts.org/abstract/cognitive-task-related-hypoperfusion-of-frontal-gyrus-in-patients-with-chronic-fatigue/