Many patients with fibromyalgia and chronic fatigue syndrome (CFS) experience brain fog (a term given to the variety of cognitive deficits that fibromyalgia and CFS sufferers face during their illness). Brain fog is often described as slow thinking, difficulty focusing, confusion, lack of concentration, forgetfulness, or a haziness in thought processes.
BRAIN FOG AND REDUCED CEREBRAL BLOOD FLOW
Adequate cerebral blood flow is necessary for the brain to function. Research has found that brain fog in patients with fibromyalgia and CFS is associated with reduced cerebral blood flow. For example, in the following study the researchers concluded that cognitive deficits in fibromyalgia were associated with alterations in cerebral blood flow.
Aberrant Cerebral Blood Flow Responses During Cognition: Implications for the Understanding of Cognitive Deficits in Fibromyalgia.
Montoro CI, et. al. Neuropsychology. 2014 Aug 25.
“There is ample evidence for cognitive deficits in fibromyalgia syndrome (FMS)…Cognitive impairment in FMS is associated with alterations in cerebral blood flow responses during cognitive processing…”
In the following study the researchers found that patients with CFS had “broad decreases” in cerebral blood flow.
Cerebral blood flow is reduced in chronic fatigue syndrome as assessed by arterial spin labeling.
Biswal B1, et. al. J Neurol Sci. 2011 Feb 15;301(1-2):9-11.
“…The patients as a group had significantly lower global CBF than the controls. The reduction in CBF occurred across nearly every region assessed. The data extend our earlier observation that CFS patients as a group have broad decreases in CBF compared to healthy controls.”
WHAT CAUSES THE REDUCED CEREBRAL BLOOD FLOW IN PATIENTS WITH FIBROMYALGIA AND CFS?
Due to a lack of the enzymes that digest dietary proteins (protease and DNase 1) patients with fibromyalgia and CFS have elevated levels of the inflammatory cytokine tumor necrosis factor (TNF). Elevated TNF is directly linked to reduced cerebral blood flow. For example, in the following study the researchers found that TNF caused a “significant, acute” reduction in cerebral blood volume.
TNF-alpha reduces cerebral blood volume and disrupts tissue homeostasis via an endothelin- and TNFR2-dependent pathway.
Sibson NR1, et. al. Brain. 2002 Nov;125(Pt 11):2446-59.
“TNF-alpha expression is elevated in a variety of neuropathologies, including multiple sclerosis…Here, using MRI, we demonstrate that a focal intrastriatal injection of TNF-alpha causes a significant, acute reduction (15-30%) in cerebral blood volume…”
TNF AND CHRONIC FATIGUE SYNDROME
In the following study the researchers concluded that TNF was “significantly increased” in patients with CFS.
TNF-alpha and chronic fatigue syndrome.
Moss RB1, et. al. J Clin Immunol. 1999 Sep;19(5):314-6.
“Based upon the clinical presentation of chronic fatigue syndrome (CFS), we hypothesized that proinflammatory cytokines may play a role in the pathogenesis of the disease. We therefore undertook a retrospective cross-sectional study to examine the role of TNF-alpha in patients with CFS. Our results suggest a significant increase serum TNF-alpha in patients with CFS (P<0.0001) compared to non-CFS controls…”
TNF AND FIBROMYALGIA
Researchers in our final study concluded that patients with fibromyalgia also have elevated levels of TNF.
Cytokine patterns in fibromyalgia and their correlation with clinical manifestations.
Bazzichi L1, et. al. Clin Exp Rheumatol. 2007 Mar-Apr;25(2):225-30.
“…Higher levels of…TNF-alpha were found in FM patients than in controls. Significant correlations between the biochemical parameters and clinical data were found…”