Characterizing “fibrofog”: Subjective appraisal, objective performance, and task-related brain activity during a working memory task

Abstract

The subjective experience of cognitive dysfunction (“fibrofog”) is common in fibromyalgia. This study investigated the relation between subjective appraisal of cognitive function, objective cognitive task performance, and brain activity during a cognitive task using functional magnetic resonance imaging (fMRI). Sixteen fibromyalgia patients and 13 healthy pain-free controls completed a battery of questionnaires, including the Multiple Ability Self-Report Questionnaire (MASQ), a measure of self-perceived cognitive difficulties. Participants were evaluated for working memory performance using a modified N-back working memory task while undergoing Blood Oxygen Level Dependent (BOLD) fMRI measurements. Fibromyalgia patients and controls did not differ in working memory performance. Subjective appraisal of cognitive function was associated with better performance (accuracy) on the working memory task in healthy controls but not in fibromyalgia patients. In fibromyalgia patients, increased perceived cognitive difficulty was positively correlated with the severity of their symptoms. BOLD response during the working memory task did not differ between the groups. BOLD response correlated with task accuracy in control subjects but not in fibromyalgia patients. Increased subjective cognitive impairment correlated with decreased BOLD response in both groups but in different anatomic regions. In conclusion, “fibrofog” appears to be better characterized by subjective rather than objective impairment. Neurologic correlates of this subjective experience of impairment might be separate from those involved in the performance of cognitive tasks.

Metabolomic Differentials in Women With and Without Fibromyalgia

“…Other studies have reported elevated levels of KYN 8 or lower levels of Trp 37 in persons with FM. Together, these studies suggest that disruption of KP metabolic homeostasis may have potential clinical consequences in persons with FM, the symptomatology of which has been reported to include cognitive impairment described as "fibrofog" 39 and distressed mood such as depression and anxiety. 1 Deciphering the complexity of differences in metabolites and their expression in different cells and tissues under different circumstances and relating them back to biological function and clinical outcomes is a current challenge for the field of metabolomics; 40 however, with preliminary data such as we have reported here, there is potential for future studies designed to target Met, oxidative stress, and FM symptoms as well as the metabolites associated with the KP and Trp metabolism and clinical outcomes in individuals with FM.…”

“…Other studies have linked high levels of plasma methionine sulfoxide with aging and memory impairment. 38 The novel finding of significantly higher plasma concentration of methionine sulfoxide suggests a mechanism of involvement in accelerated aging as well as the development of cognitive complaints 39 in persons with FM that warrants further investigation. The presence of differential levels of anthranilate between our two study groups suggests potential dysregulation of kynurenine (KYN) metabolism.…”

Hippocampal oscillatory dynamics and sleep atonia are altered in an animal model of fibromyalgia: Implications in the search for biomarkers

“…To date, no systematic studies have been conducted in FMS patients to assess cross‐frequency coupling. It is necessary to find neurologic correlates of the subjective experience of cognitive impairment (“fibrofog”) (Walitt et al, ). If the findings observed in the RIM were validated in humans, such research could provide a better understanding of the cognitive disturbances present in FMS, and would also constitute putative EEG biomarkers of this condition.…”

“…Deficits in learning, memory, attention, and decision‐making in FMS patients are involved mainly in emotionally charged cognitive tasks (Walteros et al, ). The term “fibrofog” has been recently used to refer to the subjective experience of cognitive dysfunction, related to lower blood oxygen level‐dependent (BOLD) fMRI measurements in different anatomical areas than in healthy controls (Walitt et al, ). These cognitive deficits are related to central pain modulation (Galvez‐Sánchez et al, ).…”

Digging into the construct of fibrofog: Psychometric properties of the Spanish version of the Multidimensional Inventory of Subjective Cognitive Impairment in patients with fibromyalgia

“…In this regard, accelerated brain gray matter loss has been reported in FM suggesting premature aging in this disorder (Kuchinad et al., ). In fact, a pattern of local abnormalities of gray matter (i.e., reductions or increments) involving areas related to pain processing, stress response, and cognitive control have been described in patients with FM (Wallit, et al., ). However, it is not yet clear whether these alterations may be causative or just an epiphenomenon of FM.…”