Central nervous activity during an emotional Stroop task in fibromyalgia syndrome.

Fibromyalgia syndrome (FMS) is a chronic condition of widespread pain accompanied by symptoms like depression, fatigue and cognitive impairments. In addition to central nervous pain sensitization, emotional dysregulation may be involved in FMS pathogenesis. This study investigated emotional influences on cognitive processing in FMS. Event-related potentials and theta oscillations were recorded during an emotional Stroop task including positive, negative, and neutral adjectives in 36 FMS patients and 35 controls. Patients had larger P3 amplitudes and greater theta power than controls, independent of the emotional word content. In patients, but not controls, negative words were associated with a larger late positive component (LPC) amplitude than positive words. No group difference was seen for P1, early posterior negativity or N4. Reaction times (RTs) were longer in patients than controls, independent of emotional word content. The P3 and theta oscillation findings suggest greater cognitive effort and attentional mobilization in FMS, which is needed to overcome the reduction of attentional resources resulting from central nervous pain sensitization. Although RTs do not support attentional bias in FMS, emotional modulation of the LPC amplitude may reflect preferential central nervous processing of negative information, which could contribute to pain and affective symptoms characterizing FMS. ACCESS TO RESEARCH DATA: The research data of the study are available to the public via the Open Science Framework repository (OSF: https://osf.io/tsyre/).

Central nervous activity during implicit processing of emotional face expressions in fibromyalgia syndrome.

OBJECTIVE: Fibromyalgia syndrome (FMS) is characterized by chronic widespread pain accompanied by symptoms like fatigue, insomnia, depression, anxiety and cognitive impairments. In addition to central nervous pain sensitization, emotional dysregulation may be involved in FMS pathogenesis. This study investigated central nervous correlates of affective and attentional processing in FMS using an implicit task. METHODS: Event-related potentials (ERPs) of the EEG were recorded in 25 FMS patients and 37 healthy controls while they had to name the frame color of pictures displaying emotional expressions (angry, painful, happy, neutral). The actual picture had to be ingored. Symptoms of pain, depression and anxiety were also assessed. RESULTS: Patients exhibited smaller P2 and late positive potential (LPP) amplitudes, and a greater N250 amplitude, than controls. The N250 amplitude varied according to the emotional expressions displayed in patients, but not in controls. No group differences arose for the P1 or N170 amplitudes. Patients had longer reaction times and made more errors on the task; task performance was more closely related to pain severity than to other symptoms. CONCLUSION: The reduced P2 and LPP amplitudes indicate deficient short-term mobilization of attentional resources and sustained attention in FMS; the greater N250 amplitude may reflect greater engagement in the decoding of complex facial features, which is necessary to compensate for attentional impairments. Affective modulation of the N250 suggests that the neural mechanisms underlying complex visual processes are particularly susceptible to emotional influences in FMS. The behavioral data confirm attentional deficits in the disorder and implicate clinical pain therein.

Oxidative burst of neutrophils in patients with rheumatoid arthritis: influence of various cytokines and medication.

OBJECTIVE: Toxic oxygen products are believed to be implicated in tissue damage in some complex-mediated diseases such as rheumatoid arthritis. In the present study we compared the superoxide (O2) production of polymorphonuclear leukocytes (PMNs) in 21 patients with rheumatoid arthritis (RA) with that of 9 healthy controls, examining the effect of different stimulants and cytokines on the oxidative burst (OB). Since many drugs used in the treatment of RA may alter O2 metabolism, the effects of antirheumatic medication were also studied. METHODS: Generation of superoxide anions was analysed by a flow cytometric method, using the fluorochrome dihydro-rhodamine. As stimulants for OB, we used N-formyl-methionyl-leucyl-phenylalanine (fMLP), which acts via a membrane receptor, and phorbol-myristate acetate (PMA), which acts in a membrane receptor-independent manner. As preactivating substances, TNF-alpha, G-CSF and GM-CSF were applied. RESULTS: In RA patients under treatment with antirheumatic medication, fMLP-induced OB (+/- cytokines) was significantly reduced, while O2 production after stimulation with PMA was similar compared to controls. GM-CSF showed the highest level of preactivation in controls, whereas in RA patients TNF-alpha proved to be most potent. In both controls and RA patients, a combination of GM-CSF or G-CSF with TNF-alpha further enhanced OB. No correlation between OB and clinical data or treatment could be established in RA patients. CONCLUSIONS: There is a reduced cytokine priming capacity for OB in RA patients under antirheumatic medication in spite of the presence of an intact enzyme system of OB. Antirheumatic medication combining multiple drugs capable of decreasing OB might effectively modulate oxidative metabolism.