There is ample evidence for cognitive deficits in fibromyalgia syndrome (FMS). The present study investigated cerebral blood flow responses during arithmetic processing in FMS patients and its relationship with performance. The influence of clinical factors on performance and blood flow responses were also analyzed.
Forty-five FMS patients and 32 matched healthy controls completed a mental arithmetic task while cerebral blood flow velocities in the middle (MCA) and anterior (ACA) cerebral arteries were measured bilaterally using functional transcranial Doppler sonography (fTCD).
Patients' cognitive processing speeds were slower versus healthy controls. In contrast to patients, healthy controls showed a pronounced early blood flow response (during seconds 4-6 after the warning signal) in all assessed arteries. MCA blood flow modulation during this period was correlated with task performance. This early blood flow response component was markedly less pronounced in FMS patients in both MCAs. Furthermore, patients displayed an aberrant pattern of lateralization, with right hemispheric dominance especially observed in the ACA. Severity of clinical pain in FMS patients was correlated with cognitive performance and cerebral blood flow responses.
Cognitive impairment in FMS is associated with alterations in cerebral blood flow responses during cognitive processing. These results suggest a potential physiological pathway through which psychosocial and clinical factors may affect cognition.