Cognitive impairment in fibromyalgia 'mediated by pain'
Published on 24 February 2012
People with fibromyalgia often experience cognitive impairment which appears to be closely linked to their levels of pain, a study has found.
Scientists at the University of Jaen in Spain performed neuropsychological tests on 35 people with fibromyalgia and a further 29 healthy volunteers, which were designed to assess their attention and arithmetic processing.
They expected to see cognitive impairment among the fibromyalgia patients, but wanted to know whether this was linked to factors such as pain intensity, depression, anxiety, sleep complaints, medication use or blood pressure.
Analysis confirmed that people with fibromyalgia tended to show substantially slower cognitive processing.
Depression, anxiety, fatigue and sleep complaints were all found to be unrelated to patients' test performance.
But patients with lower pain ratings and those using opiate-based medicines tended to perform better than those with worse pain and non-users of opiates.
Writing in the European Journal of Pain, the study authors said that they found "substantial cognitive impairment" in people with fibromyalgia, and that the severity of chronic pain was "crucial" in determining the level of deficit.
The researchers also observed that among healthy volunteers, lower blood pressure was associated with better mental performance.
However, the same was not seen in people with fibromyalgia, leading the study authors to suggest that people with the pain syndrome "are protected against the negative effects of high blood pressure on cognition".
A spokesman for Arthritis Research UK said that the findings were interesting but not surprising. "Pain is the major symptom of fibromyalgia, and if people are in pain, then their levels of concentration and ability to think clearly will be reduced," he added.