ALMERÍA, Spain—Fibromyalgia patients have a spatial learning deficit which suggests that the disease may cause alterations in their hippocampal system. The findings appear in an online version of Rheumatology.¹

For the first time ever, “this study has identified spatial navigation as a specific cognitive process that appears to be disrupted by fibromyalgia,” conclude the researchers who were led by Rosa Cánovas, MD, of the University of Almería in Spain.

The researchers used virtual reality spatial memory tasks and classical neuropsychological tests in 15 patients with fibromyalgia and 15 controls. Tests included the virtual versions of the Morris water maze and a virtual version of the hole board test called Boxes room. All participants also completed a comprehensive neuropsychological evaluation including measures of general intelligence, attention/working memory, and visuospatial memory.

When compared with control subjects, fibromyalgia patients performed significantly worse in the spatial navigation tasks. Patients made more errors than their matched controls in the Boxes room and Morris water maze tasks. By contrast, there were no significant differences between patients and controls in terms of standard neuropsychological testing. Fibromyalgia patients with longer chronicity had lower auditory memory span, visuospatial memory and general intelligence within their group, the study found.

“The fact that there were no differences between the groups in navigating to a visible platform suggest that these spatial memory deficits are not due to differences in understanding the tasks, motivational factors, using the joystick or computer programs,” the researchers report.

Moreover, “there is a large amount of data that indicates that the hippocampus is both involved and necessary for spatial navigation through virtual environments.”

Translating research into practice: Fibromyalgia affects memory

“This is a very interesting study,” said Jennifer Glass, PhD, an assistant research scientist at the Institute for Social Research and the department of psychiatry at the University of Michigan in Ann Arbor. “This is the first paper that shows an alteration in memory process in fibromyalgia patients.”

There may even be some treatment implications down the road, she told MSKreport.com. “This paper suggests that the spatial learning deficiency in fibromyalgia patients could be related to hippocampal function, and if this is correct, it gives us an idea about what is going wrong and what causes this memory problem.”

These virtual reality tests are not mainstream nor are there norms for comparison. “There is no normal for fibromyalgia patients to be scored against yet,” she said. But “if a person with fibromyalgia feels like they are experiencing memory problems in daily life, they could be referred for more testing,” she said.

“Doctors need to ask about cognition and memory because a lot of fibromyalgia patients experience it, and they need to be told that this is a normal and common symptom in fibromyalgia, not something else like Alzheimer’s,” she said.

“The overarching message is that it is quite common for fibromyalgia patients to have cognitive problems and it’s good for physicians to discuss this with patients so they know that it is part of their disease.”

Reference

1. Cánovas R, León I, Roldán, MD, et al. Virtual reality tests disclose spatial memory alterations in fibromyalgia. Rheumatology. 2009; [epub ahead of print Aug. 4, 2009].