SAN DIEGO – ‘Fibrofog’ – the cognitive dysfunction experienced by up to 80% of fibromyalgia patients – is not an early harbinger of Alzheimer’s disease, Dr. Robert S. Katz asserted at the annual meeting of the American College of Rheumatology.
The problems with memory, concentration, language, and thinking, collectively known as fibrofog, affect fibromyalgia patients in their 20s-50s. The onset is typically more sudden and dramatic than with classic forms of dementia. As fibrofog becomes chronic, many affected fibromyalgia patients – fearing the worst – worry they are on a road to Alzheimer’s disease in middle age.
Not so, according to Dr. Katz, professor of medicine at Rush Medical College, Chicago.
He presented a cross-sectional study involving two cohorts. One comprised 69 fibromyalgia patients with symptoms of cognitive dysfunction of 12 months duration or less. The other consisted of 39 fibromyalgia patients with fibrofog symptoms of 7-26 years duration. The long-duration group averaged 52.3 years of age, nearly 7 years older than the group with more recent onset of fibrofog. But the two groups were closely similar in terms of educational level, depression scores, and vocabulary scale scores.
The key study finding: No significant differences existed between the two groups on 13 of the 14 measures of neurocognitive function assessed in the study, including logical memory, paired associate, digit symbol, letter fluency, processing speed, and the Stroop word speed and color speed tests.
Indeed, the sole metric where the long-duration fibrofog patients fared significantly worse was the Trails A test, a measure of spatial scanning and cognitive sequencing. However, the two groups had closely similar scores on the Trails B.
Compared with standardized normative means that have been established for each of the 14 neurocognitive tests, the level of cognitive impairment in the fibromyalgia patients was markedly less than that seen in patients with Alzheimer’s disease. More specifically, measures of processing speed and episodic memory, which are significantly diminished in individuals with preclinical Alzheimer’s disease, were within normal range in both study groups. That’s reassuring. So is the fact that the cognitive deficits present in the shorter-duration group weren’t markedly more pronounced in the group troubled by cognitive problems for an additional 6-25 years. Thus, fibrofog does not appear to be a condition characterized by progressive cognitive decline, the rheumatologist observed.
Dr. Katz reported having no financial conflicts of interest with regard to this study.