Intra- and Inter-Patient Symptom Variability in Fibromyalgia: Results of a 90-Day Assessment.

Symptoms of fibromyalgia (FM)--chronic widespread pain, fatigue, unrefreshing sleep, dyscognition etcetera--present with varying degrees of severity in different individuals; however, studies reporting daily estimates of variability of symptoms are sparse. Given the limited literature on the stability and variability of FM symptoms, the purpose of the present study was to determine the feasibility of daily visual analogue, self-report measures to assess daily variability and time trends in core FM symptoms. Ten female patients completed daily assessments of common FM symptoms (pain, fatigue, anxiety, depression, stress, cognitive dysfunction, unrefreshing sleep and lightheadedness) for approximately 90 days. The completion rate was excellent (89.6%). The results demonstrated that average symptom intensity differs markedly across the different symptoms that were measured. Unrefreshing sleep, fatigue and pain are clearly higher in intensity than other symptoms and are followed by memory problems, stress, anxiety and depression. There is also notable average intra-individual change across time (10-15 points on a 100-point scale). Average symptom intensity does not appear to be related to the amount of symptom change within individuals. The results of the present study confirm that intensive longitudinal study, using comprehensive symptom assessment in patients with FM, is both possible and informative, in the sense that a rich description of the daily experience of living with FM can be obtained. Future work, utilizing larger samples, will offer the opportunity to investigate better the causes, consequences and correlates of the daily ups and downs of key symptoms that compromise quality of life in patients with FM.