Computerized cuff pressure algometry: A new method to assess deep-tissue hypersensitivity in fibromyalgia

The aim of this study was to evaluate the use of computerized cuff pressure algometry (CPA) in fibromyalgia (FM) and to correlate deep-tissue sensitivity assessed by CPA with other disease markers of FM. Forty-eight women with FM and 16 healthy age-matched women were included. A computer-controlled, pneumatic tourniquet cuff was placed over the gastrocnemius muscle. The cuff was inflated, and the subject rated the pain intensity continuously on an electronic Visual Analogue Scale (VAS). The subject stopped the inflation at the pressure-pain tolerance and the corresponding VAS-score was determined (pressure-pain limit). The pressure at which VAS firstly exceeded 0 was defined as the pressure-pain threshold. Other disease markers (FM only): Isokinetic knee muscle strength, tenderpoint-count, myalgic score, Beck Depression Inventory, and Fibromyalgia Impact Questionnaire. Student's T-test was used to compare pressure-pain threshold and pressure-pain tolerance and the Mann-Whitney test to compare pressure-pain limit. Pearson's correlation was used to detect linear relationships. Pressure-pain threshold and pressure-pain tolerance assessed by CPA were significantly lower in FM compared to healthy controls. There was no difference in pressure-pain limit. CPA-parameters were significantly correlated to isokinetic muscle strength where more hypersensitivity resulted in lower strength. Pressure-pain threshold and pressure-pain tolerance assessed by CPA were significantly lower in patients with FM indicating muscle hyperalgesia. CPA was associated with knee muscle strength but not with measures thought to be influenced by psychological distress and mood.