Objective: To determine the presence of widespread pressure hyperalgesia in multiple sclerosis (MS) patients with and without pain and its association with pain and fatigue.
Methods: One hundred and eight (n=108) individuals with definite MS, 49 men and 59 women (mean age: 44+/-8 y) and 108 age- and sex matched healthy controls (mean age: 44+/-9 y) were included. Fifty patients (n=58, 54%) reported pain and 50 (46%) did not exhibit pain. Pressure pain threshold (PPT) was bilaterally assessed over supra-orbital, infra-orbital, mental, median, radial and ulnar nerve trunks, C5-C6 joint, second metacarpal and tibialis anterior muscle by an assessor blinded to the subject's condition. The intensity of pain was assessed with a numerical pain rate scale (0-10), fatigue was determined with the fatigue impact scale (FIS), and depression was evaluated with the Beck Depression Inventory (BDI-II).
Results: The ANCOVAs revealed that PPT were significantly decreased bilaterally over the supra-orbital, infra-orbital, mental, median, ulnar, and radial nerve trunks, C5-C6 joint, second metacarpal and tibialis anterior muscles in patients with MS compared to healthy controls (all, P<0.001). No significant differences existed between MS patients with pain and those without pain (all P>0.944). Patients with pain exhibited higher fatigue and depression than those patients without pain (P<0.05). PPT was not associated with any clinical variable, i.e., pain, depression, or fatigue).
Conclusions: Our study found widespread pressure pain hyperalgesia in individuals with MS as compared to healthy controls. No differences existed between MS patients with pain and those without pain in the presence of widespread pressure sensitivity. Current results suggest that MS is associated with sensory hyper-excitability of the central nervous system or dysfunction in endogenous pain modulatory systems.
(C) 2014 by Lippincott Williams & Wilkins