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: A total of 108 individuals with definite MS, 49 men and 59 women (mean age, 44±8 y) and 108 age-matched and sex-matched pain-free controls (mean age, 44±9 y) were included. Fifty patients (n=58, 54%) reported pain and 50 (46%) did not. Pressure pain threshold (PPT) was bilaterally assessed over supraorbital, infraorbital, mental, median, radial and ulnar nerve trunks, C5-C6 joint, second metacarpal, and tibialis anterior muscle by an assessor blinded to the patient’s condition. The intensity of pain was assessed with a numerical pain rate scale (0 to 10), fatigue was determined with the Fatigue Impact Scale, and depression was evaluated with the Beck Depression Inventory.
Results: The analyses of covariance revealed that PPT were significantly decreased bilaterally over the supraorbital, infraorbital, mental, median, ulnar and radial nerve trunks, C5-C6 joint, second metacarpal, and tibialis anterior muscles in patients with MS compared with pain-free 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, that is, pain, depression, or fatigue.
Conclusions: Our study found widespread pressure pain hyperalgesia in individuals with MS as compared with pain-free 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 hyperexcitability of the central nervous system or dysfunction in endogenous pain modulatory systems.
*Department of Physical Therapy, Occupational Therapy, Rehabilitation and Physical Medicine, Universidad Rey Juan Carlos, Alcorcón
§Department of Physical Therapy, Universidad Antonio de Nebrija
†Laboratory of Esthesiology, Facultad de Ciencias de la Salud, Universidad Rey Juan Carlos, Alcorcón, Madrid
∥Department of Neurology, Hospital Nuestra Señora de Sonsoles, Avila, Spain
‡Department of Health Science and Technology, Centre for Sensory-Motor Interaction (SMI), Aalborg University, Aalborg, Denmark
The authors declare no conflict of interest.
Reprints: César Fernández-de-las-Peñas, PT, PhD, DMSc, Laboratory of Esthesiology, Facultad de Ciencias de la Salud, Universidad Rey Juan Carlos, Avenida de Atenas s/n, Alcorcón 28922, Madrid, Spain (e-mail: email@example.com).
Received November 11, 2013
Received in revised form February 19, 2014
Accepted January 28, 2014