Brain Advance Access published online on March 31, 2009
Brain, doi:10.1093/brain/awp050
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Bilateral widespread mechanical pain sensitivity in carpal tunnel syndrome: evidence of central processing in unilateral neuropathy
1 Department of Physical Therapy, Occupational Therapy, Rehabilitation and Physical Medicine, Madrid, Spain 2 Laboratory of Aesthesiology of Universidad Rey Juan Carlos, Alcorcón, Madrid, Spain 3 Centre for Sensory-Motor Interaction (SMI), Department of Health Science and Technology, Aalborg University, Aalborg, Denmark 4 Department of Neurology of Fundación Hospital Alcorcón and Universidad Rey Juan Carlos, Alcorcón, Madrid, Spain 5 Department of Neurology of Hospital Clínico San Carlos and Universidad Complutense, Madrid, Spain
Correspondence to:
César Fernández de las Peñas, Facultad de Ciencias de la Salud, Universidad Rey Juan Carlos, Avenida de Atenas s/n, 28922 Alcorcón, Madrid, Spain E-mail: cesar.fernandez{at}urjc.es
The aim of this study was to investigate whether bilateral widespread pressure hypersensitivity exists in patients with unilateral carpal tunnel syndrome. A total of 20 females with carpal tunnel syndrome (aged 22–60 years), and 20 healthy matched females (aged 21–60 years old) were recruited. Pressure pain thresholds were assessed bilaterally over median, ulnar, and radial nerve trunks, the C5–C6 zygapophyseal joint, the carpal tunnel and the tibialis anterior muscle in a blinded design. The results showed that pressure pain threshold levels were significantly decreased bilaterally over the median, ulnar, and radial nerve trunks, the carpal tunnel, the C5–C6 zygapophyseal joint, and the tibialis anterior muscle in patients with unilateral carpal tunnel syndrome as compared to healthy controls (all, P < 0.001). Pressure pain threshold was negatively correlated to both hand pain intensity and duration of symptoms (all, P < 0.001). Our findings revealed bilateral widespread pressure hypersensitivity in subjects with carpal tunnel syndrome, which suggest that widespread central sensitization is involved in patients with unilateral carpal tunnel syndrome. The generalized decrease in pressure pain thresholds associated with pain intensity and duration of symptoms supports a role of the peripheral drive to initiate and maintain central sensitization. Nevertheless, both central and peripheral sensitization mechanisms are probably involved at the same time in carpal tunnel syndrome.
Key Words: carpal tunnel syndrome; pressure pain threshold; central sensitization
Received November 22, 2008. Revised January 31, 2009. Accepted February 3, 2009.