Generalized mechanical pain sensitivity over nerve tissues in patients with strictly unilateral migraine.
OBJECTIVE
No study has previously analyzed pressure pain sensitivity of nerve trunks in migraine. This study aimed to examine the differences in mechanical pain sensitivity over specific nerves between patients with unilateral migraine and healthy controls.


METHODS
Blinded investigators assessed pressure pain thresholds (PPT) over the supra-orbital nerves (V1) and peripheral nerve trunks of both upper extremities (median, radial, and ulnar nerves) in 20 patients with strictly unilateral migraine and 20 healthy matched controls. Pain intensity after palpation over both supra-orbital nerves was also assessed. A pressure algometer was used to quantify PPT, whereas a 10-point numerical pain rate scale was used to evaluate pain to palpation over the supra-orbital nerve.


RESULTS
The analysis of covariance revealed that pain to palpation over the supra-orbital nerve was significantly higher (P<0.001) on the symptomatic side (mean: 3.4, SD: 1.5) as compared with the nonsymptomatic side (mean: 0.5, SD: 1.2) in patients with migraine and both the dominant (mean: 0.2, SD: 0.4) and nondominant (mean: 0.3, SD: 0.5) sides in healthy controls. PPT assessed over the supra-orbital nerve on the symptomatic side (mean: 1.05, SD: 0.2 kg/cm) was significantly lower (P<0.05) than PPT measurements on the nonsymptomatic side (mean: 1.35, SD: 0.3 kg/cm) and either the dominant (mean: 1.9, SD: 0.2 kg/cm) or nondominant (mean: 1.9, SD: 0.3 kg/cm) sides in controls (P<0.001). Finally, PPT assessed over the median, ulnar, and radial nerves were significantly lower in patients with migraine as compared with controls (P<0.001), without side-to-side differences (P>0.6).


CONCLUSIONS
In patients with unilateral migraine, we found increased mechano-sensitivity of the supra-orbital nerve on the symptomatic side of the head. Outside the head, the same patients showed increased mechano-sensitivity of the main peripheral nerves of both upper limbs, without asymmetries. Such diffuse hypersensitivity of the peripheral nerves lends further evidence to the presence of a state of hyperexcitability of the central nervous system in patients with unilateral migraine.
Fernández-de-las-Peñas
César
C
Department of Physical Therapy, Occupational Therapy, Physical Medicine and Rehabilitation of Universidad Rey Juan Carlos, Alcorcón, Madrid, Spain. cesar.fernandez@urjc.es
Arendt-Nielsen
Lars
L
Cuadrado
María Luz
ML
Pareja
Juan A
JA
D000328:Adult; D005260:Female; D006801:Humans; D006930:Hyperalgesia / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D008881:Migraine Disorders / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology*; D010147:Pain Measurement / Q000379:methods*; D017288:Pain Threshold; D016037:Single-Blind Method; D014110:Touch