Trigeminal neuralgia is considered as a paroxysmal single nerve phenomenon. Abnormal sensory perception has been previously described in 15-25% of patients with clinical examination. Quantitative sensory testing (QST) was used to evaluate sensory perception in patients with idiopathic trigeminal neuralgia (ITN). Nine patients and 10 normal control subjects were evaluated in all six trigeminal branches. QST abnormalities were found in the symptomatic division and in the other two branches on the same side. Minor contralateral changes were also found. Differences consisted of cold and warm hypoaesthesia and higher cold and heat pain thresholds in patients. All differences proved statistically significant. Our findings suggest that trigeminal neuralgia is not only a paroxysmal single nerve disorder, but also that other higher structures may be involved.