Cerebrovascular reactivity to hypercapnia in migraine patients measured with near-infrared spectroscopy

Migraine pain is considered to manifest itself as a result of an impaired cerebrovascular reactivity. Hence, proper quantification and diagnosis of this problem without causing more disturbance has always been a challenge in investigating migraine pathogenesis. Functional near-infrared spectroscopy system (fNIRS) is being proposed as an inexpensive, rapid, safe and accurate technique to monitor cerebrovascular dynamics. We have developed NIROXCOPE 201, a novel multi source and detector device of fNIRS, and attempted to investigate the cerebrovascular reactivity of migraine patients to a breath hold task which produces a metabolic perturbation. Six normals and six migraine patients performed four consecutive breath holding task. A typical brain hemodynamic response (BHR) is observed both for controls and migraineurs with an initial phase, main response and a recovery phase. Hence, fitting to a sum of three sequentially arranged gaussian curves proved that amplitudes of [Hb] and [HbO(2)] signals acquired by fNIRS are approximately two to five times higher in controls than migraine patients (P < 0.01) for all phases. Moreover, amplitude change between successive breath holds tends to converge to a steady value for controls whereas an uncontrolled percent change is observed for migraineurs. Our results confirm an impaired cerebrovascular reactivity in the frontal cortex of migraine patients interictally. (c) 2006 Elsevier B.V. All rights reserved.