Cerebral hemodynamic changes during limb-shaking TIA: A near-infrared spectroscopy study

Limb-shaking (LS) TIA is a rare form of TIA manifesting as involuntary movements involving one or more limbs. Cerebral ischemia in the context of hemodynamic failure has been incriminated.1 Indeed, LS-TIAs are associated with severe carotid steno-occlusive disease and often precipitated by a decrease in blood pressure.1 A limited number of studies using transcranial Doppler,2 133xenon SPECT,3 or 15O-H2O-PET4 have shown reduced regional cerebral blood flow (CBF) and diminished vasomotor reactivity. The latter techniques can only provide a single snapshot of regional CBF and do not allow for continuous assessment of cerebral hemodynamic changes during an actual LS-TIA. Functional near-infrared spectroscopy (fNIRS) is a neuroimaging technique that can noninvasively monitor at the bedside cortical changes in oxyhemoglobin (HbO2), deoxyhemoglobin (HbR), and total hemoglobin (HbT, as a proxy to cerebral blood volume).5 We report the hemodynamic changes observed throughout the course of LS-TIAs using a simultaneous multichannel fNIRS-EEG system.