Neurovascular reactivity in patients with focal epilepsy

Author(s): Gulnur Tekgol Uzuner, Nevzat Uzuner


Complex neurovascular activation by transcranial Doppler (TCD) has not been presented at the moment in drug-responsive patients with focal epilepsy. The objective of this study is to assess the neurovascular activation to complex visual stimulation of drugresponsive patients with focal epilepsy during interictal period.


Twenty-five patients with focal epilepsy and 25 healthy subjects were screened for this study in our Neurosonology Laboratory. We performed transtemporal TCD recordings from the P2-segments of both posterior cerebral arteries (PCA) simultaneously during complex visual stimulation, at least, ten days after last epileptic attack. The individual reactivity was defined as a relative increase of the blood flow velocities as a percentage change of the baseline values.


Most of the patients have an epileptic focus in the temporal lobe documented by the EEG. The Doppler data of the epileptic sides and non-epileptic sides were analysed separately. The complex visual reactivity was significantly higher at the epileptic side in the patients (52.5%) from those of the controls (36.8%) (p=0.002).


In contrast to the earlier reports of the studies that were found diminished neurovascular reactivity to simple or complex visual stimulation using TCD, our study showed the temporal and occipital region of the patients with focal epilepsy have hyperactive neurovascular units at the epileptic side during the interictal period when comparing with the healthy subjects. However, to emphasise the importance of investigating neurovascular coupling in further studies are needed.


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