Impaired attention network in temporal lobe epilepsy: a resting FMRI study

Attention deficit is a common symptom in the patient with mesial temporal lobe epilepsy (mTLE). Although presumption has been proposed by the previous study that mTLE may have impaired attention networks, no fMRI study has addressed the alteration of the dorsal attention network in mTLE. Twenty-four patients with bilateral mTLE and the same number of gender- and age-matched healthy controls participated in the current fMRI study. The resting-state network corresponding to the dorsal attention network (DAN) was extracted by using independent component analysis (ICA) from each participant. Functional connectivity in the DAN was then compared between the patients and controls. In addition, the scores of Trail Making Test (TMT) in the patients were correlated to the z-score of the voxels showing significant difference between the two groups. Compared with the controls, the patients with mTLE presented decreased functional connectivity in almost all the regions within the DAN. Moreover, there were negative correlations between the TMT scores and the z-scores in the voxels showing decreased or increased functional connectivity in mTLE. Our results suggested that the alteration of DAN might underpin the impairment of top-down attention function in mTLE. Our fMRI study may contribute to the understanding of neuro-pathophysiological mechanism of attention impairments in patients with mTLE.