Epileptic eye deviation

Ipsiversive ictal eye deviation in inferioposterior temporal lobe epilepsy—Two SEEG cases report

“…Epileptic eye deviation in seizure originated from the parieto-temporo-occipital region had been reported previously [ 8 – 16 ]. The underlying mechanisms of lateralized eye deviation during epileptic stimulation had been presumed as below: contralateral eye deviation is attributed to the involvement of cortical saccadic areas, and the stimulation of smooth pursuit cortical areas during epileptic seizures causesipsilateral ocular deviation [ 8 , 9 , 14 , 33 ]. However, actual case of epileptic ipsiversion, manifesting as eyes conjugate deviation to the ipsilateral side of the epileptic focus, was rarely reported [ 33 ], and empirical evidence on the presumed mechanisms underlying the ipsilateral eye deviation has not been documented in details.…”

“…However, the lateralizing and localizing significance of ictal eye deviation, even the versive type, during partial epileptic seizures has been questioned by clinical observations froma series of focal epilepsy studies focusing on the lateralization, particularly because of that the epileptic eye deviation may be ipsilateral or contralateral to the electroencephalography (EEG) focus, and has been associated with focal manifestations of EEG or neuroimaging evidence from frontal, central, temporal, parietal and occipital areas [ 8 – 22 ]. Although the fundamental reasons for these differences may be much more complicated than people originally understood, variations of eye movementsinduced by different pathophysiology during seizures must be considered.…”

“…Among them, smooth pursuit is the most common type of eye movement guided by retinal imaging which mediates eye deviation to the visual stimuli [ 23 , 24 ]. Although epileptic ipsiversion occurs incidentally and has been discussed curtly, ithasbeen attributed to activation of the smooth pursuit eye movements mediated by the temporo-occipital cortex [ 8 , 9 ]. By contrast, epileptic contraversion was assumed to occur as a result of the stimulation of the saccadic system by the cortico-superior collicular pathway [ 8 , 9 ].…”

“…Only a few comparative studies hitherto investigated human homology of MT/MST functional organization, and the resultsindicated that the vicinity of posterior branch of the inferior temporal sulcus is motion-sensitive area and direct stimulation to this area induces constant ipsilateral eye deviation [ 25 , 30 , 31 ]. Anatomical correlation of the eyemovement disorders during epileptic seizuresgenerated in human MT (or MST), however, has been scarcely discussed [ 8 , 13 , 32 ]. We present here two caseswhose epileptogenic zones have been confirmed by ictal stereoelectroencephalography (SEEG) and freedom from seizures during the long term follow-up after surgery.…”