Long-term cognitive and behavioural follow-up in three patients with eye closure-triggered paroxysmal activity.

PURPOSE

To study clinical, EEG, neuropsychological and behavioural evolution of three patients presenting with epileptic activity triggered by eye closure (EC) over a mean 10-year follow-up period.

METHODS

All patients were studied at the time of the first observation (T0) and after a long follow-up period (T1). At both T0 and T1, each patient underwent: 1) traditional and specific activation techniques during prolonged video-EEG monitoring to detect possible inducing factors; 2) neuropsychological evaluations during video-EEG monitoring either with eyes closed or eyes open to detect any transient cognitive impairment (TCI); 3) detailed neuropsychological assessment without simultaneous EEG recording, to detect any stable cognitive impairment (SCI).

RESULTS

EEG recordings showed transient, generalized paroxysms in one case and a continuous epileptic activity triggered by eye closure in the other two cases, at both T0 and T1. In all patients, no particular epileptiform discharge-induced factors were identified except for eye blinking (spontaneous, voluntary or induced by corneal reflex). The results of neuropsychological assessment while eyes were closed as compared to performances with eyes open, showed no significant differences at T0 or at T1 in two cases, thus possibly indicating the absence of TCI. Wechsler Intelligence Scales showed a decrease in performance at T1 in the two patients with eye closure-induced, continuous epileptiform activity. Detailed neuropsychological assessment without EEG recordings demonstrated an impairment of facial recognition ability in all three patients at T1.

CONCLUSIONS

The lack of any differences between the results of neuropsychological tests performed with eyes open and eyes closed in two patients might suggest that not all eye-closure-triggered paroxysms are associated with TCI. On the other hand, our data highlight that EC-triggered, EEG epileptic discharges can produce long-lasting neuropsychological and behavioural effects, and also indicate that EEG discharges recurring over time might exert a disruptive effect on cognitive functions. Our three patients showed extreme variability across the neuropsychological tasks except for a facial recognition deficit that was evident in all cases, thus suggesting a possible dysfunction of temporo-occipital brain structures and/or of the fusiform face area as recently demonstrated by combined fMRI/EEG studies in patients with fixation-off sensitivity.