Abstracts

RATIONALE: Postictal nosewiping (PINW) is a common feature in temporal lobe epilepsy (TLE), occuring in approximately 50% to 60% of patients with TLE, and in only 10% to 33% of those with extra-temporal epilepsy (ETE). PINW is performed with the hand ipsilateral to the epileptogenic zone in the majority of patients, thus providing localizing and lateralizing indications with respect to seizure onset. The physiopathology of PINW remains however unknown. To date, the relation between PINW and intra-cerebral EEG data has been reported in only one patient, in whom PINW correlated with an amygdala discharge (Wennberg et al. 2000). We have therefore undertaken a retrospective study in 33 patients who underwent an intra-cranial EEG monitoring, with the aim to correlate PINW with the ictal involvement of the amygdala.
METHODS: 33 patients with refractory partial epilepsy who underwent an intra-cranial EEG investigation in our institution were included in this study. Video and intra-cranial EEG data of 204 seizures were reviewed independently by two different observers who respectively studied the occurence of ictal or postictal nosewiping, and the time of onset, duration, and origin of ictal EEG discharges. These different analysis used the same time reference, allowing to eventually calculate the delay separating each nosewiping from the seizure onset and termination. Only PINW occuring during the two minutes following the later were taken into account. We evaluated the ratio of seizures with at least one PINW for each individual, and compared this ratio between patients with TLE and ETE. In a subset of 49 temporal lobe seizures, we evaluated the type (low-voltage fast activity versus other types of ictal discharge), duration and earliness of an amygdala discharge, and looked for an association between these parameters and the occurence of PINW.
RESULTS: 24 patients suffered from TLE, whereas 9 patients had ETE. PINW was observed in 51% of temporal lobe seizures, and in only 3% of extra-temporal seizures (p=0,0001). 88% of TLE and 33% of ETE patients presented at least one seizure associated with PINW (p=0,0075), whereas 79% of TLE and no ETE patients showed PINW in at least one third of their recorded seizures (p=0.0002). All selected TLE patients presented with ictal discharges that involved the amygdala at some point. The occurence of PINW did not correlate with the type or the duration of that discharge. However, there was a weak association between the likelihood of observing PINW, and the involvement of the amygdala at seizure onset, which approached significance (p=0,0732 for Chi-2 with continuity correction, p=0,0358 without correction).
CONCLUSIONS: This intra-cranial EEG study has confirmed that postictal nosewiping is significantly more frequent in TLE than in ETE, and has a strong localizing value when occuring in at least 33% of recorded seizures. The role of an amygdala dysfunction in generating PINW is midly supported by the association found between PINW and the earliness of the amygdala discharge.
[Supported by: University Claude Bernard Lyon 1]