Abstracts

Rationale: It has been repeatedly shown that attentiveness and alertness is impaired in temporal lobe epilepsy (TLE). Recently it has been reported that ylang-ylang aroma has positive effects on attentiveness and alertness. We investigated the effect of ylang-ylang essential oils on cognitive functions of patients with TLE by measuring P300 as event-related potentials. Methods: The current study included thirteen TLE patients (34.1 10.6 years old, four females, twelve right-handed and one left-handed) and fourteen age-matched healthy controls. Six of thirteen patients were seizure free for more than twenty-two months. The laterality of epilepsy focus was left in four, right in one, bilateral in one, and unclear in the rest. The electroencephalogram was recorded from scalp electrodes including Fz, Cz, Pz, Oz and bilateral mastoids as participants inhaled air with ylang-ylang essential oils and an odorless control air. The stimulus series was composed of 1000Hz of frequent tones (80%) and 1050Hz of rare tones (20%). Rare tones were presented randomly with a 0.2 probability. At least 20 responses from rare stimuli were analyzed. Participants were instructed to watch a video screen showing of a cartoon story during sessions and to count the number of rare tones through earphones. P300 was evaluated as an averaged evoked potential waveform for the rare tones at Fz, Cz, Pz. The peak amplitudes and peak latencies between 300ms and 500ms were compared using analysis of variance (ANOVA) and t-test. Results: P300 amplitudes were significantly reduced (p<0.05) by inhalation of the ylang-ylang aroma while latencies of P300 were similar between two conditions in healthy control group. In contrast, there were no significant differences in P300 amplitudes or latencies between two conditions in the TLE patients. In the patients group, there were no differences between the effect of ylang-ylang aroma on remission group and intractable group. Error rates in counting rare sounds on the aroma condition and the odorless condition for TLE group were almost the same as healthy controls. Conclusions: Our results suggest that the effect of ylang-ylang aroma on the cognitive function reflected by the auditory P300 event-related potentials of patients with temporal lobe epilepsy may be limited, which might be related to impaired cognitive functions including attentiveness and alertness in TLE.