Abstracts

Rationale: Humans have individual differences in the timing of their daily activities falling between two extremes: morning types (larks) and evening types (owls). The normal work schedules, determined by light/dark cycles, tend to favor morning types and could lead to chronic sleep deprivation in evening types. Mostly anecdotal information indicates that patients with idiopathic generalized epilepsy (IGE) show a tendency for being 'owls'. This particular circadian sleep pattern is often not recognized by treating physicians and can have important implications in the diagnosis and management of these patients. Methods: We administered the English version of the Horne-Östberg self-assessment questionnaire to 23 patients with idiopathic generalized epilepsy and 20 patients with (LRE) to determine their morningness and eveningness chronotypes. This validated test assigns a score that ranges from 16, indicating extreme eveningness, to 86, indicating extreme morningness. Results were analyzed by using a one-way ANOVA.Results: The mean test score was 41.3 (r: 28-64) for the IGE group, and 54.6 (r: 32-73) for the LRE group (F=15.36; p=0.0003), indicating that IGE patients have a strong tendency towards an evening chronotype. Table 1 shows the distribution of patients among the different categories based on their scores. Table 2 shows the results of the self-assessment of patients as to their chronotypes based on 4 categories. The mean age of the IGE population was 23.6 years, and for the LRE group was 30.2 years (F=3.1; NS). In the IGE group, 11 had juvenile myoclonic epilepsy, 5 juvenile absence, 6 IGE with generalized tonic-clonic seizures (GTC) only (2 of which were IGE with GTC on awakening), and 1 IGE with versive seizures.Conclusions: This study demonstrates that the evening chronotype strongly predominates in patients with IGE. The finding of night habits in patients with GTC may suggest a diagnosis of IGE. More important, a strong evening chronotype has been associated with delayed sleep phase syndrome and chronic sleep deprivation, a well-known seizure-precipitating factor in IGE, so its recognition may be important for clinical management. References 1. Horne JA, Östberg O. A self-assessment questionnaire to determine morningness-eveningness in human circadian rhythms. Int J Chronobiol 1976;4:97-110.