CHRONOTYPES AND SUBJECTIVE SLEEP PARAMETERS IN EPILEPSY PATIENTS: A LARGE QUESTIONNAIRE STUDY

Abstract

Accumulating evidence suggests epilepsy and seizures may influence circadian rhythms and that circadian rhythms may influence epilepsy. It is also conceivable that seizure timing influences the timing of daily activities, sleeping, and wakefulness (i.e., chronotype). Only one group has studied the distribution of chronotypes of epileptics, showing significant differences between the diurnal activity patterns in two groups of patients with different epilepsy syndromes. The authors performed a questionnaire-based study of 200 epilepsy patients to compare the distribution of chronotypes and subjective sleep parameters of sleep duration and time of mid-sleep on free days to the distribution in the general population (n = 4042). Within this large group of epilepsy patients, we also compared the chronotypes of subsamples with well-defined epilepsy syndromes, i.e., temporal lobe epilepsy [TLE; n = 46], frontal lobe epilepsy [FLE; n = 30], and juvenile myoclonic epilepsy [JME; n = 38]. In addition, 27 patients who had had surgery for TLE were compared with those with TLE who had not had surgery. Both the Morningness-Eveningness Questionnaire and Munich Chronotype Questionnaire were used to determine chronotypes and subjective sleep parameters. Significant differences in morningness/eveningness distribution, timing of mid-sleep (corrected for sleep duration), and total sleep time on free days were found between epileptics and healthy controls. Those with epilepsy were more morning oriented, had earlier mid-sleep on free days, and longer sleep duration on free days (p < .001). However, distributions of chronotypes and sleep parameters between the groups of people with TLE, FLE, and JME did not differ. Persons who had surgery for TLE had similar morningness-eveningness parameters and similar sleep durations compared to those without surgery, but mid-sleep on free days was earlier in operated patients (p = .039). In conclusion, this is the first large study focusing on chronotypes in people with epilepsy. We show that the distribution of chronotypes and subjective sleep parameters of epileptics, in general, is different from that of healthy controls. Nevertheless, no differences are observed between patients with specified epilepsy syndromes, although they exhibit seizures with different diurnal patterns. Our results suggest that epilepsy, itself, rather than seizure timing, has a significant influence on chronotype behavior and subjective sleep parameters. (Author correspondence: [email protected])

Keywords:

• Chronotypes
• Circadian rhythm
• Epilepsy
• Seizures
• Subjective sleep parameters

ACKNOWLEDGMENTS

We are indebted to the patients who participated in this study and the controls who completed an online version of the questionnaire. We also thank the technicians who distributed the questionnaires to the patients and the neurologists of SEIN Zwolle and Heemstede for their cooperation. Furthermore, we thank Professor Ley Sander for reading the article and his knowledgeable suggestions. The work of W. A. Hofstra was financially supported by the ‘Christelijke Vereniging voor de Verpleging van Lijders aan Epilepsie’ and the work of MCM Gordijn by the 6th European Framework program EUCLOCK (No. 018741).

Declaration of Interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.