Insomnia and circadian variation of attacks in episodic migraine.
OBJECTIVE
To assess the influence of insomnia on the 24-hour temporal pattern of migraine.


BACKGROUND
Migraine attacks have been reported to occur in a harmonic (monophasic) or a biphasic 24-hour cyclic manner, and in some studies to have preponderance in the morning hours. The influence of insomnia on the circadian pattern has not been evaluated.


METHODS
Based on a previous study of the circadian variation in migraine, an explorative data analysis was made to compare the circadian pattern of insomnia-related migraine attacks to the circadian pattern of migraine attacks not related to insomnia. If the patients reported difficulties in falling asleep and/or maintaining sleep the night prior to the reported attack or the night the attack occurred, the attack was defined as insomnia-related. Relapses were not counted as distinctive attacks.


RESULTS
Sixty-eight female migraineurs (mean +/- SD age: 35.5 +/- 7.0) prospectively recorded 1869 migraine attacks. Five hundred-and-thirty-three attacks (29%) were insomnia-related. Insomnia-related attacks had a biphasic temporal pattern with one peak in the morning hours and one peak after noon. They had a preponderance in the morning hours compared to attacks not related to insomnia (t= 3.27, df = 62, P= .002). In 79% of attacks insomnia was experienced prior to the headache.


CONCLUSIONS
Episodic morning migraine is associated with insomnia. The cause and consequences of insomnia in migraine is not clarified, but sleep obviously protects against attacks rather than provokes them.
Alstadhaug
Karl
K
Department of Neurology, Nordlandssykehuset, Bodø, Norway.
Salvesen
Rolf
R
Bekkelund
Svein
S
D000293:Adolescent; D000328:Adult; D002940:Circadian Rhythm; D005260:Female; D006801:Humans; D008875:Middle Aged; D008881:Migraine Disorders / Q000150:complications*; D011446:Prospective Studies; D012621:Seasons; D007319:Sleep Initiation and Maintenance Disorders / Q000150:complications*