St. Herman et al., Distribution of partial seizures during the sleep-wake cycle - Differencesby seizure onset site, NEUROLOGY, 56(11), 2001, pp. 1453-1459
Objective: To evaluate the effects of sleep on partial seizures arising fro
m various brain regions. Methods: The authors prospectively studied 133 pat
ients with localization-related epilepsy undergoing video-EEG monitoring ov
er a 2-year period. Seizure type, site of onset, sleep/wake state at onset,
duration, and epilepsy syndrome diagnosis were recorded. Periorbital, chin
EMG, and scalp/sphenoidal electrodes were used. A subset of 34 patients un
derwent all-night polysomnography with scoring of sleep stages. Results: Th
e authors analyzed 613 seizures in 133 patients. Forty-three percent (264 o
f 613) of all partial seizures began during sleep. Sleep seizures began dur
ing stages 1 (23%) and 2 (68%) but were rare in slow-wave sleep; no seizure
s occurred during REM sleep. Temporal lobe complex partial seizures were mo
re likely to secondarily generalize during sleep (31%) than during wakefuln
ess (15%), but frontal lobe seizures were less likely to secondarily genera
lize during sleep (10% versus 26%; p < 0.005). Conclusions: Partial-onset s
eizures occur frequently during NREM sleep, especially stage 2 sleep. Front
al lobe seizures are most likely to occur during sleep. Patients with tempo
ral lobe seizures have intermediate sleep seizure rates, and patients with
seizures arising from the occipital or parietal lobes have rare sleep-onset
seizures. Sleep, particularly stage 2 sleep, promotes secondary generaliza
tion of temporal and occipitoparietal, but not frontal, seizures. These fin
dings suggest that the hypersynchrony of sleep facilitates both initiation
and propagation of partial seizures, and that effects of sleep depend in pa
rt on the location of the epileptic focus.