Background and purpose: This study analyzes sawtooth waves (STW), a characteristic feature of rapid eye movement (REM) sleep, in temporal lobe epilepsy patients in order to test the hypothesis of STW dysfunction in this population.
Methods: Polysomnographic records from 16 patients with temporal lobe epilepsy and 11 controls were scored for density (STW/h of REM sleep), duration (STW duration in s), and frequency of STW (waves/second within each STW complex). These measures were compared between both groups.
Results: STW measures were significantly different in control vs. epilepsy patients; respectively, density was 60.8 vs. 20.9 waves/h (P<0.005), average duration was 6.5 vs. 5.4 s (P<0.005 cycles 1-4), and frequency was 2.75 vs. 2.61 Hz (P<0.0005 across all cycles).
Conclusions: Our measurements show a change in the density, duration and frequency of STW in patients with temporal lobe epilepsy compared to controls. Other parameters of REM sleep appear to be similar in both groups. These findings suggest a cortical influence on REM sleep either directly or through limbic-hypothalamic-brainstem connections.