Predominantly nocturnal seizures post temporal lobectomy: Characteristics of an unusual outcome group

To describe the characteristics of a patient group who, after temporal lobectomy for predominantly diurnal seizures, experience a postoperative conversion from diurnal to predominantly nocturnal seizures, and compare this group to those who continue to have a diurnal seizure pattern postoperatively.

From a cohort of 470 surgical cases with long-term follow-up, we retrospectively identified 16 patients with a predominantly nocturnal seizure pattern, including five with nocturnal seizures only (median follow-up 21 years) and compared them with 20 predominantly diurnal seizure patients.

Sustained postoperative improvement in seizure frequency was observed in 14/16 cases. Seizure recurrence after surgery occurred within the first postoperative year in 13/16 cases. In all but 3 cases the seizures were all predominantly nocturnal from the time of recurrence, whereas in 3 there was a period of diurnal seizures during the early postoperative years. One patient lapsed back to diurnal seizures after 16 years of predominantly nocturnal seizures. Compared to the predominantly diurnal group, these patients had a significantly later age at seizure onset and were older at the time of surgery.

Patients with predominantly nocturnal seizures comprise a small but distinct post-operative outcome category. Although not formally assessed, this outcome appears associated with improved quality of life, such as with eligibility to drive, with 50% of the sample confirmed as driving. This finding may help with providing prognostic information and counseling to these patients when they are identified postoperatively.