Adjunctive vagus nerve stimulation helps reduce seizure frequency

Vagus nerve stimulation (VNS) as an adjunctive treatment appears to lessen the frequency of generalized tonic–clonic seizures (GTCS) by 77 percent over 24 months, as shown in a study.

The analysis included 115 participants (median age at implantation 18 years, 62.6 percent male) with GTCS from the international, prospective observational study (CORE-VNS). Half of the participants were children (50.4 percent), and the median duration of epilepsy was 10 years. Baseline seizure frequency data and patient-reported outcome measures were collected at several time points: at 3, 6, 12, 24, and 36 months.

The participants had trialled a median of six antiseizure medications in their history of epilepsy care. Baseline cognitive status was normal in 24.3 percent of participants, minimally impaired in 20.0 percent, moderately impaired in 29.6 percent, or severely impaired in 26.1 percent. The 3-month baseline median count of GTCS was 12.

A median GTCS reduction of 73.9 percent was observed over 12 months of VNS, with 37 percent of participants reporting seizure freedom from GTCS for the last 3 months. This benefit was sustained at 24 months, with a median GTCS reduction of 77 percent and 42.6 percent of participants reporting seizure freedom for the last 3 months.

The percentage of participants reporting the postictal severity of their most debilitating seizure as “severe” or “very severe” dropped from 52.8 percent at baseline to 25.3 percent at 12 months and 26.3 percent at 24 months.

No significant changes were seen in the use of antiseizure medications during the follow-up.

In terms of safety, the reported adverse events (AEs) were typical of those previously documented in patients with drug-resistant epilepsy using VNS. These included dysphonia (11.3 percent), cough (6.1 percent), neck/oropharyngeal pain (4.3 percent), and general discomfort (1.7 percent). A total of 24 AEs in 12 participants led to VNS modification, such as change in settings or modification of medication dosage. Four AEs led to withdrawal/explant of the VNS device. Four participants died during the study period.