Rationale:
Many drug-resistant genetic epilepsy syndromes are associated with sleep problems in children, leading to additional stress for the patients themselves and caregivers . The effects of vagus nerve stimulation (VNS Therapy) on sleep quality are not fully understood: some studies -mainly in adults- report improved sleep quality in patients with drug-resistant epilepsy (DRE) undergoing VNS, while others report reduced sleep quality, and some show no difference . This analysis aims to assess sleep quality in children with confirmed genetic epilepsy undergoing VNS Therapy in the CORE-VNS study.
Methods:
Participants were enrolled in a prospective, multicenter, multinational observational study- CORE-VNS (NCT03529045), which assesses the impact of VNS Therapy in a real-world setting in DRE patients across all age groups and epilepsy etiologies. For this analysis, participants with confirmed genetic epilepsy (CGE) who received VNS Therapy were selected. Changes in the global score and subdomains of the Children’s Sleep Habits Questionnaire (CSHQ) were analysed for children aged 2-17. The CSHQ is a 33-item parent-report questionnaire designed to assess the following sleep problems in children (night waking, daytime sleepiness, behavior during sleep, and bedtime behavior). CSHQ response options are on a 5-point scale from “Always” (occurs every night) to “Never” (occurs less than once a week) based on frequency during the past week (or most recent typical week). CSHQ has been validated for screening for sleep disorders in children presenting an internal consistency of 0.68 for the global score in a population-based sample and ranging from 0.36 - 0.70 for the subscales.
Results:
Full CSHQ data was available from 48 patients with confirmed genetic epilepsy at baseline and from 29 patients at 24 months. At baseline the mean global CSHQ score was 54.21 (5.1) which is distinctly above the abnormality cut-off points of 41. CSHQ scores were lower at all follow-up visits after initiation of VNS Therapy, and this reached statistical significance at three months (p=0.005) and at six months (p=0.028) of VNS Therapy. However, this improvement was no longer significant at subsequent visits. At three months (p=0.041) and 12 months (p=0.019), the domain of morning waking and daytime sleepiness was improved compared to baseline. However, this improvement was no longer significant at 24 months. The only domain that showed significant change at 24 months of VNS Therapy compared to baseline was “waking during the night”: scores improved from 3.87 (1.4) at baseline to 3.33 (1.4) at 24 months (p=0.002).
Conclusions:
Children with genetically confirmed epilepsy in CORE-VNS displayed abnormal sleep habits as reported by their parents prior to VNS implantation. Global sleep habits did not show significant change in the course of 24 months of VNS Therapy. However, VNS Therapy for DRE may be associated with an improvement of certain sleep behaviors, like waking during the night in children with genetically confirmed epilepsy.
Funding: The CORE-VNS Study was supported by LivaNova PLC.