Longitudinal EpiTrack assessment of executive functions following vagus nerve stimulation therapy in patients with drug-resistant epilepsy

Abstract

<p>OBJECTIVE: To investigate executive functions and attention with repeated EpiTrack evaluations in a group of DR patients with drug-resistant epilepsy (DRE) receiving vagus nerve stimulation (VNS) during a follow-up duration of up to 5 years.</p><p>METHODS: The study involved 33 patients with DRE who were assessed with EpiTrack as a part of the clinical VNS protocol. Evaluations were scheduled prior to VNS implantation and then at 6 months, 12 months, and yearly thereafter. However, the COVID-19 pandemic disrupted follow-up. Therefore, changes in EpiTrack total scores over time were analyzed using a linear mixed-effects (LMEs) model to compensate for the variation in follow-up duration when predicting EpiTrack total score changes over 5 years.</p><p>RESULTS: The median follow-up time was 29 months. During each month, the EpiTrack total score was predicted to increase by 0.07 units (95% confidence interval [CI]: 0.01-0.12, P = 0.02), corresponding to a change from a baseline score of 27.3 (severe impairment) to a score of 28.9 (mild impairment) at 2 years and a score of 31.5 (almost normal) at 5 years. In the group of patients with psychiatric comorbidities, the EpiTrack total score increased by 0.14 units per month (P = 0.003), which was 3.5-fold higher than the increase of patients without psychiatric comorbidities. For the patients taking 1-2 antiseizure medications (ASMs), the EpiTrack total score increased by 0.11 units per month (P = 0.005), which was almost quadruple the rate of patients taking 3-4 ASMs.</p><p>SIGNIFICANCE: Based on EpiTrack total scores, the LME model predicted a four-point improvement in executive functions among patients with DRE at 5 years after the initiation of VNS, representing a clinically meaningful change. DRE patients with comorbid depression seemed to experience the most cognitive benefits. In addition, better cognitive outcomes were achieved if the patient took less than three ASMs.</p><p>PLAIN LANGUAGE SUMMARY: Executive functions and attention may improve during vagus nerve stimulation therapy in patients with drug-resistant epilepsy. Epilepsy patients who have depression or use fewer than three antiseizure medications are likely to benefit cognitively more from the treatment.</p>

Objective: To investigate executive functions and attention with repeated EpiTrack evaluations in a group of DR patients with drug-resistant epilepsy (DRE) receiving vagus nerve stimulation (VNS) during a follow-up duration of up to 5 years.<br/>Methods: The study involved 33 patients with DRE who were assessed with EpiTrack as a part of the clinical VNS protocol. Evaluations were scheduled prior to VNS implantation and then at 6 months, 12 months, and yearly thereafter. However, the COVID-19 pandemic disrupted follow-up. Therefore, changes in EpiTrack total scores over time were analyzed using a linear mixed-effects (LMEs) model to compensate for the variation in follow-up duration when predicting EpiTrack total score changes over 5 years.<br/>Results: The median follow-up time was 29 months. During each month, the EpiTrack total score was predicted to increase by 0.07 units (95% confidence interval [CI]: 0.01–0.12, P = 0.02), corresponding to a change from a baseline score of 27.3 (severe impairment) to a score of 28.9 (mild impairment) at 2 years and a score of 31.5 (almost normal) at 5 years. In the group of patients with psychiatric comorbidities, the EpiTrack total score increased by 0.14 units per month (P = 0.003), which was 3.5-fold higher than the increase of patients without psychiatric comorbidities. For the patients taking 1–2 antiseizure medications (ASMs), the EpiTrack total score increased by 0.11 units per month (P = 0.005), which was almost quadruple the rate of patients taking 3–4 ASMs.<br/>Significance: Based on EpiTrack total scores, the LME model predicted a four-point improvement in executive functions among patients with DRE at 5 years after the initiation of VNS, representing a clinically meaningful change. DRE patients with comorbid depression seemed to experience the most cognitive benefits. In addition, better cognitive outcomes were achieved if the patient took less than three ASMs.<br/>Plain Language Summary: Executive functions and attention may improve during vagus nerve stimulation therapy in patients with drug-resistant epilepsy. Epilepsy patients who have depression or use fewer than three antiseizure medications are likely to benefit cognitively more from the treatment.