Closed-loop vagus nerve stimulation (VNS) paired with rehabilitative training has emerged as a st... more Closed-loop vagus nerve stimulation (VNS) paired with rehabilitative training has emerged as a strategy to enhance recovery after neurological injury. Previous studies demonstrate that brief bursts of closed-loop VNS paired with rehabilitative training substantially improve recovery of forelimb motor function in models of unilateral and bilateral contusive spinal cord injury (SCI) at spinal level C5/6. While these findings provide initial evidence of the utility of VNS for SCI, the injury model used in these studies spares the majority of alpha motor neurons originating in C7-T1 that innervate distal forelimb muscles. Because the clinical manifestation of SCI in many patients involves damage at these levels, it is important to define whether damage to the distal forelimb motor neuron pools limits VNS-dependent recovery. In this study, we assessed recovery of forelimb function in rats that received a bilateral incomplete contusive SCI at C7/8 and underwent extensive rehabilitative tr...
Background: Vagus Nerve Stimulation (VNS) paired with rehabilitation improved upper extremity imp... more Background: Vagus Nerve Stimulation (VNS) paired with rehabilitation improved upper extremity impairment and function in a recent pivotal, randomised, blinded, sham-controlled trial. Here we report post-hoc sub-group analyses from the VNS Rehab trial. We aimed to determine whether treatment effects were consistent across subgroups. Methods: VNS Rehab included 108 participants with moderate to severe arm /hand weakness, at least nine months after ischaemic stroke. They were randomised to receive rehabilitation paired with active VNS or rehabilitation paired with sham stimulation (Control). The primary outcome was the change in iFugl-Meyer Assessment Upper Extremity (FMA-UE) score on the first day after completion of in-clinic therapy. The trial was registered on ClinicalTrials.gov (NCT03131960). We explored the effect of VNS treatment by sex (n=70 males; n=38 females), age (≤ 65 or >65 years)), time from stroke (median time, 2 years) and baseline FMA-UE score (<=33 severe, >...
Supplemental Material for Study protocol for a pivotal randomised study assessing vagus nerve sti... more Supplemental Material for Study protocol for a pivotal randomised study assessing vagus nerve stimulation during rehabilitation for improved upper limb motor function after stroke by Teresa J Kimberley, Cecília N Prudente, Navzer D Engineer, David Pierce, Brent Tarver, Steven C Cramer, David Alexander Dickie and Jesse Dawson in European Stroke Journal
Supplemental material, Supplementary_File1_NE for Vagus Nerve Stimulation Paired With Upper-Limb ... more Supplemental material, Supplementary_File1_NE for Vagus Nerve Stimulation Paired With Upper-Limb Rehabilitation After Stroke: One-Year Follow-up by Jesse Dawson, Navzer D. Engineer, Cecília N. Prudente, David Pierce, Gerard Francisco, Nuray Yozbatiran, W. Brent Tarver, Reema Casavant, Danielle K. Kline, Steven C. Cramer, Ann Van de Winckel and Teresa J. Kimberley in Neurorehabilitation and Neural Repair
Introduction: Chronic upper limb impairment is a major predictor of poor functional outcome after... more Introduction: Chronic upper limb impairment is a major predictor of poor functional outcome after stroke. We have developed a rehabilitation intervention to address this isuue. It pairs VNS with intensive upper limb training. Our hypothesis is that short bursts of VNS, specifically timed during therapy, will drive cortical plasticity and improve clinical outcomes via timely release of neuromodulators such as acetylcholine and norepinephrine. Methods: Our research includes preclinical and clinical studies. In pre-clinical studies VNS was paired with different types of motor training in a rat Endothelin-1 model of ischemic stroke (n=15). All studies included a sham and intensive therapy control arm (n=17). We also explored the effect of VNS timing through randomizing its timing (n=2 rats). A randomized, controlled clinical trial with blinded endpoint assessment is underway. Twenty patients, at least 6 months after ischaemic stroke with chronic arm impairment will be recruited (10 VNS ...
Introduction: Vagus Nerve Stimulation (VNS) paired with rehabilitation induces movement specific ... more Introduction: Vagus Nerve Stimulation (VNS) paired with rehabilitation induces movement specific plasticity in rat motor cortex and improves forepaw function in a rat ischemic model compared to rehabilitation alone. A 20 subject first-in-human study in the UK indicated acceptable safety and feasibility of this approach in patients with arm weakness after stroke and showed a significant difference in favour of VNS paired with rehabilitation in the per-protocol analysis (Upper Extremity Fugl Meyer difference of 9.6 points for VNS vs. 3.0 Control; p = 0.038). We conducted a new, double-blind sham controlled study to further assess this technique. Methods: Subjects with chronic moderate to severe upper extremity hemiparesis secondary to ischemic stroke (Upper Extremity Fugl Meyer (UEFM) 20-50) were enrolled at four sites (3 US, 1 UK). After baseline assessments subjects were implanted with a vagus nerve stimulation device if all eligibility criteria were met. Following implantation, ran...
The neurocybernetic prosthesis (Cyberonics, Inc.) is an implantable, multiprogrammable pulse gene... more The neurocybernetic prosthesis (Cyberonics, Inc.) is an implantable, multiprogrammable pulse generator that delivers constant current electrical signals to the vagus nerve for the purpose of reducing the frequency and/or severity of epileptic seizures. The device is implanted in a subcutaneous chest pocket just below the clavicle, similar to cardiac pacemaker placement. The stimulation signal is transmitted from the prosthesis to the vagus nerve through a stimulation lead. The prosthesis can be programmed using any IBM-compatible personal computer with programming software and a programming wand. The electrodes used in the first group of patients were found to break at an unacceptable rate. Design modifications appear to have resolved this problem.
To determine rates of all-cause mortality and of sudden, unexpected, unexplained deaths in epilep... more To determine rates of all-cause mortality and of sudden, unexpected, unexplained deaths in epilepsy (SUDEP) in a cohort of individuals treated with the Neuro Cybernetic Prosthesis (NCP) System for intractable epilepsy, and; to contrast the NCP experience with other epilepsy cohorts. Methods: A cohort of 791 individuals were followed for 1,335 person-years from implantation. Of the total cohort, 120 individuals had their NCP System devices deactivated. The 15 deaths which occurred during NCP System activation were reviewed for SUDEP by a panel. There were three additional deaths and 242.5 person-years of monitoring after deactivation. Results: The standardized mortality ratios for NCP System were 5.3, 95% confidence interval (CI) 3.0-8.7; and for the time period after device deactivation, 4.4,95% CI 0.9-12.8. Six of the deaths during stimulation were considered definite or probable SUDEP and two as possible SUDEP. Seven were not considered to be SUDEP. The incidence of definite/probable SUDEP was 4.5 per 1,000 person-years and 6.0 per 1,000 person-years for definite/probable/possible SUDEP. Conclusions: The mortality rates and standardized mortality ratios are comparable with studies of young adults with intractable epilepsy who were not treated with NCP System. These SUDEP rates are not significantly different from those reported in the recent studies of lamotrigine (LTG), gabapentin (GBP), and tiagabine (TGB). The higher rates of SUDEP in the NCP System cohort, as compared with recent drug trials, presumably is explained by the selection of relatively higher-risk patients for the NCP System device.
Background. Vagus nerve stimulation (VNS) paired with rehabilitation may improve upper-limb impai... more Background. Vagus nerve stimulation (VNS) paired with rehabilitation may improve upper-limb impairment and function after ischemic stroke. Objective. To report 1-year safety, feasibility, adherence, and outcome data from a home exercise program paired with VNS using long-term follow-up data from a randomized double-blind study of rehabilitation therapy paired with Active VNS (n = 8) or Control VNS (n = 9). Methods. All people were implanted with a VNS device and underwent 6 weeks in clinic therapy with Control or Active VNS followed by home exercises through day 90. Thereafter, participants and investigators were unblinded. The Control VNS group then received 6 weeks in-clinic Active VNS (Cross-VNS group). All participants then performed an individualized home exercise program with self-administered Active VNS. Data from this phase are reported here. Outcome measures were Fugl-Meyer Assessment—Upper Extremity (FMA-UE), Wolf Motor Function Test (Functional and Time), Box and Block Te...
Objective: In individuals with chronic tinnitus, our interest was to determine whether daily low-... more Objective: In individuals with chronic tinnitus, our interest was to determine whether daily low-level electrical stimulation of the vagus nerve paired with tones (paired-VNSt) for tinnitus suppression had any adverse effects on motor-speech production and physiological acoustics of sustained vowels. Similarly, we were also interested in evaluating for changes in pure-tone thresholds, word-recognition performance, and minimum-masking levels. Both voice and hearing functions were measured repeatedly over a period of 1 year. Study design: Longitudinal with repeated-measures. Methods: Digitized samples of sustained frontal, midline, and back vowels (/e/, /o/, /ah/) were analyzed with computer software to quantify the degree of jitter, shimmer, and harmonic-to-noise ratio contained in these waveforms. Pure-tone thresholds, monosyllabic word-recognition performance, and MMLs were also evaluated for VNS alterations. Linear-regression analysis was the benchmark statistic used to document change over time in voice and hearing status from a baseline condition. Results: Most of the regression functions for the vocal samples and audiometric variables had slope values that were not significantly different from zero. Four of the nine vocal functions showed a significant improvement over time, whereas three of the pure tone regression functions at 2-4 kHz showed some degree of decline; all changes observed were for the left ear, all were at adjacent frequencies, and all were ipsilateral to the side of VNS. However, mean pure-tone threshold changes did not exceed 4.29 dB from baseline and therefore, would not be considered clinically significant. In some individuals, larger threshold shifts were observed. No significant regression/slope effects were observed for word-recognition or MMLs.
We have previously shown the safety and feasibility of vagus nerve stimulation (VNS) paired with ... more We have previously shown the safety and feasibility of vagus nerve stimulation (VNS) paired with upper-limb rehabilitation after ischemic stroke. In this exploratory study, we assessed whether clinical and brain MRI variables predict response to treatment. We used data from two completed randomised and blinded clinical trials (N = 35). All participants had moderate to severe upper-limb weakness and were randomised to 6-weeks intensive physiotherapy with or without VNS. Participants had 3 T brain MRI at baseline. The primary outcome was change in Fugl-Meyer Assessment, upper-extremity score (FMA-UE) from baseline to the first day after therapy completion. We used general linear regression to identify clinical and brain MRI predictors of change in FMA-UE. VNS-treated participants had greater improvement in FMA-UE at day-1 post therapy than controls (8.63 ± 5.02 versus 3.79 ± 5.04 points, t = 2.83, Cohen’s d = 0.96, P = 0.008). Higher cerebrospinal fluid volume was associated with less...
Background: Vagus nerve stimulation (VNS) paired with a motor task improves motor outcome in rat ... more Background: Vagus nerve stimulation (VNS) paired with a motor task improves motor outcome in rat stroke models. It is hypothesised that VNS delivered during rehabilitation will improve upper limb function compared to control rehabilitation therapy. Two pilot clinical studies demonstrated acceptable safety and feasibility of VNS paired with rehabilitation for improved upper limb function after stroke. Participants who received rehabilitation paired with VNS demonstrated clinically meaningful improvements in motor function that exceed gains seen among controls who received similar rehabilitation without VNS. These preliminary data support a larger pivotal trial. Methods: VNS-REHAB (VNS-Rehabilitation) is a pivotal, multi-site, double-blinded, randomised trial designed to evaluate safety and efficacy of VNS paired with upper limb rehabilitation after ischaemic stroke. The study will include up to 120 participants with upper limb weakness due to stroke nine months to 10 years prior. All participants will be implanted with a VNS device and randomised to receive either Active (0.8 mA) or Control VNS (0.0 mA) paired with upper limb rehabilitation. All participants receive 18 sessions of in-clinic therapy for six weeks, followed by a homebased therapy for three months. The rehabilitation therapy involves progressive, functionally based and intensive practice of hand and arm tasks. VNS is delivered during each movement repetition. After blinded follow-up is completed, the Active vagus nerve stimulation group continues with home-based Active VNS and the Control group receive six weeks of in-clinic therapy with Active VNS followed by home-based Active VNS. The primary efficacy endpoint will be the difference in Fugl-Meyer assessment-upper extremity scores between the Active VNS and Control VNS groups at the end of six weeks of in-clinic therapy. Additional secondary endpoints will also be measured. Safety will be assessed with analysis of adverse events and device complications during study participation. Discussion: This pivotal trial will determine whether VNS paired with rehabilitation is a safe and effective treatment for improving arm function after stroke. Trial Registration: ClinicalTrials.gov, NCT03131960. Registered on
Journal of Clinical Neurophysiology Official Publication of the American Electroencephalographic Society, Sep 1, 2001
The authors studied human vagus nerve electrophysiology intraoperatively on 21 patients (age rang... more The authors studied human vagus nerve electrophysiology intraoperatively on 21 patients (age range: 4 to 31 years) during implantation of a vagus nerve stimulator for seizure control. The study was performed with direct electrical stimulation of the vagus nerve with various stimulation parameters resembling those employed by the Cyberonics NeuroCybernetic Prosthesis System (Houston, TX), which is used clinically for vagus nerve stimulation for treatment of seizures. Recordings were made directly from the rostral end of the vagus nerve. The response of the vagus nerve to various stimulus parameters in patients of different ages was studied. Based on the vagus nerve characteristics, age-related adjustments for stimulus parameters were recommended.
Closed-loop vagus nerve stimulation (VNS) paired with rehabilitative training has emerged as a st... more Closed-loop vagus nerve stimulation (VNS) paired with rehabilitative training has emerged as a strategy to enhance recovery after neurological injury. Previous studies demonstrate that brief bursts of closed-loop VNS paired with rehabilitative training substantially improve recovery of forelimb motor function in models of unilateral and bilateral contusive spinal cord injury (SCI) at spinal level C5/6. While these findings provide initial evidence of the utility of VNS for SCI, the injury model used in these studies spares the majority of alpha motor neurons originating in C7-T1 that innervate distal forelimb muscles. Because the clinical manifestation of SCI in many patients involves damage at these levels, it is important to define whether damage to the distal forelimb motor neuron pools limits VNS-dependent recovery. In this study, we assessed recovery of forelimb function in rats that received a bilateral incomplete contusive SCI at C7/8 and underwent extensive rehabilitative tr...
Background: Vagus Nerve Stimulation (VNS) paired with rehabilitation improved upper extremity imp... more Background: Vagus Nerve Stimulation (VNS) paired with rehabilitation improved upper extremity impairment and function in a recent pivotal, randomised, blinded, sham-controlled trial. Here we report post-hoc sub-group analyses from the VNS Rehab trial. We aimed to determine whether treatment effects were consistent across subgroups. Methods: VNS Rehab included 108 participants with moderate to severe arm /hand weakness, at least nine months after ischaemic stroke. They were randomised to receive rehabilitation paired with active VNS or rehabilitation paired with sham stimulation (Control). The primary outcome was the change in iFugl-Meyer Assessment Upper Extremity (FMA-UE) score on the first day after completion of in-clinic therapy. The trial was registered on ClinicalTrials.gov (NCT03131960). We explored the effect of VNS treatment by sex (n=70 males; n=38 females), age (≤ 65 or >65 years)), time from stroke (median time, 2 years) and baseline FMA-UE score (<=33 severe, >...
Supplemental Material for Study protocol for a pivotal randomised study assessing vagus nerve sti... more Supplemental Material for Study protocol for a pivotal randomised study assessing vagus nerve stimulation during rehabilitation for improved upper limb motor function after stroke by Teresa J Kimberley, Cecília N Prudente, Navzer D Engineer, David Pierce, Brent Tarver, Steven C Cramer, David Alexander Dickie and Jesse Dawson in European Stroke Journal
Supplemental material, Supplementary_File1_NE for Vagus Nerve Stimulation Paired With Upper-Limb ... more Supplemental material, Supplementary_File1_NE for Vagus Nerve Stimulation Paired With Upper-Limb Rehabilitation After Stroke: One-Year Follow-up by Jesse Dawson, Navzer D. Engineer, Cecília N. Prudente, David Pierce, Gerard Francisco, Nuray Yozbatiran, W. Brent Tarver, Reema Casavant, Danielle K. Kline, Steven C. Cramer, Ann Van de Winckel and Teresa J. Kimberley in Neurorehabilitation and Neural Repair
Introduction: Chronic upper limb impairment is a major predictor of poor functional outcome after... more Introduction: Chronic upper limb impairment is a major predictor of poor functional outcome after stroke. We have developed a rehabilitation intervention to address this isuue. It pairs VNS with intensive upper limb training. Our hypothesis is that short bursts of VNS, specifically timed during therapy, will drive cortical plasticity and improve clinical outcomes via timely release of neuromodulators such as acetylcholine and norepinephrine. Methods: Our research includes preclinical and clinical studies. In pre-clinical studies VNS was paired with different types of motor training in a rat Endothelin-1 model of ischemic stroke (n=15). All studies included a sham and intensive therapy control arm (n=17). We also explored the effect of VNS timing through randomizing its timing (n=2 rats). A randomized, controlled clinical trial with blinded endpoint assessment is underway. Twenty patients, at least 6 months after ischaemic stroke with chronic arm impairment will be recruited (10 VNS ...
Introduction: Vagus Nerve Stimulation (VNS) paired with rehabilitation induces movement specific ... more Introduction: Vagus Nerve Stimulation (VNS) paired with rehabilitation induces movement specific plasticity in rat motor cortex and improves forepaw function in a rat ischemic model compared to rehabilitation alone. A 20 subject first-in-human study in the UK indicated acceptable safety and feasibility of this approach in patients with arm weakness after stroke and showed a significant difference in favour of VNS paired with rehabilitation in the per-protocol analysis (Upper Extremity Fugl Meyer difference of 9.6 points for VNS vs. 3.0 Control; p = 0.038). We conducted a new, double-blind sham controlled study to further assess this technique. Methods: Subjects with chronic moderate to severe upper extremity hemiparesis secondary to ischemic stroke (Upper Extremity Fugl Meyer (UEFM) 20-50) were enrolled at four sites (3 US, 1 UK). After baseline assessments subjects were implanted with a vagus nerve stimulation device if all eligibility criteria were met. Following implantation, ran...
The neurocybernetic prosthesis (Cyberonics, Inc.) is an implantable, multiprogrammable pulse gene... more The neurocybernetic prosthesis (Cyberonics, Inc.) is an implantable, multiprogrammable pulse generator that delivers constant current electrical signals to the vagus nerve for the purpose of reducing the frequency and/or severity of epileptic seizures. The device is implanted in a subcutaneous chest pocket just below the clavicle, similar to cardiac pacemaker placement. The stimulation signal is transmitted from the prosthesis to the vagus nerve through a stimulation lead. The prosthesis can be programmed using any IBM-compatible personal computer with programming software and a programming wand. The electrodes used in the first group of patients were found to break at an unacceptable rate. Design modifications appear to have resolved this problem.
To determine rates of all-cause mortality and of sudden, unexpected, unexplained deaths in epilep... more To determine rates of all-cause mortality and of sudden, unexpected, unexplained deaths in epilepsy (SUDEP) in a cohort of individuals treated with the Neuro Cybernetic Prosthesis (NCP) System for intractable epilepsy, and; to contrast the NCP experience with other epilepsy cohorts. Methods: A cohort of 791 individuals were followed for 1,335 person-years from implantation. Of the total cohort, 120 individuals had their NCP System devices deactivated. The 15 deaths which occurred during NCP System activation were reviewed for SUDEP by a panel. There were three additional deaths and 242.5 person-years of monitoring after deactivation. Results: The standardized mortality ratios for NCP System were 5.3, 95% confidence interval (CI) 3.0-8.7; and for the time period after device deactivation, 4.4,95% CI 0.9-12.8. Six of the deaths during stimulation were considered definite or probable SUDEP and two as possible SUDEP. Seven were not considered to be SUDEP. The incidence of definite/probable SUDEP was 4.5 per 1,000 person-years and 6.0 per 1,000 person-years for definite/probable/possible SUDEP. Conclusions: The mortality rates and standardized mortality ratios are comparable with studies of young adults with intractable epilepsy who were not treated with NCP System. These SUDEP rates are not significantly different from those reported in the recent studies of lamotrigine (LTG), gabapentin (GBP), and tiagabine (TGB). The higher rates of SUDEP in the NCP System cohort, as compared with recent drug trials, presumably is explained by the selection of relatively higher-risk patients for the NCP System device.
Background. Vagus nerve stimulation (VNS) paired with rehabilitation may improve upper-limb impai... more Background. Vagus nerve stimulation (VNS) paired with rehabilitation may improve upper-limb impairment and function after ischemic stroke. Objective. To report 1-year safety, feasibility, adherence, and outcome data from a home exercise program paired with VNS using long-term follow-up data from a randomized double-blind study of rehabilitation therapy paired with Active VNS (n = 8) or Control VNS (n = 9). Methods. All people were implanted with a VNS device and underwent 6 weeks in clinic therapy with Control or Active VNS followed by home exercises through day 90. Thereafter, participants and investigators were unblinded. The Control VNS group then received 6 weeks in-clinic Active VNS (Cross-VNS group). All participants then performed an individualized home exercise program with self-administered Active VNS. Data from this phase are reported here. Outcome measures were Fugl-Meyer Assessment—Upper Extremity (FMA-UE), Wolf Motor Function Test (Functional and Time), Box and Block Te...
Objective: In individuals with chronic tinnitus, our interest was to determine whether daily low-... more Objective: In individuals with chronic tinnitus, our interest was to determine whether daily low-level electrical stimulation of the vagus nerve paired with tones (paired-VNSt) for tinnitus suppression had any adverse effects on motor-speech production and physiological acoustics of sustained vowels. Similarly, we were also interested in evaluating for changes in pure-tone thresholds, word-recognition performance, and minimum-masking levels. Both voice and hearing functions were measured repeatedly over a period of 1 year. Study design: Longitudinal with repeated-measures. Methods: Digitized samples of sustained frontal, midline, and back vowels (/e/, /o/, /ah/) were analyzed with computer software to quantify the degree of jitter, shimmer, and harmonic-to-noise ratio contained in these waveforms. Pure-tone thresholds, monosyllabic word-recognition performance, and MMLs were also evaluated for VNS alterations. Linear-regression analysis was the benchmark statistic used to document change over time in voice and hearing status from a baseline condition. Results: Most of the regression functions for the vocal samples and audiometric variables had slope values that were not significantly different from zero. Four of the nine vocal functions showed a significant improvement over time, whereas three of the pure tone regression functions at 2-4 kHz showed some degree of decline; all changes observed were for the left ear, all were at adjacent frequencies, and all were ipsilateral to the side of VNS. However, mean pure-tone threshold changes did not exceed 4.29 dB from baseline and therefore, would not be considered clinically significant. In some individuals, larger threshold shifts were observed. No significant regression/slope effects were observed for word-recognition or MMLs.
We have previously shown the safety and feasibility of vagus nerve stimulation (VNS) paired with ... more We have previously shown the safety and feasibility of vagus nerve stimulation (VNS) paired with upper-limb rehabilitation after ischemic stroke. In this exploratory study, we assessed whether clinical and brain MRI variables predict response to treatment. We used data from two completed randomised and blinded clinical trials (N = 35). All participants had moderate to severe upper-limb weakness and were randomised to 6-weeks intensive physiotherapy with or without VNS. Participants had 3 T brain MRI at baseline. The primary outcome was change in Fugl-Meyer Assessment, upper-extremity score (FMA-UE) from baseline to the first day after therapy completion. We used general linear regression to identify clinical and brain MRI predictors of change in FMA-UE. VNS-treated participants had greater improvement in FMA-UE at day-1 post therapy than controls (8.63 ± 5.02 versus 3.79 ± 5.04 points, t = 2.83, Cohen’s d = 0.96, P = 0.008). Higher cerebrospinal fluid volume was associated with less...
Background: Vagus nerve stimulation (VNS) paired with a motor task improves motor outcome in rat ... more Background: Vagus nerve stimulation (VNS) paired with a motor task improves motor outcome in rat stroke models. It is hypothesised that VNS delivered during rehabilitation will improve upper limb function compared to control rehabilitation therapy. Two pilot clinical studies demonstrated acceptable safety and feasibility of VNS paired with rehabilitation for improved upper limb function after stroke. Participants who received rehabilitation paired with VNS demonstrated clinically meaningful improvements in motor function that exceed gains seen among controls who received similar rehabilitation without VNS. These preliminary data support a larger pivotal trial. Methods: VNS-REHAB (VNS-Rehabilitation) is a pivotal, multi-site, double-blinded, randomised trial designed to evaluate safety and efficacy of VNS paired with upper limb rehabilitation after ischaemic stroke. The study will include up to 120 participants with upper limb weakness due to stroke nine months to 10 years prior. All participants will be implanted with a VNS device and randomised to receive either Active (0.8 mA) or Control VNS (0.0 mA) paired with upper limb rehabilitation. All participants receive 18 sessions of in-clinic therapy for six weeks, followed by a homebased therapy for three months. The rehabilitation therapy involves progressive, functionally based and intensive practice of hand and arm tasks. VNS is delivered during each movement repetition. After blinded follow-up is completed, the Active vagus nerve stimulation group continues with home-based Active VNS and the Control group receive six weeks of in-clinic therapy with Active VNS followed by home-based Active VNS. The primary efficacy endpoint will be the difference in Fugl-Meyer assessment-upper extremity scores between the Active VNS and Control VNS groups at the end of six weeks of in-clinic therapy. Additional secondary endpoints will also be measured. Safety will be assessed with analysis of adverse events and device complications during study participation. Discussion: This pivotal trial will determine whether VNS paired with rehabilitation is a safe and effective treatment for improving arm function after stroke. Trial Registration: ClinicalTrials.gov, NCT03131960. Registered on
Journal of Clinical Neurophysiology Official Publication of the American Electroencephalographic Society, Sep 1, 2001
The authors studied human vagus nerve electrophysiology intraoperatively on 21 patients (age rang... more The authors studied human vagus nerve electrophysiology intraoperatively on 21 patients (age range: 4 to 31 years) during implantation of a vagus nerve stimulator for seizure control. The study was performed with direct electrical stimulation of the vagus nerve with various stimulation parameters resembling those employed by the Cyberonics NeuroCybernetic Prosthesis System (Houston, TX), which is used clinically for vagus nerve stimulation for treatment of seizures. Recordings were made directly from the rostral end of the vagus nerve. The response of the vagus nerve to various stimulus parameters in patients of different ages was studied. Based on the vagus nerve characteristics, age-related adjustments for stimulus parameters were recommended.
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