Doeltgen SH, Dalrymple-Alford J, Ridding MC, Huckabee ML.
Neurorehabil Neural Repair. 2010 Jul-Aug;24(6):519-27. Epub 2010 Mar 12.
Neuromuscular electrical stimulation (NMES) of the muscles underlying the pharynx and faucial pillars affects the excitability of corticobulbar projections in a frequency- and duration-specific manner. The anterior hyomandibular (submental) muscles are primary targets for the clinical application of NMES to improve disordered swallowing, but the optimal NMES parameters for this application are unknown.
To determine the influence of NMES parameters on the excitability of corticobulbar projections to the submental musculature.
Transcranial magnetic stimulation (TMS) was used in event-related protocols, triggered by either volitional contraction of the submental muscles or pharyngeal swallowing, to assess corticobulbar excitability prior to, immediately following, and 30, 60, and 90 minutes post-NMES in 25 healthy volunteers. In the first 2 experiments, 4 stimulus frequencies (5, 20, 40, and 80 Hz) and 3 NMES dosages, manipulated through stimulus train durations or number of repetitions, were evaluated. The optimal excitatory NMES triggered by volitional swallowing (event-related NMES) was then replicated in a new sample and contrasted with non-event-related NMES (either discrete events or continuously for 1 hour).
It was found that 80Hz NMES increased motor-evoked potential (MEP) amplitude at 30 minutes and 60 minutes poststimulation only after 60 repetitions of 4-s event-related NMES trains. Non-event-related and continuous NMES did not affect MEP amplitudes. No changes in MEP onset latencies were observed.
Changes in corticobulbar excitability induced by NMES of the submental muscle group are frequency and dose dependent and only occur after NMES triggered by volitional swallowing. Underlying neural mechanisms are discussed.
Pattani KM, McDuffie CM, Morgan M, Armstrong C, Nathan CO.
J La State Med Soc. 2010 Jan-Feb;162(1):21-5.
We observed a significant improvement in the complaints of dysphagia in patients with head and neck cancer who had received noninvasive neuromuscular electrical stimulation (E-stim) of their pharyngeal muscles. We wanted to determine if the improvement in dysphagia was a result of decreased complaints of xerostomia and increased saliva production, since one of our first patients being treated with E-stim noticed a significant improvement in xerostomia.
Prospective trial to determine the effects of E-stim by evaluating saliva production and dysphagia questionnaires instituted by our speech pathologists on head and neck cancer patients that had received radiotherapy (XRT) and were to undergo E-stim for dysphagia.
Prior to the initiation of E-stim and one to two months after E-stim, saliva samples were collected and patients were asked to answer a Dysphagia and Xerostomia Index Questionnaire. All patients received E-stim two to four months after completing XRT. Patients received three E-stim treatments per week for a total of one to two months. Four electrodes were placed along anterior neck over pharyngeal muscles. E-stim was initiated using four to 30mA at 80-100 pulse-widths.
Five patients that received either postoperative radiation therapy or concomitant chemoradiotherapy had been treated with E-stim. All five patients noticed a significant improvement in dysphagia. Five out of five patients noticed a definite increase in saliva production with symptoms of decreased intake of water with meals, sleeping longer hours at night, and increased moistness of lips.
E-stim therapy appears to be an effective and approved treatment for dysphagia. Our study shows that it may also be beneficial for xerostomia in the post-irradiated head and neck cancer patients.
To determine if E-stim will benefit the previously irradiated patient with dysphagia and xerostomia.
Restivo DA, Casabona A, Centonze D, Marchese-Ragona R, Maimone D, Pavone A.
Brain Stimul. 2012 Sep 23. pii: S1935-861X(12)00155-6. doi: 10.1016/j.brs.2012.09.001. [Epub ahead of print]
Treatment options for dysphagia associated with multiple sclerosis (MS) are currently limited. In this study we investigated whether intraluminal electrical pharyngeal stimulation facilitates swallowing recovery in dysphagic MS patients.
PATIENTS AND METHODS:
Twenty dysphagic MS patients were randomized to receive 5 Hz “real” pharyngeal stimulation (10 patients) for 10 min or “sham” pharyngeal stimulation for 10 min (10 patients). Patients were evaluated by videofluoroscopic, and electromyographic examinations, and by the Penetration/Aspiration Scale (PAS) performed before (T(0)) and immediately after the last session of 5 consecutive days of electrical pharyngeal stimulation (T(1)), and then after two (T(2)), and four (T(3)) weeks of 5 consecutive days of pharyngeal electrical stimulation.
Patients who received “real” stimulation showed a significant improvement in all the swallowing outcome measures as compared with those receiving “sham” stimulation.
No specific treatment for oro-pharyngeal dysphagia related to MS has been described to date. Our preliminary findings suggest a potential benefit of intraluminal electrical pharyngeal stimulation for the treatment of dysphagia caused by MS.
Rodríguez L, Rodriguez P, Gómez B, Ayala JC, Saba J, Perez-Castilla A, Galvao Neto M, Crowell MD.
Surg Endosc. 2012 Oct 17.
Electrical stimulation of the lower esophageal sphincter (LES) improves LES pressure without interfering with LES relaxation. The aim of this open-label pilot trial was to evaluate the safety and efficacy of long-term LES stimulation using a permanently implanted LES stimulator in patients with gastroesophageal reflux disease (GERD).
GERD patients who were at least partially responsive to proton pump inhibitors (PPI) with abnormal esophageal pH, hiatal hernia ≤3 cm, and esophagitis ≤LA grade C were included. Bipolar stitch electrodes were placed in the LES and an IPG was placed in a subcutaneous pocket. Electrical stimulation was delivered at 20 Hz, 215 μs, 3-8 mA in 30 min sessions. The number and timing of sessions was tailored to each patient’s GERD profile. Patients were evaluated using GERD-HRQL, daily symptom and medication diaries, SF-12, esophageal pH, and high-resolution manometry.
24 patients (mean age = 53 years, SD = 12 years; 14 men) were implanted; 23 completed their 6-month evaluation. Median GERD-HRQL scores at 6 months was 2.0 (IQR = 0-5.5) and was significantly better than both baseline on-PPI [9.0 (range = 6.0-10.0); p < 0.001] and off-PPI [23 (21-25); p < 0.001] GERD-HRQL. Median% 24-h esophageal pH < 4.0 at baseline was 10.1 and improved to 5.1 at 6 months (p < 0.001). At their 6-month follow-up, 91 % (21/23) of the patients were off PPI and had significantly better median GERD-HRQL on LES stimulation compared to their on-PPI GERD-HRQL at baseline (9.0 vs. 2.0; p < 0.001). There were no unanticipated implantation- or stimulation-related adverse events or untoward sensation due to stimulation. There were no reports of treatment-related dysphagia, and manometric swallow was also unaffected.
Electrical stimulation of the LES is safe and effective for treating GERD. There is a significant and sustained improvement in GERD symptoms, esophageal pH, and reduction in PPI usage without any side effects with the therapy. Furthermore, the therapy can be optimized to address an individual patient’s disease.
Carmichael, Christine M.
UNIVERSITY OF FLORIDA, 2008, 82p; 3360648
Dysphagia, a movement disorder in which swallowing is difficult, uncomfortable or painful, is caused by problems with movement, sensation, or physical difficulties, and can disrupt nutritional status and quality of life. The study of healthy anatomy and physiology required for normal swallowing has contributed to a greater understanding of disordered swallowing and its rehabilitation. Traditional swallow therapies include diet alterations, positional changes, oral strengthening exercises and swallowing maneuvers. An emerging and controversial area for treatment of dysphagia that targets muscles for swallow is the clinical application of surface neuromuscular electrical stimulation (NMES), marketed as VitalStim Therapy, which is expanding despite only six empirical studies on NMES swallow outcomes. NMES uses electrical impulse to activate muscles through direct stimulation of the muscle belly to achieve maximal hyolaryngeal excursion in an effort to reduce or eliminate aspiration or penetration events for a safer swallow. It was the goal of this investigation to examine NMES for swallow with 5ml and 20ml thin liquid bolus sizes in order to assess its effects on hyoid movement and to determine swallowing safety of NMES therapy as measured by penetration and aspiration in a healthy population.
Results revealed significant differences in maximum displacement and maximum angle of the hyoid bone at three tested intensity levels (maximum tolerance threshold = 100%, 75% of maximum tolerance, and 50% of maximum tolerance). Significant differences were also found between the lowest (50%) and mid (75%) intensity levels and between the lowest and highest (100%) intensity levels across NMES swallows. However, the mid-intensity level (75%) was not significantly different from the highest level. Penetration-Aspiration Scale scores revealed 17 penetration events during NMES swallows with 64% occurring during the highest intensity level. These results suggest that NMES may pose risk for penetration as presently utilized at maximum intensity levels. Further, NMES intensities lower than the recommended high threshold may provide a similar effect on hyolaryngeal excursion while increasing swallowing safety and decreasing discomfort. No influence of bolus size during NMES swallow on hyoid movement was found in the present study.
University of Florida
Neuromuscular Electrical stimulation (NMES) for swallowing has recently been proposed for the treatment of dysphagia post stroke and is clinically receiving favor as a treatment modality, in the absence of strong research support. This study aims to investigate the effect of NMES therapy for dysphagia upon recovery of swallowing function following stroke. The study will follow a pilot randomized controlled trial design. Fifty one patients admitted to a sub-acute rehabilitation facility will be clinically screened for dysphagia, and randomized into one of three groups, NMES, sham NMES or usual care -behavioral swallowing therapy arm. All patients will be treated for one hour per day for 3 weeks, and their progress and outcome will be monitored. The results will add to the preliminary data on the effectiveness of this form of swallowing treatment for patients following stroke, and has the potential to enable more efficient allocation of resources to post-acute rehabilitation and thus benefit afforded to stroke patients, and the community.
Jayasekeran V, Singh S, Tyrrell P, Michou E, Jefferson S, Mistry S, Gamble E, Rothwell J, Thompson D, Hamdy S.
Gastroenterology. 2010 May;138(5):1737-46. Epub 2010 Feb 2.
Oropharyngeal dysphagia is an important disability that occurs after stroke; it contributes to aspiration pneumonia and death, and current modalities for rehabilitation of dysphagia have uncertain efficacy. We therefore examined the role of pharyngeal electrical stimulation (PES) in expediting human swallowing recovery after experimental (virtual) and actual (stroke) brain lesions.
First, healthy subjects (n = 13) were given 1-Hz repetitive transcranial magnetic stimulation to induce a unilateral virtual lesion in pharyngeal motor cortex followed by active or sham (control) PES. Motor-evoked potentials and swallow accuracy were recorded before and after the lesion to assess PES response. Thereafter, 50 acute dysphagic stroke patients underwent either a dose-response study, to determine optimal parameters for PES (n = 22), or were assigned randomly to groups given either active or sham (control) PES (n = 28). The primary end point was the reduction of airway aspiration at 2 weeks postintervention.
In contrast to sham PES, active PES reversed the cortical suppression induced by the virtual lesion (F(7,70) = 2.7; P = .015) and was associated with improvement in swallowing behavior (F(3,42) = 5; P = .02). After stroke, 1 PES treatment each day (U = 8.0; P = .043) for 3 days (U = 10.0) produced improved airway protection compared with controls (P = .038). Active PES also reduced aspiration (U = 54.0; P = .049), improved feeding status (U = 58.0; P = .040), and resulted in a shorter time to hospital discharge (Mantel-Cox log-rank test, P = 0.038).
This pilot study of PES confirms that it is a safe neurostimulation intervention that reverses swallowing disability after virtual lesion or stroke.
Xia W, Zheng C, Lei Q, Tang Z, Hua Q, Zhang Y, Zhu S.
J Huazhong Univ Sci Technolog Med Sci. 2011 Feb;31(1):73-6. Epub 2011 Feb 19.
To investigate the effects of VitalStim therapy coupled with conventional swallowing training on recovery of post-stroke dysphagia, a total of 120 patients with post-stroke dysphagia were randomly and evenly divided into three groups: conventional swallowing therapy group, VitalStim therapy group, and VitalStim therapy plus conventional swallowing therapy group. Prior to and after the treatment, signals of surface electromyography (sEMG) of swallowing muscles were detected, swallowing function was evaluated by using the Standardized Swallowing Assessment (SSA) and Videofluoroscopic Swallowing Study (VFSS) tests, and swallowing-related quality of life (SWAL-QOL) was evaluated using the SWAL-QOL questionnaire. There were significant differences in sEMG value, SSA, VFSS, and SWAL-QOL scores in each group between prior to and after treatment. After 4-week treatment, sEMG value, SSA, VFSS and SWAL-QOL scores were significantly greater in the VitalStim therapy plus conventional swallowing training group than in the conventional swallowing training group and VitalStim therapy group, but no significant difference existed between conventional swallowing therapy group and VitalStim therapy group. It was concluded that VitalStim therapy coupled with conventional swallowing training was conducive to recovery of post-stroke dysphagia.