Transcutaneous electrical stimulation as a resistance force in lingual exercise: A preliminary proof-of-concept study.

BACKGROUND: Limited knowledge exists regarding whether transcutaneous electrical stimulation (TES)-based exercise can improve the lingual pressure generation. OBJECTIVES: To compare the effect of submental TES with two different pulse durations (PD) coupled with isometric lingual exercises on lingual pressure measures. METHODS: Twenty-eight healthy volunteers were divided into two submental TES groups: short PD (300 µs) and long PD (700 µs). The Iowa Oral Performance Instrument (IOPI) was used for lingual pressure measurements and exercise. In total, participants attended six exercise sessions 3 days per week for 2 consecutive weeks. Maximum and swallowing lingual pressures were measured 1 h following each exercise session and 3 days after the final session to assess any detraining effect. Data were analysed using repeated measure ANOVA. RESULTS: Mean maximum lingual pressure change was significantly greater in TES with short PD versus the long PD condition following the first week of exercise. Following the 2-week exercise, a significant increase was found in mean maximum lingual pressure for short and long PD conditions compared with the baseline. However, no significant difference was found between PD conditions for maximum lingual pressure. Likewise, no significant differences in swallowing lingual pressure were found compared with the baseline or across the two TES conditions. CONCLUSION: Although short PD induced greater gain in maximum lingual pressure than the long PD after week 1, the enhanced effect faded after week 2, leading to a comparable increase in maximum lingual pressure for both groups. However, increased gain in maximum lingual pressure was not transferred to lingual pressure during swallowing.

Immediate effects of transcutaneous electrical stimulation on physiological swallowing effort in older versus young adults.

OBJECTIVE: This study compared the immediate impact of different transcutaneous electrical stimulation (TES) amplitudes on physiological swallowing effort in healthy older adults versus young adults. BACKGROUND: Swallowing physiology changes with age. Reduced physiological swallowing effort in older adults including lower lingua-palatal and pharyngeal pressures may increase risk for swallowing dysfunction (i.e. dysphagia). Transcutaneous electrical stimulation (TES) has been advocated as an adjunctive modality to enhance outcomes in exercise-based therapy for individuals with dysphagia. However, significant variation in how TES is applied during therapy remains and the physiological swallowing response to TES is poorly studied, especially in older adults. MATERIALS AND METHODS: Physiological change in swallowing associated with no stimulation, sensory stimulation and motor stimulation was compared in 20 young adults versus 14 older adults. Lingua-palatal and pharyngeal manometric pressures assessed physiological swallowing effort. RESULTS: Multivariate analyses identified interactions between age and stimulation amplitude on lingual and pharyngeal functions. Motor stimulation reduced anterior tongue pressure in both age groups but selectively reduced posterior lingua-palatal pressures in young adults only. Sensory stimulation increased base of tongue (BOT) pressures in older adults but decreased BOT pressures in young adults. Motor stimulation increased hypopharyngeal pressures in both groups. CONCLUSION: Age and TES level interact in determining immediate physiological responses on swallow performance. A one-size-fit-all approach to TES in dysphagia rehabilitation may be misdirected.

Adoption into clinical practice of two therapies to manage swallowing disorders: exercise-based swallowing rehabilitation and electrical stimulation.

PURPOSE OF REVIEW: To review recent literature depicting a shift in dysphagia rehabilitation in adults. Distinguishing rehabilitation from compensation in dysphagia management, a review of basic exercise principles is followed by description of recent publications depicting exercise-based therapies. Subsequently, transcutaneous electrical stimulation (TES) is reviewed as it may contribute to exercise-based dysphagia rehabilitation in adults. RECENT FINDINGS: Surveys have documented extensive variability in the clinical application of dysphagia therapy techniques. Despite this variability, two trends are emerging in dysphagia rehabilitation research: documentation of physiologic and functional changes within the swallowing mechanism subsequent to therapy; and prophylactic exercise-based therapies. In addition, extensive efforts have emerged describing the potential application of TES in dysphagia rehabilitation. Though results of these efforts are conflicted, TES may serve a useful role as an adjunct to well developed exercise-based rehabilitation for dysphagia. SUMMARY: The focus of dysphagia rehabilitation in adults is changing. Current efforts indicate that exercise-based therapies should incorporate multiple principles of exercise physiology and document physiologic change within the impaired swallowing mechanism. TES may function as an adjunctive modality; however, current practices should be evaluated to develop additional parameters of stimulation that are focused toward specific dysphagia impairments.

Functional and physiological outcomes from an exercise-based dysphagia therapy: a pilot investigation of the McNeill Dysphagia Therapy Program.

OBJECTIVE: To investigate functional and physiological changes in swallowing performance of adults with chronic dysphagia after an exercise-based dysphagia therapy. DESIGN: Intervention study: before-after trial with 3-month follow-up evaluation. SETTING: Outpatient clinic within a tertiary care academic health science center. PARTICIPANTS: Adults (N=9) with chronic (>12 mo) dysphagia after unsuccessful prior therapies. Subjects were identified from among patients referred to an outpatient dysphagia clinic. Subjects had dysphagia secondary to prior treatment for head/neck cancer or from neurologic injury. All subjects demonstrated clinical and fluoroscopic evidence of oropharyngeal dysphagia. No subject withdrew during the course of this study. INTERVENTIONS: All subjects completed 3 weeks of an intensive, exercise-based dysphagia therapy. Therapy was conducted daily for 1h/d, with additional activities completed by subjects each night between therapy sessions. MAIN OUTCOME MEASURES: Primary outcomes were clinical and functional change in swallowing performance with maintenance at 3 months after intervention. Secondary, exploratory outcomes included physiological change in swallow performance measured by hyolaryngeal elevation, lingual-palatal and pharyngeal manometric pressure, and surface electromyographic amplitude. RESULTS: Clinical and functional swallowing performances improved significantly and were maintained at the 3-month follow-up examination. Subject perspective (visual analog scale) on functional swallowing also improved. Four of 7 subjects who were initially feeding tube dependent progressed to total oral intake after 3 weeks of intervention. Physiological indices demonstrated increased swallowing effort after intervention. CONCLUSIONS: Significant clinical and functional improvement in swallowing performance followed a time-limited (3 wk) exercise-based intervention in a sample of subjects with chronic dysphagia. Physiological changes after therapy implicate improved neuromuscular functioning within the swallow mechanism.

"Pharyngocise": randomized controlled trial of preventative exercises to maintain muscle structure and swallowing function during head-and-neck chemoradiotherapy.

PURPOSE: Dysphagia after chemoradiotherapy is common. The present randomized clinical trial studied the effectiveness of preventative behavioral intervention for dysphagia compared with the "usual care." METHODS AND MATERIALS: A total of 58 head-and-neck cancer patients treated with chemoradiotherapy were randomly assigned to usual care, sham swallowing intervention, or active swallowing exercises (pharyngocise). The intervention arms were treated daily during chemoradiotherapy. The primary outcome measure was muscle size and composition (determined by T(2)-weighted magnetic resonance imaging). The secondary outcomes included functional swallowing ability, dietary intake, chemosensory function, salivation, nutritional status, and the occurrence of dysphagia-related complications. RESULTS: The swallowing musculature (genioglossus, hyoglossuss, and mylohyoid) demonstrated less structural deterioration in the active treatment arm. The functional swallowing, mouth opening, chemosensory acuity, and salivation rate deteriorated less in the pharyngocise group. CONCLUSION: Patients completing a program of swallowing exercises during cancer treatment demonstrated superior muscle maintenance and functional swallowing ability.

McNeill dysphagia therapy program: a case-control study.

OBJECTIVE: To compare the effectiveness of the McNeill Dysphagia Therapy Program, a systematic exercise-based rehabilitation framework for swallowing remediation, with traditional swallowing therapy techniques paired with surface electromyography (sEMG) biofeedback. DESIGN: Matched case-control study. SETTING: University medical center. PARTICIPANTS: Dysphagic patients referred to an outpatient swallowing therapy service. INTERVENTIONS: Cases were individually matched to 2 separate controls for age, sex, and primary medical diagnosis (N=24). Cases were patients with dysphagia who entered the McNeill Dysphagia Therapy Program from September 2006 to October 2008. Controls entered a traditional swallowing therapy program augmented with sEMG biofeedback (traditional therapy with biofeedback group) from February 1994 to June 1999. MAIN OUTCOME MEASURES: The primary outcome was the proportion of patients who improved clinical swallowing ability and functional oral intake. The secondary outcomes were the presence (or not) of tube feeding, physiologic change on instrumental swallowing studies, and occurrence of aspiration on posttreatment assessment. RESULTS: Case patients were more likely to demonstrate dysphagia recovery at posttreatment re-evaluation (adjusted odds ratio for dysphagia recovery=13.0 [95% CI, 1.27-63.89]; Mantel-Haenszel chi(2)=6.7; P=.009; relative risk reduction=.69). Dysphagia was reduced by 69% in the McNeill Dysphagia Therapy Program treatment group compared with the traditional therapy with biofeedback group. CONCLUSIONS: Both approaches facilitated improved swallowing function. The McNeill Dysphagia Therapy Program resulted in superior outcomes compared with traditional dysphagia therapy supplemented with sEMG biofeedback.

Treatment of vocal fold bowing using neuromuscular electrical stimulation.

OBJECTIVE: To investigate the clinical effectiveness and safety of a novel behavioral voice therapy program combining structured vocal exercise with adjunctive neuromuscular electrical stimulation for rehabilitating dysphonia secondary to vocal fold bowing. DESIGN: Prospective interventional clinical case series with a 3-month follow-up. SETTING: Outpatient speech and hearing clinic in an academic medical center. PATIENTS: Convenience sample of 7 patients diagnosed by an otolaryngologist as having chronic dysphonia for at least 3 months due to bilateral vocal fold bowing. INTERVENTION: A novel voice therapy program incorporating exercise principles and sustained phonations of increasing length, volume, and pitch paired with concurrent transcutaneous neuromuscular electrical stimulation. MAIN OUTCOME MEASURES: Change in maximum phonation time, highest attainable pitch, glottal closure, supraglottic compression, and Voice Handicap Index. RESULTS: Maximum phonation time for /i/ increased significantly (z = -2.201, P < .03), with a modest effect demonstrated (Hedges g, 0.65; 95% confidence interval, -0.56 to 1.75). Voice Handicap Index trended toward significance (z = -1.787, P < .07). Glottal closure during phonation improved, and supraglottic compression decreased. Improvements were maintained or enhanced at the 3-month follow-up. Analysis of highest attainable pitch data was limited owing to aperiodicity in the baseline evaluations. CONCLUSIONS: Behavioral voice therapy with adjunctive neuromuscular electrical stimulation reduced vocal fold bowing, resulting in improved acoustic, laryngeal, and patient-centered outcomes. Maximum phonation time and glottal closure results imply increased vocal fold tension secondary to enhanced thyroarytenoid or cricothyroid muscle function after voice therapy.

Adjunctive neuromuscular electrical stimulation for treatment-refractory dysphagia.

OBJECTIVES: Neuromuscular electrical stimulation (NMES) has been proposed as an adjunctive modality for the treatment of swallowing disorders. We present data from a prospective case series to define and measure effects of a systematic therapy for chronic pharyngeal dysphagia using adjunctive NMES. METHODS: Six adult patients with pharyngeal dysphagia received 15 sessions of a standardized protocol of swallowing exercises with adjunctive NMES. The patients completed clinical and instrumental baseline, posttreatment, and 6-month follow-up evaluations. Outcome measures included the proportion of patients who improved in clinical swallowing ability, functional oral intake, and change in body weight; patient perception of swallowing ability; and changes in kinematic aspects of swallowing. RESULTS: Significant change was demonstrated for clinical swallowing ability (p < .042), functional oral intake (p < .02), weight gain (p < .026), and patient perception of swallowing ability (p < .043). Hyoid and laryngeal elevation during swallowing demonstrated bolus-specific patterns of change. No patient experienced a treatment-related or swallowing-related complication. Patients (4 of 5) who were followed out to 6 months after treatment maintained functional gains. CONCLUSIONS: A systematic therapy for chronic pharyngeal dysphagia using adjunctive NMES produced improvement in clinical swallowing ability and functional oral intake without significant weight loss or complications.

Examining the evidence on neuromuscular electrical stimulation for swallowing: a meta-analysis.

OBJECTIVE: To evaluate the effect of transcutaneous neuromuscular electrical stimulation (NMES) on swallowing rehabilitation. DATA SOURCES: MEDLINE, PubMed, CINAHL, NML, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, doc online, Google, and EMBASE were searched for studies using NMES to treat dysphagia between January 1966 and August 2006. STUDY SELECTION: Included were published or unpublished, English-language, clinical trials with a quantifiable dependent variable. DATA EXTRACTION: Two researchers independently performed data extraction. A random-effects model was used to pool study results. The Cochran Q test was used to evaluate heterogeneity, and a funnel plot and Egger test were used to evaluate publication bias. A best-research synthesis using a methodological quality analysis was conducted. DATA SYNTHESIS: A total of 81 studies were reviewed. Seven were accepted for analysis. A significant summary effect size was identified for the application of NMES for swallowing (Hedges g, 0.66; P<.001). Heterogeneity was significant for the combined trials (P<.10). When 2 outlier trials were removed, heterogeneity was no longer significant (P<.08). Publication bias was not identified on the funnel plot or Egger test (P = .25). Best-evidence synthesis showed indicative findings in favor of NMES for swallowing. CONCLUSIONS: This preliminary meta-analysis revealed a small but significant summary effect size for transcutaneous NMES for swallowing. Because of the small number of studies and low methodological grading for these studies, caution should be taken in interpreting this finding. These results support the need for more rigorous research in this area.

Electrical stimulation therapy for dysphagia: descriptive results of two surveys.

Given the paucity of objective information on neuromuscular electrical stimulation approaches to dysphagia therapy, and the expanding utilization of this clinical approach, we designed and conducted two surveys to gather large-scale information regarding reported practice patterns, outcomes, complications, and professional perceptions associated with electrical stimulation approaches to dysphagia therapy. Self-administered questionnaires were mailed to 1000 randomly selected speech-language pathologists in each of two groups: (1) clinicians who had completed a formal electrical stimulation training course and were actively using these techniques, and (2) clinicians who were members of Special Interest Division 13 of the American Speech-Language and Hearing Association. Survey responses were anonymous and no incentive to respond was included. Acceptable response rates were achieved for both surveys (47% and 48%). Both groups of respondents were demographically similar and reported similar practice patterns. Stroke was the most common etiology of dysphagia treated with this approach. The majority of respondents identified no specific dysphagia criteria for application of electrical stimulation, used varied behavioral treatment methods, and did not follow patients beyond therapy. Clinicians reported positive outcomes with no treatment-related complications. Satisfaction with this approach was reported to be high among patients and professionals. Clinicians who did not report using these techniques indicated that they were waiting for more objective information on clinical outcomes and safety. Results of these surveys form an initial description of practice patterns and outcomes associated with electrical stimulation approaches to dysphagia therapy.

Functional benefits of dysphagia therapy using adjunctive sEMG biofeedback.

This article describes a retrospective analysis of functional outcome, time in therapy, and cost per unit of functional change in patients who received therapy for pharyngeal dysphagia. Twenty-five patients presenting dysphagia following stroke and 20 patients with dysphagia following treatment for head/neck cancer completed a systematic therapy program supplemented with surface electromyographic (sEMG) biofeedback. Eighty-seven percent (39/45) of all patients increased their functional oral intake of food/liquid including 92% of stroke patients and 80% of head/neck cancer patients. Patients with dysphagia following stroke demonstrated greater improvement than those in the head/neck cancer group. Patients in the stroke group completed more therapy sessions thus increasing the total cost of therapy, but they made more functional progress resulting in lower costs per unit of functional change than patients in the head/neck cancer group. Limitations of this study are described in reference to implications for future clinical research on the efficacy of this therapy approach.