Anatomical considerations of closure of the laryngeal vestibule during swallowing

Morphologic correlates of physiologic closure mechanisms of the laryngeal vestibule were investigated in plastinated serial sections of 25 normal adult larynges. The anterior part of the laryngeal vestibule was seen to be bounded by the epiglottis and the thyroepiglottic ligament medially, and by lateral extensions of the periepiglottic adipose tissue laterally. The posterior part of the laryngeal vestibule was bordered by the aryepiglottic folds. Morphologically, the periepiglottic space and the aryepiglottic folds were completely separated by several transversely oriented collagenous fiber layers attached to the thyroid perichondrium laterally. This may suggest a corresponding functional separation, as described previously in the literature. Closure of the anterior part of the laryngeal vestibule during swallowing is probably related to the lowering of the epiglottis, with both depending on pressure exerted onto the periepiglottic adipose tissue. Closure of the posterior part of the laryngeal vestibule is most likely related to closure of the rima glottidis, with both depending on adduction of the arytenoid cartilage.     

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 STUDY SELECTION: Included were published or unpublished, English-language, clinical trials with a quantifiable dependent variable.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.     

The effect of transcutaneous electrical nerve stimulation (TENS) on chronic subjective tinnitus

ObjectivesChronic Subjective Tinnitus is a very highly prevalent disorder worldwide. There is no definitive treatment. The aim of this study is to investigate the efficacy of transcutaneous electrical nerve stimulation (TENS) applied to the auricula for treating tinnitus using the Depression Anxiety Stress Scales (DASS) and Tinnitus Handicap Inventory (THI).MethodsThe 60 patients were randomly divided into 3 groups of 20 patients. The first group (A) had one ear stimulated with TENS, and the second group (B) had both ears stimulated. Group C (placebo group) received no electrical or sound stimulation. All group patients received total of 10 sessions with a maximum of 4 days between the sessions.ResultsThe THI and DASS scores decreased significantly after the treatment (p < 0.05). A significant difference was also observed between the groups after treatment (p < 0.05). While there was no difference between group A and B, it was shown that group C's post-treatment score was significantly higher than those of both groups (p < 0.05.)ConclusionIt is important to note that TENS has a therapeutic effect on subjective chronic tinnitus as well as a placebo effect.     

The effects of chronic electrical stimulation on laryngeal muscle reinnervation

The present study examined the effects of functional neuromuscular stimulation (FNS) on reinnervation of the posterior cricoarytenoid (PCA) muscle. In 4 canines, the recurrent laryngeal nerve (RLN) was sectioned and anastomosed and a patch electrode array implanted for stimulation and recording at multiple PCA sites. Following implantation, FNS was applied to 2 canines for a period of 6 weeks. Two additional animals served as nonstimulated controls. In each animal, histomorphometric analysis of the RLN was used to assess the quality of nerve regeneration and the potential for muscle reconnection. The magnitude of reinnervation was monitored by electromyographic (EMG) potentials evoked by RLN stimulation. The appropriateness of reconnection was determined by the pattern of spontaneous EMG activity and recovery of vocal fold abduction. Results of this preliminary study indicated that FNS caused an overall repression of reinnervation. However, the repression preferentially inhibited reconnection by foreign nerve fibers, promoting selective reinnervation and preventing synkinesis.     

The effect of tracheostomy on the laryngeal closure reflex

The clinical observation of aspiration following prolonged tracheostomy prompted a neurophysiologic investigation of the glottic closure reflex in dogs longitudinally evaluated after permanent tracheostomy. The data support significant alterations in the central organization of the protective closure reflex heretofore considered phylogenetically primitive and therefore physiologically stable over wide ranges of functional demand. The data indicate that chronic upper airway bypass results in: 1. increased threshold of the evoked adductor response; 2. random shifts in its latency; 3. rapid attenuation of the primary evoked response to repetitive SLN stimulation; and U. reduced after-discharge activity, all of which contribute to a weakened, ill-coordinated closure response.     

Treatment of hemifacial spasm with transcutaneous electrical stimulation

A transcutaneous electrical stimulation method was used to treat hemifacial spasms. This treatment was applied concomitantly with drug therapy to 21 patients, and was found effective in 17 patients (81%). Electrotherapy is considered to be useful in patients with mild spasms and in those with severe spasms for whom surgical treatment is not possible.     

Dose response of topical anesthetic on laryngeal neuromuscular electrical transmission

OBJECTIVES: Our purpose was to determine the effect of a dose response to decreasing concentrations of topical anesthetic upon laryngeal neuromuscular electrical transmission. METHODS: We performed a prospective study at a neurolaryngology referral center. Forty-three patients were divided into 5 groups. Each patient underwent laryngeal electromyography (EMG) of a thyroarytenoid muscle before and 60 seconds after topical laryngotracheal lidocaine hydrochloride, normal saline solution, or nothing was applied. The pretreatment and posttreatment measurements were recorded with the same indwelling EMG electrode. Group 1 (n = 12) received 4% lidocaine, group 2 (n = 9) received 2% lidocaine, and group 3 (n = 8) received 1% lidocaine. Group 4 (n = 5) received topical normal saline solution instead of lidocaine. A fifth group (group 5, n = 9) had 2 EMG recordings measured, each separated by 60 seconds, without topical anesthetic. RESULTS: Groups 1, 2, and 3 showed significant decreases in the maximum peak-to-peak amplitude of the EMG recording (48.5%, 49.7%, 44.7%, respectively). Groups 4 and 5 failed to show a significant change in peak-to-peak amplitude after 60 seconds. There was no dose response change in EMG with decreasing lidocaine concentrations. CONCLUSIONS: All concentrations of lidocaine administered in this study decreased the laryngeal neuromuscular electrical transmission as measured by laryngeal EMG. This group of patients did not exhibit any dose response to anesthetic concentration. This finding is clinically significant for both diagnostic and therapeutic uses of laryngeal EMG preceded by administration of topical anesthetic.     

阻塞性睡眠呼吸暂停综合征电刺激部位选择的临床研究

目的　探讨对阻塞性睡眠呼吸暂停综合征 (obstructivesleepapneasyndrome,OSAS)有效的颌下经皮电刺激颏舌肌部位。方法　应用局部解剖提供颏舌肌及支配神经的刺激部位 ,1 1例健康人和 9例OSAS患者清醒状态下颌下恒流刺激 ,对刺激点半径、刺激强度及颌下皮肤厚度进行比较 ,并对 9例舌后咽 (retrotonguebasepharynx ,RTBP)狭窄的OSAS患者进行睡眠颌下经皮电刺激效果对比。结果　选定的颏下及下颌角内侧两刺激部位 ,能有效刺激颏舌肌 ,两刺激点半径、刺激强度无差异 (P>0 0 5 ) ,并不受颌下皮肤厚度影响。睡眠期颌下电刺激所测呼吸紊乱指标均明显下降 (P <0 0 5 ) ,血氧饱和度指标显著提高 (P <0 0 5 ) ,临床症状改善。结论　选择的颌下电刺激部位经刺激能有效改善OSAS的临床表现和各项呼吸紊乱指标 ,其机制可能是因刺激颏舌肌使舌体向前运动而开放咽腔的结果。     

The effects of chronic electrical stimulation on laryngeal muscle physiology and histochemistry

The present study examined the effects of functional neuromuscular stimulation (FNS) on posterior cricoarytenoid (PCA) muscle physiology and histochemistry. In 4 canines, 10 cm of the recurrent laryngeal nerve was resected. A patch electrode array was implanted for PCA stimulation. FNS was applied to 2 canines for a period of 4 weeks with 2 additional animals serving as nonstimulated controls. Results indicated that FNS increased PCA muscle contractility over the period of intervention but had no effect on contraction speed. FNS also protected the muscle from atrophy by preventing muscle weight loss and type 2 fiber deterioration. Finally, it rescued muscle fibers from ensuing fibrosis.     

阻塞性睡眠呼吸暂停综合征电刺激部位选择的临床研究

目的 探讨对阻塞性睡眠呼吸暂停综合征（ｏｂｓｔｒｕｃｔｉｖｅｓｌｅｅｐｑｐｎｅａｓｙｎｄｒｏｍｅ,ＯＳＡＳ）有效的颌下经皮电刺激舌肌部位。方法 应用局部解剖提供舌肌及支配神经的刺激部位,１１例健康人和９例ＯＳＡＳ患者清醒状态下颌下恒流刺激,对刺激点半径,刺激强度及颌下皮肤厚度进行比较,并对９例舌后咽（ｒｅｔｒｏｔｏｎｇｕｅｂａｓｅｐｈａｒｙｎｘ,ＲＴＢＰ）狭窄的ＯＳＡＳ患者进行睡眠颌下经皮电刺激效     

Effect of voice therapy with or without transcutaneous electrical stimulation on recovery of injured macroscopically intact recurrent laryngeal nerve after thyroid surgery

European Archives of Oto-Rhino-Laryngology - Electrical stimulation-supported therapy is an often used modality. However, it still belongs to experimental methods in the human larynx. Data are...     

Respiratory rhythmically regulated electrical stimulation of paralyzed laryngeal muscles

Electrical stimulation of the posterior cricoarytenoid muscle, synchronized with inspiration, was achieved in dogs, utilizing a radio frequency stimulus triggered by a chest wall expansion transducer. This system brings about the abduction of the paralyzed vocal cord for the entire duration of inspiration, which allows a normal flow of air through the larynx. The stimulation system could be tested successfully in actual experiments in dogs with artificial paralysis of the recurrent laryngeal nerve. Its effectiveness could be proved through observation of the vocal cord movements (photographic documentation) and recording subglottic pressure variations. Transmission of stimulation energy is effected by electrical induction.     

The effect of neuromuscular stimulation of the genioglossus on the hypopharyngeal airway

OBJECTIVES: To determine the effects of neuromuscular stimulation (NS) of the genioglossus muscle on hypopharyngeal airway size. STUDY DESIGN: Fourteen consecutively recruited healthy volunteers underwent percutaneous electrical NS of the genioglossus muscle. METHODS: Bipolar hooked wires were inserted percutaneously into the genioglossus muscle and used for NS. The anterior--posterior diameter of the hypopharynx was measured at the level of the superior edge of the epiglottis at baseline and during NS from recorded video endoscopic examinations. RESULTS: NS of the genioglossus muscle resulted in a significant increase in the diameter of the hypopharyngeal airway (P =.002) compared with baseline, ranging from a 33% to 284% increase in airway diameter. Three of the 14 patients demonstrated modest decreases in airway diameter, likely the result of faulty electrode placement in surrounding tongue retrusive muscles. CONCLUSIONS: NS of the genioglossus muscle was effective in increasing the hypopharyngeal airway and may provide a useful alternative to direct stimulation of the hypoglossal nerve with a nerve cuff electrode in the development of neuroprosthetic treatments for obstructive sleep apnea.     

The effect of surface electrical stimulation on vocal fold position

OBJECTIVES/HYPOTHESIS: Closure of the true and false vocal folds is a normal part of airway protection during swallowing. Individuals with reduced or delayed true vocal fold closure can be at risk for aspiration and may benefit from intervention to ameliorate the problem. Surface electrical stimulation is currently used during therapy for dysphagia, despite limited knowledge of its physiological effects. DESIGN: Prospective single effects study. METHODS: The immediate physiological effect of surface stimulation on true vocal fold angle was examined at rest in 27 healthy adults using 10 different electrode placements on the submental and neck regions. Fiberoptic nasolaryngoscopic recordings during passive inspiration were used to measure change in true vocal fold angle with stimulation. RESULTS: Vocal fold angles changed only to a small extent during two electrode placements (P < or = .05). When two sets of electrodes were placed vertically on the neck, the mean true vocal fold abduction was 2.4 degrees; while horizontal placements of electrodes in the submental region produced a mean adduction of 2.8 degrees (P = .03). CONCLUSIONS: Surface electrical stimulation to the submental and neck regions does not produce immediate true vocal fold adduction adequate for airway protection during swallowing, and one position may produce a slight increase in true vocal fold opening.     

The effects of neuromuscular electrical stimulation for dysphagia in opercular syndrome: a case study

A 76-year-old man with opercular syndrome characterized by complete bilateral loss of voluntary control of facial, lingual, pharyngeal and masticatory muscles is presented with focus on the severe dysphagia. Three years earlier the patient had experienced two strokes resulting in opercular syndrome with severe dysphagia. Despite initial logopedic dysphagia treatment, swallowing did not improve. A new treatment for dysphagia, consisting of neuromuscular electrical stimulation was applied on the patient. He returned to oral feeding. Clinical and treatment observations are reported.     

Treatment of tinnitus with transcutaneous electrical nerve stimulation improves patients' quality of life

OBJECTIVES: Tinnitus can adversely affect patients' quality of life. Transcutaneous electrical nerve stimulation (TENS) may be effective in the management of tinnitus. No study has investigated the efficacy of TENS for the management of tinnitus by means of quality of life measures. In this study, we evaluated the efficacy of TENS for the management of tinnitus symptoms by using the visual analogue scale (VAS), tinnitus handicap inventory test, Nottingham health profile (NHP) and short form-36 (SF-36) questionnaires. METHODS: Twenty-two patients were included in this study (male/female, 16/6; mean age, 48.04 +/- 15.57 years). Nine patients had unilateral and 13 patients had bilateral tinnitus. RESULTS: After TENS, improvement measured by VAS was only marginally significant (p = 0.059). However, after TENS, there were statistically significant improvements regarding tinnitus severity scores, tinnitus handicap inventory scores, NHP fatigue, social isolation and emotional problems scores, and many parameters measured by the SF-36 (physical functioning, general health, vitality, social functioning, role limitations due to emotional problems, and mental health)(p < 0.05). CONCLUSION: Transcutaneous electrical nerve stimulation is a useful method to improve the quality of life of patients with tinnitus.     

Effects of laryngeal cancer on voice and swallowing

Specific deficits that may be encountered as well as interventional strategies and evidence-based practice are discussed. When discussing the voice, it is important to consider that for many people the voice is not just a tool for communication, but also an identifying feature that allows expression of personality. Eating and swallowing are vital to life sustenance and also allow for a myriad of social interactions. Laryngeal cancer can have a dramatic impact on this delicately balanced system leading to disturbances of voice and swallowing.