Critical evaluation of neurolaryngological disorders

Practice Parameter: Laryngeal Electromyography (An Evidence-Based Review)

This paper reports on an evidence-based review of laryngeal electromyography (EMG) as a technique for use in the diagnosis, prognosis, and treatment of laryngeal movement disorders including the laryngeal dystonias, vocal fold paralysis, and other neurolaryngological disorders. The authors performed a systematic review of the medical literature from 1944 through 2001 on the clinical application of EMG to laryngeal disorders. The review yielded 584 articles of which 33 met the predefined inclusion criteria. The evidence demonstrated that in a double-blind treatment trial of botulinum toxin versus saline, laryngeal EMG used to guide injections into the thyroarytenoid muscle in persons with adductor spasmodic dysphonia was beneficial. A cross-over comparison between laryngeal EMG-guided injection and endoscopic injection of botulinum toxin into the posterior cricoarytenoid muscle in abductor spasmodic dysphonia found no significant difference between the 2 techniques and no significant treatment benefit. Based on the evidence, laryngeal EMG is possibly useful for the injection of botulinum toxin into the thyroarytenoid muscle in the treatment of adductor spasmodic dysphonia. There were no evidence-based data sufficient to support or refute the value of laryngeal EMG for the other uses investigated, although there is extensive anecdotal literature suggesting that it is useful for each of them. There is an urgent need for evidence-based research addressing other applications in the use of laryngeal EMG for other applications. (Otolaryngol Head Neck Surg 2004;130: 770-9.)

Videoendoscopic Evaluation of Swallowing After Thyroidectomy: 7 and 60 Days

Deglutition complaints are frequent after thyroidectomy. The purpose of this study was to follow-up on patients with thyroidectomy indication to compare the videoendoscopic evaluation of swallowing on the seventh day (early postoperative, EPO) and on the 60th day after thyroidectomy, (late postoperative, LPO) and to compare patients that evolved with normal laryngeal mobility (NLM) and abnormal laryngeal mobility (ALM). Nasofibroscopic evaluation was performed preoperatively (PRE), on the EPO and LPO. Two groups were compared: ALM and NLM. The majority of people were women, age bracket 46-65, who underwent total thyroidectomy and with high frequency of carcinoma. 30 out of the 54 patients in the study had change in swallowing (55 %). Dysphagia occurred in 87 % (13/15) of patients with ALM in the EPO and remained in 67 % of them in the LPO. In the NLM group, dysphagia occurred in 44 % (17/39) in EPO and 25 % in LPO. There was a statistical difference between PRE and EPO, and PRE and LPO (P < 0,001). In the ALM group, liquid penetration and aspiration were identified in 33 % of the cases during EPO (P = 0,014); retention of food occurred in 87 % in EPO and in 60 % in LPO (P < 0,001). Dysphagia occurs in patients after thyroid surgery (regardless of larynx mobility alteration) and characterized by stasis of food in the oro and hypopharynx, which is also noticed in LPO, though more frequently in EPO.

[Neurolaryngology]

The neuroanatomy of voice and speech is complex. An intricate neural network is responsible for ensuring the main functions of the larynx: airway protection, cough and Valsalva production, and providing voice. Coordination of these roles is very susceptible to disruption by neurological disorders. Neurological disorders that affect laryngeal function include Parkinson's disease, stroke, amyotrophic lateral sclerosis, multiple sclerosis, dystonia and essential tremor. A thorough neurological evaluation should be routine for any patient presenting with voice complaints suggestive of neurogenic cause. Endoscopic visualisation of the larynx using a dynamic voice assessment with a flexible laryngoscope is a crucial part of the evaluation and ancillary tests are sometimes performed. Otolaryngologic evaluation is important in the diagnosis and treatment of neurological disorders that affect laryngeal function.

Swallowing Evaluation in Patients With Unilateral Vocal Fold Immobility

BACKGROUND

Unilateral vocal fold immobility is the neurological disorder most frequently seen in the larynx that may cause swallowing dysfunction. The objective of this investigation was to evaluate the oral and pharyngeal phases of swallowing in patients with unilateral vocal fold immobility.

METHODS

It was evaluated by videofluoroscopy of the swallowing of 14 patients with unilateral vocal fold immobility and 11 control subjects. The examination was performed with swallows of 5 mL and 10 mL of liquid and paste boluses. The oral transit, pharyngeal transit and clearance, the duration of upper esophageal sphincter (UES) transit, the duration of the hyoid movement, and the timing of the events were measured.

RESULTS

With swallows of 10 mL of liquid bolus (controls: 0.23 ± 0.04s, patients: 0.27 ± 0.05s, p = 0.03) and 5 mL of paste bolus (controls: 0.18 ± 0.04s, patients: 0.22 ± 0.04s, p = 0.01) there was a longer duration of UES transit in patients compared with controls. The UES opened earlier in the control subjects with the increase in bolus volume from 5 mL to 10 mL (p < 0.05), an effect that was not seen in patients with vocal fold immobility.

CONCLUSIONS

We conclude that patients with unilateral vocal fold immobility may have alteration of bolus transit through the UES and have no adaptation in the swallowing timing related to the increase in bolus volume.

Recommendations of the Neurolaryngology Study Group on laryngeal electromyography

The Neurolaryngology Study Group convened a multidisciplinary panel of experts in neuromuscular physiology, electromyography, physical medicine and rehabilitation, neurology, and laryngology to meet with interested members from the American Academy of Otolaryngology Head and Neck Surgery, the Neurolaryngology Subcommittee and the Neurolaryngology Study Group to address the use of laryngeal electromyography (LEMG) for electrodiagnosis of laryngeal disorders. The panel addressed the use of LEMG for: 1) diagnosis of vocal fold paresis, 2) best practice application of equipment and techniques for LEMG, 3) estimation of time of injury and prediction of recovery of neural injuries, 4) diagnosis of neuromuscular diseases of the laryngeal muscles, and, 5) differentiation between central nervous system and behaviorally based laryngeal disorders. The panel also addressed establishing standardized techniques and methods for future assessment of LEMG sensitivity, specificity and reliability for identification, assessment and prognosis of neurolaryngeal disorders. Previously an evidence-based review of the clinical utility of LEMG published in 2004 only found evidence supported that LEMG was possibly useful for guiding injections of botulinum toxin into the laryngeal muscles. An updated traditional/narrative literature review and expert opinions were used to direct discussion and format conclusions. In current clinical practice, LEMG is a qualitative and not a quantitative examination. Specific recommendations were made to standardize electrode types, muscles to be sampled, sampling techniques, and reporting requirements. Prospective studies are needed to determine the clinical utility of LEMG. Use of the standardized methods and reporting will support future studies correlating electro-diagnostic findings with voice and upper airway function.

Practice parameter: laryngeal electromyography (an evidence-based review)

This paper reports on an evidence-based review of laryngeal electromyography (EMG) as a technique for use in the diagnosis, prognosis, and treatment of laryngeal movement disorders, including the laryngeal dystonias, vocal fold paralysis, and other neurolaryngological disorders. The authors performed a systematic review of the medical literature from 1944 through 2001 on the clinical application of EMG to laryngeal disorders. Thirty-three of the 584 articles met the predefined inclusion criteria. The evidence demonstrated that in a double-blind treatment trial of botulinum toxin versus saline, laryngeal EMG used to guide injections into the thyroarytenoid muscle in persons with adductor spasmodic dysphonia was beneficial. A cross-over comparison between laryngeal EMG-guided injection and endoscopic injection of botulinum toxin into the posterior cricoarytenoid muscle in abductor spasmodic dysphonia found no significant difference between the two techniques and no significant treatment benefit. Based on the evidence, laryngeal EMG is possibly useful for the injection of botulinum toxin into the thyroarytenoid muscle in the treatment of adductor spasmodic dysphonia. There were no evidence-based data sufficient to support or refute the value of laryngeal EMG for the other uses investigated, although there is extensive anecdotal literature suggesting that it is useful for each of them. There is an urgent need for evidence-based research addressing other applications in the use of laryngeal EMG for other applications.

Laryngeal electromyography: an evidence-based review

This article reports on an evidence-based review of laryngeal electromyography (EMG) as a technique for use in the diagnosis, prognosis, and treatment of laryngeal movement disorders including the laryngeal dystonias, vocal fold paralysis, and other neurolaryngological disorders. The authors performed a systematic review of the medical literature from 1944 through 2001 on the clinical application of EMG to laryngeal disorders. Thirty-three of the 584 articles met the predefined inclusion criteria. The evidence demonstrated that in a double-blind treatment trial of botulinum toxin versus saline, laryngeal EMG used to guide injections into the thyroarytenoid muscle in persons with adductor spasmodic dysphonia was beneficial. A cross-over comparison between laryngeal EMG-guided injection and endoscopic injection of botulinum toxin into the posterior cricoarytenoid muscle in abductor spasmodic dysphonia found no significant difference between the two techniques and no significant treatment benefit. Based on the evidence, laryngeal EMG is possibly useful for the injection of botulinum toxin into the thyroarytenoid muscle in the treatment of adductor spasmodic dysphonia. There were no evidence-based data sufficient to support or refute the value of laryngeal EMG for the other uses investigated, although there is extensive anecdotal literature suggesting that it is useful for each of them. There is an urgent need for evidence-based research addressing the use of laryngeal EMG for other applications.

The Effect of Bolus Consistency on Dysphagia in Unilateral Vocal Cord Paralysis

OBJECTIVE: To examine the risk of aspiration for liquid versus paste bolus consistencies in patients with unilateral vocal cord paralysis (UVCP).

METHODS: The swallowing function of adult patients with UVCP was prospectively studied videofluoro-graphically to examine the incidence of laryngeal penetration and aspiration for both liquid and paste boluses. The degree of penetration or aspiration was quantified using the penetration-aspiration scale (PAS). The presence and location of pharyngeal bolus residue were also documented for each consistency. Results were compared between liquid and paste bolus consistencies.

RESULTS: Fifty-five patients with UVCP were studied with a mean age of 60.2 years. Intrathoracic surgery or malignancy accounted for 38 (69.1%) of cases. The mean PAS scores for liquid and paste bolus consistency were 3.1 vs. 1.5, respectively ( P < 0.001). The liquid bolus penetrated in 19 (34.5%) patients and was aspirated in 11 (20%) patients. In contrast, the paste bolus penetrated in 12 (21.8%) cases and was aspirated in 0 cases ( P < 0.001). Pharyngeal residue was more likely to occur at the base of the tongue or vallecula for the paste bolus consistency versus the liquid bolus.

CONCLUSIONS: A significant percentage of patients with UVCP will aspirate thin liquids. Paste bolus consistencies are safer for patients with UVCP as they are much less likely to lead to penetration or aspiration despite a higher prevalence of pharyngeal residue.

Dysphagia and aspiration with unilateral vocal cord immobility: incidence, characterization, and response to surgical treatment

To objectively determine the incidence of dysphagia associated with unilateral vocal cord immobility (UVCI) and to evaluate the potential for response to vocal cord medialization, we made videofluoroscopic swallowing (VFS) recordings of patients with newly diagnosed UVCI and prospectively analyzed them in a blinded fashion using the Penetration-Aspiration Scale (PAS) and pharyngeal transport function measures. A subset of patients underwent vocal cord medialization and were evaluated with a postoperative VFS study. Comparison was made between preoperative and postoperative VFS results to study the effects of vocal cord medialization in this setting. Eighty-seven VFS recordings were studied in 64 adult patients with UVCI; 23 patients underwent VFS testing before and after vocal cord medialization. The UVCI was most commonly left-sided (53 cases) and most commonly resulted from thoracic or cardiac surgery (53.1%), followed by malignancy (15.6%). Overall, the median PAS score was 2.0 (25th-75th percentiles, 1.0-5.0), with 20 patients (31.3%) and 15 patients (23.4%) exhibiting penetration or aspiration, respectively. No significant differences in swallowing function were noted between surgical and nonsurgical causes of paralysis (PAS scores of 2.0 and 2.0, respectively; p = .901). The median PAS score improved from 4.0 to 3.0 (p = .395, Wilcoxon paired samples test) in patients studied after undergoing a vocal cord medialization procedure (6 laryngoplasties and 17 vocal cord injections). Laryngoplasty was not more successful than vocal cord injection in resolving aspiration (p = .27). Radiographically significant penetration or aspiration occurs in approximately one third of patients with UVCI, independent of the cause of paralysis. Vocal cord medialization may not be as effective as thought for eliminating aspiration in these patients.