Recommendations of the Neurolaryngology Study Group on laryngeal electromyography

Abstract

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.

Figure 1

Peripheral innervation of the laryngeal muscles and sensory feedback to the brain stem are identified on the lower left side of the figure and upper motor neuron input pathways to the laryngeal motor neurons are identified on the upper right side of the figure in this schematic drawing. NA is nucleus ambiguus, LxC is laryngeal motor cortex, ACC is Anterior Cingulate Cortex, PAG is periaquaductal gray, BG is Basal Ganglia, Thal is Thalamus, CBL is cerebellum, SMA is supplementary motor are, RLN is recurrent laryngeal nerve, SLN is Superior laryngeal nerve, NG is nodose ganglion, and CT is cricothyroid muscle.