ABSTRACT
BACKGROUND AND OBJECTIVES: Some objective and quantitative diagnositc methods are introduced to evaluate vocal cord paralysis, such as electro glottography (EGG) and laryngeal electromyography (LEMG). LEMG is an invasive and highly technical method requiring patient's cooperation. It records action potential generated when intrinsic laryngeal musculature contracts. EGG, on the other hand, records changes of impedence between both vocal cords when theses vibrate and represents many information of vocal cord movements. This method is non-invasive and very simple offering some valuable information about voice function of laryngeal diseases. MATERIALS AND METHODS: From January 1998 through May 2000, we evaluated 15 vocal cord paralysis patients by LEMG and EGG and compared the usefulness of these two methods by determining the lesions of vagal nerve injury. RESULTS: For patients who had severe recurrent laryngeal nerve injuries, EGG and dEGG showed no plateau phase but a loss of two-mass movements. Some showed very irregular saw-tooth shaped wave patterns. Patients with vagal nerve injury, EGG and dEGG showed relatively well maintained plateau phases because they had paralyzed cricothyroid muscles which are counteract to abductor of vocal cord. CONCLUSION: Although EGG did not provide information about such diseases as laryngeal myopathy and arthropathy, it is simple and non-invasive, and may he much valuable as a topodiagnostic method of vocal cord paralysis.