The role of laryngeal electromyography in the diagnosis of vocal fold immobility in children.
BACKGROUND
Pathology may affect the muscles that control vocal function directly by affecting peripheral function or indirectly by affecting the central nervous system. Clinically, muscle function can be assessed by observing the movements of the structures themselves or by recording the electrical activity of the muscles (electromyography, EMG). Since EMG is an invasive technique, it has enjoyed limited use in the diagnosis and management of voice disorders, especially in children. Laryngeal EMG may be helpful in those patients with voice problems of suspected neurological or neuromuscular etiology.


OBJECTIVE
The purpose of this paper is to study the role of laryngeal EMG in the clinical evaluation of unilateral vocal fold immobility in children.


METHODS
Twenty-five children with unilateral vocal fold paralysis were studied. Twenty-five patients with vocal pathologies secondary to vocal abuse and misuse were studied as controls. The sensitivity and specificity of the EMG as a diagnostic marker for vocal fold paralysis were obtained. Additionally, nine patients with traumatic arytenoid dislocation were also studied. All patients were subjected to laryngeal EMG. EMG showed a sensitivity of 100%, and specificity of 92%. Only two patients, present with a functional voice disorder, showed abnormalities in the EMG recordings. In the nine patients with arytenoid dislocation, EMG showed normal parameters.


CONCLUSIONS
EMG seems a safe and reliable test for evaluating patients with vocal fold immobility. Moreover, the EMG recordings were helpful in differentiating vocal fold paralysis from arytenoid dislocation. EMG can provide useful data concerning muscle denervation, and more importantly, reinnervation. Besides its utility for the diagnosis, serial EMG can be useful for monitoring recovery and for establishing a reliable prognosis, and hence, an adequate treatment plan.
Ysunza
Antonio
A
Department of Otolaryngology, Hospital Gea Gonzalez, Mexico City, Mexico. amysunza@terra.com.mx
Landeros
Luis
L
Pamplona
Ma Carmen
MC
Prado
Héctor
H
Arrieta
José
J
Fajardo
Germán
G
D000293:Adolescent; D001193:Arytenoid Cartilage / Q000293:injuries; D016022:Case-Control Studies; D002648:Child; D003937:Diagnosis, Differential; D004576:Electromyography / Q000379:methods* / Q000706:statistics & numerical data; D005260:Female; D006801:Humans; D004204:Joint Dislocations / Q000175:diagnosis / Q000503:physiopathology; D007821:Laryngeal Muscles / Q000503:physiopathology*; D007828:Laryngoscopy; D008297:Male; D011237:Predictive Value of Tests; D061226:Recurrent Laryngeal Nerve Injuries; D012449:Safety; D012680:Sensitivity and Specificity; D014826:Vocal Cord Paralysis / Q000175:diagnosis* / Q000503:physiopathology; D014827:Vocal Cords / Q000294:innervation; D014832:Voice Disorders / Q000175:diagnosis / Q000503:physiopathology