NEW TEST OFFERS
EARLIER AND BETTER DIAGNOSIS
FOR VOICE PATIENTS

The voice program at GBMC's Milton J. Dance, Jr. Head and Neck Rehabilitation Center added a new service this winter: laryngeal electromyography (EMG). They join one of only a handful of medical centers in the country to offer this interdisciplinary diagnostic test to assess the nerve activity and recovery potential of the larynx. The first team to perform laryngeal EMG at GBMC includes A. Daniel Pinheiro, MD, PhD, Otolaryngology/Head and Neck surgery, Richard Weisman, MD, Neurology, and Barbara Messing, MA, CCC-SLP, Speech and Language Pathology Manager.

Impaired motion of the vocal cords can result from many causes, including viral infection, cancer, neuropathy, neurological diseases and nerve injury following surgical trauma. In the past, clinicians could only observe patients over a several-month period in order to determine whether a vocal cord was partially or completely paralyzed. If a nerve problem was suspected, prognosis and expected recovery could not be directly ascertained, and patients had to wait six months or more before a definitive intervention (such as surgery) could be performed. Now, nerve activity and recovery potential can be more directly studied with laryngeal EMG.

The otolaryngologist begins the EMG by placing small electrodes in some of the muscles that move the vocal cords. Electrical responses are recorded from these muscles (in response to a series of voice tasks evoked by the speech pathologist), and analyzed as the patient speaks (neurologist). The study takes about thirty minutes to complete.

It will be useful for evaluating patients with vocal cord paralysis, as well as other vocal cord disorders, such as spasmodic dysphonia, voice tremors, and the symptoms of progressive neurological diseases (e.g., myasthenia gravis).  The patients' responses are correlated with their symptoms to determine which nerves are affected; in some cases, the potential for recovery can be inferred. This may indicate that they are showing signs of recovery in spite of a lack of apparent clinical improvement. On the other hand, some patients who show no evidence of recovery may benefit from earlier surgical intervention aimed at improving their voice.

Laryngeal EMG can also be used to pinpoint the site of the lesion in patients with unexplained vocal cord paralysis. "If both the superior and inferior laryngeal nerves are affected, this would imply that the nerve was damaged higher up than the level of the larynx," says Dr. Pinheiro. "Alternatively, abnormal responses on both sides of the larynx may represent a more diffuse process, such as a virally induced neuropathy."

Otolaryngologists with EMG experience and privileges at GBMC may schedule and perform a laryngeal EMG study on their own patients at the Dance Center. Alternatively, patients can be referred to the Dance Center to have the study performed by Ms. Messing and Drs. Pinheiro and Weisman. For further information, call 443-849-2087.

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