The complexity of voice problems-from laryngitis to vocal cord paralysis-need not leave you speechless.
by Lori Baker Schena
The voice is one of the most important instruments of communication, at one moment intimate and caressing, the next commanding and resolute. To truly appreciate the intricacies of the human voice, it is helpful to understand just how it works.
Many people believe the vocal cords vibrate much like the strings of a guitar. In reality, however, they are not like strings at all. The source of vocal tone comes from the vibration of several independent layers of tissue-like skin-that are wrapped around the vocalis muscle. Voice specialists therefore prefer the term vocal folds rather than cords.
Although vocal fold vibration is essential to good voice quality and volume, it is just one aspect of a network that starts with respiration and ends with resonance. The vocal folds are the crucial middle-pieces in this well-integrated system.
"Once you realize how many things must be 'just right' to produce a good quality voice with adequate volume, you can begin to understand how many things can interfere with producing voice," says Daniel Kempler, Ph.D., speech pathologist at the Voice and Airway Disorders Center at USC University Hospital.
Kempler says there are some common parameters that must work together to produce a good voice: There must be enough air in the lungs to make the vocal folds vibrate-inadequate airflow will leave the voice weak or strained. The layers of the vocal folds must be flexible with just the right amount of tension applied to them so that they vibrate optimally. Vocal folds that are too tense or too lax will not vibrate well, and the voice will suffer. And both vocal folds must move symmetrically, meeting each other completely at the center of the larynx, and then vibrating open.
Accurate Diagnosis
Uttam K. Sinha, M.D., assistant professor and vice-chair, Department of Otolaryngology/Head and Neck Surgery at the Keck School of Medicine of USC, serves as director for the USC Voice and Airway Disorders Center, which opened in 1997. The Voice Center offers treatment for the full range of problems-from laryngitis and hoarseness caused by muscle tension and vocal nodules to the sometimes serious voice problems caused by laryngeal dystonia (involuntary muscle contractions), Parkinson's disease, vocal cord paralysis and the loss of voice caused by the surgical removal of the larynx.
The Voice Center is staffed by speech pathologists and surgeons who work as a team to improve voice function and quality. Speech pathologists evaluate vocal use patterns, the sound of the voice and any related psychological issues to help determine whether surgery is necessary.
Dale Rice, M.D., chair of the Department of Otolaryngology/Head and Neck Surgery, believes the strength of the Voice Center lies in the team's ability to offer an accurate diagnosis. "Physicians send us a lot of patients just for evaluation. And then we refer them back for treatment. Others rely on our expertise for diagnosis and treatment."
Rice, who holds the Leon J. Tiber and David S. Alpert Chair in Medicine, says voice disorders are a challenge to diagnose because their causes can be complicated. Yet, successful treatment greatly depends on an accurate diagnosis. He says the classic case is the patient who is constantly clearing his throat because he feels a lump, and is always hoarse. While many times these symptoms are attributed to a virus or other problem, they can in fact be due to acid reflux-although these patients may not experience heartburn. They are often given antibiotics, but what they really need is treatment for their reflux disease.
A principal diagnostic tool for vocal disorders is videostroboscopy, a device with a stroboscopic light and camera on the end of a probe that allows vocal cord vibrations to be "freeze-framed" on a television monitor. This procedure may be videotaped for later review or to chart the patient's progress, and helps detect subtle early lesions and movement problems that would be difficult to identify without the technology. Rice says that with videostroboscopy, early cancers are often detected before they are visible to the eye. The exam allows physicians to note changes of the vocal cord vibration on a single vocal cord, indicating a possible early cancer.
Specialists at the Voice Center also use a sophisticated computer program to analyze speech, focusing on pitch and frequency to pinpoint vocal problems.
Behavioral and Functional Disorders
According to Kempler, professor of otolaryngology at the Keck School, many individuals have nothing organically wrong with their vocal cords. Instead, they have what is referred to as "vocal misuse syndrome"-an umbrella term for an array of behavioral and functional disorders.
Some of the causes of vocal misuse and abuse include excessive talking, strained or excessive voice use during periods of inflammation (e.g. allergy, infection, sinusitis, reflux), excessive coughing and throat clearing. Additional causes are sports requiring excessive intrathoracic pressure (e.g. weight lifting), environmental irritants such as smoke and noxious fumes, and uncoordinated or inadequate breath support for speech.
Even a personal trauma, such as the loss of a loved one, can trigger a voice problem. "People do things to compensate for their stress and anxiety, such as excessive throat clearing," Kempler notes. "And sometimes there is actually mucous in the throat that needs to be cleared, but clearing your throat adds to the irritation, and a vicious cycle begins."
Since surgery cannot solve the underlying problem in misuse and abuse voice problems, patients with such functional voice disorders must be treated with behavioral therapy. Once the vocal misuse and abuse has been identified, speech pathologists work one-on-one with patients to modify abnormal voice and breathing patterns. The speech pathologists try to increase patient awareness of the disorder so they can eliminate abusive vocal habits. "We use auditory and visual feedback with computers," says Kempler, "as well as relaxation and imagery techniques." The team also addresses predisposing conditions such as acid reflux, and investigates any psychosocial stress.
Vocal Cord Paralysis
On the other end of the spectrum is vocal cord paralysis, which can result from vascular, traumatic, congenital, degenerative or metabolic disorders, or surgery. Probably the most common cause of vocal cord paralysis is damage to the laryngeal nerve during thyroid or cardiac surgery.
"When the nerve is damaged, the affected vocal cord can be paralyzed into an open, fixed position," Sinha says. "Although the remaining intact vocal cord may still vibrate as air flows past it, contact between the cords is limited, causing voice problems. In addition, since a primary function of vocal cord closure is to protect the trachea from saliva and food, a paralyzed vocal cord can result in choking."
While these patients have enough airway to breathe, their voice sounds breathy and they have problems communicating. To help these patients regain their voice, Sinha inserts an implant in the thyroid cartilage. The implant extends the paralyzed cord to a point where the normal cord can meet it. "The purpose of this procedure is three-fold," Sinha explains. "It helps improve swallowing so the patient doesn't choke, gives the patient an effective cough to expel mucous and prevent possible pneumonia and it can dramatically improve voice quality."
Currently, the specialists use three types of implants: Gore-Tex, hydroxyapatite, and silicone. Sinha says the Voice Center's physicians are also investigating other implant materials. "Through clinical and bench research, we are determining which implant works best in which patient to improve vocal cord function," Sinha says. "Through this research, we can establish guidelines for optimal implant material use."
Compromised Airways
Sinha also treats bilateral vocal cord paralysis, as well as laryngotracheal stenosis. Both conditions can occur from trauma, previous surgery, ingestion of a caustic substance, burns or when an airway tube has been in place for a long time. These patients have compromised airways because of the narrowness of the trachea. "To treat them, we perform laryngeal trachea reconstruction, taking cartilage grafted from the ribs to rebuild the airway," Sinha says.
This procedure requires skill, caution and advanced technology because the airways of these patients can be so compromised that there isn't opportunity to insert a breathing tube in the throat during an operation. Such patients are placed on ECMO (extracorporeal membrane oxygenation), a constellation of biomedical devices that reproduce the functions of the heart and lungs. ECMO gives the surgeons time to establish an airway. Sinha recalls one patient with pneumonia who was on a ventilator for a long period of time and subsequently underwent a tracheotomy. Because of these procedures, a long segment of his trachea became extremely narrow and he was dependent on the tracheotomy tube to breathe.
"We were able to remove the tracheotomy tube by performing a laser procedure that vaporized the scar tissue," Sinha says. "If we hadn't put him on ECMO, we may have lost him. But we had the expertise and technology to enlarge his airway. Today, he is eating and breathing on his own-without any tubes."
Spasmodic Dysphonia
Another problem Sinha and his group treat is spasmodic dysphonia, a condition in which the patient has laryngeal spasms that cause a loss of voice projection. "With these patients, we inject botulinum (Botox) into the vocal cord, causing temporary paralysis of the muscle," he explains. Botox is the commercial form of the deadly bacterial toxin that causes food poisoning, a case in which a substance that is often lethal can be used to benefit patients.
The procedure is done under local anesthesia. The patient makes the sound "e" which causes the vocal folds to contract so the physician can see exactly where to place the injection. Sinha adds that the Botox remains in the muscle and does not travel into the body. It relieves the spasm by partially paralyzing the muscle, allowing the patient's speech to improve. Frequency of the Botox injections can range from every six weeks to once a year, depending on the severity of the spasm.
Pediatric Voice Disorders
Dennis M. Crockett, M.D., associate professor of otolaryngology/head and neck surgery at the Keck School, divides his time among USC University Hospital, LAC+USC Medical Center, and Childrens Hospital Los Angeles. He specializes in treating velopharyngeal incompetence, a condition usually seen in children associated with cleft lip and palate as well as in adults after various operations. In this instance, the palate does not function properly for articulation. "We can perform a video nasendoscopy exam to determine the exact pattern of closure of the palate, which helps to determine whether surgery is needed," Crockett says. "In this procedure, we place a flexible scope through the nose to look at the palate."
He adds, "There are several distinct types of surgery we can perform, depending on the patient's anatomy and the pattern of closure."
The Aging Voice
There are elderly individuals, who-as part of the aging process-have lost bulk in their vocal cord muscle. Says Sinha, "As we age, we not only become weaker in our arms and legs, but we experience weakening of the muscles of the vocal cords. This decrease in muscle volume due to atrophy affects the voice."
To bulk up the muscle, Sinha injects collagen into the vocal cords (much like collagen is injected into lips to give them a fuller appearance). Previously, Sinha used collagen from cows, but this causes an allergy in one percent of patients. Recently, a human collagen has been introduced and is being used at USC. "The advantage is that there is no reactivity to this collagen," he says. "Injecting human collagen is a minor office procedure that improves the voice."
Rice is quick to point out that no matter what age, anyone with a voice disorder needs to be thoroughly evaluated by experts who can examine the vocal cords and make a definitive diagnosis. In addition, he stresses that anyone with an upper airway disorder that includes choking, aspirating and coughing should be evaluated.
"We tend to take our voices for granted until something goes wrong," Rice says. "We often underestimate how voice disorders can adversely affect the quality of life. These individuals find it difficult to function well at social gatherings, to order a meal at a restaurant, or, in a life-threatening situation, to be able to call out for help." But with the expertise of Rice, Sinha, Kempler, Crockett and their colleagues, circumstances that can become frustrating or frightening for someone with a voice disorder need not be permanent. n
For more information about the Voice and Airway Disorders Center at USC University Hospital, or to learn more about the Doctors of USC, call 1-800-USC-CARE (1-800-872-2273).