Voice Disorders

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Voice DisordersAll of us are likely to have experienced problems with our voices at one time or another, be it sounding hoarse, raspy or even times when sound will not come out at all. Having an upper respiratory tract infection such as the common cold or flu, allergies, exposure to irritants such as excessive smoke, or even just cheering for your favourite football team can result in changes to ones voice.

Voice production is the result of remarkable and complex interactions involving the lungs, voice box, mouth, tongue, teeth etc. When you speak, air travels through your vocal cords causing them to vibrate. This generates the unique sound of your voice.

Common causes of voice disorders include:

1. Acute or chronic laryngitis

2. Nodules, polyps, cysts or tumours of the vocal cords

3. Vocal fold paralysis

4. Muscle tension imbalances

LARYNGITIS


Laryngitis refers to inflammation of the vocal folds. Depending on the cause, this inflammation may be acute or chronic (generally meaning more than 3 weeks).

Causes of Acute Laryngitis include:
• Viral infections of the upper respiratory tract, such as the common cold
• Vocal strain due to screaming, shouting or overuse of the voice

Causes of Chronic Laryngitis include:
• Smoking or chronic inhalation of irritants (such as chemical fumes)
Gastric reflux disease
• Chronic inflammation or infection of the sinuses
• Chronic voice overuse

Doctors diagnose laryngitis by taking a history of your symptoms and performing a physical examination. An ENT specialist may pass a nasoendoscope (a thin scope with a camera at the end of it) through your nose down to the voice box to view your vocal folds. In laryngitis, the vocal folds appear inflammed.

Treatment of laryngitis will depend on the cause. Simple measures like stopping smoking and resting the voice, go a long way in healing inflammed vocal cords. Treating the underlying cause such as a cold, sinusitis or acid reflux may also be necessary. Anti-inflammatory medication is often required, and antibiotics may be prescribed if there is an underlying bacterial infection.

VOCAL CORD NODULES, POLYPS, CYSTS AND TUMOURS


Vocal fold nodules are benign thickened areas that occur on both vocal folds. These vocal fold nodules are also commonly known as singer's nodules because it is typically caused by repeated abuse of the vocal cords. Over time, this repeated excessive straining of the voice causes areas on the vocal cords to become swollen. With time, these swollen areas harden, developing callous-like growths called nodules.

Vocal fold polyps, on the other hand, typically present on only one vocal fold (although on occasions have been found on both). Most polyps tend to be larger than nodules and are sometimes referred to as polypoid degeneration or Reinke's edema.

Both vocal fold nodules and polyps are typically caused by repeated trauma, such as due to frequent shouting or voice overuse. Reflux of acid from the stomach into the larynx and regular exposure to irritants (eg. cigarette smoke) can also contribute to the development of vocal cord nodules and polyps.

It is not entirely clear how vocal fold cysts are formed, but it is believed that they are the result of mucous glands becoming blocked. This may occur spontaneously, but it is likely that they are more prone to being clogged when the vocal cords are irritated.

Tumours of the vocal folds are uncommon. Smoking and alcohol are risk factors for it.

Diagnosis is made by direct visualization of the vocal folds using a nasoendoscope. Occasionally, videostroboscopy of the larynx is done to look at the function and motion of the voice box and vocal cords. A tiny camera attached to the end of a rigid endoscope is passed down the throat to view the vocal folds. Because the vocal folds vibrate so rapidly, a strobe light is used to simulate a slow motion of the vibrating vocal folds. This allows the examiner to check for vocal fold stiffness, inappropriate closure, irregularity of movement etc.

Treatment once again will depend on the cause, but in general will involve voice rest and reducing aggravating factors (eg. stopping smoking, managing gastric reflux). Voice therapy with a speech therapist may also be required. Many benign vocal fold growths resolve with conservative management, however, for those that persist, surgery may be performed. Phono-microsurgery is surgery performed to the vocal folds using microsurgical techiniques.

VOCAL FOLD PARALYSIS


Vocal fold paralysis refers to the immobility of a vocal fold. This paralysis may be unilateral (one-sided) or bilateral (two-sided) and it occurs because of damage or dysfunction of its principal nerve - the recurrent laryngeal nerve. This nerve travels from the brain, down the neck into the chest, before turning back up again to run to the voice box. As the nerve on the left side is longer, it is more prone to injury. Hence left vocal fold paralysis is about twice as common as paralysis on the right.

Causes of vocal fold paralysis include tumours pressing on the nerve, injury to the nerve during surgery or following radiotherapy, as well as conditions affecting nerve function as in a stroke.

Diagnosis, as with other voice disorders, often involves nasoendoscopy and/or videostroboscopy. Depending on the suspected cause, other investigations such as CT or MRI imaging may be required.

Some cases of vocal fold paralysis recover spontaneously over time. It is reasonable to try voice therapy while waiting for the nerve to recover, in order to learn how to obtain the best voice in the meantime. Occasionally, surgery may be required to help shift the paralysed vocal fold. Rarely, if there is bilateral vocal fold paralysis which causes obstruction to breathing, a tracheostomy may be required.

MUSCLE TENSION DYSPHONIA


Muscle tension dysphonia refers to excessive tightness or imbalance of the muscles in and around the voice box, which results in hoarseness or difficulty in using the voice. It may be due to poor voicing technique or habitual misuse of the voice muscles. It may also result from the voice muscles trying to compensate from some underlying inflammatory or neurological condition of the vocal fold.

As with other voice disorders, examination by nasoendoscopy or videostroboscopy may be required.

Treatment involves speech therapy to improve voicing technique and correct bad vocal habits that cause unnecessary strain to the vocal folds. All underlying causes will also need to be managed properly.

Spasmodic dysphonia is a type of dystonia that causes involuntary movements of the vocal folds. Accurate diagnosis is required as the mainstay of treatment for spasmodic dysphonia is laryngeal injections with botulinum toxin.

 

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The article above is meant to provide general information and does not replace a doctor's consultation.
Please see your doctor for professional advice.