The stroboscopy test uses a rapidly flashing light to examine the voice-box (larynx) and the vocal cords. It is a quick procedure that helps in the diagnosis of the underlying problems that may be causing voice issues, such as hoarseness. Our vocal cords, which are responsible for voice production, have a loose layer on top that moves like a wave. This layer vibrates with a frequency that can be as high as 400 times a minute. When vocal cords are examined with a stroboscope, the finer details are easily visible in a simple endoscopic procedure.
During the test:
- The patient may be seated in the clinic or the hospital.
- Numbing medicine may be sprayed into the nose and throat to make the test more comfortable.
- The doctor may then insert a small tube (scope) into the nose. It will be passed back into the throat until it is level with the top of the mouth.
- The patient may be asked to do some voice exercises. The scope will record the vocal cords while voice exercises are performed.
- The scope will be gently removed once the test is done.
- The procedure may take less than 30 minutes depending on the voice exercises recommended by the doctor.
- The test can be a little uncomfortable; however, it is not painful for most patients.
- In some cases, additional procedures, such as vocal fold injections or endoscopic excision of nodules, may be performed at the same time as stroboscopy.
- If no additional procedures are performed the patient may leave after the test is done. They may be able to return to normal activities on the same day.
Types of stroboscopy scopes
Two different kinds of scopes are used for stroboscopy. They are:
- The rigid scope is placed on the tongue and looks over the back edge. It does not go down the throat; it may just go to the back of the mouth. Because the rigid scope can have a larger diameter, it often provides a better, more detailed, and well-lit image.
- Sometimes a thin (3 mm) flexible scope is used. This is placed through the nose and sits behind the uvula. This naso-endoscope allows viewing more of the throat, the nasal passages, and the vocal folds. Because the camera chip is at the leading tip of this scope, it can also provide a clear, detailed picture.
The limitation of stroboscopy is that the procedure is operator dependent. This means that the success of the procedure and the quality of the images depend on the skills of the physician performing the procedure. The interpretation of stroboscopy results is likewise dependent on the clinician.
In general, stroboscopy is a safe procedure and is well tolerated by patients. However, the following are a few complications:
- The patient’s discomfort during the procedure.
- Pain is minimal (if any) and resolves spontaneously.
- Problems with the airway, such as breathing difficulty, may occur but rarely happens.
- There have also been reports of adverse reactions to the anesthetic used or the scope; however, these also occur infrequently.
- Other problems may be attributed to other associated procedures performed at the same time.
Why is the stroboscopy test performed?
A doctor may order a stroboscopy test to look for causes of voice problems, such as:
- Loss of voice (may occur because of inflamed voice box or laryngitis, especially when associated with a painful cough and harsh breathing).
- Hoarseness that has no clear cause and does not go away.
- Other symptoms include breathing difficulty or hemoptysis (blood in the sputum).
- The procedure can likewise diagnose benign conditions including vocal cord nodules, cysts, and polyps. The test can also be used to evaluate patients with vocal cord paralysis. Stroboscopy can also be performed to diagnose malignant conditions, such as laryngeal cancer, and monitor the effectiveness of the treatment of various laryngeal pathologies.