The Role of Laryngoscopy and Videostroboscopy in Diagnosing Dysphonia

But beyond such obvious, common causes of dysphonia, relying on a basic history and physical to diagnose and treat voice disorders—even for an initial three-month period—may be dangerous. A 2013 study compared the diagnostic accuracy of history, laryngoscopy and stroboscopy and found that a history and physical exam (HPE) led to a correct diagnosis just 5 percent of the time. The accuracy of diagnosis increased to nearly 70 percent after visualizing the larynx with flexible laryngoscopy and videostroboscopy. Laryngoscopy and stroboscopy did not miss any cancer diagnoses, while clinicians missed five cases of cancer based on HPEs (Laryngoscope. 2013:123:215-219).

The article did not assess the accuracy of diagnosis when mirror examination of the larynx was included as part of the initial exam, because primary care doctors—a major target audience of the 2009 clinical practice guideline—are not able to perform mirror laryngoscopy. “The article studied history and simple physical exam alone, and did not include mirror exam or even sound samples of the voice, due to technical reasons. This is also pretty much what primary care doctors do when they see a patient with hoarseness,” Dr. Amin said. “Mirror exam (and to some degree, listening to the voice) may increase diagnostic accuracy. The point of the article is that history is a poor guide to diagnosis, and the hoarseness clinical practice guideline uses history to stratify patients according to risk levels. But if history is a poor guide, then recommendations based on history alone are not helpful. Somebody should get eyes on that larynx within a relatively short period of time. Nobody would ever treat a skin rash without looking at it, or treat glaucoma without measuring the pressure. How do you treat a laryngeal condition if you have no idea what you’re treating?”

Most practicing otolaryngologists, including some who helped draft the guidelines, believe that waiting three months before visializing the larynx is unreasonably long. “If a voice problem is lasting more than two or three weeks, then that’s not acute laryngitis, and you don’t know what it is unless you look at the larynx,” said Seth Cohen, MD, MPH, associate professor of surgery in the division of otolaryngology-head and neck surgery at Duke University and an author of the 2009 guidelines.

Laryngoscopy

Using a flexible laryngoscope is an easy, relatively low-cost way to visualize the larynx, and the risks to the patient are minimal. A 2012 study of 250 patients found that it is also well tolerated by patients (Ann Otol Rhinol Laryngol. 2012:121:708-713). Given the advantages of laryngoscopy, it “should be a bare minimum for somebody with a voice complaint lasting longer than two or three weeks,” Dr. Rosen said.