Secrets of Listening (hearing a voice disorder). Using your ear for accurate diagnosis of hoarseness
Hearing a voice disorder is the most valuable tool available to the laryngologist/phoniatrist/voice therapist and yet listening remains the most underutilized test in laryngology. Vocal capabilities consists of identifying the comfortable speaking pitch, maximum phonation time, highest and lowest pitch while noting the quality of voice production. Loud and soft voice production at low pitch and repeating at high pitch will elicit audible vocal cues revealing vibratory impairment, also suggesting the pitch and volume at which to record the stroboscopic examination.
Visual Neurolaryngology
Visual diagnosis of laryngeal neurologic impairments is not only possible, but is perhaps the most accurate method for evaluating the neurologic status of the upper airway. The actions of each intrinsic muscle can be isolated visually by the
careful observer.
Although electromyography is a valuable tool, it is a cumbersome examination, uncomfortable for the patient, difficult to interpret and careful endoscopic evaluation seems at least as precise.
A complete endoscopic neurolaryngology examination begins in the mouth and nasopharynx, examining all of the muscles innervated by the Xth cranial nerve, not just the vocal cords. Topical anesthesia, slow observation during respiration,
stroboscopy, video recording and post examination slowing of movement lead to an accurate neurolaryngeal diagnosis.
Principles of the neurolaryngology examination include:
1. Each muscle has only a single action,
2. That action can be isolated,
3. That action can be elicited and visualized,
4. The patient always attempts to compensate and the examiner’s goal is to remove compensation in order to better visualize the neurologic impairment.
Some of the concepts covered in this lecture will include endoscopic visualization of paralysis, paresis, synkinesis, dyskinesis, fixation, tremor, spasm, and reinnervation. Extensive use of video recordings will support the precepts.