What is loss of voice? Loss of voice or hoarseness is the inability to use the vocal cords (larynx) effectively for speech. Medical terms for this symptom are dysphonia (change in voice) and aphonia (loss of voice). When speaking, air moves through folds in the larynx responsible for producing sound vibrations. If swelling or obstruction occurs within the vocal cords, the vibration is altered, thereby causing changes in or loss of voice. It’s remarkable how tiny changes in the vocal cord anatomy can result in profound changes in voice – good or bad. The most common cause of loss of voice is inflammation of the larynx. Inflammation of the larynx results from infection or voice strain. Misuse of the voice can cause the vocal folds to swell and become unable to vibrate as needed for speech; it is one of the most common causes of voice problems. When infection occurs within the larynx due to bacterial or viral organisms, inflammation leads to swelling of the vocal folds. Loss of voice may also occur with any infection of the upper respiratory tract or with serious allergic reactions, such as anaphylaxis. In addition to inflammation, many different types of nervous system conditions and diseases can cause loss of voice. Aphonia may occur from conditions that impair the vocal cords, such as cerebrovascular accident (stroke), myasthenia gravis (neuromuscular disease), and cerebral palsy. Loss of voice related to nervous system conditions is caused by an interruption in signals (neural impulses) between the larynx and the brain. Without these impulses the vocal folds do not open and close, thereby preventing speech from occurring. Loss of voice can also arise from conditions that obstruct the normal function of the vocal cords. Tumors, nodules or benign growths, bony growths, or goiters occurring within the region of the larynx may all cause loss of voice. Malignancies of the oropharynx, larynx, and thyroid gland may obstruct the normal function of the vocal cords due to their close proximity to the larynx. Loss of voice is rarely associated with a medical emergency. Seek immediate medical care (call 911) if your loss of voice is associated with loss of vision or numbness or weakness on one side of the body. Seek prompt medical care if your loss of voice is persistent or causes you concern.