APHO'NIA (Gr. a, not, and voice) is the term used in medicine to signify a more or less complete loss of voice. It is altogether distinct from mutism, in which it is impossible to form articulate sounds, and in most cases the voice is not entirely gone, but only more or less lost or suppressed. The voice is essentially produced (as has been proved in the special article on that subject) by three distinct agents—viz., (1) the expi ration of air, (2) the opening of the glottis, and (3) the tension of the vocal cords—and hence anything interfering with expiration, or with the functions of the glottis and vocal cords, may cause aphonia- Thus, it may result from paralysis of the respiratory muscles, from pulmonary emphysema, and sometimes from pneumonia; or it may be caused by diseases of the larynx, as chronic laryngitis, oedema of the glottis, polypus, etc.; or by pressure on the Jarynx caused by abscesses, vegetations, and any kind of morbid growth; or it may bd traced to some functional or organic disturbance of the inferior vocal cords. Thus, the muscular fibres which act on these cords may become affected in acute laryngitis by extension of the inflammation, or their action may be impeded by the pressure of false membrane in croup. In typhoid fever, the aphonia which is so com monly observed is due to ulceration extending to these structures. Again, in cases of lead or phosphorus poisoning, there is aphonia due to fatty degeneration of the muscles. Not unfrequcutly, aphonia may be traced to compression of the recurrent or inferior laryngeal nerve, which is the nerve supplying motor power to all the muscles of the larynx, with one trifling exception. ,
Such pressure is not unfrcquently caused by an aneurism, an abscess, tumor, etc. In the same way, a wound or contusion of the pneumogastric nerve, or one of the recurrent branches, will cause aphonia, or, more commonly, an extremely hoarse modification of the voice, in consequence of the laryngeal muscles being paralyzed on one side, and remain ing active on the other. There are cases of direct nervous action being interfered with; bulthere are many cases of what may be termed reflex aphonia, as when the voice is often mac or less lost in the course of pregnancy when accompanied with convulsions, or in consequence of the presence of intestinal worms, or after the rapid suppression of an exanthematous rash, or of a long-continued hemorrhagic discharge. Aphonia is, more over, very commonly associated with hysteria.
When aphonia is not due to irremovable causes, as tumors pressing on the recurrent nerve, fatty degeneration of the laryngeal muscles, etc., it generally disappears after a longer or shorter interval. It occasionally assumes remarkable intermittent shapes. In one instance, the affection came on regularly at the same time of the year for 17 years, beginning daily at noon, and lasting the remainder of the day, for a period vary ing from 3 to 7 months. Another case is recorded in which during 14 years, a young woman could only speak during two or three hours daily.
In those cases which are amenable to treatment, emetics, electricity, strychnine, leeching, blistering, croton-oil liniment, and internal application of nitrate of silver, have been found to be the most useful remedies.