ABSTRACT

An often-repeated maxim is that sensorineural hearing loss is irreversible, and damage to the auditory nerve fibers cannot be cured. Although the generalization may be true in many cases, the catch lies in the term "damage." In numerous cases of sensorineural hearing impairment the patient gets better, mostly spontaneously, but medication may be of some help. What the maxim really means is that there is no cure for permanent damage to the auditory nerve. It is not true that all sensorineural damage is permanent. The simplest example of the reversibility of sensorineural damage is auditory fatigue following exposure to gunfire. There can be a marked sensorineural hearing loss which gradually reverts to normal. There are many other cases of sensorineural hearing loss that have all the characteristics of being permanent, and yet they improve dramatically, often with medication or even without. Sensorineural hearing loss can be very severe and yet return to an excellent level, as demonstrated in Fig. I 0.4. The chief lesson to be learned from such examples is that it is possible for some cases of sensorineural hearing loss to improve, but at present there is not sufficient knowledge to forecast consistently when this will happen, nor is there any specific therapy known to promote the return of hearing consistently in many cases. One generalization need to be considered of value. The cases more likely to be reversible are those of sudden onset rather than those which develop slowly over a period of months. As we have gained experience with conditions such as luetic labyrinthitis and autoimmune sensorineural hearing loss, we have realized that this generalization is not a good one. The onset of hearing loss of the sensorineural type is often helpful in establishing its possible cause. Included in this chapter is a chart showing the known and likely causes of sensorineural hearing loss of sudden and insidious onset. Examples of each cause in the list are found in the following chapters.