While there are several issues concerning hearing aids on Shabbat from a halachic perspective, all of the major poskim who discussed this topic permitted their use. They were well aware that a hearing aid is used in cases of significant need and that the public understands that it is an exceptional situation. This helps explain why it wasn’t forbidden or frowned upon despite the fact that its mechanism is similar to that of a microphone, which most poskim forbade. Some poskim included need as a major part of the lenient ruling’s rationale.[1] Others made it an absolute condition. (For example, the Minchat Yitzchak[2] quotes Rav Yosef Henkin, who suggests that only those who cannot hear at all without the hearing aid should use it). However, as we know, people who wear hearing aids do so only when the need is substantial, and the minhag has developed to allow their use freely on Shabbat. We feel that this practice should be continued, certainly considering its impact on the quality of life and the enjoyment of Shabbat.
We will deal now with some of the issues that arise. [In this context, we have the liberty to deal with these issues only in a superficial manner and request our readers not to extrapolate from our discussion to other applications.] The first concerns creating circuits, which could be a problem of boneh (building) or metaken mana (fixing a utensil) or a related rabbinic prohibition. Indeed, this is a problem when one turns on a battery-operated device or shuts it off. Therefore, the hearing aid should remain on for all of Shabbat.
Another issue is the fact that speaking causes an increase in electrical current. It is far from clear that increasing the current in an existing circuit is considered creating something new. Even if it is, there is room for leniency, because the change occurs to something that has no real substance and the change is fleeting in duration.[3]
There is a general question whether devices that produce sound are included in the prohibition of using musical instruments.[4] There are several ways to deal with the issue in our context. One is based on the fact that the sound that is created is not heard by those standing around but only by the person who wears the hearing aid in his ear. Also, one who speaks does not talk directly into the instrument.[5] The fact that it is not audible to others has other halachic advantages.[6]
A further question is whether, as a battery-operated device that is usually used by turning it on and off, a hearing aid should be muktzeh. The Tzitz Eliezer has a variety of ways to deal with the issue. He concludes that, at worst, it is a kli shemelachto l’issur (a utensil which is generally used by doing an action that is forbidden on Shabbat). Even such an item may be moved in order to use it for a permitted purpose or because its place is needed.[7]
In summary, while this response is not an exhaustive one that deals with the subject in depth or with every pertinent question relating to the use of a hearing aid on Shabbat, we hope to have explained the general basis for its use on Shabbat. We think it also displays the interest of the poskim to find room for leniency in such a case, where the need is great, and despite the fact that one could have raised objections on several fronts.