Cochlear Implants

Terminology

In scientific literature, in the context of cochlear implants, the abbreviations M, C, T, MCL, THL, USL or MSL are all used to denote specific levels of electrical stimulation:

M: Stands for Most Comfortable Level or Maximum Comfortable Level. This is the sound level that the user finds comfortable, as discussed earlier. C: Stands for Comfortable Level. This is sometimes used as an alternative to "M" and also refers to the level of stimulation that is comfortable for the user. In some systems or literature, this can be synonymous with "M." T: Stands for Threshold Level. This is the lowest level of electrical stimulation that the user can perceive. It sets the threshold for sounds that the user can just hear.

The choice between using "M" or "C" depends on the specific terminology and preferences used by different manufacturers or within certain scientific studies. In many cases, "M" and "C" are interchangeable terms that refer to the same concept, namely the most comfortable level of stimulation.

USL: The pain threshold, or the level of electrical stimulation at which sound becomes painful or uncomfortable for the cochlear implant user, is usually indicated by the term Upper Stimulus Level or sometimes Maximum Stimulation Level (MSL). In some cases, the term MCL (Maximum Comfortable Level) is used to indicate the level just below the pain threshold, but the actual pain threshold is often specifically indicated with USL or a similar term. This term is important during the tuning of the implant to ensure that sounds do not become too loud and painful for the user.

MCL: Most Comfortable Level. This is the sound level that the user of the implant finds most comfortable for hearing sounds. It is an important parameter set during the programming of the cochlear implant to ensure that sounds are heard clearly without causing discomfort.

THL: Threshold Level. This is the lowest sound level that the user of the implant can perceive. This level is determined during the tuning of the implant and is essential to ensure that the user can detect the softest sounds.

These levels are typically adjusted during the programming of the cochlear implant to optimize the user’s hearing experience.

The most commonly used convention for the abbreviation MCL in cochlear implants is Most Comfortable Level and is recommended to avoid confusion. This term is widely used in audiology and in the tuning of cochlear implants to refer to the level at which sounds are comfortably perceived without being too loud or too soft. The term Maximum Comfortable Level does appear sometimes, but it is less common and can cause confusion. The difference is subtle: "Maximum Comfortable Level" might imply the highest level that is still just comfortable, whereas "Most Comfortable Level" refers to the level that the user finds most pleasant. However, in most contexts where "Maximum Comfortable Level" is used, it is meant to convey the same idea as "Most Comfortable Level."