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 or MCL: Stands for Most Comfortable Level or Maximum Comfortable Level. The most commonly used convention for the abbreviation MCL 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."

• 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 or THL: 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.

• USL or MSL: Stands for Upper Stimulus Level or Maximum Stimulation Level, which indicates the level of electrical stimulation at which sound becomes painful or uncomfortable for the cochlear implant user.

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.

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.