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Course: MCAT > Unit 4

Lesson 1: Foundations of behavior passages

Differential effectiveness of cochlear implants


Individuals who are profoundly hard-of-hearing or deaf can greatly benefit from cochlear implants. These implants process sounds from the environment and stimulate the auditory nerve, therein bypassing the damaged parts of the inner ear. Cochlear implants can either be single-channel (older technology), or multi-channel (newer technology). Single-channel cochlear implants transmit all sound frequencies as a single signal to the inner ear. This stimulates the surviving auditory nerve, and allows individuals to be aware of environmental sounds (such as sirens) and resulted in improved lip-reading capabilities. Today, nearly 188,000 individuals worldwide have received a cochlear implant, and tremendous benefit has been shown in young recipients (improved language skills for example).
In a study done to test the effectiveness of various cochlear implants in hearing impaired versus controls, one individual received a single channel cochlear implant, one individual received a multi-channel implant and one control each had to detect sounds of varying frequencies. The results are outlined in Table 1.
Table 1
Frequency LevelSingle-Channel ImplantMulti-Channel ImplantControl
100 HzUnable to detectAble to detectAble to detect
1,000 HzAble to detectAble to detectAble to detect
10,000 HzAble to detectAble to detectAble to detect
20,000 HzUnable to detectUnable to detectAble to detect
25,000 HzUnable to detectUnable to detectUnable to detect
Individual stereocilia are connected to one another by which structure?
Choose 1 answer: