Cochlear Implants & Implantable Hearing Devices Flashcards

Which imaging study is most commonly ordered prior to cochlear implant surgery to evaluate cochlear anatomy and patency?

Answer: Computed tomography (CT) of the temporal bones

High-resolution CT of the temporal bones is the standard pre-operative imaging to assess cochlear anatomy, detect ossification, malformations, and surgical landmarks.

In CI programming, the 'C-level' (comfort level or MCL) represents:

Answer: The loudest comfortable level of electrical stimulation before discomfort

The C-level (also called MCL or M-level) is the maximum comfortable loudness level — the highest electrical stimulation that is loud but not uncomfortable for the CI user.

Which cochlear implant processing strategy uses a 'n-of-m' approach where only the channels with the highest amplitude outputs are stimulated each cycle?

Answer: Advanced Combination Encoder (ACE)

ACE (Advanced Combination Encoder) selects the n channels with the greatest energy from a bank of m filters each cycle, providing a balance between spectral and temporal information.

Electrode impedance checks in CI programming primarily assess:

Answer: The integrity of the electrical circuit between the electrode and the tissue interface

Impedance measurements evaluate the integrity of the electrode–tissue interface; abnormally high impedances may indicate an open circuit, and very low impedances can indicate a short circuit.

A child receives a cochlear implant at age 18 months. According to research on critical periods, when should auditory rehabilitation be most intensively initiated?

Answer: Immediately following device activation

Auditory rehabilitation should begin immediately at device activation to take advantage of the sensitive period for auditory cortical development and maximize speech/language outcomes.

What does 'stapedius reflex threshold' measurement provide in the context of cochlear implant programming?

Answer: An objective way to estimate C-levels by detecting the reflexive middle ear muscle contraction

Electrically evoked stapedial reflex thresholds (ESRT) can serve as objective landmarks for setting C-levels, as the reflex typically occurs near the upper end of the comfortable range.

Bilateral cochlear implantation is most supported by evidence for which outcome benefit?

Answer: Enhanced sound localization and speech understanding in noise

Bilateral CI provides binaural hearing, which significantly improves sound source localization and speech understanding in background noise compared to unilateral implantation.