Assessing temporal modulation sensitivity using electrically evoked auditory steady state responses.
Temporal cues are important for cochlear implant (CI) users when listening to speech. Users with greater sensitivity to temporal modulations show better speech recognition and modifications to stimulation parameters based on modulation sensitivity have resulted in improved speech understanding. Behavioural measures of temporal sensitivity require cooperative participants and a large amount of time. These limitations have motivated the desire for an objective measure with which to appraise temporal sensitivity for CI users. Electrically evoked auditory steady state responses (EASSRs) are neural responses to periodic electrical stimulation that have been used to predict threshold (T) levels. In this study we evaluate the use of EASSRs as a tool for assessing temporal modulation sensitivity. Modulation sensitivity was assessed behaviourally using modulation detection thresholds (MDTs) for a 20 Hz rate. On the same stimulation sites, EASSRS were measured using sinusoidally amplitude modulated pulse trains at 4 and 40 Hz. Measurements were taken using a bipolar configuration on 12 electrode pairs over 5 participants. Results showed that EASSR amplitudes and signal-to-noise ratios (SNRs) were significantly related to the MDTs. Larger EASSRs corresponded with sites of improved modulation sensitivity. This relation was driven by across-subject variation. This result indicates that EASSRs may be used as an objective measure of site-specific temporal sensitivity for CI users.
ExpORL, Department Neurosciences, KULeuven, O&N 2, Herestraat 49 bus 721, 3000 Leuven, Belgium. Electronic address: robert.luke@med.kuleuven.be.
Robert
R
Luke
ExpORL, Department Neurosciences, KULeuven, O&N 2, Herestraat 49 bus 721, 3000 Leuven, Belgium.
Lieselot
L
Van Deun
ExpORL, Department Neurosciences, KULeuven, O&N 2, Herestraat 49 bus 721, 3000 Leuven, Belgium.
Michael
M
Hofmann
ExpORL, Department Neurosciences, KULeuven, O&N 2, Herestraat 49 bus 721, 3000 Leuven, Belgium.
Astrid
A
van Wieringen
ExpORL, Department Neurosciences, KULeuven, O&N 2, Herestraat 49 bus 721, 3000 Leuven, Belgium.
Jan
J
Wouters
D000161:Acoustic Stimulation / Q000379:methods; D000328:Adult; D000368:Aged; D001307:Auditory Perception; D001309:Auditory Threshold / Q000502:physiology*; D019929:Cochlear Implantation; D003054:Cochlear Implants; D003638:Deafness / Q000628:therapy*; D004558:Electric Stimulation / Q000379:methods*; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D059629:Signal-To-Noise Ratio; D013067:Speech Perception; D013997:Time Factors; D055815:Young Adult