PhD defence by Scott Charles Aker

On Wednesday 15 November, Scott Charles Aker will defend his PhD thesis "Vibrotactile stimulation can enhance music for cochlear implant users, but it is complicated".

Time: 09:00

Place: Building 341, auditorium 21 & zoom: https://dtudk.zoom.us/meeting/register/u5AtcOmhrjgvE9JUNLmhvaZKq6ISgyBET_nt

Please be aware that the PhD defense may be recorded - This will also be informed at the beginning of the PhD defense.

Supervisor: Associate Professor Jeremy Marozeau

Co-supervisor: Dr. Kathleen F. Faulkner, Oticon A/S

Affiliated Professor Hamish Innes-Brown, Eriksholm Research Centre and DTU Health Tech

Ms. Marianna Vatti, Oticon A/S

Assessment committee:
Associate Professor Jens Hjortkjær, DTU Health Tech

Professor Charles Spence, Oxford University

Associate Professor Waldo Nogueira Vazquez, Medical University Hannover

Chairperson:
Professor Torsten Dau, DTU Health Tech

Abstract:
Imagine yourself at a loud concert or in a car with a big subwoofer. You might find the vibrations are enhancing your music listening experience. How can we capture this phenomenon to enhance music for people with hearing impairment? Particularly, cochlear implant users, who can have remarkable speech perception yet can still be dissatisfied by music due to a myriad of factors, might be able to benefit from this interaction. In this thesis we investigated the feasibility of using vibrotactile stimulation for enhancing music for cochlear implant users. In the first study, we investigated what parameters of vibrotactile stimulation need to be congruent with the auditory music for music enhancement to occur. In a task which had normal-hearing participants rating different tactile accompaniments with varying levels of congruence to an associated melody, it was found that intensity and timing congruence were consistently weighted highly in participant ratings. The second study repeated the procedure from the first, but with cochlear implant users. It was found that some cochlear implant users also found intensity and timing congruence important for vibrotactile music enhancement, but the benefit was not universal, and many cochlear implant users rated the stimulation independently of its congruence. A third study tested the benefits of mapping the fundamental frequency of the melody to the spatial elevation on a listener's back, using a gilet-style haptic device with five tactile actuators arranged vertically on the user's back. However, the fundamental frequency-height map did not provide the same, clear benefit as intensity and timing congruence. Finally, an established audio-tactile loudness bias, in which tactile stimulation can increase the loudness of a tone, was successful tested to see if tactile stimulation could be used to decrease the loudness of a tone as well. The results provide a clearer picture of what a musical-haptic device for cochlear implant users might look like, and insight into what perceptual mechanisms are at play during vibrotactile music enhancement.