Dorothea Wendt

Scientist, PostDoc

Objective measures of cognitive hearing- Pupillometry

Everyday communication requires understanding of speech in acoustical adverse listening situations, which can be a challenge for people with hearing impairment. We use pupillometry to understand the everyday communication problems for hearing aid users.

Understanding and processing speech in noise requires the allocation of (extra) cognitive resources for several cognitive operations that are needed to process and interpret speech.
As a consequence, speech understanding can be perceived as demanding and effortful. In particular, people with hearing loss often experience difficulties when communicating in everyday life. Hearing devices are supposed to help the user allocating less cognitive resources for communicating.

Our main objective is to understand when people with hard of hearing encounter problems in everyday communication, and how the hearing devices and the signal processing provide a benefit.

Thus, we work on developing new methods and outcome measures to assess the impact of the signal processing of a hearing device. For that, we focus on everyday listening situations where more conventional speech in noise tests might be insensitive, i.e. high signal-to-noise-ratios and high speech intelligibility.


Pupillometry as an outcome measure

Our eyes can actually help us understand those cognitive operations. Pupillometry, the measurement of our pupil size, has a long history of application as an outcome measure of cognitive processing load in research. For example, the pupils become larger when a person invest more effort in listening. We refer to this as listening effort.

The dilation of the pupil when doing a task is associated with Autonomic Nervous Systems (ANS) activity, more specifically with the sympathetic and parasympathetic nervous branch of the ANS. See the dilation of the pupil in this video.

Within the field of cognitive hearing science, it has been demonstrated that pupil dilation can index the cognitive processing load and effort mobilization involved in speech communication.

Within our group, we use pupillometry to learn more about effort mobilization and fatigue in people with hearing loss. Our recent work demonstrated that pupillometry can be applied to identify a benefit of the hearing-aid signal processing on listening effort.