PP309 - Changes in the P300 Wave Before and After Amplification Use

Abstract:
The P300 difference wave can be indicative of auditory processing changes, with previous research showing amplitude increases with hearing aid use. This case study assessed whether the P300 could be used to look at outcomes after amplification use and understand the time scale in which these changes happen. This case study looked at the EEG data of a 72-year-old male who was newly fit with hearing aids over three months. An overall trend towards an increase in amplitude of the P300 difference wave was seen along with a slight latency shift after hearing aid use, suggesting improved auditory processing.

Summary:

Background: The P300 difference wave can be used to look at auditory processing changes in a person, as it is dependent on attention, discrimination and memory. This wave is elicited when a rare stimulus is detected in the presence of a frequent stimulus. Literature has shown increases in P300 amplitude following approximately 4 weeks of hearing aid use. The purpose of this case study was to assess whether longitudinal changes in an auditory P300 evoked potential could be used to look at outcomes after amplification and to better understand the time scale in which cortical auditory changes may happen.

Methods: This case study looked at a 72-year-old, left-handed male with no history of amplification use. The patient was fit with a pair of Oticon OPN 1 hearing aids and came in for 5 visits over a period of three-months where EEG data was collected. Data was collected using a 2000 Hz frequent click stimulus and 4000 Hz rare click stimulus and the participant was instructed to click a mouse each time he detected the rare stimulus. Two runs of P300 measurements were collected to ensure replicability from a 19-channel electrode cap.

Results: An overall trend towards an increase in amplitude of the P300 difference wave was seen as the time of hearing aid usage increased. Specifically 45 days after fitting we saw a significant increase in amplitude in the P300 difference wave. Additionally, a slight latency decrease is seen following approximately 45 days of hearing aid use. The participant’s speech perception in noise outcomes improved after before fitting hearing aid use and the participant also experienced an increase in the Global MoCA score by 2 points after 30 days of hearing aid use.

Conclusion: This case study shows the feasibility of using P300 measurements to objectively monitor cortical changes following hearing aid use. The participant demonstrated both amplitude increase and slight latency decrease over time, which suggest improved auditory processing and may be related to his improved cognitive processing and speech perception in noise. While our preliminary results are promising for the use of P300 as a potential clinical tool in audiology, While future research with larger subject numbers is needed to observe changes in P300 responses over time as well as individual variability patterns.