Electrophysiological Variations in Auditory Potentials in Chronic Tinnitus Individuals: Treatment Response and Tinnitus Laterality

Abstract

Background: This study investigates electrophysiological distinctions in auditory evoked potentials (AEPs) among individuals with chronic subjective tinnitus, with a specific focus on the impact of treatment response and tinnitus localisation. Methods: Early AEPs, known as Auditory Brainstem Responses (ABR), and middle AEPs, termed Auditory Middle Latency Responses (AMLR), were analysed in tinnitus patients across four clinical centers in an attempt to verify increased neuronal activity, in accordance with the current tinnitus models. Our statistical analyses primarily focused on discrepancies in time-domain core features of ABR and AMLR signals, including amplitudes and latencies, concerning both treatment response and tinnitus laterality. Results: Statistically significant differences were observed in ABR wave III and V latencies, ABR wave III peak amplitude, and AMLR wave Na and Nb amplitudes when comparing groups based on their response to treatment, accompanied by varying effect sizes. Conversely, when examining groups categorised by tinnitus laterality, no statistically significant differences emerged. Conclusions: These results provide valuable insights into the potential influence of treatment responses on AEPs. However, further research is imperative to attain a comprehensive understanding of the underlying mechanisms at play.

Keywords: auditory brainstem response; auditory evoked potential; auditory middle latency response; chronic subjective tinnitus; electrophysiological differences; statistical analysis; tinnitus; tinnitus laterality; treatment response; underlying mechanisms.

Figure 1

Violin plots of ABR latency components by treatment response: (a) III Peak latency, with significance indicated by asterisks (** p-value < 0.01); (b) V Peak latency, with significance indicated by asterisks (** p-value < 0.01).

Figure 2

Violin plots of ABR amplitude components by treatment response. III Peak amplitude is shown, with significance indicated by asterisks (** p-value < 0.01).

Figure 3

Violin plots of AMLR amplitude components by treatment response: (a) Na trough amplitude, with significance indicated by asterisks (* p-value < 0.05); (b) Nb trough amplitude, with significance indicated by asterisks (* p-value < 0.05).

Figure 4

Violin plots of ABR waveform latencies based on tinnitus laterality.

Figure 5

Violin plots of ABR waveform amplitudes based on tinnitus laterality.

Figure 6

Violin plots of AMLR waveform latencies based on tinnitus laterality.

Figure 7

Violin plots of AMLR waveform amplitudes based on tinnitus laterality.