Brainstem evoked auditory potentials in tinnitus: A best-evidence synthesis and meta-analysis

Abstract

IntroductionAccumulating evidence suggests a role of the brainstem in tinnitus generation and modulation. Several studies in chronic tinnitus patients have reported latency and amplitude changes of the different peaks of the auditory brainstem response, possibly reflecting neural changes or altered activity. The aim of the systematic review was to assess if alterations within the brainstem of chronic tinnitus patients are reflected in short- and middle-latency auditory evoked potentials (AEPs).MethodsA systematic review was performed and reported according to the PRISMA guidelines. Studies evaluating short- and middle-latency AEPs in tinnitus patients and controls were included. Two independent reviewers conducted the study selection, data extraction, and risk of bias assessment. Meta-analysis was performed using a multivariate meta-analytic model.ResultsTwenty-seven cross-sectional studies were included. Multivariate meta-analysis revealed that in tinnitus patients with normal hearing, significantly longer latencies of auditory brainstem response (ABR) waves I (SMD = 0.66 ms, p < 0.001), III (SMD = 0.43 ms, p < 0.001), and V (SMD = 0.47 ms, p < 0.01) are present. The results regarding possible changes in middle-latency responses (MLRs) and frequency-following responses (FFRs) were inconclusive.DiscussionThe discovered changes in short-latency AEPs reflect alterations at brainstem level in tinnitus patients. More specifically, the prolonged ABR latencies could possibly be explained by high frequency sensorineural hearing loss, or other modulating factors such as cochlear synaptopathy or somatosensory tinnitus generators. The question whether middle-latency AEP changes, representing subcortical level of the auditory pathway, are present in tinnitus still remains unanswered. Future studies should identify and correctly deal with confounding factors, such as age, gender and the presence of somatosensory tinnitus components.Systematic review registrationhttps://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021243687, PROSPERO [CRD42021243687].

Enhanced 40 and 80 Hz Auditory Steady State Responses in Idiopathic Tinnitus

“…This was further proven in tinnitus studies with no hearing deficits [34]. Considering that the origin of wave III and V ABR are cochlear nucleus and lateral lemniscus [34, 36, 37], these results support our findings of significantly enhanced 80 Hz steady state responses in tinnitus group.…”

“…As the main contributors to ASSRs at MFs higher than 60 Hz are auditory brainstem nuclei such as cochlear nucleus and inferior colliculus [29][30][31], the enhanced responses at 80 Hz could point to disturbed sensory processing in these regions. Consistent with our findings, several studies have shown abnormal ABR measurements related to wave III and V in tinnitus subjects [32][33][34][35]. For instance, Said [35] compared the ABR wave latencies between sensory-neural hearing loss (SNHL) patients with and without tinnitus, and observed enhanced latency of III-V peaks for tinnitus patients compared to no tinnitus control group.…”

“…Since this study used subjects with SNHL in both groups, the longer wave V latency could not be the result of hearing loss and is most likely due to the pathophysiology underlying tinnitus [35]. This was further proven in tinnitus studies with no hearing deficits [34]. Considering that the origin of wave III and V ABR are cochlear nucleus and lateral lemniscus [34, 36, 37], these results support our findings of significantly enhanced 80 Hz steady state responses in tinnitus group.…”

A systematic review of the association of Type I diabetes with sensorineural hearing loss

“…individual during the first 10ms after the stimulus. This technique is particularly useful in infants as it can be performed without participation from the subject under testing [44]. The second technique is the pure-tone audiometry (PTA) that is used to determine hearing thresholds at different frequencies, usually 125-8000 Hz, which is considered speech frequency [46,47].…”

“…The auditory function and hearing thresholds can be determined clinically in several ways [42,43]. The first technique is the auditory evoked potential (AEP), which evaluates neural activity from the cochlea to the auditory cortex [44,45]. The short-latency AEP is the auditory brainstem response (ABR).…”