Sources of auditory brainstem responses revisited: Contribution by magnetoencephalography

Abstract

Auditory brainstem responses provide diagnostic value in pathologies involving the early parts of the auditory pathway. Despite that, the neural generators underlying the various components of these responses have remained unclear. Direct electrical recordings in humans are possible only in limited time periods during surgery and from small regions of the diseased brains. The evidence of the generator sites is therefore fragmented and indirect, based strongly on lesion studies and animal models. Source modeling of EEG has been limited to grand averages across multiple subjects. Here, we employed magnetoencephalography (MEG) to shed more light on the neural origins of the auditory brainstem responses (ABR) and to test whether such deep brain structures are accessible by MEG. We show that the magnetic counterparts of the electric ABRs can be measured in 30 min and that they allow localization of some of the underlying neural sources in individual subjects. Many of the electric ABR components were present in our MEG data; however, the morphologies of the magnetic and electric responses were different, indicating that the MEG signals carry information complementary to the EEG data. The locations of the neural sources corresponding to the magnetic ABR deflections ranged from the auditory nerve to the inferior colliculus. The earliest cortical responses were detectable at the latency of 13 ms.

Lateralization and Binaural Interaction of Middle-Latency and Late-Brainstem Components of the Auditory Evoked Response

“…Like many previous M/EEG, intracranial, and lesioneffect studies, our data clearly implicate primary auditory cortex as the main generator of the MLR (Celesia 1976;Kraus et al 1982;Özdamar et al 1982;Scherg and Von Cramon 1986;Liégeois-Chauvel et al 1994;Hashimoto et al 1995;Kuriki et al 1995;Gutschalk et al 1999;Godey et al 2001;Rupp et al 2002b;Yvert et al 2005;Parkkonen et al 2009). Lateralization of the MLR in response to monaural stimulation, however, has historically been controversial, with some EEG studies reporting lateralization (Woods and Clayworth 1985;Woods et al 1987;Cacace et al 1990;Kaseda et al 1991) and others reporting balance (Peters and Mendel 1974;Scherg and Von Cramon 1986;Kileny et al 1987;Jacobson and Grayson 1988).…”

Lateralization of Interimplant Timing and Level Differences in Children Who Use Bilateral Cochlear Implants

“…(Hall 1992). Activity in the auditory brainstem can be visualized non-invasively in animal models and in humans using a far-field evoked potential response referred to as the auditory brainstem response (ABR), which consists of five characteristic peaks (Fig 1.2 (B)). Numerous investigations into the neural generators of the ABR, including lesion studies, brain pathology analyses, and calculated neural conduction times have led to the following associations: I and II reflect activity along the auditory nerve; III has been associated with activity in the cochlear nucleus; IV and V are attributed to activity in the lateral lemniscus (Hall 1992;Moller et al 1995;Parkkonen et al 2009). …”

Multichannel recordings of the human brainstem frequency-following response: Scalp topography, source generators, and distinctions from the transient ABR

“…While multichannel descriptions of other brainstem responses exist in the literature, previous studies have focused on phase-locked responses to the envelope of complex tones (auditory steady-state response, ASSR: Bharadwaj and Shinn-Cunningham, 2014;Herdman et al, 2002) or the transient, click-evoked auditory brainstem response (ABR) (Parkkonen et al, 2009). We are aware of no study which has directly examined multichannel FFRs elicited by speech stimuli.…”