Biology subjects

Hannemann, R.

Publications and source records attributed to Hannemann, R..

6 recordsLinked to original sources

bioRxiv2025

Speech, gait, and brain dynamics during natural conversation in motion

Communication connects us to others and immerses us in our environment. Mobile EEG and hearing aid-embedded motion sensors allow investigation of communi-cation and movement in real-world contexts. Here we reliably record and model neural responses to natural conversational speech while participants are walking, demonstrating the feasibility of combining EEG with whole-body movement moni-toring. Participants (N = 61) performed focused listening and natural conversation while walking indoors and outdoors. Motion sensors, EEG, and audio recordings captured behavioural, neural, and motor dynamics. Walking speed varied with en-vironment and task: faster outdoors and slower during speaking. Temporal align-ment between gait and speech revealed coordinated rhythmic interactions, stronger during speaking than listening. Auditory temporal response functions were preserved across listening tasks. Gait TRFs displayed lateralized and temporal dy-namics consistent across tasks. These results provide insight into the coordinated interplay of speech, brain activity, and movement. This highlights the potential of multimodal approaches in ecologically valid settings.

neuroscience↗

bioRxiv2024

Does amplitude compression help or hinder attentional neural speech tracking?

Amplitude compression is an indispensable feature of contemporary audio production and especially relevant in modern hearing aids. The cortical fate of amplitude-compressed speech signals is not well-studied, however, and may yield undesired side effects: We hypothesize that compressing the amplitude envelope of continuous speech reduces neural tracking. Yet, leveraging such a compression side effect on unwanted, distracting sounds could potentially support attentive listening if effectively reducing their neural tracking. In this study, we examined 24 young normal-hearing (NH) individuals, 19 older hearing-impaired (HI) individuals, and 12 older normal-hearing individuals. Participants were instructed to focus on one of two competing talkers while ignoring the other. Envelope compression (1:8 ratio, loudness-matched) was applied to one or both streams containing short speech repeats. Electroencephalography (EEG) allowed us to quantify the cortical response function and degree of speech tracking. With compression applied to the attended target stream, HI participants showed reduced behavioural accuracy, and compressed speech yielded generally lowered metrics of neural tracking. Importantly, we found that compressing the ignored stream resulted in a stronger neural representation of the uncompressed target speech. Our results imply that intelligent compression algorithms, with variable compression ratios applied to separated sources, could help individuals with hearing loss suppress distraction in complex multi-talker environments. Significant statementAmplitude compression, integral in contemporary audio production and hearing aids, poses an underexplored cortical challenge. Compressing the amplitude envelope of continuous speech is hypothesized to diminish neural tracking. Yet, capitalizing on this compression side effect for distracting sounds might enhance attentive listening. Studying normal-hearing (NH), older hearing-impaired (HI), and older normal hearing individuals in dual-talker scenarios, we applied envelope compression to speech streams. Both NH and HI participants showed diminished neural tracking with compression on the speech streams. Despite weaker tracking of a compressed distractor, HI individuals exhibited stronger neural representation of the concurrent target. This suggests that adaptive compression algorithms, employing variable ratios for distinct sources, could aid individuals with hearing loss in suppressing distractions in complex multi-talker environments.

neuroscience↗

bioRxiv2023

Electromyographic Correlates of Effortful Listening in the Vestigial Auriculomotor System

Recently, electromyographic (EMG) signals of auricular muscles have been shown to be an indicator of spatial auditory attention in humans, based on a vestigial pinna-orienting system. Because spatial auditory attention in a competing speaker task is closely related to the more gen-eralized concept of attentional effort in listening, the current study inves-tigated the possibility that the EMG activity of auricular muscles could also reflect correlates of effortful listening in general. Twenty subjects were recruited. EMG signals from the left and right superior and poste-rior auricular muscles (SAM, PAM) were recorded while subjects attended a target podcast in a competing speaker paradigm. Three different lev-els of listening effort, low, medium, and high, were generated by varying the number and pitch of distractor streams, as well as the signal-to-noise ratio. All audio streams were either presented from a loudspeaker placed in front of the participants (0{degrees}), or in the back (180{degrees}). Averaged PAM activity was not affected by different levels of listening effort, but was sig-nificantly larger when stimuli were presented from the back, as opposed to the front. Averaged SAM activity, however, was significantly larger in the high listening effort condition, compared to low and medium, but was not affected by stimulus direction. We hypothesize that the increased SAM activity is a response of the vestigial pinna-orienting system to effortful stream segregation task.

neuroscience↗

bioRxiv2022

Auditory neural tracking reflects target enhancementbut not distractor suppression in a psychophysically augmented continuous-speech paradigm

Selective attention modulates the neural tracking of speech in auditory cortical regions. It is unclear whether this attention modulation is dominated by enhanced target tracking, or suppression of distraction. To settle this long-standing debate, we here employed an augmented electroencephalography (EEG) speech-tracking paradigm with target, distractor, and neutral streams. Concurrent target speech and distractor (i.e., sometimes relevant) speech were juxtaposed with a third, never task-relevant speech stream serving as neutral baseline. Listeners had to detect short target repeats and committed more false alarms originating from the distractor than the neutral stream. Speech tracking revealed target enhancement but no distractor suppression below the neutral baseline. Speech tracking of the target (not distractor or neutral speech) explained single-trial accuracy in repeat detection. In sum, the enhanced neural representation of target speech is specific to processes of attentional gain for behaviourally relevant target speech rather than neural suppression of distraction.

neuroscience↗

bioRxiv2021

Neural speech tracking shifts from the syllabic to the modulation rate of speech as intelligibility decreases

The most prominent acoustic features in speech are intensity modulations, represented by the amplitude envelope of speech. Synchronization of neural activity with these modulations is vital for speech comprehension. As the acoustic modulation of speech is related to the production of syllables, investigations of neural speech tracking rarely distinguish between lower-level acoustic (envelope modulation) and higher-level linguistic (syllable rate) information. Here we manipulated speech intelligibility using noise-vocoded speech and investigated the spectral dynamics of neural speech processing, across two studies at cortical and subcortical levels of the auditory hierarchy, using magnetoencephalography. Overall, cortical regions mostly track the syllable rate, whereas subcortical regions track the acoustic envelope. Furthermore, with less intelligible speech, tracking of the modulation rate becomes more dominant. Our study highlights the importance of distinguishing between envelope modulation and syllable rate and provides novel possibilities to better understand differences between auditory processing and speech/language processing disorders. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=160 SRC="FIGDIR/small/437033v1_ufig1.gif" ALT="Figure 1"> View larger version (23K): org.highwire.dtl.DTLVardef@6364adorg.highwire.dtl.DTLVardef@166daaeorg.highwire.dtl.DTLVardef@19eedd2org.highwire.dtl.DTLVardef@10f7aed_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2019

Vestigial Auriculomotor Activity Indicates the Direction of Auditory Attention in Humans

It is commonly assumed that, unlike dogs and cats, we humans do not make ear movements when focusing our attention reflexively toward novel sounds or voluntarily toward those that are goal-relevant. In fact, it has been suggested that we do have a pinna-orienting system. Although this system became vestigial about 25 million years ago, it still exists as a \"neural fossil\" within the brain. Consistent with this hypothesis, we demonstrate for the first time that the direction of auditory attention is reflected in the sustained electrical activity of muscles within the vestigial auriculomotor system.\n\nSurface electromyograms (EMGs) were taken from muscles that either move the pinna or alter its shape. To assess reflexive, stimulus-driven attention we presented novel sounds from speakers at four different lateral locations while the participants silently read a boring text in front of them. To test voluntary, goal-directed attention we instructed participants to listen to a short story coming from one of these speakers, while ignoring a competing story from the corresponding speaker on the opposite side.\n\nIn both experiments, EMG recordings showed larger activity at the ear on the side of the attended stimulus, but with slightly different patterns. Upward movement (perking) differed according to the lateral focus of attention only during voluntary orienting; rearward folding of the pinnas upper-lateral edge exhibited such differences only during reflexive orienting. The existence of a pinna-orienting system in humans, one that is experimentally accessible, offers opportunities for basic as well as applied science. It could lead to a better understanding of the evolution of auditory attention and support the near real-time decoding of auditory attention in technical applications, for example, for attentionally controlled hearing aids that preferentially amplify sounds the user is attempting to listen to.

neuroscience↗