Exaggerated Cortical Representation of Speech in Older Listeners: Mutual Information Analysis

AbstractAging is associated with an exaggerated representation of the speech envelope in auditory cortex. The relationship between this age-related exaggerated response and a listener’s ability to understand speech in noise remains an open question. Here, information-theory-based analysis methods are applied to magnetoencephalography (MEG) recordings of human listeners, investigating their cortical responses to continuous speech, using the novel non-linear measure of phase-locked mutual information between the speech stimuli and cortical responses. The cortex of older listeners shows an exaggerated level of mutual information, compared to younger listeners, for both attended and unattended speakers. The mutual information peaks for several distinct latencies: early (∼50 ms), middle (∼100 ms) and late (∼200 ms). For the late component, the neural enhancement of attended over unattended speech is affected by stimulus SNR, but the direction of this dependency is reversed by aging. Critically, in older listeners and for the same late component, greater cortical exaggeration is correlated with decreased behavioral inhibitory control. This negative correlation also carries over to speech intelligibility in noise, where greater cortical exaggeration in older listeners is correlated with worse speech intelligibility scores. Finally, an age-related lateralization difference is also seen for the ∼100 ms latency peaks, where older listeners show a bilateral response compared to younger listeners’ right-lateralization. Thus, this information-theory-based analysis provides new, and less coarse-grained, results regarding age-related change in auditory cortical speech processing, and its correlation with cognitive measures, compared to related linear measures.New & NoteworthyCortical representations of natural speech are investigated using a novel non-linear approach based on mutual information. Cortical responses, phase-locked to the speech envelope, show an exaggerated level of mutual information associated with aging, appearing at several distinct latencies (∼50, ∼100 and ∼200 ms). Critically, for older listeners only, the ∼200 ms latency response components are correlated with specific behavioral measures, including behavioral inhibition and speech comprehension.

Download Full-text

Exaggerated cortical representation of speech in older listeners: mutual information analysis

Journal of Neurophysiology ◽

10.1152/jn.00002.2020 ◽

2020 ◽

Vol 124 (4) ◽

pp. 1152-1164

Author(s):

Peng Zan ◽

Alessandro Presacco ◽

Samira Anderson ◽

Jonathan Z. Simon

Keyword(s):

Mutual Information ◽

Speech Comprehension ◽

Information Analysis ◽

Behavioral Measures ◽

Nonlinear Approach ◽

Cortical Responses ◽

Latency Response ◽

Speech Envelope ◽

Cortical Representations ◽

Mutual Information Analysis

Cortical representations of natural speech are investigated using a novel nonlinear approach based on mutual information. Cortical responses, phase-locked to the speech envelope, show an exaggerated level of mutual information associated with aging, appearing at several distinct latencies (∼50, ∼100, and ∼200 ms). Critically, for older listeners only, the ∼200 ms latency response components are correlated with specific behavioral measures, including behavioral inhibition and speech comprehension.

Download Full-text

Neural markers of speech comprehension: measuring EEG tracking of linguistic speech representations, controlling the speech acoustics

10.1101/2021.03.24.436758 ◽

2021 ◽

Author(s):

Marlies Gillis ◽

Jonas Vanthornhout ◽

Jonathan Z Simon ◽

Tom Francart ◽

Christian Brodbeck

Keyword(s):

Word Frequency ◽

Language Processing ◽

Speech Intelligibility ◽

Acoustic Properties ◽

Speech Comprehension ◽

Speech Acoustics ◽

Brain Responses ◽

Cortical Responses ◽

Linguistic Representations ◽

Acoustic Processing

When listening to speech, brain responses time-lock to acoustic events in the stimulus. Recent studies have also reported that cortical responses track linguistic representations of speech. However, tracking of these representations is often described without controlling for acoustic properties. Therefore, the response to these linguistic representations might reflect unaccounted acoustic processing rather than language processing. Here we tested several recently proposed linguistic representations, using audiobook speech, while controlling for acoustic and other linguistic representations. Indeed, some of these linguistic representations were not significantly tracked after controlling for acoustic properties. However, phoneme surprisal, cohort entropy, word surprisal and word frequency were significantly tracked over and beyond acoustic properties. Additionally, these linguistic representations are tracked similarly across different stories, spoken by different readers. Together, this suggests that these representations characterize processing of the linguistic content of speech and might allow a behaviour-free evaluation of the speech intelligibility.

Download Full-text

Transcranial alternating current stimulation with speech envelopes modulates speech comprehension

10.1101/097576 ◽

2017 ◽

Author(s):

Anna Wilsch ◽

Toralf Neuling ◽

Jonas Obleser ◽

Christoph S. Herrmann

Keyword(s):

Auditory Cortex ◽

Speech Signal ◽

Speech Intelligibility ◽

Sentence Comprehension ◽

Average Frequency ◽

Speech Comprehension ◽

Time Lags ◽

Transcranial Alternating Current Stimulation ◽

Speech Envelope ◽

Cortical Entrainment

AbstractCortical entrainment of the auditory cortex to the broadband temporal envelope of a speech signal is crucial for speech comprehension. Entrainment results in phases of high and low neural excitability, which structure and decode the incoming speech signal. Entrainment to speech is strongest in the theta frequency range (4–8 Hz), the average frequency of the speech envelope. If a speech signal is degraded, entrainment to the speech envelope is weaker and speech intelligibility declines. Besides perceptually evoked cortical entrainment, transcranial alternating current stimulation (tACS) entrains neural oscillations by applying an electric signal to the brain. Accordingly, tACS-induced entrainment in auditory cortex has been shown to improve auditory perception. The aim of the current study was to modulate speech intelligibility externally by means of tACS such that the electric current corresponds to the envelope of the presented speech stream (i.e., envelope-tACS). Participants performed the Oldenburg sentence test with sentences presented in noise in combination with envelope-tACS. Critically, tACS was induced at time lags of 0 to 250 ms in 50-ms steps relative to sentence onset (auditory stimuli were simultaneous to or preceded tACS). We performed single-subject sinusoidal, linear, and quadratic fits to the sentence comprehension performance across the time lags. We could show that the sinusoidal fit described the modulation of sentence comprehension best. Importantly, the average frequency of the sinusoidal fit was 5.12 Hz, corresponding to the peaks of the amplitude spectrum of the stimulated envelopes. This finding was supported by a significant 5-Hz peak in the average power spectrum of individual performance time series. Altogether, envelope tACS modulates intelligibility of speech in noise, presumably by enhancing and disrupting (time lag with in-or out-of-phase stimulation, respectively) cortical entrainment to the speech envelope in auditory cortex.

Download Full-text

Mutual Information Reveals Non-linear Relationships between Electrocardiographic Conduction or Repolarization Indices and Mechanical Dispersion by Speckle-Tracking Echocardiography in the General Population

Ultrasound in Medicine & Biology ◽

10.1016/j.ultrasmedbio.2021.01.027 ◽

2021 ◽

Vol 47 (5) ◽

pp. 1408-1420

Author(s):

Ana Ciobanu ◽

Gabriela Silvia Gheorghe ◽

Oana Mihaela Inţă ◽

Jiandong Zhou ◽

Qingpeng Zhang ◽

...

Keyword(s):

General Population ◽

Mutual Information ◽

Speckle Tracking ◽

Speckle Tracking Echocardiography ◽

Mechanical Dispersion ◽

Linear Relationships ◽

Non Linear

Download Full-text

Single-Word Speech Intelligibility in Children and Adults With Down Syndrome

American Journal of Speech-Language Pathology ◽

10.1044/2017_ajslp-17-0002 ◽

2018 ◽

Vol 27 (1) ◽

pp. 222-236 ◽

Cited By ~ 9

Author(s):

Alyssa Wild ◽

Houri K. Vorperian ◽

Ray D. Kent ◽

Daniel M. Bolt ◽

Diane Austin

Keyword(s):

Down Syndrome ◽

Speech Intelligibility ◽

Word Identification ◽

Typically Developing ◽

Single Word ◽

Vowel Production ◽

Adult Men ◽

Age Related ◽

Assessment And Treatment ◽

High Vowels

Purpose A single-word identification test was used to study speech production in children and adults with Down syndrome (DS) to determine the developmental pattern of speech intelligibility with an emphasis on vowels. Method Speech recordings were collected from 62 participants with DS aged 4–40 years and 25 typically developing participants aged 4–7 years. Panels of 5 adult lay listeners transcribed the speech recordings orthographically, and their responses were scored in comparison with the speakers' target words. Results Speech intelligibility in persons with DS improved with age, especially between the ages of 4 and 16 years. Whereas consonants contribute to intelligibility, vowels also played an important role in reduced intelligibility with an apparent developmental difference in low versus high vowels, where the vowels /æ/ and/ɑ/ developed at a later age than /i/ and /u/. Interspeaker variability was large, with male individuals being generally less intelligible than female individuals and some adult men having very low intelligibility. Conclusion Results show age-related patterns in speech intelligibility in persons with DS and identify the contribution of dimensions of vowel production to intelligibility. The methods used clarify the phonetic basis of reduced intelligibility, with implications for assessment and treatment.

Download Full-text

Predicting speech intelligibility from EEG in a non-linear classification paradigm

Journal of Neural Engineering ◽

10.1088/1741-2552/ac33e9 ◽

2021 ◽

Author(s):

Bernd Accou ◽

Mohammad Jalilpour Monesi ◽

Hugo Van hamme ◽

Tom Francart

Keyword(s):

Speech Intelligibility ◽

Linear Classification ◽

Non Linear

Download Full-text

The Effect of Binaural Beamforming Technology on Speech Intelligibility in Bimodal Cochlear Implant Recipients

Audiology and Neurotology ◽

10.1159/000487749 ◽

2018 ◽

Vol 23 (1) ◽

pp. 32-38 ◽

Cited By ~ 1

Author(s):

Jantien L. Vroegop ◽

Nienke C. Homans ◽

André Goedegebure ◽

J. Gertjan Dingemanse ◽

Teun van Immerzeel ◽

...

Keyword(s):

Cochlear Implant ◽

Repeated Measures ◽

Speech Intelligibility ◽

Real Life ◽

Speech Comprehension ◽

Noise Sources ◽

Additional Advantage ◽

Listening Condition ◽

Repeated Measures Design ◽

Speech Reception Thresholds

Although the benefit of bimodal listening in cochlear implant users has been agreed on, speech comprehension remains a challenge in acoustically complex real-life environments due to reverberation and disturbing background noises. One way to additionally improve bimodal auditory performance is the use of directional microphones. The objective of this study was to investigate the effect of a binaural beamformer for bimodal cochlear implant (CI) users. This prospective study measured speech reception thresholds (SRT) in noise in a repeated-measures design that varied in listening modality for static and dynamic listening conditions. A significant improvement in SRT of 4.7 dB was found with the binaural beamformer switched on in the bimodal static listening condition. No significant improvement was found in the dynamic listening condition. We conclude that there is a clear additional advantage of the binaural beamformer in bimodal CI users for predictable/static listening conditions with frontal target speech and spatially separated noise sources.

Download Full-text

Information Measures

Formalized Probability Theory and Applications Using Theorem Proving ◽

10.4018/978-1-4666-8315-0.ch009 ◽

2015 ◽

pp. 129-142

Keyword(s):

Information Theory ◽

Mutual Information ◽

Order Logic ◽

Unified Framework ◽

Higher Order Logic ◽

Absolutely Continuous ◽

Information Measures ◽

Finite Spaces ◽

Nikodym Derivative ◽

Lebesgue Integration

This chapter presents a higher-order-logic formalization of the main concepts of information theory (Cover & Thomas, 1991), such as the Shannon entropy and mutual information, using the formalization of the foundational theories of measure, Lebesgue integration, and probability. The main results of the chapter include the formalizations of the Radon-Nikodym derivative and the Kullback-Leibler (KL) divergence (Coble, 2010). The latter provides a unified framework based on which most of the commonly used measures of information can be defined. The chapter then provides the general definitions that are valid for both discrete and continuous cases and then proves the corresponding reduced expressions where the measures considered are absolutely continuous over finite spaces.

Download Full-text