Ältere Menschen klagen oft über Hörschwierigkeiten, besonders wenn mehrere Personen durcheinander sprechen. Forscher am Max-Planck-Institut für Kognitions- und Neurowissenschaften in Leipzig haben herausgefunden, dass der Grund hierfür nicht nur im Ohr, sondern ebenso in veränderten Aufmerksamkeitsprozessen im Gehirn älterer Menschen zu finden ist. Eine besondere Bedeutung kommt dabei den Alpha-Wellen zu, deren Anpassung an veränderte Hörsituationen das Sprachverständnis in Alltagssituationen verbessert.
It nicely wraps up Malte’s experiment on alpha dynamics in younger and older listeners. Check the link above for the full article (German).
References
Wöstmann M1, Herrmann B2, Wilsch A2, Obleser J3. Neural alpha dynamics in younger and older listeners reflect acoustic challenges and predictive benefits. J Neurosci. 2015 Jan 28;35(4):1458–67. PMID: 25632123. [Open with Read]
Speech comprehension in multitalker situations is a notorious real-life challenge, particularly for older listeners. Younger listeners exploit stimulus-inherent acoustic detail, but are they also acti […]
Here is the abstract and my favourite figure from Malte’s paper.
Abstract
Speech comprehension in multi-talker situations is a notorious real-life challenge, particularly for older listeners. Younger listeners exploit stimulus-inherent acoustic detail, but are they also actively predicting upcoming information? And further, how do older listeners deal with acoustic and predictive information? To understand the neural dynamics of listening difficulties and according listening strategies, we contrasted neural responses in the alpha-band (~10 Hz) in younger (20−30 years, n = 18) and healthy older (60−70 years, n = 20) participants under changing task demands in a two-talker paradigm. Electroencephalograms were recorded while humans listened to two spoken digits against a distracting talker and decided whether the second digit was smaller or larger. Acoustic detail (temporal fine structure) and predictiveness (the degree to which the first digit predicted the second) varied orthogonally. Alpha power at widespread scalp sites decreased with increasing acoustic detail (during target digit presentation) but also with increasing predictiveness (in-between target digits). For older compared to younger listeners, acoustic detail had a stronger impact on task performance and alpha power modulation. This suggests that alpha dynamics plays an important role in the changes in listening behavior that occur with age. Lastly, alpha power variations resulting from stimulus manipulations (of acoustic detail and predictiveness) as well as task-independent overall alpha power were related to subjective listening effort. The present data show that alpha dynamics is a promising neural marker of individual difficulties as well as age-related changes in sensation, perception, and comprehension in complex communication situations.
Update #2
German radio broadcasterMDR Info did an interview & feature on Malte’s Experiment. Check out the stream below:
References
Wöstmann M1, Herrmann B2, Wilsch A2, Obleser J3. Neural alpha dynamics in younger and older listeners reflect acoustic challenges and predictive benefits. J Neurosci. 2015 Jan 28;35(4):1458–67. PMID: 25632123. [Open with Read]
Speech comprehension in multitalker situations is a notorious real-life challenge, particularly for older listeners. Younger listeners exploit stimulus-inherent acoustic detail, but are they also acti […]
Enhanced alpha power compared with a baseline can reflect states of increased cognitive load, for example, when listening to speech in noise. Can knowledge about “when” to listen (temporal expectations) potentially counteract cognitive load and concomitantly reduce alpha? The current magnetoencephalography (MEG) experiment induced cognitive load using an auditory delayed-matching-to-sample task with 2 syllables S1 and S2 presented in speech-shaped noise. Temporal expectation about the occurrence of S1 was manipulated in 3 different cue conditions: “Neutral” (uninformative about foreperiod), “early-cued” (short foreperiod), and “late-cued” (long foreperiod). Alpha power throughout the trial was highest when the cue was uninformative about the onset time of S1 (neutral) and lowest for the late-cued condition. This alpha-reducing effect of late compared with neutral cues was most evident during memory retention in noise and originated primarily in the right insula. Moreover, individual alpha effects during retention accounted best for observed individual performance differences between late-cued and neutral conditions, indicating a tradeoff between allocation of neural resources and the benefits drawn from temporal cues. Overall, the results indicate that temporal expectations can facilitate the encoding of speech in noise, and concomitantly reduce neural markers of cognitive load.
References
Wilsch A, Henry MJ, Herrmann B, Maess B, Obleser J. Alpha Oscillatory Dynamics Index Temporal Expectation Benefits in Working Memory. Cereb Cortex. 2014 Jan 31. PMID: 24488943. [Open with Read]
Enhanced alpha power compared with a baseline can reflect states of increased cognitive load, for example, when listening to speech in noise. Can knowledge about “when” to listen (temporal expectation […]
Erb J, Obleser J. Upregulation of cognitive control networks in older adults’ speech comprehension. Front Syst Neurosci. 2013 Dec 24;7:116. PMID: 24399939. [Open with Read]
Speech comprehension abilities decline with age and with age-related hearing loss, but it is unclear how this decline expresses in terms of central neural mechanisms. The current study examined neural […]
Thalamic and parietal brain morphology predicts auditory category learning
Categorizing sounds is vital for adaptive human behavior. Accordingly, changing listening situations (external noise, but also peripheral hearing loss in aging) require listeners to flexibly adjust their categorization strategies, e.g., switch amongst available acoustic cues. However, listeners differ considerably in these adaptive capabilities. For this reason, we employed voxel-based morphometry (VBM) in our study (Neuropsychologia, In press), in order to assess the degree to which individual brain morphology is predictive of such adaptive listening behavior.
When we listen to sounds like speech and music, we have to make sense of different acoustic features that vary simultaneously along multiple time scales. This means that we, as listeners, have to selectively attend to, but at the same time selectively ignore, separate but intertwined features of a stimulus.
Brain regions associated with selective attending to and selective ignoring of temporal stimulus features. (more)
A newly published fMRI study by Molly Henry, Björn Herrmann, and Jonas Obleser found a network of brain regions that responded oppositely to identical stimulus characteristics depending on whether they were relevant or irrelevant, even when both stimulus features involved attention to time and temporal features.
Henry MJ, Herrmann B, Obleser J. Selective Attention to Temporal Features on Nested Time Scales. Cereb Cortex. 2013 Aug 26. PMID: 23978652. [Open with Read]
Meaningful auditory stimuli such as speech and music often vary simultaneously along multiple time scales. Thus, listeners must selectively attend to, and selectively ignore, separate but intertwined […]
Listeners show a remarkable ability to quickly adjust to degraded speech input. Here, we aimed to identify the neural mechanisms of such short-term perceptual adaptation. In a sparse-sampling, cardiac-gated functional magnetic resonance imaging (fMRI) acquisition, human listeners heard and repeated back 4‑band-vocoded sentences
Erb J, Henry MJ, Eisner F, Obleser J. The brain dynamics of rapid perceptual adaptation to adverse listening conditions. J Neurosci. 2013 Jun 26;33(26):10688–97. PMID: 23804092. [Open with Read]
Listeners show a remarkable ability to quickly adjust to degraded speech input. Here, we aimed to identify the neural mechanisms of such short-term perceptual adaptation. In a sparse-sampling, cardiac […]