ISAAR 2013 Listening with the brain

Friday 13 Sep 13

Contact

Sébastien Santurette
Affiliated Associate Professor
DTU Health Tech

Contact

Torsten Dau
Head of Sections, Professor
DTU Health Tech
+4545 25 39 77
29 lectures were given in the auditorium, 52 posters were presented, and 200 professionals from the hearing aid industry, clinics, university research departments and students participated in the symposium. Fifteen countrys were represented at ISAAR 2013.

 

ISAAR International Symposium on Auditory and Audiological Research, formerly known as Danavox Symposium was founded in 1968. It takes place every second year. The symposium is organized by the Danavox Jubilee Foundation and supported by GN Resound. The foundation is managed by a board of scientific specialists within hearing research, independent of GN ReSound.
Read more and see all abstracts on www.isaar.eu
The next ISAAR Symposium will be held in 2015 in at Hotel Nyborg Strand, Denmark.

 

Read more about Michael Merzenich’s brain plasticity training program that improves hearing and language skills with age:
www.soft-wired.com

On August 26 to 28 two hundred professional researchers, scientists, and phD students from all over the world travelled to Nyborg, Denmark in order to participate in the fourth International Symposium on Auditory and Audiological Research. This year’s theme was ‘Auditory Plasticity: Listening with the brain’.

“We need to understand the mechanisms underlying signal encoding in the auditory system, particularly in challenging conditions. We need to have the right questions, the right tools and the right outcome measures to characterize our hearing,” Torsten Dau, Head of Hearing Systems DTU, addressed the Symposium.

“We need more knowledge about the individual listener’s deficits and the relation between impaired auditory functions. However, even with this knowledge, how can we compensate for the deficits?   
-Via acoustical filtering of the input signal?
-Through ”inverse engineering” providing the same ”information” as to the normal hearing person?
-Using sparce coding principles?
-Through training and learning programs? “

With these questions the scene of the three day conference was set. Hearing Systems was well represented both as presenters and participants. A number of lectures focused on how it is possible to train the brain in distinguishing different soundsources, and to improve speech intelligibility in everyday situations. Brian Moore, University of Cambridge, gave an interesting lecture on how learning effects can help  to determine different pitch coding strategies and pitch perception cues.

 


Doris Wu explains how the cochlea develops on a microbiological level in a mouse and a chicken. Photo:Torben Poulsen.

Cochlea at micro level

Doris Wu, a molecular biologist at the National Institute of Deafness and other Communication Disorders, Maryland, presented a study about the genetic mechanism underlying cochlear development. At a microbiological level, she investigated the role of specific molecules triggering developmental stages of the inner ear at early embryonic phases. By the use and comparison of animal models (mouse and chicken) with genetic modifications, she could identify the time and location where specific molecules were expressed and triggered differentiation and specialization of cells to build the structural and sensory elements (Inner hair cell, ourter hair cell spiral ganglions) of the inner ear. It was clearly shown in which order apical and basal structures and sensory elements started to evolve and how the local suppression or global absence of certain molecules (correlated with hearing impairments resulting from genetic defects in humans) affects the evolution of the inner ear. The formation of the inner ear is the necessary condition in order to provide sensory input to the brain in order to form specialized brain structures. These findings are important for a fundamental understanding of the impact of genetic deficits and allow for the development of potential therapies for hearing impaired children with resulting developmental issues due to the absence of plasticity.


For many PhD students it was a good opportunity to get professional input and feedback on posters. 52 posters from 15 countries, investigating a broad range of hearing research topics, were displayed and discussed.
Photo: Eva Helena Andersen

 

Modelling of plasticity

What are the neural correlates of cortical plasticity? How are the spectro-temporal patterns transformed to auditory objects and which plasticity mechanisms are involved? Jonathan Fritz, research scientist at the Institute for Systems Research, Maryland, demonstrated by his studies of ferrets, how to measure brain cells in real time, and how to train animals to distinguish specific sounds.

How effective is brain-plasticity based training in humans? Does training improve measures of attention, memory, speech production, and cognitive control in people with neurological problems?
Neurologist Michael Merzenich from the University of California revealed one of the brain's incredible secrets, namely its ability to actively create new nerve connections. He has spent years researching various methods to exploit the brain's plasticity for the purpose of enhancing our skills and recovering lost functions.

 

Reorganization of the brain

Anu Sharma, University of Colorado at Boulder, explained how the brain reorganizes itself by hearing loss. She said that one of the parameters that determine whether children that are born deaf are able to use a cochlear implant is dependent on when they get their first implant. If the implant happens before they are about 3 1/2 year old, a child is likely to be good at understanding speech. If the implant happens later than 7 years of age, a child will be able to hear sounds, but not able to get any meaning from the sounds. Sharma and her group's research show that there is a reorganization of parts of the auditory cortex to take over functions of other sensory inputs, especially visual funtions. This means that for children who are born deaf, and who never gets stimulated acoustically, the part of the brain that would normally interpret and understand sounds will be used to interpret visual stimuli. If this reorganization takes place, the benefit of a cochlear implant reduces, as the brain no longer has the resources to process the acoustic stimuli. Conversely, adults who recieve a cochlear implant because they have become deaf later in life, do not have the same problem, because the part of the brain that interprets acoustic signals has already been formed.

Another interesting presentation was a demonstration of musical training for young people with cochlear implants by musician Bjørn Petersen from the University of Aarhus.

"The brain is much more malleable, than we thought just a few years ago.This gives a whole new dimension to research on auditory plasticity in the brain in the future"
Jakob Christensen-Dalsgaard


Many professionals were very impressed with the composition and structure of the program on the theme of auditory plasticity in the brain arranged by Sébastien Santurette, CAHR, in coollaboration with Torsten Dau.
Photo: Eva Helena Andersen

Machine learning
Several researchers gave lectures about the potential of machine learning technology, where future hearing aids can learn to adapt via automatic measurements.
After three days of lectures, poster exchanges and networking there was very positive reactions from the participants:
“ The brain is much more malleable, than we thought just a few years ago. For instance Jonathan Fritz's lecture on the training of ferrets showed, that neurons behave differently at specific training impacts. This gives a whole new dimension to research on auditory plasticity in the brain in the future,“ said Jakob Christensen-Dalsgaard from the University of Southern Denmark.


Torben Poulsen, Chairman of the Danavox Jubilee Foundation that organizes ISAAR, was like many other professionals fascinated by Doris Wu's work and lecture. Here he had the opportunity to talk further with her on the subject over lunch at Nyborg Strand. Photo: Eva Helena Andersen

Presenters from CAHR research group and affiliates

Interaual bimodal pitch matching with two-formant vowels
Francois Guérit, Sébastien Santurette and Torsten Dau, all three from Centre for Applied Hearing Research, DTU, Joseph Chalupper and Iris Arweller.

Facial configuration and the McGurk illusion: a mismatch negatively study by Kasper Eskelund and Tobias Andersen, both from Cognitive Systems, DTU.

Investigating the relationship between simultaneously recorded cortical evoked responses and behavioral AM detection task James Harte, institute of National healthcare, University of Warwick. From October 1. 2013 leader of the new Interacoustics research group, DTU.

Task-modulated encoding of auditory objects in human auditory cortex.
Jens Hjortkjær Danish Research Centre for Magnetic Resonance(and CAHR DTU) with Tanja Kassuba, Kristoffer Madsen, Hartwig Siebner and Martin Skov.

Profiling hearing-aid sound by Morten Løve Jepsen (Guest researcher at CAHR) and Christian Norup both from Widex.

Separating the effects of energetic, modulation, and informational masking on speech intelligibility by Søren Jørgensen and Torsten Dau, CAHR DTU.

Modeling auditory evoked brainstem responses to speech syllables: Can variations in cochlea tuning explain argued brainstem plasticity?
Filip Rønne, Eriksholsm Research Centre/ CAHR DTU, James Harte UK, Torsten Dau CAHR, DTU.

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22 OCTOBER 2019