Electrically evoked compound action potential artifact rejection by independent component analysis: Technique validation

The electrically-evoked compound action potential (ECAP) is the synchronous whole auditory nerve activity in response to an electrical stimulus, and can be recorded in situ on cochlear implant (CI) electrodes. A novel procedure (ECAP-ICA) to isolate the ECAP from the stimulation artifact, based on independent component analysis (ICA), is described here. ECAPs with artifact (raw-ECAPs) were sequentially recorded for the same stimulus on 9 different intracochlear recording electrodes. The raw-ECAPs were fed to ICA, which separated them into independent sources. Restricting the ICA projection to 4 independent components did not induce under-fitting and was found to explain most of the raw-data variance. The sources were identified and only the source corresponding to the neural response was retained for artifact-free ECAP reconstruction. The validity of the ECAP-ICA procedure was supported as follows: N(1) and P(1) peaks occurred at usual latencies; and ECAP-ICA and artifact amplitude-growth functions (AGFs) had different slopes. Concatenation of raw-ECAPs from multiple stimulus currents, including some below the ECAP-ICA threshold, improved the source separation process. The main advantage of ECAP-ICA is that use of maskers or alternating polarity stimulation are not needed

The Backlash to CRT in France

In November 2021, Josephine Baker became the latest recipient of one of France’s highest honors—induction into the Pantheon. This honor is reserved for those who have made an indelible impact on French culture and history. Baker became the first black woman to be inducted, but the honor was also notable for the fact that she was born American. In a speech at the event, French President Emmanuel Macron praised Baker’s commitment to universalism

ANALYSE DE L'ENCODAGE DES SIGNAUX DE PAROLE DANS LE TRONC CEREBRAL (SPEECH AUDITORY BRAINSTEM RESPONSE)

In this dissertation, speech encoding in the peripheral auditory system is investigated by the speech-evoked brainstem responses (Speech-ABR) electrophysiological approach – in normal-hearing adults. Section 1 addresses technical aspects related to Speech ABR. Firstly, a parametric study that quantifies electromagnetic artefact influences from stimulation is presented in order to prove the authenticity of Speech-ABR recordings. Second, advantages related to time-frequency analysis of Speech ABR are detailed, particularly for high-frequency signals (500 Hz and above). Finally, an empirical approach is proposed to narrow-down the Speech-ABR physiological generators within the brainstem, using specific stimuli. In Section 2, the influence of the stimuli acoustic structure on Speech ABR is discussed. Firstly, the temporal relationship between the /ba/ syllable and Speech ABR is described. Second, the effect of stimulus intensity on Speech-ABR latencies is presented and third, the effects of pitch and stimulus nature (speech, non-speech and music) on the ABR. The last part attempted to link perception quality to Speech ABR synchronisation accuracy.Les Speech ABR sont un outil prometteur d'exploration fonctionnelle auditive, qui pourrait à terme être implémenté en routine clinique afin de dépister la surdité et d'évaluer l'efficacité des techniques de réhabilitation auditive. Dans la Partie 1, nous présentons d'abord (i) une étude paramétrique quantifiant les effets de l'artefact électromagnétique, issu du couplage entre la chaine de stimulation et d'acquisition, sur le Speech ABR. Puis nous discutons (ii) les avantages de la représentation temps-fréquence dans l'analyse des Speech ABR, en particulier dans le cas des stimuli de haute fréquence de l'ordre de 500 Hz ou plus. Enfin (iii), nous tentons de déceler les probables générateurs neurophysiologiques sous-jacents du Speech ABR, d'après son comportement en réponse a des stimuli de différentes structures acoustiques. Dans la Partie 2, nous évaluons en premier lieu (i) la relation entre la structure temporelle d'une syllabe /ba/ et la forme temporelle du Speech ABR. Ensuite (ii), nous confrontons le comportement du Speech ABR en fonction de l'intensité de stimulation aux résultats bien connus pour les clics-ABR. Puis, nous étudions (iii) les effets de la hauteur tonale, ainsi que de la nature du stimulus (parole, analogue non-langagier et musique) sur le Speech ABR. La dernière étude de cette Partie 2 (iv) tente de faire le lien entre la qualité de perception d'un analogue non-langagier et la qualité de synchronisation du Speech ABR

Prise en charge médicamenteuse et non médicamenteuse du stress et des troubles anxieux

BORDEAUX2-BU Santé (330632101) / SudocSudocFranceF

Gestion du stress par la cohérence cardiaque (intérêt de son utilisation au cabinet dentaire)

Lorsqu un individu n arrive plus à gérer ses émotions, le stress associé entraine une dysharmonie incontrôlable des fonctions physiologiques dans tout l organisme. Une analyse informatique de la fréquence cardiaque démontre qu une variabilité chaotique s installe lorsque l on éprouve une émotion négative, alors qu elle reste régulière dans un état de bien-être. Une reproductibilité de cette courbe cohérente est également observée lors du contrôle de la fonction respiratoire ce qui, par résonance, grâce à l existence d un réseau de neurones récemment mis en évidence, va agir positivement sur le corps entier permettant ainsi une gestion du stress. Une telle technique trouve tout son intérêt dans un cabinet dentaire où elle peut servir aussi bien au praticien qu à son patient. En effet, les chiffre attestent d une part que les pathologies du stress professionnel, telle le Burn-out, sont une des causes principales de la pénibilité du travail de chirurgien-dentiste et d autre part que la peur, voir la phobie dentaire, touche un grand nombre de soignés.When a person can no more keep his own emotions under control, the resulting stress leads to an uncontrollable disorder of the physiological functions all over the organism. A computer analysis of the heart rate proves that the chaotic variability occurs when a negative emotion is felt but it stays regular in a well-being condition. A reproducibility of this coherent curve is also noticed when breathing is controlled. Thanks to a neural network that have recently been discovered, it will consequently have a positive effect on the whole body and stress will remain under control. Such a method is interesting in a dental surgery since it is helpful for both practitioner and his patient. In fact, data attest these two maters : on the ane hand, professional stress pathologies, such ans Burn-out syndrome, are one of the main source of difficulty for dental surgeon ; on the other hand, fear, or even dental phobia, affects a lot of patients.BORDEAUX2-BU Sci.Homme/Odontol. (330632102) / SudocSudocFranceF

Electrophysiological analysis of brainstem encoding of speech: Speech Auditory Brainstem Response.

n this PhD work, we have setup an speech-ABR stimulation and recording chain. Firstly, we have verified the validity and authenticity of speech-ABR recording (Akhoun et al., 2008b). Then, we have studied the link between the acoustic features of speech stimuli and the speech-ABR signal. We have found that speech-ABR reflects the stimulus temporal envelope (Akhoun et al., 2008a), but it appeared that this fact was rather due to the presence of high-frequency harmonics rather than the temporal envelope itself (Akhoun et al., 2010)

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The Backlash to CRT in France: Special Feature

What has the response to Critical Race Theory (CRT) been in France? What are the commonalities between France and the U.S. with respect to the reception and backlash to CRT? How do the ideas of victimhood and dispossession fit into the larger narrative of white supremacy and the vilification of the essentialization of marginalized groups in France? Join us as we discuss all of the above with Professor Sylvie Laurent in this extra feature