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Background and Purpose Use of unilateral cochlear implant (UCI) is associated with limited spatial hearing skills. Evidence that training these abilities in UCI user is possible remains limited. In this study, we assessed whether a Spatial training based on hand-reaching to sounds performed in virtual reality improves spatial hearing abilities in UCI users Methods Using a crossover randomized clinical trial, we compared the effects of a Spatial training protocol with those of a Non-Spatial control training. We tested 17 UCI users in a head-pointing to sound task and in an audio-visual attention orienting task, before and after each training. Study is recorded in clinicaltrials.gov (NCT04183348). Results During the Spatial VR training, sound localization errors in azimuth decreased. Moreover, when comparing head-pointing to sounds before vs. after training, localization errors decreased after the Spatial more than the control training. No training effects emerged in the audio-visual attention orienting task. Conclusions Our results showed that sound localization in UCI users improves during a Spatial training, with benefits that extend also to a non-trained sound localization task (generalization). These findings have potentials for novel rehabilitation procedures in clinical contexts.

The aim of this study was to evaluate the feasibility of a virtual reality-based spatial hearing training protocol in bilateral cochlear implant (CI) users and to provide pilot data on the impact of this training on different qualities of hearing.Twelve bilateral CI adults aged between 19 and 69 followed an intensive 10-week rehabilitation program comprised eight virtual reality training sessions (two per week) interspersed with several evaluation sessions (2 weeks before training started, after four and eight training sessions, and 1 month after the end of training). During each 45-minute training session, participants localized a sound source whose position varied in azimuth and/or in elevation. At the start of each trial, CI users received no information about sound location, but after each response, feedback was given to enable error correction. Participants were divided into two groups: a multisensory feedback group (audiovisual spatial cue) and an unisensory group (visual spatial cue) who only received feedback in a wholly intact sensory modality. Training benefits were measured at each evaluation point using three tests: 3D sound localization in virtual reality, the French Matrix test, and the Speech, Spatial and other Qualities of Hearing questionnaire.The training was well accepted and all participants attended the whole rehabilitation program. Four training sessions spread across 2 weeks were insufficient to induce significant performance changes, whereas performance on all three tests improved after eight training sessions. Front-back confusions decreased from 32% to 14.1% (p = 0.017); speech recognition threshold score from 1.5 dB to -0.7 dB signal-to-noise ratio (p = 0.029) and eight CI users successfully achieved a negative signal-to-noise ratio. One month after the end of structured training, these performance improvements were still present, and quality of life was significantly improved for both self-reports of sound localization (from 5.3 to 6.7, p = 0.015) and speech understanding (from 5.2 to 5.9, p = 0.048).This pilot study shows the feasibility and potential clinical relevance of this type of intervention involving a sensorial immersive environment and could pave the way for more systematic rehabilitation programs after cochlear implantation.

Supplemental Digital Content is available in the text., Objectives: The aim of this study was to assess three-dimensional (3D) spatial hearing abilities in reaching space of children and adolescents fitted with bilateral cochlear implants (BCI). The study also investigated the impact of spontaneous head movements on sound localization abilities. Design: BCI children (N = 18, aged between 8 and 17) and age-matched normal-hearing (NH) controls (N = 18) took part in the study. Tests were performed using immersive virtual reality equipment that allowed control over visual information and initial eye position, as well as real-time 3D motion tracking of head and hand position with subcentimeter accuracy. The experiment exploited these technical features to achieve trial-by-trial exact positioning in head-centered coordinates of a single loudspeaker used for real, near-field sound delivery, which was reproducible across trials and participants. Using this novel approach, broadband sounds were delivered at different azimuths within the participants’ arm length, in front and back space, at two different distances from their heads. Continuous head-monitoring allowed us to compare two listening conditions: “head immobile” (no head movements allowed) and “head moving” (spontaneous head movements allowed). Sound localization performance was assessed by computing the mean 3D error (i.e. the difference in space between the X-Y-Z position of the loudspeaker and the participant’s final hand position used to indicate the localization of the sound’s source), as well as the percentage of front–back and left–right confusions in azimuth, and the discriminability between two nearby distances. Several clinical factors (i.e. age at test, interimplant interval, and duration of binaural experience) were also correlated with the mean 3D error. Finally, the Speech Spatial and Qualities of Hearing Scale was administered to BCI participants and their parents. Results: Although BCI participants distinguished well between left and right sound sources, near-field spatial hearing remained challenging, particularly under the “ head immobile” condition. Without visual priors of the sound position, response accuracy was lower than that of their NH peers, as evidenced by the mean 3D error (BCI: 55 cm, NH: 24 cm, p = 0.008). The BCI group mainly pointed along the interaural axis, corresponding to the position of their CI microphones. This led to important front–back confusions (44.6%). Distance discrimination also remained challenging for BCI users, mostly due to sound compression applied by their processor. Notably, BCI users benefitted from head movements under the “head moving” condition, with a significant decrease of the 3D error when pointing to front targets (p < 0.001). Interimplant interval was correlated with 3D error (p < 0.001), whereas no correlation with self-assessment of spatial hearing difficulties emerged (p = 0.9). Conclusions: In reaching space, BCI children and adolescents are able to extract enough auditory cues to discriminate sound side. However, without any visual cues or spontaneous head movements during sound emission, their localization abilities are substantially impaired for front–back and distance discrimination. Exploring the environment with head movements was a valuable strategy for improving sound localization within individuals with different clinical backgrounds. These novel findings could prompt new perspectives to better understand sound localization maturation in BCI children, and more broadly in patients with hearing loss.

International audience; Studies on audiovisual interactions in sound localization have primarily focused on the relations between the spatial position of sounds and their perceived visual source, as in the famous ventriloquist effect. Much less work has examined the effects on sound localization of seeing aspects of the visual environment. In this study, we took advantage of an innovative method for the study of spatial hearing-based on real sounds, virtual reality and real-time kinematic tracking-to examine the impact of a minimal visual spatial frame on sound localization. We tested sound localization in normal hearing participants (N = 36) in two visual conditions: a uniform gray scene and a simple visual environment comprising only a grid. In both cases, no visual cues about the sound sources were provided. During and after sound emission, participants were free to move their head and eyes without restriction. We found that the presence of a visual spatial frame improved hand-pointing in elevation. In addition, it determined faster first-gaze movements to sounds. Our findings show that sound localization benefits from the presence of a minimal visual spatial frame and confirm the importance of combining kinematic tracking and virtual reality when aiming to reveal the multisensory and motor contributions to spatial-hearing abilities.

Total official support for sustainable development (TOSSD) is a new international statistical measure that provides a complete picture of all official resources and private finance mobilised by official interventions in support of sustainable development and the SDGs. It consists of two pillars: cross-border resources to developing countries (pillar I) and support to international public goods and global challenges (pillar II). To test the TOSSD concept and operationalise the reporting, a data survey was carried out in 2019 on 2017 resources. This paper analyses the main lessons learnt from the survey with the objective to help further refine the TOSSD Reporting Instructions and data collection process, and provide evidence to the international community about the usefulness, relevance and feasibility of TOSSD as a measurement framework for the SDG era. TOSSD can respond to developing countries’ needs for information on external financing for sustainable development (pillar I), with estimates showing that between 18% and 26% of the volume of resources captured in the survey relate to additional data captured in TOSSD. TOSSD can fill a key information gap on financing for international public goods (IPGs) that support the achievement SDGs (pillar II). The TOSSD framework is appropriate for various providers of financing for sustainable development, including traditional providers, South-South Co-operation providers and multilateral institutions. To enhance the usefulness and relevance of TOSSD, efforts will need to continue to fill the remaining data gaps and enhance data quality.

When localising sounds in space the brain relies on internal models that specify the correspondence between the auditory input reaching the ears and initial head-position with coordinates in external space. These models can be updated throughout life, setting the basis for re-learning spatial hearing abilities in adulthood. This is particularly important for individuals who experience long-term auditory alterations (e.g., hearing loss, hearing aids, cochlear implants) as well as individuals who have to adapt to novel auditory cues when listening in virtual auditory environments. Until now, several methodological constraints have limited our understanding of the mechanisms involved in spatial hearing re-learning. In particular, the potential role of active listening and head-movements have remained largely overlooked. Here, we overcome these limitations by using a novel methodology, based on virtual reality and real-time kinematic tracking, to study the role of active multisensory-motor interactions with sounds in the updating of sound-space correspondences. Participants were immersed in a virtual reality scenario showing 17 speakers at ear-level. From each visible speaker a free-field real sound could be generated. Two separate groups of participants localised the sound source either by reaching or naming the perceived sound source, under binaural or monaural listening. Participants were free to move their head during the task and received audio-visual feedback on their performance. Results showed that both groups compensated rapidly for the short-term auditory alteration caused by monaural listening, improving sound localisation performance across trials. Crucially, compared to naming, reaching the sounds induced faster and larger sound localisation improvements. Furthermore, more accurate sound localisation was accompanied by progressively wider head-movements. These two measures were significantly correlated selectively for the Reaching group. In conclusion, reaching to sounds in an immersive visual VR context proved most effective for updating altered spatial hearing. Head movements played an important role in this fast updating, pointing to the importance of active listening when implementing training protocols for improving spatial hearing.HIGHLIGHTS- We studied spatial hearing re-learning using virtual reality and kinematic tracking- Audio-visual feedback combined with active listening improved monaural sound localisation- Reaching to sounds improved performance more than naming sounds- Monaural listening triggered compensatory head-movement behaviour- Head-movement behaviour correlated with re-learning only when reaching to sounds

International audience; When localising sounds in space the brain relies on internal models that specify the correspondence between the auditory input reaching the ears, initial head-position and coordinates in external space. These models can be updated throughout life, setting the basis for re-learning spatial hearing abilities in adulthood. In addition, strategic behavioural adjustments allow people to quickly adapt to atypical listening situations. Until recently, the potential role of dynamic listening, involving head-movements or reaching to sounds, have remained largely overlooked. Here, we exploited visual virtual reality (VR) and real-time kinematic tracking, to study the role of active multisensory-motor interactions when hearing individuals adapt to altered binaural cues (one ear plugged and muffed). Participants were immersed in a VR scenario showing 17 virtual speakers at ear-level. In each trial, they heard a sound delivered from a real speaker aligned with one of the virtual ones and were instructed to either reach-to-touch the perceived sound source (Reaching group), or read the label associated with the speaker (Naming group). Participants were free to move their heads during the task and received audio-visual feedback on their performance. Most importantly, they performed the task under binaural or monaural listening. Results show that both groups adapted rapidly to monaural listening, improving sound localisation performance across trials and changing their head-movement behaviour. Reaching the sounds induced faster and larger sound localisation improvements, compared to just naming its position. This benefit was linked to progressively wider head-movements to explore auditory space, selectively in the Reaching group. In conclusion, reaching to sounds in an immersive visual VR context proved most effective for adapting to altered binaural listening. Head-movements played an important role in adaptation, pointing to the importance of dynamic listening when implementing training protocols for improving spatial hearing.

This Working Paper presents the main findings and recommendations of the pilot study carried out on the treatment of peace and security expenditures in the statistical measure of total official support for sustainable development (TOSSD). The pilot study explored the relevance of including various peace and security expenditures in the TOSSD framework, and formulated recommendations to the International TOSSD Task Force on the eligibility criteria, the potential safeguards and the delineation between TOSSD pillar I and II for peace and security expenditures. On this basis, the Task Force adopted in June 2019 specific text on the treatment of peace and security in the TOSSD Reporting Instructions. The pilot study also allowed to derive first estimates of TOSSD flows for peace and security and a light assessment was carried out of the capacity of the organisations / countries met during the pilot to provide TOSSD data on peace and security.

Nowadays behavioral and cognitive neuroscience studies have turned ‘naturalistic’, aiming at understanding brain functions by maintaining complexity close to everyday life. Many scholars started using commercially available VR devices, which, were not conceived as research tools. It is therefore important to assess their spatio-temporal reliability and inform scholars about the basic resolutions they can achieve. Here we provide such an assessment for the VIVE (HTC Vive) by comparing it with a VICON (BONITA 10) system. Results show a submillimeter Vive precision (0.237mm) and a nearest centimeter accuracy (8.7mm static, 8.5mm dynamic). we also report the Vive reaction to a tracking loss: the system takes 319.5 +/− 16.8 ms to detect the loss and can still be perturbed for about 3 seconds after tracking recovery. The Vive device allows for fairly accurate and reliable spatiotemporal measurements and may be well-suited for studies with typical human behavior, provided tracking loss is prevented.

When reaching to an object, information about the target location as well as the initial hand position is required to program the motor plan for the arm. The initial hand position can be determined by proprioceptive information as well as visual information, if available. Bayes-optimal integration posits that we utilize all information available, with greater weighting on the sense that is more reliable, thus generally weighting visual information more than the usually less reliable proprioceptive information. The criterion by which information is weighted has not been explicitly investigated; it has been assumed that the weights are based on task- and effector-dependent sensory reliability requiring an explicit neuronal representation of variability. However, the weights could also be determined implicitly through learned modality-specific integration weights and not on effector-dependent reliability. While the former hypothesis predicts different proprioceptive weights for left and right hands, e.g., due to different reliabilities of dominant vs. nondominant hand proprioception, we would expect the same integration weights if the latter hypothesis was true. We found that the proprioceptive weights for the left and right hands were extremely consistent regardless of differences in sensory variability for the two hands as measured in two separate complementary tasks. Thus we propose that proprioceptive weights during reaching are learned across both hands, with high interindividual range but independent of each hand’s specific proprioceptive variability. NEW & NOTEWORTHY How visual and proprioceptive information about the hand are integrated to plan a reaching movement is still debated. The goal of this study was to clarify how the weights assigned to vision and proprioception during multisensory integration are determined. We found evidence that the integration weights are modality specific rather than based on the sensory reliabilities of the effectors.

Objectives After a coma, one major challenge is the detection of awareness in patients with disorders of consciousness. In some patients, the only manifestation indicative of awareness is an appropriate emotional response. Preferred music is a powerful medium to elicit emotions and autobiographical memory. Furthermore, music has been shown to improve cognitive functions both in healthy subjects and patients with neurological impairment. We hypothesized that signs of awareness could be enhanced in some patients with disorders of consciousness under appropriate emotional stimulation such as preferred music and also probably preferred odors. Methods To investigate an objective, easily recordable marker of emotions at the patients’ bedside, electrodermal activity (skin conductance level, SCL) was assessed with stimulations in auditory and olfactory modalities, notably with preferred music, neutral sound, preferred odors, and neutral odors. The study was conducted in 11 patients with disorders of consciousness (DOC) and 7 healthy participants. Results In healthy subjects, the mean amplitude of the SCL was increased during exposure to preferred music as compared to neutral sounds (respectively: 0.00037 ± 0.0004 vs. – 0.00004 ± 0.00019 μS). No significant difference between conditions was detected in patients. Conclusion The results of this study suggest that electrodermal activity could be a useful marker of emotions induced by music in healthy controls. However, it failed to show any significant difference between conditions in patients with DOC.

This working paper presents the results of the first country pilot carried out in a recipient country in the context of the development of the new framework of total official support for sustainable development (TOSSD). The results of the pilot indicate that a global measurement framework such as TOSSD is very much needed in light of profound changes in the development finance landscape, particularly given the new role played by emerging economies and related flows. The pilot also highlights the critical role that TOSSD could play in supporting transparency of development finance flows, particularly in capturing information about different components of complex financing arrangements, which would enable countries to learn from other countries’ experience in leveraging finance. The paper sheds light on critical questions related to the TOSSD measure, including the inclusion of private amounts mobilised through public interventions in the framework or of investments in global programmes supporting development enablers and addressing global challenges. The pilot study also provides estimates of orders of magnitude of total official support for sustainable development to Senegal.

Visuo-motor adaptation has been classically studied using movements aimed at visual targets with visual feedback. In this type of experimental design, the respective roles of the different error signals cannot be fully disentangled. Here, we show that visuo-motor adaptation occurs despite the terminal success of the action and the compensation of the external error by a jump of the visual target. By using three grasping task conditions we manipulated the retinal error signal between the seen hand and the target (external error) and the conflict between the hand's visual reafference and either the proprioceptive or the efference copy signal (internal error), in order to estimate their respective roles in prism adaptation. In all conditions, subjects were asked to rapidly grasp an object. In the classical 'Prism' condition the object was stationary, which provided both external and internal errors. In the 'Prism & Jump' condition, at movement onset the object was suddenly displaced (jump) toward its virtual image location (visually displaced by the prism) which also corresponded to the location where the movement was planned to and executed through prisms. This jump therefore cancelled the external error (between the seen target and the seen hand), whereas the internal error (between the seen hand and the expected visual reafference of the hand, or between the seen hand and the hand felt by proprioception) was unchanged (because it is independent of the presence of the goal). In the 'Jump' condition, the movement was planned and executed without prismatic goggles and consequently with no internal error (no difference between where the hand visual reafference is expected to be and where it actually is), but the object was suddenly displaced at movement onset by a displacement equivalent to a prism shift which provided an external error. The 'Prism' and 'Prism & Jump' conditions exhibited similar aftereffects, whereas no aftereffect was observed in the 'Jump' condition. These results suggest that successful actions can be subjected to adaptation and that internal error is the only signal necessary to elicit true visuomotor adaptation characterized by context-independent generalization.

Following the princeps investigations of Marc Jeannerod on action–perception, specifically, goal-directed movement, this review article addresses visual and non-visual processes involved in guiding the hand in reaching or grasping tasks. The contributions of different sources of correction of ongoing movements are considered; these include visual feedback of the hand, as well as the often-neglected but important spatial updating and sharpening of goal localization following gaze-saccade orientation. The existence of an automatic online process guiding limb trajectory toward its goal is highlighted by a series of princeps experiments of goal-directed pointing movements. We then review psychophysical, electrophysiological, neuroimaging and clinical studies that have explored the properties of these automatic corrective mechanisms and their neural bases, and established their generality. Finally, the functional significance of automatic corrective mechanisms–referred to as motor flexibility–and their potential use in rehabilitation are discussed.

Patients with bilateral optic ataxia fail to show rapid perturbation-induced corrections during manual aiming movements. Based on this, it has been proposed that this pathology results from a disruption of processes of on-line motor control in the posterior parietal cortex (PPC). Here, we show that on-line motor control performance in a patient with unilateral optic ataxia is similar to that of pointing towards stationary targets in peripheral vision, showing the same combination of hand and field effects. We also show that in the patient, manual correction towards his ataxic field was possible only when a preceding saccade (100 msec earlier) rapidly provides foveal information about the new target location. In control subjects, manual correction was often, but not necessarily preceded by a saccade. These results allow us to put forward a model of visuo-manual transformation, which involves updating of the reach plan based on the target–eye error, and rely upon two dissociated spatial representations (of the hand and of the target, respectively) within the PPC. a 2007 Elsevier Masson Srl. All rights reserved.

The gain of reactive saccades was manipulated in 17 subjects using a target-jump paradigm. Following adaptation three sub-groups were formed: (1) rest 15 min in the dark, eyes closed; (2) perform self-generated saccades for 15 min; (3) perform reactive saccades for 15 min. The series of saccades were the same in groups 2 and 3 (amplitude, sequence), except that group 3 performed fewer saccades (same number as the lowest number of saccades performed by one subject in group 2). Neither the rest period nor the series of self-generated saccades affected the adapted gain. The series of reactive saccades generated, by contrast, quick de-adaptation. These results support the conclusion that the gain of self-generated and reactive saccades is independently controlled.

International audience; A saccade is a rapid shift of the position of the eyes (< 100 ms). Saccades are generally considered too quick to be influenced by retinal signals. To address this idea, we displaced the visual target of a rightward horizontal saccade at eye movement onset (when there is suppression of conscious perception). To prevent adaptive and learning effects to occur, jump saccades were always followed by a random series of 10 no-jump saccades. Results indicated that the target jump influenced significantly the amplitude and the peak velocity of the ongoing saccade (opposite effects were found for rightward and leftward jumps). Changes in saccade kinematics occurred as early as 50 ms after the target jump. These results show that retinal information is processed quickly during eye movements, presumably through sub-cortical pathways.

This study addressed the question of the possible functional relevance of two different oscillatory activities, beta and gamma (15-40 and 60-90 Hz, respectively) for perception and memory processes in olfactory areas of mammals. Local field potentials were recorded near relay olfactory bulb neurons while rats performed an olfactory discrimination task. Signals reflected the mass activity from this region and characteristics of oscillatory activities were used as an index of local synchrony. Beta and gamma oscillatory activities were quantified by time-frequency methods before during and after odour sampling. In rats early in their training, olfactory sampling was associated with a significant decrease in power in the gamma band in parallel with a weak but significant increase in the beta band (centred on 27 Hz). Several days later, in well-trained rats, the gamma oscillatory depression was significantly enhanced both in duration and amplitude. It appeared within the 500 ms time period preceding odour onset and was further reduced during the odour period. Concurrently the beta oscillatory response (now centred on 24 Hz) during odour sampling was amplified by a twofold factor. The beta band response was modulated according to the chemical nature of the stimuli and rat's behavioural response. This study showed for the first time that odour sampling in behaving animals is associated with a clear shift in the olfactory bulb neuronal activity from a gamma to a beta oscillatory regime. Moreover, the data stress the importance of studying the odour-induced beta activity and its relation to perception and memory.

In 2010, the international community, under the auspices of the Convention on Biological Diversity, agreed on 20 biodiversity-related “Aichi Targets” to be achieved within a decade. We provide a comprehensive mid-term assessment of progress toward these global targets using 55 indicator data sets. We projected indicator trends to 2020 using an adaptive statistical framework that incorporated the specific properties of individual time series. On current trajectories, results suggest that despite accelerating policy and management responses to the biodiversity crisis, the impacts of these efforts are unlikely to be reflected in improved trends in the state of biodiversity by 2020. We highlight areas of societal endeavor requiring additional efforts to achieve the Aichi Targets, and provide a baseline against which to assess future progress.

This study examines the area of eye movement dysfunctions as an indicator of vulnerability to schizophrenia. Eye movement performance was investigated with three different paradigms: Smooth Pursuit Eye Movements (SPEM); Visually Guided Saccades (VGS); and Antisaccades (AS) in 21 clinically stable patients with schizophrenia, 21 of their healthy, biological full siblings and 21 healthy control subjects. The three groups did not differ on VGS performance, whereas both patients and their siblings showed lower SPEM gain, an increased catch-up Saccades (CUS) rate, reduced AS accuracy and an increased number of AS errors in comparison to control subjects. In addition, patients with schizophrenia exhibited increased AS latency. Among the patients with schizophrenia, eye movement abnormalities did not correlate with age, gender, clinical state or duration of illness. These data suggest that abnormalities of SPEM and AS may represent neurobiological markers of the vulnerability to schizophrenia in individuals at high genetic risk for the disease.

International audience; Movement accuracy depends crucially on the ability to detect errors while actions are being performed. When inaccuracies occur repeatedly, both an immediate motor correction and a progressive adaptation of the motor command can unfold. Of all the movements in the motor repertoire of humans, saccadic eye movements are the fastest. Due to the high speed of saccades, and to the impairment of visual perception during saccades, a phenomenon called ''saccadic suppression'', it is widely believed that the adaptive mechanisms maintaining saccadic performance depend critically on visual error signals acquired after saccade completion. Here, we demonstrate that, contrary to this widespread view, saccadic adaptation can be based entirely on visual information presented during saccades. Our results show that visual error signals introduced during saccade execution-by shifting a visual target at saccade onset and blanking it at saccade offset-induce the same level of adaptation as error signals, presented for the same duration, but after saccade completion. In addition, they reveal that this processing of intra-saccadic visual information for adaptation depends critically on visual information presented during the deceleration phase, but not the acceleration phase, of the saccade. These findings demonstrate that the human central nervous system can use short intra-saccadic glimpses of visual information for motor adaptation, and they call for a reappraisal of current models of saccadic adaptation.

The aim of this work was to investigate ocular control in patients with optic ataxia (OA). Following a lesion in the posterior parietal cortex (PPC), these patients exhibit a deficit for fast visuo-motor control of reach-to-grasp movements. Here, we assessed the fast visuo-motor control of saccades as well as spontaneous eye-hand coordination in two bilateral OA patients and five neurologically intact controls in an ecological "look and point" paradigm. To test fast saccadic control, trials with unexpected target-jumps synchronised with saccade onset were randomly intermixed with stationary target trials. Results confirmed that control subjects achieved visual capture (foveation) of the displaced targets with the same timing as stationary targets (fast saccadic control) and began their hand movement systematically at the end of the primary saccade. In contrast, the two bilateral OA patients exhibited a delayed visual capture, especially of displaced targets, resulting from an impairment of fast saccadic control. They also exhibited a peculiar eye-hand coordination pattern, spontaneously delaying their hand movement onset until the execution of a final corrective saccade, which allowed target foveation. To test whether this pathological behaviour results from a delay in updating visual target location, we had subjects perform a second experiment in the same control subjects in which the target-jump was synchronised with saccade offset. With less time for target location updating, the control subjects exhibited the same lack of fast saccadic control as the OA patients. We propose that OA corresponds to an impairment of fast updating of target location, therefore affecting both eye and hand movements.

We briefly address three issues that might be important to evaluate the validity of the “emulation theory”: (1) Does it really say something new? (2) Are similar processes engaged in action, imagery, and perception? (3) Does a brain amodal emulator exist?

Spatial auditory localization is a complex process that contributes to the construction of our perceptual space. In collaboration with other sensory modalities like vision, it provides a unique sensory experience. Its optimal functioning depends on the integrity of the auditory structures that pick up sounds in periphery until their extraction and interpretation in central regions. Deafness deteriorates these key stages of sound signal processing. Technological innovation has transformed the management of profound deafness with cochlear implants, but many questions remain about how to preserve and rehabilitate spatial auditory localization in cochlear implant users. This PhD work therefore focuses on these two aspects of localization. In a first study, we evaluated sound localization performance of bilateral cochlear implant children in 3D compared to normal hearing children. In a second study, we validated a short form in French of the pediatric questionnaire "Speech, Spatial, and Qualities of hearing". In a third study, we developed and tested the feasibility of a spatial auditory training for bilateral cochlear implant adults. All these studies allowed us to better characterize spatial hearing skills in cochlear implant users. Patients had significant difficulties and we noticed an important inter-individual variability. However, the development of a spatial hearing training seems to be a future perspective to improve individual performances., La spatialisation auditive est un processus complexe qui participe à la construction de notre espace perceptuel. En collaboration avec d’autres afférences sensorielles telle que la vision, elle offre une expérience sensorielle unique. Son fonctionnement optimal passe par l’intégrité des structures auditives captant les sons en périphérie jusqu’à l’extraction et l’interprétation centrale. Toute surdité détériore ces étapes clés du traitement du signal sonore. L’innovation technologique a révolutionné la prise en charge des surdités profondes grâce auximplants cochléaires mais de nombreuses questions demeurent quant aux modalités de préservation et de réadaptation de la spatialisation auditive chez les patients implantés. Nos travaux de thèse se portent ainsi sur ces deux facettes de la localisation. Dans une 1ère étude, nous avons évalué dans les trois dimensions de l’espace les performances de localisation d’enfants bi-implantés cochléaires comparées à un groupe d’enfants normoentendant. Dans une 2ème étude, nous avons validé une forme courte en français du questionnaire pédiatrique « Speech, Spatial, and Qualities of hearing ». Dans une 3ème étude, nous avons développé et testé la faisabilité d’un protocole d’entraînement de la spatialisation auditive à destination d’adultes bi-implantés cochléaires. Chacune des études menées a permis de mieux caractériser les compétences spatiales dans chaque population testée. Les patients implantés conservent d’importantes difficultés soumises à variabilité inter-individuelle. Mais la mise en place d’un entraînement spatial apparaît comme une perspective d’avenir dans la modulation de ces difficultés.