INTRODUCTION:Cochlear implant outcomes vary widely and are difficult to predict, with traditional methods explaining <20% of variance. This study tested whether machine learning approaches offer superior performance predicting outcomes and better identify key factors driving variability compared to traditional linear methods. METHODS:This retrospective observational study analyzed clinical data from 2,251 adult cochlear implant recipients (>18 years) with post-lingual hearing loss (onset >15 years) across fifteen centers in Australia, Europe, and North America. Data were collected between 2003 and 2011, with follow-up at 6 months and 2 years post-implantation. Linear regression was compared against seven other machine learning models: eXtreme Gradient Boosting (XGBoost), random forest, categorical boosting (CatBoost), Light Gradient Boosting Machine (LightGBM), support vector regression, ridge regression, and Lasso regression. Models were optimized using grid search with 5-fold cross-validation on an 80/20 training-test split. The primary outcome was prediction of percentile-ranked postoperative speech recognition scores in quiet, assessed using mean-squared error (MSE) and coefficient of determination (R2). SHapley Additive exPlanations values identified feature importance. RESULTS:XGBoost achieved the best performance with a modest but significant 4.11% reduction in prediction error compared to linear regression (MSE: 739.67 ± 19.27 vs. 771.41 ± 21.51, p = 0.003; R2: 0.114 ± 0.011 vs. 0.076 ± 0.012, p < 0.001). All ensemble methods significantly outperformed linear regression. Duration of cochlear implant use, age at implantation, duration of severe/profound hearing loss, and preoperative hearing scores emerged as the most influential predictors across all models. CONCLUSIONS:Machine learning models modestly improve cochlear implant outcome prediction, though substantial variance remains unexplained (>80%). Critical determinants of cochlear implant performance likely extend beyond variables routinely measured in clinical practice, highlighting the need for novel predictive factors.

This review integrates anthropological and neuroscientific perspectives to elucidate music-induced trance processes and their relevance to non-ordinary states of consciousness (NSCs). The objectives are to deepen the understanding of trance phenomena, delineate links across diverse trance expressions, and inform future neuroscientific research. Drawing on anthropological insights, we examine the phenomenology, reported benefits, and central role of music in trance-inducing practices. Examples ranging from traditional shamanism to contemporary rave culture reveal shared cultural narratives and highlight a common set of musical features that facilitate trance induction and maintenance across ritualistic and recreational contexts. On the neuroscientific front, we review brain imaging studies that map neural activity and connectivity during music-induced trance processes. Findings suggest that different forms of trance may engage partially overlapping neural dynamics, including increased synchronization in low-frequency bands and shifts from executive control networks to limbic and default mode networks. These patterns underline the dynamic interplay between cognitive, emotional, and sensory systems during trance, although the current empirical evidence remains fragmented and methodologically heterogeneous. Our interdisciplinary synthesis emphasizes trance as both a cultural and biological phenomenon and calls for future integration of phenomenological and neurophysiological data to build comprehensive models of music-induced NSCs.

BACKGROUND:While both cannabis and music have demonstrated significant independent impacts on emotional states, the synergies between these two modalities remain underexplored. This study investigates the interactions between cannabis consumption and music listening, focusing on their effects on emotional experiences, mood regulation, and sensory perceptions. METHODS:An online cross-sectional survey consisting of 176 questions was administered to 122 cannabis users. The survey captured detailed information on demographics, cannabis use patterns, music engagement behaviors, emotional responsiveness, and the interplay between cannabis and music perception. RESULTS:Most participants viewed the combination of cannabis and music favorably, reporting enhanced relaxation, improved mood, and increased feelings of connection. Cannabis use was also associated with altered responses to imposed music in various settings and a heightened likelihood of using music during routine activities. In addition, participants frequently reported the use of cannabis as a substitute for pharmaceutical treatments for pain, anxiety, and sleep disorders, with music further amplifying these therapeutic effects. However, no significant differences were observed in overall music reward experiences with or without cannabis, highlighting the nuanced and context-dependent nature of these interactions. CONCLUSION:These findings provide novel insights into the potential for cannabis and music to act as complementary tools for emotional well-being, underscoring the need for further research to elucidate the mechanisms underlying their combined effects. This study provides a foundation for future investigations into the therapeutic integration of music as a supportive adjunct to cannabinoid-based interventions targeting emotional and psychological health.

Singing and vocalization practices are reportedly associated with increased relaxation, better emotional regulation, and enhanced social closeness. Here, we investigate the neural underpinnings of such effects and ask whether they are related to processes linked to the vocalization aspect or are a result of modified breathing patterns. Toning is a form of vocalization involving the expression of vocal sounds for the duration of the exhalation, often resulting in a slower breathing frequency compared to rest. It is increasingly used in therapeutic environments, but its neural underpinnings are poorly understood. EEG studies have shown increases in alpha power for slow breathing interventions, believed to be mediated by vagal activity, as shown in increased heart rate variability (HRV). We aimed to describe the neural responses to toning and singing familiar songs with a slow rhythm in a group of participants without prior music training, and their autonomic responses measured by HRV. We contrasted these vocal conditions with matched breathing-only conditions. We ask whether toning is related to increases in alpha power and further explore the patterns for other frequencies of brain activity. We find that alpha and theta power increase in the resting state following toning and singing interventions, but not in the resting state following breathing at matching frequencies. Respiratory-mediated HRV, as indexed by the standard deviation of N-N intervals, showed significant increases during toning and toning-matched slow breathing as previously reported, while vagal tone, as indexed by the root mean square of successive differences of HRV, increased when participants were breathing slowly but not when participants were vocalizing, suggesting differential effects between neural and autonomic responses for vocalization and slow breathing. These results provide insights into the neural mechanisms of vocalization and singing practices, with implications for their use as part of well-being and health interventions.

Perception of rhythm significantly impacts various aspects of daily life, including engaging with music, discerning speech prosody nuances, and coordinating physical activities like walking and sports. Numerous studies in cognitive sciences have highlighted that human rhythmic synchronization is more precise when responding to auditory rhythmic stimuli than to visual ones when the timing cues are identical. However, deaf individuals were shown to display a heightened proficiency in synchronizing their movements with visual timing cues, outperforming hearing controls (HC). Furthermore, it was demonstrated that cochlear implant (CI) users can synchronize their movements with the rhythm of unpitched drum tones. These findings raise an important question: do CI users possess a visual synchronization advantage from their pre-implant deafness, while maintaining auditory synchronization skills comparable to those of HC? Alternatively, does the neural reorganization post-implantation negate the visual synchronization advantage acquired before the implant? This study aims to answer these questions by using a sensorimotor synchronization task to probe multisensory processing abilities in CI users. Specifically, we assessed unimodal and multimodal auditory and visual abilities in CI users compared to HC using a finger tapping synchrony task with four isochronous stimulus conditions: an auditory metronome, a visual metronome, a synchronous presentation of both the auditory and visual metronomes at the same tempo, and an asynchronous presentation of the auditory and visual stimuli at differing tempos. Synchronization to auditory stimuli surpassed synchronization to visual stimuli in both groups. CI users and HC demonstrated similar unisensory synchronization consistency within the visual and auditory conditions. While HC enhanced their consistency in the audio-visual synchronous condition compared to the unisensory visual condition, CI users did not display the same improvement. Furthermore, the interference from incongruent auditory information in the asynchronous condition was comparable in HC and CI users. This study highlights that, although pitch processing is known to be impaired in CI users, our findings suggest that rhythm processing remains relatively spared. As anticipated, CI users demonstrate similar auditory rhythmic synchronization skills to those of HC, in line with existing research. Moreover, we find that, unlike deaf individuals, CI users do not exhibit an advantage in visual rhythmic synchronization, which may be due to the relatively few CI users in the study who had early prolonged pre-implantation deafness. The observed shift in audio-visual integration among CI users suggests that post-deafness or post-implantation reorganization of their auditory cortex may impede the effective integration of temporal auditory stimulation from the implant and visual information.

Purpose: Postoperative rehabilitation programs for cochlear implant (CI) recipients primarily emphasize enhancing speech perception. However, effective communication in everyday social interactions necessitates consideration of diverse verbal social cues to facilitate language comprehension. Failure to discern emotional expressions may lead to maladjusted social behavior, underscoring the importance of integrating social cues perception into rehabilitation initiatives to enhance CI users' well-being. After conventional rehabilitation, CI users demonstrate varying levels of emotion perception abilities. This disparity notably impacts young CI users, whose emotion perception deficit can extend to social functioning, encompassing coping strategies and social competence, even when relying on nonauditory cues such as facial expressions. Knowing that emotion perception abilities generally decrease with age, acknowledging emotion perception impairments in aging CI users is crucial, especially since a direct correlation between quality-of-life scores and vocal emotion recognition abilities has been observed in adult CI users. After briefly reviewing the scope of CI rehabilitation programs and summarizing the mounting evidence on CI users' emotion perception deficits and their impact, we will present our recommendations for embedding emotional training as part of enriched and standardized evaluation/rehabilitation programs that can improve CI users' social integration and quality of life. Conclusions: Evaluating all aspects, including emotion perception, in CI rehabilitation programs is crucial because it ensures a comprehensive approach that enhances speech comprehension and the emotional dimension of communication, potentially improving CI users' social interaction and overall well-being. The development of emotion perception training holds promises for CI users and individuals grappling with various forms of hearing loss and sensory deficits. Ultimately, adopting such a comprehensive approach has the potential to significantly elevate the overall quality of life for a broad spectrum of patients.

Rhythm is an omnipresent element of many daily activities. Numerous studies in cognitive sciences have highlighted that humans exhibit greater precision in synchronizing their movements with auditory rhythmic stimuli compared to visual ones. Deaf individuals were shown to excel in synchronizing with visual cues, surpassing those with normal hearing (NH). Furthermore, it was demonstrated that cochlear implant (CI) users were able to move in time to the beat of music, although not as well as NH controls. This study aims to investigate whether CI users retain a visual synchronization advantage from their pre-implant deafness, while maintaining auditory synchronization skills comparable to those of NH individuals, or if the neural reorganization post-implantation negates the visual synchronization advantage acquired pre-implantation. Specifically, we assessed both unimodal and multimodal auditory and visual abilities in CI users compared to NH controls using a standard sensorimotor synchronization paradigm. Results revealed that CI users exhibit comparable auditory rhythmic synchronization abilities to NH individuals, which is consistent with existing research, while not displaying a superior ability in synchronizing with visual rhythms, likely due to neural reorganization following implantation. This shift in audio-visual integration among CI users suggests that the post-implant reorganization of their auditory cortex might hinder the effective integration of temporal auditory input from the implant with visual information.

Music is integral to Psilocybin-assisted psychotherapy (PAP), believed to enhance therapeutic outcomes by structuring experiences and facilitating emotional expression. However, the effects of conducting PAP without music are underexplored. This study examines the experiences of two breast cancer patients undergoing psilocybin therapy under Canada's compassionate access program, specifically focusing on sessions that incorporated intentional periods without music. Patients had previously experienced psychedelics in therapeutic contexts but only with continuous music, as is common practice. Here, each patient participated in a 30-min silent period involving mindfulness exercises and therapist discussions. These periods of relative silence resulted in both challenges and benefits. One patient found that the absence of music was difficult initially, but that the relative silence allowed for engagement with mindfulness exercises that were experienced as highly meaningful. The other patient reported that music had evoked challenging past memories early in the dosing session, which were then productively explored with her guides during the subsequent period without music. These findings suggest that integrating silent intervals in PAP can enhance mindfulness practices and therapist-patient interactions, potentially offering distinct therapeutic benefits. Further research is necessary to delineate the differential impacts of music, silence, and guided activities in PAP, given that these three common treatment activities can be understood as both complementary and competing. Finally, we emphasize the importance of more detailed reporting on session components in psychedelic research publications, particularly regarding the balance between patients listening to music and interacting with their guides, which is often not clearly detailed in existing studies.

Background: The resurgent interest in psychedelic-assisted therapy for conditions like depression, end-of-life anxiety, and post-traumatic stress disorder is generating highly promising results. Within this therapeutic context, music's role is multifaceted, seen as a critical environmental component and even akin to a hidden therapist. Contemporary clinical protocols often advocate for music that is lyric-free and unfamiliar, yet these guidelines are based on limited empirical evidence.Methods: Our study, drawing on data from over 2,000 participants in the Canadian Psychedelic Survey (CPS), explores the interplay between music and 11 classical and non-classical psychedelic substances in predominantly non-clinical usage scenarios. This cross-sectional survey included 14 questions delving into patterns of psychedelic use and music preferences in naturalistic environments.Results: Our findings reveal that a substantial majority of respondents experienced both therapeutic benefits and enjoyment from integrating music with psychedelic substances, although the extent of these benefits varied significantly across different substances.Discussion: Contrary to clinical recommendations, only 10% and 22%, respectively, of survey respondents agreed that music for psychedelic experiences should be unfamiliar and without understandable lyrics. Furthermore, our data suggest potential unique benefits of psychedelic experiences devoid of music, particularly with the shortest and longest acting substances. These insights indicate that the prevailing guidelines for music selection in psychedelic therapies may benefit from further, nuanced research into substance-specific effect.

For individuals with hearing loss, even successful speech communication comes at a cost. Cochlear implants transmit degraded information, specifically for voice pitch, which demands extra and sustained listening effort. The current study hypothesized that abnormal pitch patterns contribute to the additional listening effort, even in non-tonal language native speaking normally hearing listeners. We manipulated the fundamental frequency (F0) within and across words, while participants listen and repeat (simple intelligibility task), or listen, repeat, and later recall (concurrent encoding task) the words. In both experiments, the F0 manipulations resulted in small changes in intelligibility but no difference in free recall or subjective effort ratings. Pupillary metrics were yet sensitive to these manipulations: pupil dilations were larger when words were monotonized (flat contour) or inverted (the natural contour flipped upside-down), and larger when successive words were organized into a melodic pattern. The most likely interpretation is that the natural or expected F0 contour of a word contributes to its identity and facilitate its matching and retrieval from the phonological representation stored in long-term memory. Consequently, degrading words' F0 contour can result in extra listening effort. Our results call for solutions to improve pitch saliency and naturalness in future development of cochlear implants' signal processing strategies, even for non-tonal languages.

Abstract Background Although cochlear implants can restore auditory inputs to deafferented auditory cortices, the quality of the sound signal transmitted to the brain is severely degraded, limiting functional outcomes in terms of speech perception and emotion perception. The latter deficit negatively impacts cochlear implant users’ social integration and quality of life; however, emotion perception is not currently part of rehabilitation. Developing rehabilitation programs incorporating emotional cognition requires a deeper understanding of cochlear implant users’ residual emotion perception abilities. Methods To identify the neural underpinnings of these residual abilities, we investigated whether machine learning techniques could be used to identify emotion-specific patterns of neural activity in cochlear implant users. Using existing electroencephalography data from 22 cochlear implant users, we employed a random forest classifier to establish if we could model and subsequently predict from participants’ brain responses the auditory emotions (vocal and musical) presented to them. Results Our findings suggest that consistent emotion-specific biomarkers exist in cochlear implant users, which could be used to develop effective rehabilitation programs incorporating emotion perception training. Conclusions This study highlights the potential of machine learning techniques to improve outcomes for cochlear implant users, particularly in terms of emotion perception.

PURPOSE:For patients with single-sided deafness (SSD), choosing between bone conduction devices (BCDs) and contralateral routing of signal hearing aids (CROS) is challenging due to mixed evidence on their benefits. The lack of clear guidelines complicates clinical decision making. This study explores whether realistic spatial listening measures can reveal a clinically valid benefit and if the optimal choice varies among patients. By assessing listening effort through objective and subjective measures, this research evaluates the efficacy of BCD and CROS, seeking to provide evidence-based recommendation anchored in the effectiveness of these devices in real-world scenarios. METHOD:Thirteen participants with SSD performed the Hearing-in-Noise Test while using a BCD, CROS hearing aids, and no hearing device (unaided). Subjective listening effort was assessed using the National Aeronautics and Space Administration Task Load Index (NASA-TLX) questionnaire after each testing block. An objective measurement of listening effort was obtained by measuring the peak pupil dilation (PPD) during the task using eye tracking glasses. RESULTS:No significant difference of either PPD or NASA-TLX scores was observed between the three device conditions (BCD, CROS, and unaided). However, a trend is noted toward reduced PPD in the BCD and CROS conditions. The lack of significance in pupillometry results does not stem from technical issues, as the study's findings confirm its effectiveness in measuring task difficulty, and validate its use for assessing listening effort. CONCLUSIONS:Although the results from the present study cannot significantly differentiate the hearing devices, we observe a trend that points toward reduced listening effort when using hearing devices. Future investigations should aim to optimize metrics of listening effort, perhaps making them clinically useful on an individual level.

Purpose: Greater recognition of the impact of hearing loss on cognitive functions has led speech/hearing clinics to focus more on auditory memory outcomes. Typically evaluated by scoring participants' recall on a list of unrelated words after they have heard the list read out loud, this method implies pitch and timing variations across words. Here, we questioned whether these variations could impact performance differentially in one language or another. Method: In a series of online studies evaluating auditory short-term memory in normally hearing adults, we examined how pitch patterns (Experiment 1), timing patterns (Experiment 2), and interactions between the two (Experiment 3) affected free recall of words, cued recall of forgotten words, and mental demand. Note that visual memory was never directly tested; written words were only used after auditory encoding in the cued recall part. Studies were administered in both French and English, always conducted with native listeners. Result: Confirming prior work, grouping mechanisms facilitated free recall, but not cued recall (the latter being only affected by longer presentation time) or ratings of mental demand. Critically, grouping by pitch provided more benefit for French than for English listeners, while grouping by time was equally beneficial in both languages. Conclusion: Pitch is more useful to French- than to English-speaking listeners for encoding spoken words in short-term memory, perhaps due to the syllable-based versus stress-based rhythms inherent to each language. Supplemental Material: https://doi.org/10.23641/asha.27048328

Psilocybin, a psychoactive substance derived from fungi, has been utilized historically by diverse cultures for both medicinal and non-medicinal purposes, owing to its ability to elicit profound sensory and cognitive alterations and sustain long-term changes in mood and cognition. Promising results from recent clinical studies have generated a wave of interest in employing psilocybin to treat neuropsychiatric and neuro-degenerative conditions. How psychedelics cause acute perceptual effects, and how these relate to long-lasting alterations is still debated. Whereas it is thought that perceptual disturbances may be caused by disrupted flow of information between sensory and higher order areas, in vivo studies have focused mostly on the latter. In particular, there has been little study of how psilocybin affects sensory representations in primary auditory cortex (A1). We used two-photon microscopy and wide field calcium imaging to examine how psilocybin affects A1 neuron response properties in the mouse. Administration of 1 mg/kg psilocybin prevented habituation of sound-evoked responses to repeated stimuli, maintaining overall responsiveness, bandwidth, and sound-level response thresholds after repeated stimulation. This was in contrast to marked habituation of responses and narrowing of tuning in controls. We observed no effect on overall distribution of best frequencies at the cortical level, suggesting psilocybin in A1 disrupts normal sensory gating, rather than tonotopic organization. This supports models of psychedelic action in which perceptual disturbances are driven by disrupted hierarchical sensory gating. With further research, influences of psychedelics on sensory representations could be harnessed to target maladaptive sensory processing in conditions such as tinnitus. ### Competing Interest Statement The authors have declared no competing interest.

Auditory memory is an important everyday skill evaluated more and more frequently in clinical settings as there is recently a greater recognition of the cost of hearing loss to cognitive systems. Testing often involves reading a list of unrelated items aloud; but prosodic variations in pitch and timing across the list can affect the number of items remembered. Here, we ran a series of online studies on normally-hearing participants to provide normative data (with a larger and more diverse population than the typical student sample) on a novel protocol characterizing the effects of suprasegmental properties in speech, namely investigating pitch patterns, fast and slow pacing, and interactions between pitch and time grouping. In addition to free recall, and in line with our desire to work eventually with individuals exhibiting more limited cognitive capacity, we included a cued recall task to help participants recover specifically the words forgotten during the free recall part. We replicated key findings from previous research, demonstrating the benefits of slower pacing and of grouping on free recall. However, only slower pacing led to better performance on cued recall, indicating that grouping effects may decay surprisingly fast (over a matter of one minute) compared to the effect of slowed pacing. These results provide a benchmark for future comparisons of short-term recall performance in hearing-impaired listeners and users of cochlear implants.

Cochlear implants (CI) have had tremendous success restoring a sense of hearing in the deaf. However, even after months of intensive rehabilitation, many CI users struggle with appreciating emotive tones in speech and music despite good speech comprehension. Failure to perceive emotional expression can result in maladjusted social behaviour, leading to detrimental socio-economic consequences. Recent advances in automated pattern identification of neuroimaging data can bring empirical support to developing training programs for emotion perception rehabilitation in CI users. We used a machine-learning approach to identify emotion-processing bio-markers in high-density electroencephalograms collected from CI users (22) and matched normal-hearing controls (22). Participants’ brain responses elicited by short musical and vocal emotional (happy, sad, and neutral) stimuli were used to train an algorithm to help identify, in each group, the pattern of brain responses that can best predict the presented emotion. Using this approach, we were able to confirm the presence of emotion-specific patterns of brain activity in CI users despite their reported emotion perception deficit. Identifying these patterns brings forward support for implementing a rehabilitation program for emotion perception for this population; if an algorithm can differentiate aurally presented emotions, perhaps CI users can learn to discriminate emotions.

OBJECTIVE:Using voice to speak or to sing is made possible by remarkably complex sensorimotor processes. Like any other sensorimotor system, the speech motor controller guides its actions with maximum performance at minimum cost, using available sources of information, among which, auditory feedback plays a major role. Manipulation of this feedback forces the speech monitoring system to refine its expectations for further actions. The present study hypothesizes that the duration of this refinement and the weight applied on different feedbacks loops would depend on the intended sounds to be produced, namely reading aloud versus singing.MATERIAL AND METHODS:We asked participants to sing "Happy Birthday" and read a paragraph of Harry Potter before and after experiencing pitch-shifted feedback. A detailed fundamental frequency (F0) analysis was conducted for each note in the song and each segment in the paragraph (at the level of a sentence, a word, or a vowel) to determine whether some aspects of F0 production changed in response to the pitch perturbations experienced during the adaptation paradigm.RESULTS:Our results showed that changes in the degree of F0-drift across the song or the paragraph was the metric that was the most consistent with a carry-over effect of adaptation, and in this regard, reading new material was more influenced by recent remapping than singing.CONCLUSION:The motor commands used by (normally-hearing) speakers are malleable via altered-feedback paradigms, perhaps more so when reading aloud than when singing. But these effects are not revealed through simple indicators such as an overall change in mean F0 or F0 range, but rather through subtle metrics, such as a drift of the voice pitch across the recordings.

BackgroundSubanesthetic ketamine has accumulated meta-analytic evidence for rapid antidepressant effects in treatment-resistant depression (TRD), resulting in both excitement and debate. Many unanswered questions surround ketamine’s mechanisms of action and its integration into real-world psychiatric care, resulting in diverse utilizations that variously resemble electroconvulsive therapy, conventional antidepressants, or serotonergic psychedelics. There is thus an unmet need for clinical approaches to ketamine that are tailored to its unique therapeutic properties.MethodsThis article presents the Montreal model, a comprehensive biopsychosocial approach to ketamine for severe TRD refined over 6 years in public healthcare settings. To contextualize its development, we review the evidence for ketamine as a biomedical and as a psychedelic treatment of depression, emphasizing each perspectives’ strengths, weaknesses, and distinct methods of utilization. We then describe the key clinical experiences and research findings that shaped the model’s various components, which are presented in detail.ResultsThe Montreal model, as implemented in a recent randomized clinical trial, aims to synergistically pair ketamine infusions with conventional and psychedelic biopsychosocial care. Ketamine is broadly conceptualized as a brief intervention that can produce windows of opportunity for enhanced psychiatric care, as well as powerful occasions for psychological growth. The model combines structured psychiatric care and concomitant psychotherapy with six ketamine infusions, administered with psychedelic-inspired nonpharmacological adjuncts including rolling preparative and integrative psychological support.DiscussionOur integrative model aims to bridge the biomedical-psychedelic divide to offer a feasible, flexible, and standardized approach to ketamine for TRD. Our learnings from developing and implementing this psychedelic-inspired model for severe, real-world patients in two academic hospitals may offer valuable insights for the ongoing roll-out of a range of psychedelic therapies. Further research is needed to assess the Montreal model’s effectiveness and hypothesized psychological mechanisms.

There is an increasing interest in the field of audiology and speech communication to measure the effort that it takes to listen in noisy environments, with obvious implications for populations suffering from hearing loss. Pupillometry offers one avenue to make progress in this enterprise but important methodological questions remain to be addressed before such tools can serve practical applications. Typically, cocktail-party situations may occur in less-than-ideal lighting conditions, e.g. a pub or a restaurant, and it is unclear how robust pupil dynamics are to luminance changes. In this study, we first used a well-known paradigm where sentences were presented at different signal-to-noise ratios (SNR), all conducive of good intelligibility. This enabled us to replicate findings, e.g. a larger and later peak pupil dilation (PPD) at adverse SNR, or when the sentences were misunderstood, and to investigate the dependency of the PPD on sentence duration. A second experiment reiterated two of the SNR levels, 0 and +14 dB, but measured at 0, 75, and 220 lux. The results showed that the impact of luminance on the SNR effect was non-monotonic (sub-optimal in darkness or in bright light), and as such, there is no trivial way to derive pupillary metrics that are robust to differences in background light, posing considerable constraints for applications of pupillometry in daily life. Our findings raise an under-examined but crucial issue when designing and understanding listening effort studies using pupillometry, and offer important insights to future clinical application of pupillometry across sites.

Cochlear implants (CI) are neural prostheses that can restore hearing in individuals with severe to profound hearing loss. Although CIs significantly improve quality of life, clinical outcomes are still highly variable. An important part of this variability is explained by the brain reorganization following cochlear implantation. Therefore, clinicians and researchers are seeking objective measurements to investigate post-implantation brain plasticity. Electroencephalography (EEG) is a promising technique because it is objective, non-invasive, and implant-compatible, but is nonetheless susceptible to massive artifacts generated by the prosthesis's electrical activity. CI artifacts can blur and distort brain responses; thus, it is crucial to develop reliable techniques to remove them from EEG recordings. Despite numerous artifact removal techniques used in previous studies, there is a paucity of documentation and consensus on the optimal EEG procedures to reduce these artifacts. Herein, and through a comprehensive review process, we provide a guideline for designing an EEG-CI experiment minimizing the effect of the artifact. We provide some technical guidance for recording an accurate neural response from CI users and discuss the current challenges in detecting and removing CI-induced artifacts from a recorded signal. The aim of this paper is also to provide recommendations to better appraise and report EEG-CI findings.