Loudness Differences Research Articles

Adaptation and evaluation of Pyroomacoustics for auralization purposes

An open-source room simulation software that relies on geometrical acoustics - Pyroomacoustics - was used to compute Binaural Room Impulse Responses (BRIRs) of existing rooms that are modeled in the Benchmark for Room Acoustical Simulation (BRAS). Modifications were made to the software to investigate the impact of the scattering model on the acoustic parameter values. A comparison with the acoustic parameter measurements showed that the values of EDT, C80 and D50 were found to be closer when using the Vector-Mixing method in comparison with the original scattering method. Overall, the alternative method reduced by 95% the mean squared error on the acoustic parameter values. The sound source directivity was also considered in the simulations to quantify its influence on the perceived auditory scenes. A listening test was then conducted to compare binaural renderings derived from measured and simulated BRIRs. Results showed that ratings of the modified versions of the software were either not significantly different or significantly higher than those of the original version depending on the room and sound source. Including the source directivity significantly improved the perceptual ratings, which is thought to be due to the reduction of spectral and loudness differences with the measured reference.

Poster Session II: Kandinsky was right: Few do "express bright yellow in the bass notes, or dark lake in the treble".

Cross-modal correspondence is a sense of the inherent belongingness between two different senses; in our study these were pitch and color. Our goal was to investigate the confound in previous literature of individual differences in color brightness and pitch loudness. We tested twenty male participants. We determined equal brightness for each participant, across six colors: red, orange, yellow, green, blue, and purple; and equal loudness across seven pitches: 125, 250, 500, 2000, 4000, 8000, and 12,500 Hz. Then participants matched pitch with color in three different conditions: prototypical color hues, gray scale, and isobright colors. Our results indicated that in the prototypical condition, the participants chose yellow for high pitches, and blue and purple for the lowest pitches. In the gray scale condition, they chose white for high pitches and black for low pitches. These findings are consistent with previous research in the literature. However, we found that when controlling for individual differences in brightness, participants still chose yellow with higher pitches. Thus, there appears to be an inherent sense of belongingness between yellow and high pitches, even when controlling for the confounds of individual differences in brightness and loudness.

Pilot study on evaluation indices for aircraft noise considering sound quality

In Japan, Lden is currently used as an evaluation index for aircraft noise. It is based on the A-weighted sound pressure. It evaluates differences in noise loudness, but it does not necessarily take into account differences due to changes in sound quality. Over the past several decades, single event of aircraft noise has been significantly reduced. As a result, we have experienced a change from the "noisy" sound quality of the old generation jets to the "soft" sound quality of the recent aircrafts. Has the sound quality really improved, and has its improvement been evaluated? On the other hand, since the 2000's, we have sometimes experienced hearing the extraordinary tonal sounds from landing aircraft. It has the characteristics of pure tonal tone with 250-500 Hz and has a short duration and a prominent level fluctuation. Doessuch a sudden tonality change, which is also negatively perceived, not affect the evaluation? This paper describes the results of trial calculation in order to examine the possibility of evaluating aircraft noise considering its sound quality, based on several indices such as EPNL, loudness, sharpness, and Tonal Audibility (TA), in addition to the A-weighted noise (LAmax, LEA), and its comparative verification including differences in aircraft generations.

Further investigation of horizontal sound localization in noise

The accuracy of sound localization suffers significantly in a noisy environment. Noise can have an impact on the binaural localization cues such as interaural time difference (ITD) and interaural level difference (ILD). This impact is not only related to the signal-to-noise ratio (SNR), but also to the noise level. Therefore, it's crucial to understand how to describe binaural localization cues in noise. This study investigates the effect of noise level (ranging from 80 dB to 95 dB) and SNR (ranging from -15 dB to -5 dB) on the localization of horizontal sound sources at different azimuths. By analyzing the interaction between different binaural cues and localization accuracy in noise, the results demonstrate that there is a strong association between localization accuracy and interaural partial loudness difference. A follow-up experiment with modified ILD confirmed that the interaural partial loudness difference might more accurately reflect the auditory localization properties of the horizontal sound source in noise.

Personalized Neuromodulation: A Novel Strategy for Improving Tinnitus Treatment.

This study evaluated the efficacy of personalized neuromodulation, where treatment modalities are chosen based on the patient's responses in a pilot trial. A total of 71 patients with tinnitus were divided into two groups: a personalized group and a randomized neuromodulation group. In the personalized group (n = 35), repetitive transcranial magnetic stimulation (rTMS) and transcranial direct-current stimulation (tDCS) were assessed in a pilot trial, and responsive modalities were administered to 16 patients, while the non-responders (n = 19) were randomly assigned to rTMS, tDCS, or combined modalities. Patients in the randomized group (n = 36) were randomly allocated to rTMS, tDCS, or combined modalities. The Tinnitus Handicap Inventory (THI) score improvement after 10 sessions of each neuromodulation was significantly greater in the personalized group than in the randomized group (p = 0.043), with no significant differences in tinnitus loudness, distress, or awareness. The treatment success rate was highest in the personalized responder subgroup (92.3%), and significantly greater than that in the non-responder subgroup (53.0%; p = 0.042) and the randomized group (56.7%; p = 0.033). Personalized neuromodulation, where the treatment modality is chosen based on the patient's responses in a pilot trial, is an advantageous strategy for treating tinnitus.

A comparison between auditory hallucinations, interpretation of voices, and formal thought disorder in dissociative identity disorder and schizophrenia spectrum disorders.

Dissociative identity disorder (DID) and schizophrenia-spectrum disorders (SSD) share some overlapping phenomenological features making accurate diagnosis more difficult. Childhood abuse and depersonalization have been associated with psychotic symptoms across psychological disorders but their relationship to psychotic phenomenology remains understudied. The present study used quantitative measures to examine (1) similarities and differences in phenomenological voice hearing experiences, interpretations of voices, and thought disorder symptoms in individuals with DID (n = 44) or SSD (n = 45), and (2) whether depersonalization and childhood maltreatment influenced the initial pattern of findings. DID participants perceived their voices as being more internally located and generated, louder, and uncontrollable than SSD participants. Furthermore, the DID participants endorsed a greater frequency of thought disorder symptoms. Adding the covariates (sex, depersonalization, and child maltreatment) did not change the findings associated with location and origin of voices, and derailment, but there were now no differences in loudness or controllability. However, the schizophrenia sample reported more distress and metaphysical beliefs associated with voices, as well as more thought disorder incoherence and word substitution with the covariates controlled. While tentative, metaphysical interpretations of voices, incoherent thoughts and word substitution may reflect more psychotic processes.

Subjective evaluation of wind turbine noise using 3-dimensional audio- visual reproduction system

In recent years, the installation of new wind turbines has been promoted in Japan. Since wind turbines are often installed in quiet countryside, it is necessary to properly evaluate the noise impact of wind turbine installation. Since wind turbines are thought to have visual as well as auditory effects, we conducted a subjective evaluation experiment on the loudness and annoyance of wind turbine noise (WTN) and road traffic noise (RTN) by magnitude estimation method, using a three-dimensional audio-visual reproduction system consisting of 6 channels of loudspeakers installed around the sound receiving point and a dome screen. As a result, the loudness and annoyance of WTN tended to be evaluated higher than that of RTN. These results were considered to be influenced by the amplitude modulation called "swish sound" and the low-frequency dominant frequency characteristics, which are characteristics of WTN. In addition, when comparing the differences in loudness and annoyance with and without visual information, the two attributes tended to be lower when visual information was present.

Vehicle noise: comparison of loudness ratings in the field and the laboratory

Objective Distorted loudness perception is one of the main complaints of hearing aid users. Measuring loudness perception in the clinic as experienced in everyday listening situations is important for loudness-based hearing aid fitting. Little research has been done comparing loudness perception in the field and in the laboratory. Design Participants rated the loudness in the field and in the laboratory of 36 driving actions. The field measurements were recorded with a 360° camera and a tetrahedral microphone. The recorded stimuli, which are openly accessible, were presented in three conditions in the laboratory: 360° video recordings with a head-mounted display, video recordings with a desktop monitor and audio-only. Study samples Thirteen normal-hearing participants and 18 hearing-impaired participants with hearing aids. Results The driving actions were rated as louder in the laboratory than in the field for the condition with a desktop monitor and for the audio-only condition. The less realistic a laboratory condition was, the more likely it was for a participant to rate a driving action as louder. The field–laboratory loudness differences were bigger for louder sounds. Conclusion The results of this experiment indicate the importance of increasing realism and immersion when measuring loudness in the clinic.

Developmental Changes in the Perception of Vocal Loudness and Voice Quality in 3- to 6-Year-Old Children.

The study's primary aim was to investigate developmental changes in the perception of vocal loudness and voice quality in children 3-6 years of age. A second aim was to evaluate a testing procedure-the intermodal preferential looking paradigm (IPLP)-for the study of voice perception in young children. Participants were categorized in two age groups: 3- to 4-year-olds and 5- to 6-year-olds. Children were tested remotely via a Zoom appointment and completed two perceptual tasks: (a) voice discrimination and (b) voice identification. Each task consisted of two tests: a vocal loudness test and a voice quality test. Children in the 5- to 6-year-old group were significantly more accurate than children in the 3- to 4-year-old group in discriminating and identifying differences between voices for both loudness and voice quality. The IPLP, used in the identification task, was found to successfully detect differences between the age groups for overall accuracy and for most of the sublevels of vocal loudness and voice quality. Results suggest that children's ability to discriminate and identify differences in vocal loudness and voice quality improves with age. Findings also support the use of the IPLP as a useful tool to study voice perception in young children.

Muscle Activity and Aerodynamic Voice Changes at Different Body Postures: A Pilot Study

Body posture is a commonly discussed component of voice training and therapy. However, body postures, postural changes, related posturing muscle monitoring, and the potential changes in voice production (eg, glottal aerodynamic changes, acoustic differences) have been inconsistently described in the literature, leaving room for free interpretation and possible misunderstandings. The primary purpose of this pilot study was to compare the magnitude of electromyographical activation of muscles involved in phonation-breathing functions and their changes due to four standardized body postures in experienced singers. Secondly, to identify which body posture produces greater changes in aerodynamic parameters, vocal pitch, and loudness. Eight healthy adults with experience in singing voice performed a vocal task during different body postures commonly used in both voice training and therapy. A 3D-capture system was used to control and quantify the alignment of each posture. During the performances, surface electromyography (sEMG) was used to measure the muscular activity involved in the breathing/phonation and posture processes. A nonparametric Kruskal-Wallis test was used to compare the sEMG activity of phonatory muscles and aerodynamic voice variables between postures. Our study did not reveal significant differences in sEMG activity, aerodynamic parameters, vocal pitch, and loudness among body postures during vocal task productions. However, the vocal pitch (in semitones) revealed significant differences in the unstable surface when compared to the upright posture, modified upright, and leaning postures. The body postures selected did not generate voice aerodynamic modifications of the voice nor in the levels of activation of muscles involved in the phonation-breathing process in individuals with experience in singing voice. Modifications of body posture as a tool for voice therapy should be further investigated, considering the population with voice problems and no voice training experience.

The Effect of Different Preparatory Conducting Gestures on Breathing Behavior and Voice Quality of Choral Singers

The breathing technique is a determining factor for the singer's sound quality and consequently crucial for the choral sound. However, very little is known about possible influences of the conductor's preparatory gesture on the way choral singers inhale before the beginning of a piece (respectively every subsequent phrase). The conducting literature does not discriminate between out- and inward preparatory gestures and even describes them as equivalent, but previous studies suggest that singers assign different types of inhalation to different preparatory gestures. It may therefore be assumed that the type of preparatory gesture has a direct influence on the singer's inhalation and tone production, and the aim of this study is hence to examine possible effects of two contrasting preparatory gestures on the singer's inhalation type and the resulting tone quality. In our within-subjects study design, 18 healthy choral singers (9 male/ 9 female) were recruited to participate in a laboratory experiment. The participants were asked to sing a tone suitable for their voice register in response to different video stimuli. These consisted of two conducting-videos, each showing a different preparatory gesture, and two control conditions with an animated bar and an arrow indicating the desired breathing type. The singers reacted to 10 sets of videos, each set consisting of the four stimuli in randomized order. For evaluation of the breathing behavior and vocal output during the different experimental conditions, chest wall kinematics of upper rib cage, abdominal rib cage and abdomen were measured via 3D motion capture and voice samples were recorded. The obtained data were filtered and compared using the repeated measures analysis of variance and post hoc Tukey test for significant results. The level of significance was set at P < 0.05. The results of the study show significant differences in volume of the abdomen between the two different gestures (F1,17=24.04, η2=0.59, P=0.0001), which can be validated by the two control measurements (F1,17=21.12, η2=0.55, P=0.0002). An outward preparatory gesture evoked an abdominal breathing type while an inward-upward movement led to an inhalation with a higher portion of clavicular breathing. Furthermore, significant differences in timbre and loudness of the produced tone could be observed. The maximum sound pressure level of the outward preparatory gesture was significantly higher than in case of the inward-upward movement (F1,17=20.4, η2=0.56, P=0.0004). In contrast to the existing conducting literature, which does not discriminate between out- and inward preparatory gestures, the results of this study show that the conductor's choice of trajectory direction and form of the preparatory gestures elicit spontaneous, gesture-specific reactions in singers' breathing behavior as well as the corresponding loudness and sound quality.

Cortical Reorganization Following Psychoeducational Counselling and Residual Inhibition Therapy (RIT) in Individuals with Tinnitus.

Introduction Psychoeducational counselling and residual inhibition therapy (RIT) are traditional approaches used in many clinics to manage tinnitus. However, neurophysiological studies to evaluate posttreatment perceptual and functional cortical changes in humans are scarce. Objectives The present study aims to explore whether cortical auditory-evoked potentials (CAEPs; N1 and P3) reflect the effect of modified RIT and psychoeducational counselling, and whether there is a correlation between the behavioral and electrophysiological measures. Methods Ten participants with continuous and bothersome tinnitus underwent a session of psychoeducational counselling and modified RIT. Perceptual measures and CAEPs were recorded pre- and posttreatment. Further, the posttreatment measures were compared with age and gender-matched historical control groups. Results Subjectively, 80% of the participants reported a reduction in the loudness of their tinnitus. Objectively, there was a significant reduction in the posttreatment amplitude of N1 and P3, with no alterations in latency. There was no correlation between the perceived difference in tinnitus loudness and the difference in P3 amplitude (at Pz). Conclusion The perceptual and functional (as evidenced by sensory, N1, and cognitive, P3 reduction) changes after a single session of RIT and psychoeducational counselling are suggestive of plastic changes at the cortical level. The current study serves as preliminary evidence that event-related potentials (ERPs) can be used to quantify the physiological changes that occur after the intervention for tinnitus.

The time course of first formant movement in normal and loud speech

Louder speech tends to be slower than typical speech. For some vowels (viz., low and lax ones), louder speech may also be associated with higher first formant frequencies (F1s) at vowel midpoint. Possibly, increased duration allows speakers more time to reach a lower jaw position, thus a higher value of F1, in loud speech. In earlier work, we found that some loudness differences appeared at 25% and 75% of vowel durations, i.e., they were seen for much of the vowel. The current study presents data from 11 German-speaking women producing naturally elicited typical and loud speech. Target words included high, low, tense, and lax vowels with surrounding consonantal place controlled. We will present full vowel trajectories, i.e., from preceding to following consonants, to assess the time course of F1 differences across vowel types and loudness conditions. F1 will also be considered within normalized time intervals to control for durational differences between conditions. We expect that F1 formant trajectories will show minimal loudness differences throughout the vowel for high tense vowels, but time-varying differences will be more apparent for low and lax vowels, and appear rather early in the vowel.

Towards single-trial classification of invasively recorded auditory evoked potentials in cochlear implant users

Objective. One promising approach towards further improving cochlear implants (CI) is to use brain signals controlling the device in order to close the auditory loop. Initial electroencephalography (EEG) studies have already shown promising results. However, they are based on noninvasive measurements, whereas implanted electrodes are expected to be more convenient in terms of everyday-life usability. If additional measurement electrodes were implanted during CI surgery, then invasive recordings should be possible. Furthermore, implantation will provide better signal quality, higher robustness to artefacts, and thus enhanced classification accuracy. Approach. In an initial project, three additional epidural electrodes were temporarily implanted during the surgical procedure. After surgery, different auditory evoked potentials (AEPs) were recorded both invasively (epidural) and using surface electrodes, with invasively recorded signals demonstrated as being markedly superior. In this present analysis, cortical evoked response audiometry (CERA) signals recorded in seven patients were used for single-trial classification of sounds with different intensities. For classification purposes, we used shrinkage-regularized linear discriminant analysis (sLDA). Clinical speech perception scores were also investigated. Main results. Analysis of CERA data from different subjects showed single-trial classification accuracies of up to 99.2% for perceived vs. non-perceived sounds. Accuracies of up to 89.1% were achieved in classification of sounds perceived at different intensities. Highest classification accuracies were achieved by means of epidural recordings. Required loudness differences seemed to correspond to speech perception in noise. Significance. The proposed epidural recording approach showed good classification accuracy into sound perceived and not perceived when the best-performing electrodes were selected. Classifying different levels of sound stimulation accurately proved more challenging. At present, the methods explored in this study would not be sufficiently reliable to allow automated closed-loop control of CI parameters. However, our findings are an important initial contribution towards improving applicability of closed auditory loops and for next-generation automatic fitting approaches.

고무공 충격음의 최소인지한계

Rubber balls are used to measure the low-frequency impact sound on reinforced concrete and wooden structured apartment buildings. Previous studies on rubber ball impact sound showed that the physical properties of a rubber ball cause its impact sound to be similar to real impacts such as jumping and running of children. The rubber ball was standardized in ISO 10140-5 and ISO 16283-2, and studies on the SNQ of rubber ball were conducted. In addition, a classification on rubber ball impact sound is needed for the evaluation and labelling of low-frequency impact sounds. In this study, a subjective evaluation on the just noticeable difference (JND) of rubber ball impact sound was conducted. The presented rubber ball impact sound was recorded from wooden and reinforced concrete structures in apartment buildings. The JND of rubber ball impact sound, in which 75 % of the subjects can distinguish the loudness difference of two kinds of presented sound, was 4.65 dB for the wooden structure and 4.67 dB for the reinforced structure. On average, the JND of the rubber ball impact sound was 4.66 dB. For considering the harmonization with the classification scheme of other noise sources such as service equipment and airborne sound insulation in ISO/PRF TS 19488, a difference of 4 dB between classes is reasonable.

Loudness Differences for Voice-Over-Voice Audio in TV and Streaming

Voice-over-Voice (VoV) is a common mixing practice observed in news reports and docu- mentaries, where a foreground voice is mixed on top of a background voice, e.g., to translate an interview. This is achieved by ducking the background voice so that the foreground voice is more intelligible, while still allowing the listener to perceive the presence and tone of the background voice. Currently there is little published research on ducking practices for VoV or on technical details such as the Loudness Difference (LD) between foreground and background speech. This paper investigates the ducking practices of nine expert audio engineers and the preferred LDs of 13 non-expert listeners of ages 57 years and older. Results highlight a clear difference between the LDs used by the experts and those preferred by the non-expert listeners. Experts tended toward LDs of 11.5–17 LU, while non-experts preferred a range of 20–30 LU. Based on these results, a minimum LD of 20 LU is recommended for VoV. High inter-subject variance due to personal preference was observed. This variance makes a substantial case for the introduction of personalization in broadcast and streaming. The audiovisual material used for the tests is provided at https://www.audiolabs-erlangen.de/resources/2020-VoV-DB.

Uni- and bilateral spectral loudness summation and binaural loudness summation with loudness matching and categorical loudness scaling

Objective Current hearing aid prescription rules assume that spectral loudness summation decreases with hearing impairment and that binaural loudness summation is independent of hearing loss and signal bandwidth. Previous studies have shown that these assumptions might be incorrect. Spectral loudness summation was measured and compared for loudness scaling and loudness matching. Design In this study, the effect of bandwidth on binaural summation was investigated by comparing loudness perception of low-pass filtered, high-pass filtered, and broadband pink noise at 35 Categorical Units for both unilateral and bilateral presentation. Study sample Sixteen hearing-impaired listeners. Results The results show that loudness differences between the three signals are different for bilateral presentation than for unilateral presentation. In specific, binaural loudness summation is larger for the low-pass filtered pink noise than for the high-pass filtered pink noise. Finally, individual variability in loudness perception near loudness discomfort level was found to be very large. Conclusions Loudness matching is offered as a fast and reliable method to measure individual loudness perception. As discomfort with loud sounds is one of the major problems encountered by hearing aid users, measurement of individual loudness perception could improve hearing aid fitting substantially.

Rate pitch discrimination in cochlear implant users with the use of double pulses and different interpulse intervals

The rate pitch discrimination ability of cochlear implant (CI) users is poor compared to normal-hearing (NH) listeners. At low pulse rates, the just noticeable difference (JND) is on average 20% of the base rate, while NH listeners can discriminate small frequency differences of 0.2% at 1 kHz. Recent investigations suggest that double pulses with short interpulse intervals (IPIs) may have a beneficial effect on rate pitch discrimination in CI users. In a first experiment psychophysical tests were carried out to establish whether rate pitch in CI users could be improved by applying double pulses with equal amplitude and short IPIs. Pulse trains with base rates of 200 and 400 pps, composed of either single pulses or double pulses with IPIs of 15, 50, and 150 μs were presented. In a second experiment pairwise comparisons were carried out between pitch of a pulse train composed of alternating double and single pulses with pitch of pulse trains composed of single pulses. The alternating pulse train had a base rate of 400 pps, the pulse trains with solely single pulses had base rates of 200, 300, and 400 pps. The loudness and pitch perception of the different stimulus types were evaluated and compared. A significant loudness difference was found between single and double pulses for both pulse rates. The JND for pitch discrimination between double-pulse IPIs had a high inter-subject variability, and no significant group effect was found. No subject reported a pitch change between double pulse and single pulse stimulation. In contrast, most of the subjects recognized a change in pitch between single-pulse trains and pulse trains with alternating double and single pulses. The latter was lower in pitch than the single-pulse train stimulation. To conclude, using (equal amplitude) double pulses instead of single pulses in a pulse train does not effect pitch perception. Instead, loudness differs between double pulses and single pulses with the same amplitude.

Individual Reliability of the Standard Clinical Method vs Patient-Centered Tinnitus Likeness Rating for Assessment of Tinnitus Pitch and Loudness Matching

Current individualized sound therapies for tinnitus rely on tinnitus pitch assessment, which is commonly derived from the standard clinical 2-alternative forced-choice (2-AFC) approach driven by the examiner. However, this method is limited by lack of individual test-retest reliability and focuses on a single rather than multiple tinnitus frequencies. To assess individual test-retest reliability of the 2-AFC, with a single final frequency (and corresponding loudness), and the tinnitus likeness rating (TLR), with the participant exposed to the entire audible frequency spectrum, from which 3 dominant frequencies and corresponding loudness were extracted. In this case series, participants with tinnitus underwent testing twice with both methods at a 1-month interval by experienced clinicians from January 6 through March 17, 2017. Each clinician tested each patient only once at visit 1 or 2 in a university audiology training setting with standardized equipment and was blind to previous assessment. Participants with bilateral or unilateral chronic tinnitus for longer than 6 months, in good health, without total deafness in either ear, and without cerumen in the ear canal were recruited through advertisements (community and clinics) and word of mouth (volunteer sample). The audiologists were likewise participants in the planned comparison between TLR and 2-AFC in the test-retest measures. Test-retest concordance with 95% CIs for each method, calculated as the proportion of participants with the same final frequency between the 2 visits (2-AFC) or with at least 1 concordant dominant frequency (TLR) as well as loudness differences of no greater than 10 dB. The study sample included 31 participants (55% men; mean [SD] age, 50.7 [13.7] years). For TLR, 26 of 31 participants had at least 1 concordant dominant frequency between the 2 visits (proportion, 0.84; 95% CI, 0.66-0.95), whereas for 2-AFC, 7 of 31 participants had a concordant final tinnitus pitch in either ear (proportion, 0.23; 95% CI, 0.10-0.41). Loudness reliability followed the same pattern, with more concordant loudness levels in the TLR (proportion, 0.73; 95% CI, 0.52-0.88) than in the 2-AFC (proportion, 0.40; 95% CI, 0.05-0.85). Mean time taken to complete the tests was less than 15 minutes, and general appreciation by participants with tinnitus and audiologists were overall similar for both. Superior test-retest concordance can be demonstrated at the individual level using the several dominant frequencies extracted from the patient-centered TLR.

CONGENITAL MYOPATHIES (CNM): P.136INCEPTUS pre-phase 1, prospective, non-interventional, natural history run-in study to evaluate subjects aged 3 years and younger with X-linked myotubular myopathy: preliminary findings

XLMTM is a rare disease caused by mutations in the MTM1 gene and characterized by profound muscle weakness, respiratory failure, and early death. INCEPTUS is a prospective, non-interventional study to evaluate XLMTM patients under 4 years of age. The objective is to characterize adverse events; neuromuscular, respiratory, and functional assessments; and to generate within-patient control data to support a Phase 1/2 gene therapy clinical trial (the ASPIRO study). 23 male patients (0.5-4.0 years of age) have been enrolled and followed with assessments every 3 months for up to 18 months. There have been 3 deaths and 38 serious adverse events, mainly due to respiratory tract infections. Neuromuscular function is severely compromised in this population, with high inter-patient variability: Children's Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP-INTEND) mean scores show a 4-point decline (baseline mean [SD, min-max]= 33.6 [8.4, 17-52] and month 12 mean= 29.6 [6.5, 19-40]). Motor Function Measure (MFM-20) mean scores show a 3.5% increase (baseline mean= 28.6% [16.0, 5-48.3] and month 12 mean= 31.5% [13.2, 11.7-50]). The majority of patients (n= 16/23, 69.6%) require invasive ventilatory support, many for 24h/day. Respiratory muscle strength measured as maximum inspiratory pressure (MIP, also referred to as Pimax) is low and mean scores show a 5.1 cmH2O decline (baseline mean= 33.6 cmH2O [15.2, 17.6-64.5] and month 12 mean= 28.5 cmH2O [8.35, 15.1-41.4]). Vocalization evaluations by handheld acoustic analyzer show no differences in loudness between talking and crying, further evidencing poor respiratory muscle strength. INCEPTUS data increase our understanding of respiratory issues and neuromuscular weakness in XLMTM and reinforce the severity and heterogeneity of the disease. The INCEPTUS study has additional operational value, as study sites build experience with the use of outcome measures also being used in ASPIRO.