Pitch Perturbation Research Articles

Bayesian inference of state feedback control parameters for fo perturbation responses in cerebellar ataxia.

Behavioral speech tasks have been widely used to understand the mechanisms of speech motor control in typical speakers as well as in various clinical populations. However, determining which neural functions differ between typical speakers and clinical populations based on behavioral data alone is difficult because multiple mechanisms may lead to the same behavioral differences. For example, individuals with cerebellar ataxia (CA) produce atypically large compensatory responses to pitch perturbations in their auditory feedback, compared to typical speakers, but this pattern could have many explanations. Here, computational modeling techniques were used to address this challenge. Bayesian inference was used to fit a state feedback control (SFC) model of voice fundamental frequency (fo) control to the behavioral pitch perturbation responses of speakers with CA and typical speakers. This fitting process resulted in estimates of posterior likelihood distributions for five model parameters (sensory feedback delays, absolute and relative levels of auditory and somatosensory feedback noise, and controller gain), which were compared between the two groups. Results suggest that the speakers with CA may proportionally weight auditory and somatosensory feedback differently from typical speakers. Specifically, the CA group showed a greater relative sensitivity to auditory feedback than the control group. There were also large group differences in the controller gain parameter, suggesting increased motor output responses to target errors in the CA group. These modeling results generate hypotheses about how CA may affect the speech motor system, which could help guide future empirical investigations in CA. This study also demonstrates the overall proof-of-principle of using this Bayesian inference approach to understand behavioral speech data in terms of interpretable parameters of speech motor control models.

Effectiveness of a Voice Training Program for Religious Officials in Turkey.

This study examines the effectiveness of a voice training program designed for Islamic religious officials, who are occupational voice users with a significant vocal load. The participants included 34 healthy religious officials whose acoustic measures were within normal voice ranges for healthy adults (jitter < 1%; shimmer < 3%) and reported no voice complaints. Participants were randomly divided into two groups (experimental, n = 17; control, n = 17). The two-stage voice training program consisted of 32 sessions over 8 weeks with informative and voice exercise stages. Objective and subjective voice measurements were performed at the beginning and end of the research. Objective measurements included fundamental frequency, percentage of vocal pitch perturbation (jitter), percentage of vocal intensity perturbation (shimmer), and harmonics-to-noise ratio. Subjective voice measurements included the Singing Voice Handicap Index, Vocal Fatigue Index (VFI), and Voice-Related Quality of Life (V-RQoL) scores. All initial measurements other than VFI scores were within acceptable limits for both groups. There were no significant differences between the groups initially (p > 0.05) and no significant changes in the control group in the second evaluation (p > 0.05). However, there was significant improvement in the experimental group after the training program in all measures, including VFI scores (p < 0.05). This study shows the positive results of a voice training program. Voice training should be integrated into the formal education of occupational voice users or in-service training programs of relevant institutions.

Using altered auditory feedback to study pitch compensation and adaptation in tonal language speakers.

Human speech production is strongly influenced by the auditory feedback it generates. Auditory feedback-what we hear when we speak-enables us to learn and maintain speaking skills and to rapidly correct errors in our speech. Over the last three decades, the real-time altered auditory feedback (AAF) paradigm has gained popularity as a tool to study auditory feedback control during speech production. This method involves changing a speaker's speech and feeding it back to them in near real time. More than 50% of the world's population speak tonal languages, in which the pitch or tone used to pronounce a word can change its meaning. This review article aims to offer an overview of the progression of AAF paradigm as a method to study pitch motor control among speakers of tonal languages. Eighteen studies were included in the current mini review and were compared based on their methodologies and results. Overall, findings from these studies provide evidence that tonal language speakers can compensate and adapt when receiving inconsistent and consistent pitch perturbations. Response magnitude and latency are influenced by a range of factors. Moreover, by combining AAF with brain stimulation and neuroimaging techniques, the neural basis of pitch motor control in tonal language speakers has been investigated. To sum up, AAF has been demonstrated to be an emerging tool for studying pitch motor control in speakers of tonal languages.

Do Not Cut Off Your Tail: A Mega-Analysis of Responses to Auditory Perturbation Experiments.

The practice of removing "following" responses from speech perturbation analyses is increasingly common, despite no clear evidence as to whether these responses represent a unique response type. This study aimed to determine if the distribution of responses to auditory perturbation paradigms represents a bimodal distribution, consisting of two distinct response types, or a unimodal distribution. This mega-analysis pooled data from 22 previous studies to examine the distribution and magnitude of responses to auditory perturbations across four tasks: adaptive pitch, adaptive formant, reflexive pitch, and reflexive formant. Data included at least 150 unique participants for each task, with studies comprising younger adult, older adult, and Parkinson's disease populations. A Silverman's unimodality test followed by a smoothed bootstrap resampling technique was performed for each task to evaluate the number of modes in each distribution. Wilcoxon signed-ranks tests were also performed for each distribution to confirm significant compensation in response to the perturbation. Modality analyses were not significant (p > .05) for any group or task, indicating unimodal distributions. Our analyses also confirmed compensatory reflexive responses to pitch and formant perturbations across all groups, as well as adaptive responses to sustained formant perturbations. However, analyses of sustained pitch perturbations only revealed evidence of adaptation in studies with younger adults. The demonstration of a clear unimodal distribution across all tasks suggests that following responses do not represent a distinct response pattern, but rather the tail of a unimodal distribution. https://doi.org/10.23641/asha.24282676.

Pitch perturbation effects on a revolving wing at low Reynolds number

Pitch perturbation effects on a revolving wing at low Reynolds number

Sulcus Vocalis: Clinical and Surgical Aspects

To analyze clinical, vocal, and videolaryngoscopic parameters, as well as the treatments of patients with sulcus vocalis. This is an observational study. The medical records of patients diagnosed with sulcus vocalis (type II or III) were selected and demographic data, vocal symptoms, videolaryngostroboscopies, vocal analyses (perceptual and acoustic), and maximum phonation time (MPT) were collected. The vocal parameters of patients who underwent microsurgery to treat the sulcus were compared before and after surgery. Exactly 109 patients were diagnosed with sulcus; however, only 60 completed the inclusion criteria (39 women and 21 men), with a mean age of 45 years. Hoarseness and vocal fatigue were reported in 100% and 88% of cases, respectively. Laryngoscopy indicated a type II sulcus (90%), type III sulcus (10%), and an association of the sulcus with other benign lesions (23%), especially polyps. Perceptual evaluations indicated mild to moderate dysphonia, roughness and breathiness of the voice, mean MPT of 10seconds, and high values of jitter, pitch perturbation coefficient, and soft phonation index (SPI). Twenty-two patients (14 women and 8 men) underwent sulcus microsurgery. The surgery promoted a decrease in the GRBAS scores, an increase in the MPT, and a decrease in the SPI; however, other acoustic parameters remained unchanged. Patients with sulcus vocalis had mild to moderate dysphonia, in addition to voice roughness and breathiness and elevated fundamental frequency. Surgical treatment improved vocal parameters but maintained some degree of dysphonia, indicating incomplete restoration of vocal qualities.

Right, but not left, posterior superior temporal gyrus is causally involved in vocal feedback control

The posterior superior temporal gyrus (pSTG) has been implicated in the integration auditory feedback and motor system for controlling vocal production. However, the question as to whether and how the pSTG is causally involved in vocal feedback control is currently unclear. To this end, the present study selectively stimulated the left or right pSTG with continuous theta burst stimulation (c-TBS) in healthy participants, then used event-related potentials to investigate neurobehavioral changes in response to altered auditory feedback during vocal pitch regulation. The results showed that, compared to control (vertex) stimulation, c-TBS over the right pSTG led to smaller vocal compensations for pitch perturbations accompanied by smaller cortical N1 and larger P2 responses. Enhanced P2 responses received contributions from the right-lateralized temporal and parietal regions as well as the insula, and were significantly correlated with suppressed vocal compensations. Surprisingly, these effects were not found when comparing c-TBS over the left pSTG with control stimulation. Our findings provide evidence that supports a causal relationship between right, but not left, pSTG and auditory-motor integration for vocal pitch production. This lends support to a right-lateralized contribution of the pSTG in not only detecting vocal feedback errors but also driving motor commands for error correction.

Auditory-Motor Function Pre- and Post-Therapy in Hyperfunctional Voice Disorders: A Case Series

Behavioral voice therapy is the most common treatment for hyperfunctional voice disorders (HVDs) but has limited long-term effectiveness since the comprehensive mechanisms underlying HVDs remain unclear. Recent work has implicated disordered sensorimotor integration during speech in some speakers with HVDs and suggests that auditory processing is a key factor to consider in HVD assessment and therapy. The purpose of this case-series study was to assess whether current voice therapy approaches for HVDs resulted in improvements to auditory-motor function. Longitudinal (pre-post) study. Pre and postvoice therapy for HVDs, 11 speakers underwent an assessment of auditory-motor function via auditory discrimination of vocal pitch, responses to unanticipated auditory perturbations, and responses to predictable auditory perturbations of vocal pitch. At the post-therapy session, 10 out of 11 participants demonstrated voice therapy success (via self-reported voice problems and/or auditory-perceptual judgements of voice by a clinician) and eight of the 11 participants demonstrated improvements in at least one measure of auditory discrimination and/or auditory-motor control. Specifically, three speakers demonstrated improvements in auditory discrimination, five speakers demonstrated improved (within typical cutoffs) responses to predictable perturbations, and two speakers demonstrated improvements in both auditory discrimination and auditory-motor measures. Together, these findings support that voice therapy in individuals with HVDs may impact auditory-motor control and highlight the potential benefit of systematically addressing auditory function in voice therapy and assessment for HVDs.

Effect of perturbation timing on recovering whole-body angular momentum during very slow walking

Humans prioritize regulation of the whole-body angular momentum (WBAM) during walking. When perturbed, modulations of the moment arm of the ground reaction force (GRF) with respect to the centre of mass (CoM) assist in recovering WBAM. For sagittal-plane perturbations of the WBAM given at toe off right (TOR), horizontal GRF modulations and not centre of pressure (COP) modulations were mainly responsible for these moment arm modulations. In this study, we aimed to find whether the instant of perturbations affects the contributions of the GRF and/or CoP modulations to the moment arm changes, in balance recovery during very slow walking. Perturbations of the WBAM were applied at three different instants of the gait cycle, namely at TOR, mid-swing (MS), and heel strike right (HSR). Forces equal to 16% of the participant’s body weight were applied simultaneously to the pelvis and upper body in opposite directions for a duration of 150 ms. The results showed that the perturbation onset did not significantly affect the GRF moment arm modulation. However, the contribution of both the CoP and GRF modulation to the moment arm changes did change depending on the perturbation instant. After perturbations resulting in a forward pitch of the trunk a larger contribution was present from the CoP modulation when perturbations were given at MS or HSR, compared to perturbations at TOR. After backward pitch perturbations given at MS and HSR the CoP modulation counteracted the moment arm required for WBAM recovery. Therefore a larger contribution from the horizontal GRF was needed to direct the GRF posterior to the CoM and recover WBAM. In conclusion, the onset of WBAM perturbations does not affect the moment arm modulation needed for WBAM recovery, while it does affect the way CoP and GRF modulation contribute to that recovery.

Right, but not left, posterior superior temporal gyrus is causally involved in vocal feedback control

The posterior superior temporal gyrus (pSTG) has been implicated in the integration of auditory feedback and motor system for controlling vocal production. However, the question as to whether and how the pSTG is causally involved in vocal feedback control is currently unclear. To this end, the present study selectively stimulated the left or right pSTG with continuous theta burst stimulation (c-TBS) in healthy participants, then used event-related potentials to investigate neurobehavioral changes in response to altered auditory feedback during vocal pitch regulation. The results showed that, compared to control (vertex) stimulation, c-TBS over the right pSTG led to smaller vocal compensations for pitch perturbations accompanied by smaller cortical N1 and larger P2 responses. Enhanced P2 responses received contributions from the right-lateralized temporal and parietal regions as well as the insula, and were significantly correlated with suppressed vocal compensations. Surprisingly, these effects were not found when comparing c-TBS over the left pSTG with control stimulation. Our findings provide evidence, for the first time, that supports a causal relationship between right, but not left, pSTG and auditory-motor integration for vocal pitch regulation. This lends support to a right-lateralized contribution of the pSTG in not only the bottom-up detection of vocal feedback errors but also the involvement of driving motor commands for error correction in a top-down manner.

Advances in Clinical Voice Quality Analysis with VOXplot.

The assessment of voice quality can be evaluated perceptually with standard clinical practice, also including acoustic evaluation of digital voice recordings to validate and further interpret perceptual judgments. The goal of the present study was to determine the strongest acoustic voice quality parameters for perceived hoarseness and breathiness when analyzing the sustained vowel [a:] using a new clinical acoustic tool, the VOXplot software. A total of 218 voice samples of individuals with and without voice disorders were applied to perceptual and acoustic analyses. Overall, 13 single acoustic parameters were included to determine validity aspects in relation to perceptions of hoarseness and breathiness. Four single acoustic measures could be clearly associated with perceptions of hoarseness or breathiness. For hoarseness, the harmonics-to-noise ratio (HNR) and pitch perturbation quotient with a smoothing factor of five periods (PPQ5), and, for breathiness, the smoothed cepstral peak prominence (CPPS) and the glottal-to-noise excitation ratio (GNE) were shown to be highly valid, with a significant difference being demonstrated for each of the other perceptual voice quality aspects. Two acoustic measures, the HNR and the PPQ5, were both strongly associated with perceptions of hoarseness and were able to discriminate hoarseness from breathiness with good confidence. Two other acoustic measures, the CPPS and the GNE, were both strongly associated with perceptions of breathiness and were able to discriminate breathiness from hoarseness with good confidence.

Transcranial direct current stimulation over left dorsolateral prefrontal cortex facilitates auditory-motor integration for vocal pitch regulation.

A growing body of literature has implicated the left dorsolateral prefrontal cortex (DLPFC) in the online monitoring of vocal production through auditory feedback. Specifically, disruption of or damage to the left DLPFC leads to exaggerated compensatory vocal responses to altered auditory feedback. It is conceivable that enhancing the cortical excitability of the left DLPFC may produce inhibitory influences on vocal feedback control by reducing vocal compensations. We used anodal transcranial direct current stimulation (a-tDCS) to modulate cortical excitability of the left DLPFC and examined its effects on auditory-motor integration for vocal pitch regulation. Seventeen healthy young adults vocalized vowel sounds while hearing their voice pseudo-randomly pitch-shifted by ±50 or ±200 cents, either during (online) or after (offline) receiving active or sham a-tDCS over the left DLPFC. Active a-tDCS over the left DLPFC led to significantly smaller peak magnitudes and shorter peak times of vocal compensations for pitch perturbations than sham stimulation. In addition, this effect was consistent regardless of the timing of a-tDCS (online or offline stimulation) and the size and direction of the pitch perturbation. These findings provide the first causal evidence that a-tDCS over the left DLPFC can facilitate auditory-motor integration for compensatory adjustment to errors in vocal output. Reduced and accelerated vocal compensations caused by a-tDCS over left DLPFC support the hypothesis of a top-down neural mechanism that exerts inhibitory control over vocal motor behavior through auditory feedback.

Effects of sensorimotor voice training on event-related potentials to pitch-shifted auditory feedback.

The pitch perturbation technique is a validated technique that has been used for over 30 years to understand how people control their voice. This technique involves altering a person's voice pitch in real-time while they produce a vowel (commonly, a prolonged /a/ sound). Although post-task changes in the voice have been observed in several studies (e.g., a change in mean fo across the duration of the experiment), the potential for using the pitch perturbation technique as a training tool for voice pitch regulation and/or modification has not been explored. The present study examined changes in event related potentials (ERPs) and voice pitch in three groups of subjects due to altered voice auditory feedback following a brief, four-day training period. Participants in the opposing group were trained to change their voice fo in the opposite direction of a pitch perturbation stimulus. Participants in the following group were trained to change their voice fo in the same direction as the pitch perturbation stimulus. Participants in the non-varying group did not voluntarily change their pitch, but instead were asked to hold their voice constant when they heard pitch perturbations. Results showed that all three types of training affected the ERPs and the voice pitch-shift response from pre-training to post-training (i.e., "hold your voice pitch steady" task; an indicator of voice pitch regulation). Across all training tasks, the N1 and P2 components of the ERPs occurred earlier, and the P2 component of the ERPs occurred with larger amplitude post-training. The voice responses also occurred earlier but with a smaller amplitude following training. These results demonstrate that participation in pitch-shifted auditory feedback tasks even for brief periods of time can modulate the automatic tendency to compensate for alterations in voice pitch feedback and has therapeutic potential.

The Comparison of Electroacoustic and Subjective Voice Quality in Type 3 and 4 Transoral Laser Cordectomy for Early-Stage Glottic Carcinoma.

One of the main issues in early-stage glottic carcinoma management is the voice quality following different types of treatment modalities. In type 3 and 4 transoral laser cordectomies, the voice outcomes can show significant differences due to the extent of the vocal muscle resection. This study aims to compare the voice quality in patients who underwent type 3 and 4 laser cordectomy for early-stage glottic carcinoma. A total of 30 patients who underwent type 3 (15 patients) and type 4 (15 patients) laser cordectomy for T1a glottic carcinoma between May 2018 and 2020 were included in this retrospective comparative study. Electroacoustic voice analysis and Voice Handicap Index-10 were performed in the postoperative twelfth month and the outcomes were compared between two laser cordectomy groups. The mean age of all patients was 48.6 ± 4.2 years. Noise-to-harmonic ratio, jitter, shimmer, pitch perturbation quotient and amplitude perturbation quotient values were significantly different between two groups (p < 0.05). Fundamental frequency and Voice Handicap Index-10 scores showed no statistically significant difference (p > 0.05). This study reports significantly better results for type 3 against type 4 laser cordectomy by means of objective voice analysis outcomes, except fundamental frequency. On the other hand, self-reported subjective analysis showed very similar results for both groups. Further studies combining data with multiple objective and subjective analyses with larger patient series and longer follow-up are warranted.

Theta burst stimulation over left cerebellum does not modulate auditory feedback control of vocal production.

Accumulating evidence has shown significant contributions of the right cerebellum to auditory-motor integration for vocal production. Whether the left cerebellum is likewise involved in vocal motor control, however, remains unclear. By applying neuronavigated continuous and intermittent theta burst stimulation (cTBS/iTBS) over the left cerebellar lobule VII (Crus I), the present event-related potential (ERP) study investigated whether the left cerebellum exerts causal effects in modulating auditory feedback control of vocal pitch production. After receiving cTBS, iTBS, or sham stimulation over the left cerebellum, a group of fifteen young adults produced sustained vowels while hearing their voice unexpectedly shifted in pitch upwards or downwards by 200 cents. The effects of cerebellar stimulation were assessed by measuring the vocal and ERP (N1/P2) responses to pitch perturbations across the conditions. When compared to sham stimulation, cTBS or iTBS over the left cerebellar lobule VII (Crus I) led to no systematic changes in vocal compensations for pitch perturbations in auditory feedback. Also, the cortical N1/P2 responses did not vary significantly across the three stimulation sessions. These findings present the first neurobehavioral evidence suggesting that the left cerebellum is not causally associated with auditory feedback control of vocal production. Together with previously reported causal effects of the right cerebellum in modulating vocal pitch regulation, the present study lends support to the hypothesis that there is a functional lateralization of the cerebellum in vocal motor control though auditory feedback.

A causal link between left supplementary motor area and auditory-motor control of vocal production: Evidence by continuous theta burst stimulation

The supplementary motor area (SMA) has been implicated in the feedforward control of speech production. Whether this region is involved in speech motor control through auditory feedback, however, remains uncertain. The present event-related potential (ERP) study examined the role of the left SMA in vocal pitch regulation in a causal manner by combining auditory feedback manipulations and neuronavigated continuous theta bust stimulation (c-TBS). After receiving c-TBS over the left SMA or the control site (vertex), twenty young adults vocalized the vowel sound /u/ while hearing their voice unexpectedly pitch-shifted -50 or -200 cents. Compared to the control stimulation, c-TBS over the left SMA led to decreased vocal compensations for pitch perturbations of -50 and -200 cents. A significant decrease of N1 and P2 responses to -200 cents perturbations was also found when comparing active and control stimulation. Major neural generators of decreased P2 responses included the right-lateralized superior and middle temporal gyrus and angular gyrus. Notably, a significant correlation was found between active-control differences in the vocal compensation and P2 responses for the -200 cents perturbations. These findings provide neurobehavioral evidence for a causal link between the left SMA and auditory-motor integration for vocal pitch regulation, suggesting that the left SMA receives auditory feedback information and mediates vocal compensations for feedback errors in a bottom-up manner.

The left inferior frontal gyrus is causally linked to vocal feedback control: evidence from high-definition transcranial alternating current stimulation.

Current models of speech motor control propose a role for the left inferior frontal gyrus (IFG) in feedforward control of speech production. There is evidence, however, that has implicated the functional relevance of the left IFG for the neuromotor processing of vocal feedback errors. The present event-related potential (ERP) study examined whether the left IFG is causally linked to auditory feedback control of vocal production with high-definition transcranial alternating current stimulation (HD-tACS). After receiving active or sham HD-tACS over the left IFG at 6 or 70Hz, 20 healthy adults vocalized the vowel sounds while hearing their voice unexpectedly pitch-shifted by ±200 cents. The results showed that 6 or 70Hz HD-tACS over the left IFG led to larger magnitudes and longer latencies of vocal compensations for pitch perturbations paralleled by larger ERP P2 responses than sham HD-tACS. Moreover, there was a lack of frequency specificity that showed no significant differences between 6 and 70Hz HD-tACS. These findings provide first causal evidence linking the left IFG to vocal pitch regulation, suggesting that the left IFG is an important part of the feedback control network that mediates vocal compensations for auditory feedback errors.

Quantitatively characterizing reflexive responses to pitch perturbations.

Reflexive pitch perturbation experiments are commonly used to investigate the neural mechanisms underlying vocal motor control. In these experiments, the fundamental frequency-the acoustic correlate of pitch-of a speech signal is shifted unexpectedly and played back to the speaker via headphones in near real-time. In response to the shift, speakers increase or decrease their fundamental frequency in the direction opposing the shift so that their perceived pitch is closer to what they intended. The goal of the current work is to develop a quantitative model of responses to reflexive perturbations that can be interpreted in terms of the physiological mechanisms underlying the response and that captures both group-mean data and individual subject responses. A model framework was established that allowed the specification of several models based on Proportional-Integral-Derivative and State-Space/Directions Into Velocities of Articulators (DIVA) model classes. The performance of 19 models was compared in fitting experimental data from two published studies. The models were evaluated in terms of their ability to capture both population-level responses and individual differences in sensorimotor control processes. A three-parameter DIVA model performed best when fitting group-mean data from both studies; this model is equivalent to a single-rate state-space model and a first-order low pass filter model. The same model also provided stable estimates of parameters across samples from individual subject data and performed among the best models to differentiate between subjects. The three parameters correspond to gains in the auditory feedback controller's response to a perceived error, the delay of this response, and the gain of the somatosensory feedback controller's "resistance" to this correction. Excellent fits were also obtained from a four-parameter model with an additional auditory velocity error term; this model was better able to capture multi-component reflexive responses seen in some individual subjects. Our results demonstrate the stereotyped nature of an individual's responses to pitch perturbations. Further, we identified a model that captures population responses to pitch perturbations and characterizes individual differences in a stable manner with parameters that relate to underlying motor control capabilities. Future work will evaluate the model in characterizing responses from individuals with communication disorders.

Dysarthric speech detection from telephone quality speech using epoch-based pitch perturbation features

Dysarthric speech detection from telephone quality speech using epoch-based pitch perturbation features

Voice Quality in Telephone Interviews: A preliminary Acoustic Investigation

To investigate the impact of standardized mobile phone recordings passed through a telecom channel on acoustic markers of voice quality and on its perception by voice experts in normophonic speakers. Continuous speech and a sustained vowel were recorded for fourteen female and ten male normophonic speakers. The recordings were done simultaneously with a head-mounted high-quality microphone and through the telephone network on a receiving smartphone. Twenty-two acoustic voice quality, breathiness and pitch-related measures were extracted from the recordings. Nine vocologists perceptually rated the G, R and B parameters of the GRBAS scale on each voice sample. The reproducibility, the recording type, the stimulus type and the gender effects, as well as the correlation between acoustic and perceptual measures were investigated. The sustained vowel samples are damped after one second. Only the frequencies between 100 and 3700Hz are passed through the telecom channel and the frequency response is characterized by peaks and troughs. The acoustic measures show a good reproducibility over the three repetitions. All measures significantly differ between the recording types, except for the local jitter, the harmonics-to-noise ratio by Dejonckere and Lebacq, the period standard deviation and all six pitch measures. The AVQI score is higher in telephone recordings, while the ABI score is lower. Significant differences between genders are also found for most of the measures; while the AVQI is similar in men and women, the ABI is higher in women in both recording types. For the perceptual assessment, the interrater agreement is rather low, while the reproducibility over the three repetitions is good. Few significant differences between recording types are observed, except for lower breathiness ratings on telephone recordings. G ratings are significantly more severe on the sustained vowel on both recording types, R ratings only on telephone recordings. While roughness is rated higher in men on telephone recordings by most experts, no gender effect is observed for breathiness on either recording types. Finally, neither the AVQI nor the ABI yield strong correlations with any of the perceptual parameters. Our results show that passing a voice signal through a telecom channel induces filter and noise effects that limit the use of common acoustic voice quality measures and indexes. The AVQI and ABI are both significantly impacted by the recording type. The most reliable acoustic measures seem to be pitch perturbation (local jitter and period standard deviation) as well as the harmonics-to-noise ratio from Dejonckere and Lebacq. Our results also underline that raters are not equally sensitive to the various factors, including the recording type, the stimulus type and the gender effects. Neither of the three perceptual parameters G, R and B seem to be reliably measurable on telephone recordings using the two investigated acoustic indexes. Future studies investigating the impact of voice quality in telephone conversations should thus focus on acoustic measures on continuous speech samples that are limited to the frequency response of the telecom channel and that are not too sensitive to environmental and additive noise.