Absolute Jitter Research Articles

The effect of wearing face masks on voice and intelligibility of speech during the COVID-19 pandemic

BackgroundThe study aims at evaluating the effect of wearing face masks on voice and intelligibility of speech in Egyptian working individuals during the COVID-19 pandemic to identify if there are any adverse effects of wearing face masks in the working environment.Materials and methodsA cross-section analytical study was conducted on 153 participants. Personal data and data about the nature of their workplaces were collected. The evaluation included a subjective assessment of voice and intelligibility of speech using a specifically designed questionnaire addressing self-perception of voice fatigue, speech unintelligibility, received auditory feedback and breathing difficulty, and objective voice assessment by Computerized Speech Lab, while objective speech unintelligibility assessment by the Arabic Speech Intelligibility Test.ResultsThe study revealed poor workplace acoustics and increased their self-perception of voice fatigue, speech unintelligibility, auditory feedback, and breathing difficulty while wearing masks. Medical professionals showed increased self-perception of speech unintelligibility and the received auditory feedback. No significant difference was found in absolute jitter with and without a face mask. Increasing shimmer and mean fundamental frequency and decreasing noise to harmonic ratio and maximum phonation time were found. The study revealed decreased speech intelligibility especially with the N95 mask.ConclusionWearing face masks negatively affects communication in the workplace, with poor room acoustics. It affects both speech intelligibility and voice subjectively and objectively. It caused increased self-perception of voice fatigue and changes in objective voice parameters.

Acoustic Changes in Patients with Laryngopharyngeal Reflux Disease without Voice Complaints: A Cross-sectional Study

Introduction: In Laryngopharyngeal Reflux (LPR), refluxate rich in acid, pepsin, and bile regurgitates above the upper oesophageal sphincter onto the laryngeal mucosa. However, not all patients with LPR present with subjective voice changes. This may be due to a gradual change in voice that remains unnoticed. The clinical subtlety is important for diagnosis or at least awareness for better treatment and care. Aim: To objectively determine preclinical acoustic changes in patients with LPR who have not reported any voice complaints. Materials and Methods: This cross-sectional study was conducted on adult patients visiting the Out-patient department of a Tertiary Care Teaching Institute in Northern India, from September 2022 to October 2022. Patients with LPR but without voice changes were included in the study. They underwent multidimensional voice analysis during the phonation of the vowel /a/. Mean fundamental frequency (MF0), absolute jitter, absolute shimmer, and Soft Phonation Index (SPI) were analysed for the sample and compared to the gender-specific mean values provided by the software used. Statistical significance was determined using the one-sample t-test. Results: A total of 27 participants (20 females, 7 males) completed the study. In the female group, the mean MF0 (204.30±32.49 Hz) was significantly lower, absolute jitter (92.41±87.93 μs), absolute shimmer (0.38±0.31 dB), and SPI (25.62±15.24) were significantly higher than the reference mean. In the male group, the mean MF0 (138.03 Hz), absolute jitter (104.01±84.28 μs), and absolute shimmer (0.34±0.16 dB) were not significantly different from the reference mean. However, SPI (25.09±16.95) remained significantly higher than the reference mean. Conclusion: Increased jitter, shimmer, and SPI are primary acoustic changes observed in patients with LPR. These changes appear even before patients experience any voice changes.

The effect of anterior esthetic fixed appliance of prematurely lost primary incisors on sound production and speech intelligibility

AimsThis work aimed to compare the sound production and speech pattern in children with prematurely extracted anterior teeth after prosthetic rehabilitation with fixed functional space maintainer.Settings and designThe study was conducted as a clinical trial. The clinical part was carried out at Pediatric Dentistry Department, Faculty of Dentistry, Tanta University and speech evaluation and assessment was done in Phoniatric Unit, ENT Department, Faculty of Medicine, Tanta University.Patients and methodsTwenty-five children of both sexes aged from 3 to 6 years old were included in the study. The selected children were in need for extraction of maxillary primary incisors or had already got extracted and treated by anterior esthetic fixed appliance. Children attended for speech and language evaluation at before appliance delivery, immediately after appliance insertion, 7 days after appliance insertion, 14 days after appliance insertion and 1 month after appliance insertion. And they were evaluated by articulation test, speech intelligibility test, and spectrographic parameters.Statistical analysis usedAll test statistics were performed using the SPSS software statistical package and the significance was set at P value less than or equal to 0.05.ResultsThere were statistically significant differences between follow up periods for/S/,/S/, and/Z/sounds but no statistically significant difference for/z/and/∫/sounds. The mean shimmer in dB, the mean absolute Jitter and the mean noise to harmonic ratio for the sounds were diminished after adaptation of the appliance. Also, high significant differences were found between 1 month after appliance insertion and all different follow up periods. No difference with immediately after appliance insertion.ConclusionsReplacement of prematurely lost primary incisors with fixed prosthetic appliances will assist in the proper development and intelligibility of speech. Also, in accurate consonants sounds production as/s/,/s/,/z/,/∫/(alveolar fricatives), and/z/(dental fricatives).

Quality of Voice in Patients With Partial Deafness Before and After Cochlear Implantation

Quality of Voice in Patients With Partial Deafness Before and After Cochlear Implantation

Jitter Detection Method Based on Sequence CMOS Images Captured by Rolling Shutter Mode for High-Resolution Remote Sensing Satellite

Satellite platform jitter is a non-negligible factor that affects the image quality of optical cameras. Considering the limitations of traditional platform jitter detection methods that are based on attitude sensors and remote sensing images, this paper proposed a jitter detection method using sequence CMOS images captured by rolling shutter for high-resolution remote sensing satellite. Through the three main steps of dense matching, relative jitter error analysis, and absolute jitter error modeling using sequence CMOS images, the periodic jitter error on the imaging focal plane of the spaceborne camera was able to be measured accurately. The experiments using three datasets with different jitter frequencies simulated from real remote sensing data were conducted. The experimental results showed that the jitter detection method using sequence CMOS images proposed in this paper can accurately recover the frequency, amplitude, and initial phase information of satellite jitter at 100 Hz, 10 Hz, and 2 Hz. Additionally, the detection accuracy reached 0.02 pixels, which can provide a reliable data basis for remote sensing image jitter error compensation.

Enabling Fine Sample Rate Settings in DSOs with Time-Interleaved ADCs.

The time-base used by digital storage oscilloscopes allows limited selections of the sample rate, namely constrained to a few integer submultiples of the maximum sample rate. This limitation offers the advantage of simplifying the data transfer from the analog-to-digital converter to the acquisition memory, and of assuring stability performances, expressed in terms of absolute jitter, that are independent of the chosen sample rate. On the counterpart, it prevents an optimal usage of the memory resources of the oscilloscope and compels to post processing operations in several applications. A time-base that allows selecting the sample rate with very fine frequency resolution, in particular as a rational submultiple of the maximum rate, is proposed. The proposal addresses the oscilloscopes with time-interleaved converters, that require a dedicated and multifaceted approach with respect to architectures where a single monolithic converter is in charge of signal digitization. The proposed time-base allows selecting with fine frequency resolution sample rate values up to 200 GHz and beyond, still assuring jitter performances independent of the sample rate selection.

Acoustic Measures of Brazilian Transgender Women's Voices: A Case-Control Study.

Objective: This study aims to compare the acoustic vocal analysis results of a group of transgender women relative to those of cisgender women.Methods: Thirty transgender women between the ages of 19 and 52 years old participated in the study. The control group was composed of 31 cisgender women between the ages of 20 and 48 years old. A standardized questionnaire was administered to collect general patient data to better characterize the participants. The vowel /a/ sounds of all participants were collected and analyzed by the Multi-Dimensional Voice Program advanced system.Results: Statistically significant differences between cisgender and transgender women were found on 14 measures: fundamental frequency, maximum fundamental frequency, minimum fundamental frequency, standard deviation of fundamental frequency, absolute jitter, percentage or relative jitter, fundamental frequency relative average perturbation, fundamental frequency perturbation quotient, smoothed fundamental frequency perturbation quotient, fundamental frequency variation, absolute shimmer, relative shimmer, voice turbulence index (lower values in the cases), and soft phonation index (higher values in the cases). The mean fundamental frequency value was 159.046 Hz for the cases and 192.435 Hz for the controls.Conclusion: Through glottal adaptations, the group of transgender women managed to feminize their voices, presenting voices that were less aperiodic and softer than those of cisgender women.

How Does Our Voice Change as We Age? A Systematic Review and Meta-Analysis of Acoustic and Perceptual Voice Data From Healthy Adults Over 50 Years of Age.

Purpose Approximately 30% of adults over the age of 50 years present with altered vocal function. Our understanding of how these changes manifest acoustically and perceptually is derived from relatively modest-sized studies using a diversity of tools. Voice changes can arise from the onset of disease or disorder, but also age-related physiological changes, which may not reflect pathology as such. Here, we bring together data on acoustic, perceptual, and instrumental assessments (electroglottography), with the aim of gaining a better understanding of the changes occurring across these measurement domains. We consider these changes in the context of different acoustic features, software programs, and perceptual protocols. Method Studies of voice function in healthy older adults over the age of 50 years were sought. Literature was systematically searched with 746 abstracts reviewed. Forty-seven studies were included in the review. A meta-analysis of included studies compared voice acoustic parameters between sex and age. Sixteen acoustic parameters collected from 1,475 participants were analyzed in the meta-analysis. These included some previously unpublished analyses using data provided by authors of included studies. Results Data from the systematic review suggest that older individuals are perceived to present with higher overall scores of dysphonia and roughness, breathiness, strain, and instability. Acoustically, males have significantly higher scores on measures of perturbation, including noise-to-harmonic ratio and absolute jitter. The meta-analysis outcomes suggest that participants aged 80-89 years produce significantly higher fundamental frequency, jitter percent, shimmer percent, and shimmer in decibels compared to participants aged 60-69 years and a significant increase in relative average perturbation, jitter percent, and shimmer in decibels compared to participants aged 70-79 years. Limited data were available comparing acoustic measures using the same acoustic software. Conclusions Variations in fundamental frequency and frequency and amplitude perturbation increase as healthy adults age. It was difficult to draw definitive conclusions based on existing literature due to variability in hardware used, limited descriptions of study cohorts, or missing data from statistical analysis. Supplemental Material https://doi.org/10.23641/asha.11868663.

Jitter Minimization in Digital PLLs with Mid-Rise TDCs

This paper analyzes the absolute jitter performance of digital phase-locked loops and compares the case when either a multi-bit time-to-digital converter with mid-rise characteristic or a bang-bang phase detector is adopted. The linear equivalent model of the PLL and expressions for random-noise and limit-cycle jitter are first derived for the case of a 2-bit time-to-digital converter with a mid-rise characteristic, and the optimal TDC resolution is determined. The analysis, which account for TDC mismatches, shows that, compared to the 1-bit one, the 2-bit time-to-digital converter can substantially reduce the quantization noise in the case of dominant random-walk noise at the TDC input. Moving to the $N_{b}$ -bit midrise TDC case, the quantization noise can be further reduced at the cost of higher complexity and finer time resolution. The choice of $N_{b}=2$ seems to be the best compromise between jitter reduction and complexity increase. Time-domain simulations assess the theoretical framework and demonstrate the validity of the assumptions made throughout the paper.

Impact of patient-related factors on successful autologous fat injection laryngoplasty in thyroid surgical treated related unilateral vocal fold paralysis- observational study.

The aim of this study was to compare major voice indicators in different sub-categories, the outcome of lipoinjection for patients might be refined and some voice prognostic factors could be more particularized in specific sub-groups. This is an observational study, and sub-grouped UVFP patients into 3 categories: male vs female, BMI ≥ 24 vs BMI < 24, Age ≥ 60 vs Age < 60 for more detailed exploring whether sub-categories affected voice diagnostic and prognostic parameters. Patients’ voice data is recorded before and after the autologous fat injection laryngoplasty by a multidimensional voice program. Overall, 73 patients’ voice performance were improved 12 months later by vocal fold lipoinjection. In the comparison of the male with female revealed female obtained better Jita than male by surgery (Female: 174.50 ± 100.58 Hz; Male: 294.82 ± 253.65 Hz; P < .05). BMI ≥ 24 vs BMI < 24 showed no statistical difference. Patients aged under 60 demonstrated better Highest F0, lowest F0, NHR and ShdB than elder ones 12 months after receiving vocal fold lipoinjection. Thus, Noise-to-harmonics ratio (NHR), voice turbulence index (VTI), and ShdB (Absolute shimmer, dB) may be the major post-operative evaluating markers of patients’ age under 60. Voice parameters showed no significant correlation with BMI. Female patients performed lower Jita (Absolute jitter, μsec) than male patients 1 year after receiving treatment. The experimental results in this study showed UVFP patients’ gender and age may stand as significant categories on analyzing clinical voice prognostic indicators, ShdB and Jita of autologous injection laryngoplasty.

Low-Noise Repetition-Rate Multiplication by Injection Locking and Gain- Saturated Amplification

Low-noise repetition-rate multiplication of optical pulses is demonstrated through harmonic injection locking of a mode-locked laser and gain-saturated amplification by a semiconductor optical amplifier (SOA). The approach employs strong optical injection for lowering the repetition-rate phase noise, followed by gain-saturated SOA for suppression of pulse intensity irregularities. In this way, we can achieve low phase noise level and high side-mode suppression ratio (SMSR) at the same time. Experimentally, we show repetition-rate multiplication of a 250-MHz commercial mode-locked laser to 1-GHz repetition-rate, with 3% modulation depth, 33-dB SMSR, and 14-fs absolute rms timing jitter (when integrated from 10 kHz to 10 MHz offset frequency).

Parameters Used For Objective Acoustic Vocal Analysis In Paediatric Patients with Bronchiectasis

Objectives: Bronchiectasis typically manifests with persistent coughing, pus-filled discharge, lethargy, dyspnoea, sternal pain, haemoptysis and dilated airways. Such symptoms can adversely affect the quality of life and voice characteristics of sufferers from bronchiectasis. This study had as its objective the objective comparison of vocal differences between healthy children and those with bronchiectasis. Methods: The parameters examined were jitter, percentage jitter, shimmer, noise-to-harmonics ratio (NHR), voice turbulence index (VTI), and soft phonation index (SPI). Data from the cases and controls were compared by means of paired t-tests. Results: The mean age for the cases was 11.53 years. In terms of absolute jitter, percentage jitter, shimmer and SPI, no differences were detected at the level of statistical significance. However, the NHR and VTI did differ between cases and controls at the level of statistical significance. Conclusion: The research reveals that a holistic approach has an influence on patient outcomes. Sufferers from bronchiectasis experience vocal alterations, especially with respect to NHR and VTI, the values of which were raised in comparison with healthy controls.

Acoustic characteristics of voice in examinees with moderately-severe hearing loss

&amp;lt;p&amp;gt;Introduction.Voice is the result of vocal cord vibrations and resonance effects of the vocal tract, therefore, the instrumental monitoring of the vibrations themselves is one of the essential aspects of objective instrumental assessment of voice. Inadequate height and volume, as well as increased nasality, represent the basic characteristics of voice in hearing-impaired persons. The aim of the study was to perform a detailed analysis of the acoustic structure of vowel /a/ in the hearing-impaired persons and in those with normal hearing and voice. Methods. The sample comprised 40 participants, aged 17 to 20 years (18.50 &amp;amp;plusmn;1.13), both sexes (50% males), divided into two groups. The first group consisted of 20 participants with moderately-severe hearing loss (56-70 dB), while the second group included 20 normal-hearing participants. Members of both groups were equal to each other in sex and age (&amp;amp;plusmn; 3 months). The research was conducted in secondary schools, the Faculty of Medicine in Foča, as well as in Special School with a Student's Dormitory &amp;quot;Bubanj&amp;quot; in Ni&amp;amp;scaron; during May 2018. Results. A statistically significant difference between hearing-impaired and normal-hearing speakers was found in 11 out of 14 tested acoustic parameters of vowel /a/: Standard Deviation of Fundamental Frequency (STD), Absolute Jitter (Jitta), Percentage of Jitter (Jitt), Relative Average Perturbation (RAP), Fundamental Frequency Variation (vFo), Shimmer (Shdb), Percentage of Shimmer (Shim), Amplitude Perturbation Quotient (APQ), Noise-to-Harmonic Ratio (NHR), Soft Phonation Index (SPI) and Frequency Tremor Intensity Index (FTRI) whereby the hearing-impaired participants showed higher values of the above-mentioned parameters. Conclusion: The obtained results show pathological changes in the voice of hearing-impaired persons, as well as the need for voice rehabilitation.&amp;lt;/p&amp;gt;

2.856 GHz microwave signal extraction from mode-locked Er-fiber lasers with sub-100 femtosecond timing jitter

A balanced optical microwave phase detector (BOMPD) based on a 3 × 3 coupler is presented. This system was developed to extract ultra-low-jitter microwave signals from optical pulse trains emitted by mode-locked Er-fiber lasers, and synchronized microwave and laser systems. We demonstrate that the BOMPD achieves a precision of synchronization of less than 100 femtosecond of timing jitter. The experimental setup can be applied to the soft X-ray free-electron laser located on the campus of the Shanghai synchrotron radiation facility. A microwave signal with a 2.856 GHz frequency is extracted from a 238 MHz mode-locked Er-laser, with an absolute timing jitter of 34 fs in the 10 Hz–10 MHz frequency offset range. In addition, the microwave and 238 MHz optical pulse signals are synchronized with a relative timing jitter of 16 fs at the same frequency offset range.

Low‐jitter spread spectrum clock generator using charge pump frequency detector in 0.18 μm CMOS for USB3.1 transceivers

This study presents a spread spectrum clock generator (SSCG) circuit for high-speed applications. The proposed SSCG adopts a phased locked loop with two dual voltage-controlled oscillators and a frequency modulation loop implemented with a novel control unit to achieve the desired spectrum-spreading profile. The control unit consists of an analogue charge pump-based frequency comparator that can determine the deviation of spread spectrum clock frequency from the reference frequency. Using this analogue frequency comparator simplifies the SSCG control unit and mitigates the design constraints, particularly the speed requirements of SSCG control unit. Hence, the structure becomes a suitable solution for high-speed applications. The proposed SSCG is tailored for USB3.1 standard with −4000 to −5000 ppm down spreading at 5 GHz clock frequency and 30–33 kHz modulation frequencies. The circuit is designed in TSMC 0.18 μm 1P6M CMOS process that occupies 0.13 mm2 active area. Based on simulation results, with a 1.8 V supply, it consumes 53.46 mW. The RMS value of absolute jitter at 5 GHz output of non-spread spectrum is 1.1 ps rms, and the EMI reduction is 22.7 dB with −5000 ppm down spread. The simulation results of the proposed system are compared with recent works.

Acoustic Analysis of Normal Voice Patterns in Pakistani Adults

This study was designed to find out normative acoustic measures of adults in Pakistan. Age and gender differences in these parameters were also studied. The study variables include fundamental frequency, absolute jitter, relative jitter, relative average perturbation, 5-point period perturbation quotient perturbation quotient, jitter average absolute difference between consecutive periods, divided by the average period, shimmer local, shimmer decibel, three-point amplitude perturbation quotient, five-point amplitude perturbation quotient, average absolute difference of consecutive differences between the consecutive periods' amplitudes, and harmonics-to-noise ratio. Participants (N = 71; men = 34; women = 37) were recruited through two-stage sampling; convenience and purposive sampling. Participants were selected from students, staff, and faculty of the University of the Punjab, caretakers of the clients coming for clinical services, and researchers' friends, family, and acquaintances. Gender groups were further divided into three subgroups based on the age bands of 21-30, 31-40, and 41-50 years. After screening for health issues, the voice samples were recorded in a sound-proof acoustic laboratory by using a stand-held microphone and Praat software. Praat was also used for voice analyses. Means and standard deviations were conducted for the participants. Age and gender differences were investigated by using the two-way analysis of variance. Normative values were also measured for men and women between the age bracket of 21 and 50 years. Age differences were not significant for any variable. Gender differences were significant in fundamental frequency, absolute jitter, relative jitter, jitter period perturbation quotient, shimmer five-point amplitude perturbation quotient, and harmonics-to-noise ratio. The interaction between age and gender was significant in all the jitter measures. The interaction showed an increase in all these measures between the ages of 31 and 40 years and a decrease between the ages of 41 and 50 years in women, whereas men showed a reverse effect both in the age ranges of 31-40 and 41-50 years.

A 1-to-2048 Fully-Integrated Cascaded Digital Frequency Synthesizer for Low Frequency Reference Clocks Using Scrambling TDC

Generation of low jitter, high frequency clock from a low frequency reference clock using classical analog phaselocked loops (PLLs) requires large loop filter capacitor and power hungry oscillator. Digital PLLs can help reduce area but their jitter performance is severely degraded by quantization error. Specifically, their deterministic jitter (DJ), which is proportional to the loop update rate becomes prohibitively large at low reference clock frequencies. We propose a scrambling TDC (STDC) to improve DJ performance and a cascaded architecture with digital multiplying delay locked loop as the first stage and hybrid analog/digital PLL as the second stage to achieve low random jitter in a power efficient manner. Fabricated in a 90 nm CMOS process, the prototype frequency synthesizer consumes 4.76 mW power from a 1.0 V supply and generates 160 MHz and 2.56 GHz output clocks from a 1.25 MHz crystal reference frequency. The long-term absolute jitter of the 160 MHz digital MDLL and 2.56 GHz digital PLL outputs are 2.4 psrms and 4.18 psrms, while the peak-to-peak jitter are 22.1 ps and 35.2 ps, respectively. The proposed frequency synthesizer occupies an active die area of 0.16mm2 and achieves power efficiency of 1.86 mW/GHz.

Differences of the Voice Parameters Between the Population of Different Hearing Tresholds: Findings by Using the Multi-Dimensional Voice Program.

Objectives To compare voice parameters in subjects with different hearing level.Methods The evaluation consisted of Multi-Dimensional Voice Program (MDVP) and electroglottography. Group 1 consisted of normal hearing subjects which is bilateral average hearing better than 25 decibels (dB) whereas group 2 consisted of patients who have bilateral average hearing between the 25 and 60 dB and group 3 consisted of patients who have bilateral average hearing between the 60 and 90 dB. The evaluations were performed on males and females separately.Results In female subjects, fundamental frequency (F0), absolute jitter, %jitter and soft phonation index (SPI) were significantly different between the group 1 and group 2. Also, we detected significant difference on maximum phonation time (MPT), fundamental frequency, absolute jitter and %jitter, and variable F0 (vF0) values between group 1 and group 3. Male subjects demonstrated significant difference between the group 1 and group 2 in MPT, absolute jitter, %jitter, vF0, and SPI parameters. Between the group 3 and group 1; differences in absolute jitter, %jitter, shimmer, %shimmer, vF0, and SPI were also significant.Conclusion This study concluded that even mild to moderate hearing losses may affect voice patterns in adults and also females and males react differently to hearing loss in some parameters.

Multi-Dimensional Voice Program (MDVP) vs Praat for Assessing Euphonic Subjects: A Preliminary Study on the Gender-discriminating Power of Acoustic Analysis Software

The aim of this study was to compare the discriminatory power of the Multi-Dimensional Voice Program (MDVP) and Praat in distinguishing the gender of euphonic adults. This is a cross-sectional study. The recordings of 100 euphonic volunteers (50 males and 50 females) producing a sustained vowel /a/ were analyzed with MDVP and Praat software. Both computer programs identified significant differences between male and female volunteers in absolute jitter (MDVP P < 0.00001 and Praat P < 0.00001) and in shimmer in decibel (dB) (MDVP P = 0.006 and Praat P = 0.001). Using the scale proposed by Hosmer and Lemeshow, we found no gender discrimination for shimmer in dB with either the MDVP (area under the receiver operating characteristics curve [AUC] = 0.658) or Praat (AUC = 0.682). In our series, on the other hand, MDVP absolute jitter achieved an acceptable discrimination between males and females (AUC = 0.752), and Praat absolute jitter achieved an outstanding discrimination (AUC = 0.901). The discriminatory power of Praat absolute jitter was significantly higher than that of the MDVP (P = 0.003). Absolute jitter sensitivity and specificity were also higher for Praat (83% and 80%) than for the MDVP (74% and 49%). Differences attributable to a subject's gender and to the software used to measure acoustic parameters should be carefully considered in both research and clinical settings. Further studies are needed to test the discriminatory power of different voice analysis programs when differentiating between normal and dysphonic voices.

Commentary: Is the effect of desiccation large enough?

I certainly agree with the authors (Everett at al. 2016) that the question whether there is an environmental influence on the sound systems of languages (or on other aspects of language) is worth investigating and that the position that there is no such influence is not empirically founded. Their point that individual counterexamples do not invalidate statistical tendencies is also valid and important. However, it is also essential to keep in mind the a priori plausibility of the proposed correlation, and this may be problematic. The main evidence of the influence of ambient humidity on the vocal folds—provided in this article and in Everett et al. (2015)—is the work by Hemler et al. (1997) as it presents quantitative data that is directly relevant to the relation between humidity and control over pitch. Other referenced papers mainly focus on the relation between overall hydration (i.e. through water intake) and pitch or on the relation between mouth breathing (which dehydrates the vocal folds more effectively than nasal breathing) and phonation threshold pressure (Sivasankar and Erickson-Levendoski 2012). Hemler et al. (1997) show that after orally breathing extremely dry air (2.1 per cent relative humidity) at 23°C for ten minutes, absolute jitter (random variation of timing in the …