Vocal Acoustic Parameters Research Articles

Evaluation of Subjective and Objective Voice Characteristics in Patients With Bulimia Nervosa

ObjectiveThe present study aims to examine subjectively and objectively the voice changes in Bulimia Nervosa patients at different stages of treatment. MethodThe study was conducted with a study group including 10 patients followed up with a diagnosis of Blum,ia Nerrvosa and a control group consisting of 10 healthy participants of a similar age group without eating disorders. The reflux symptom index was used for stroboscopic evaluation. The fundamental frequency (F0), jitter, shimmer, and noise-to-harmonics ratio (NHR) were determined during acoustic voice analysis. Maximum phonation time was analysed. A subjective evaluation was performed using the Voice Handicap Index-10 (VHI-10). ResultsJitter, Shimmer, VHI-10 Score, and RFS values showed a statistically significant difference in the patient and control groups (p<0.05). The mean values of Jitter, Shimmer, VHI-10 Score, and RFS were higher in the patient group than in the control group. MPT did not differ between goups (p>0.05)Age and F0 (Hz) values showed no statistically significant difference in the patient and control groups (p>0.05). ConclusionIn BN patients, the laryngopharyngeal reflux mechanism causes negative effects on vocal cord examination and acoustic sound analysis parameters, leading to subjective dissatisfaction.

Seven Days of Voice Rest Post-phonosurgery Is Not Better than 3 days: A Prospective Randomized Short-term Outcome Study.

The aim of the study is to compare the short-term effect of 7 versus 3 days of voice rest (VR) on objective vocal (acoustic) parameters following phonosurgery. A prospective randomized study conducted at a tertiary referral medical center. Patients with vocal fold nodules, polyps, or cysts and scheduled for phonosurgery were recruited from the Voice Clinic. They were randomized into groups of 7- or 3-day postoperative VR periods and their voices were recorded preoperatively and at 4-week postoperatively. A mixed linear model statistical analysis (MLMSA) was used to compare pre- and postoperative jitter, shimmer, harmonic-to-noise ratio, and maximum phonation time between the two groups. Sixty-five patients were recruited, but only 34 fully complied with the study protocol, and their data were included in the final analysis (19 males, 20 females; mean age: 40.6 years; 17 patients in the 7-day VR group and 16 in the 3-day VR group). The groups were comparable in age, sex, and type of vocal lesion distribution. The preoperative MLMSA showed no significant group differences in the tested vocal parameters. Both groups exhibited significant (p < 0.05) and comparable improvement in all vocal parameters at postoperative week 4. A VR duration of 7 days showed no greater benefit on the examined vocal parameters than the 3-day protocol 4-week postoperatively. Our results suggest that a 3-day VR regimen can be followed by patients who undergo phonosurgery without compromising the vocal results. Larger-scale and longer-duration studies are needed to confirm our findings. 2 Laryngoscope, 134:4661-4666, 2024.

Characterizing Dysphonia After Pediatric Open Airway Reconstruction: Systematic Review and Meta-Analysis.

Pediatric laryngotracheal stenosis often requires open airway reconstruction. While these surgeries establish an airway for adequate ventilation, many patients develop subsequent dysphonia. Numerous studies have reported outcomes related to voice. This study aims to evaluate dysphonia in pediatric patients following open airway reconstruction, focusing on acoustic parameters, perceptual voice quality, and voice-related quality of life. A comprehensive search using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines across 6 databases identified articles involving pediatric patients who underwent open airway reconstruction and reported postoperative vocal acoustic parameters, perceptual voice quality, voice-related quality of life, or vocal mechanics. Articles were assessed for bias risk, and common outcomes were synthesized qualitatively and quantitatively using meta-analyses. Among 4089 articles, 21 were included, involving 497 pediatric patients. Laryngotracheoplasty was the most common procedure followed by cricotracheal resection. The Consensus Auditory-Perceptual Evaluation of Voice (CAPE-V) scale was frequently used to assess voice quality, with a mean score of 55.6 [95% confidence intervals (CIs): 47.9-63.3]. Voice-related quality of life was measured using the pediatric Voice Handicap Index (pVHI) and Pediatric Voice-Related Quality of Life Survey, with mean scores of 35.6 (95% CI: 21.4-49.7) and 83.7 (95% CI: 74.1-93.2), respectively. The fundamental frequency was 210.5 (95% CI: 174.6-246.3). Other common findings included supraglottic phonation, anterior commissure blunting, posterior glottic diastasis, and abnormal vocal cord mobility. Pediatric patients experiencing dysphonia after open airway reconstruction exhibited moderately decreased voice quality and reduced voice-related quality of life. However, there was inconsistency in study protocols and outcome measures used. Preserving voice quality during airway reconstruction is crucial to avoid negative impacts on quality of life.

Test-Retest Reliability of Behavioral Assays of Feedforward and Feedback Auditory-Motor Control of Voice and Articulation.

Behavioral assays of feedforward and feedback auditory-motor control of voice and articulation frequently are used to make inferences about underlying neural mechanisms and to study speech development and disorders. However, no studies have examined the test-retest reliability of such measures, which is critical for rigorous study of auditory-motor control. Thus, the purpose of the present study was to assess the reliability of assays of feedforward and feedback control in voice versus articulation domains. Twenty-eight participants (14 cisgender women, 12 cisgender men, one transgender man, one transmasculine/nonbinary) who denied any history of speech, hearing, or neurological impairment were measured for responses to predictable versus unexpected auditory feedback perturbations of vocal (fundamental frequency, fo) and articulatory (first formant, F1) acoustic parameters twice, with 3-6 weeks between sessions. Reliability was measured with intraclass correlations. Opposite patterns of reliability were observed for fo and F1; fo reflexive responses showed good reliability and fo adaptive responses showed poor reliability, whereas F1 reflexive responses showed poor reliability and F1 adaptive responses showed moderate reliability. However, a criterion-referenced categorical measurement of fo adaptive responses as typical versus atypical showed substantial test-retest agreement. Individual responses to some behavioral assays of auditory-motor control of speech should be interpreted with caution, which has implications for several fields of research. Additional research is needed to establish reliable criterion-referenced measures of F1 adaptive responses as well as fo and F1 reflexive responses. Furthermore, the opposite patterns of test-retest reliability observed for voice versus articulation add to growing evidence for differences in underlying neural control mechanisms.

Testosterone treatment unveils testosterone-insensitive song in an early-branched hummingbird

Birdsong often plays a crucial role in sexual behavior, including territorial defense and mate attraction. This behavior is particularly well studied in species in which only males sing and respond to gonadal testosterone depending on the breeding season. Although hummingbirds are long known to sing in a breeding context, the sensitivity of these vocalizations to testosterone in both sexes remains unknown. Therefore, we investigated (i) which vocalizations are emitted during their breeding season, (ii) the testosterone levels in free-ranging birds, and (iii) the effect of testosterone on these vocalizations in a semi-natural environment in both sexes of the black jacobin (Florisuga fusca), an early-branched hummingbird. Females and males of black jacobin produced the same set of vocalizations (high-pitched song and chirp call) at a similar rate during the breeding season, although testosterone levels in males were significantly higher. Testosterone treatment did not affect the vocal activity or acoustic parameters of their song in both sexes. However, testosterone maintained high levels of aggression in treated birds of both sexes and hyper-developed the oviduct of females. In contrast to almost all well-studied bird species studied so far, the vocal behavior of the black jacobins in their breeding season seems to be insensitive to high testosterone levels.

Relationship Between Vocal Fatigue Index and Acoustic Voice Scales in Patients With Coronavirus Infection

The voice quality of patients with Coronavirus Disease 2019 (COVID-19) seems to be affected due to lower and upper respiratory involvement. Patient-based voice assessment scales are important clinical measures to diagnose voice disorders and monitor treatment outcomes in COVID-19 patients. This study compared vocal fatigue between COVID-19 patients and those with normal voices. Furthermore, the relationship between vocal fatigue and acoustic voice parameters of COVID-19 patients was evaluated. This cross-sectional study enrolled 30 laboratory-confirmed patients with COVID-19 (18 males and 12 females) and 30 healthy individuals with normal voices (14 males and 16 females) to compare their respiratory or phonatory parameters. The Persian versions of the Consensus Auditory Perceptual Evaluation of Voice (CAPE-V) and the vocal fatigue index (VFI) were conducted before and after reading the text. The Jitter, shimmer, maximum phonation time, and harmonic-to-noise ratio (HNR) were analyzed by Praat software based on the recorded voices of CAPE-V tasks. The acoustic assessment and VFI questionnaire results were compared between COVID-19 patients and the control group. There were significant differences between COVID-19 patients and their healthy counterparts in all VFI subscales (P<0.001). Moreover, after reading the text, we found significant differences between the two groups regarding Jitter, shimmer, and HNR of /a/ and /i/ vowels (P<0.05). Our findings also indicated a significant correlation between symptom improvement with rest and acoustic parameters in all tasks, except the Jitter of /a/ before reading the text. Patients with COVID-19 showed significantly more vocal fatigue than people with normal voices after reading the text. Moreover, there was a significant relationship between Jitter, shimmer, and HNR and the tiredness of voice and physical discomfort subscales of VFI.

Acoustic Screening of the "Wet voice": Proof of Concept in an ex vivo Canine Laryngeal Model.

Current protocols for bedside swallow evaluation have high rates of false negative results. Though experts are not consistently able to screen for aspiration risk by assessing vocal quality, there is emerging evidence that vocal acoustic parameters are significantly different in patients at risk of aspiration. Herein, we aimed to determine whether the presence of material on the vocal folds in an excised canine laryngeal model may have an impact on acoustic and aerodynamic measures. Two ex vivo canine larynges were tested. Three liquids of different viscosities (1:100 diluted glycerin, pure glycerin, and honey-thick Varibar) were placed on the vocal folds at a constant volume. Acoustic and aerodynamic measures were obtained in both adducted and abducted vocal fold configurations. Intraglottal high-speed imaging was used to approximate the maximum divergence angle of the larynges in the studied conditions and examine its relationship to vocal efficiency (VE) and acoustic measures. In glottic insufficiency conditions only, we found that several acoustic parameters could predict the presence of material on the vocal folds. Based on the combination of the aerodynamic and acoustic data, we found that decreased spectral energy in the higher harmonics was associated with decreased VE in the presence of material on the vocal folds and/or glottic insufficiency. Decreased spectral energy in the higher harmonics of the voice was found to be a potential biomarker of swallowing dysfunction, as it correlates with decreased vocal efficiency due to material on the vocal folds and/or glottic insufficiency, both of which are known risk factors for aspiration. NA Laryngoscope, 133:2517-2524, 2023.

Do Flexible Silicone Tubes Immersed in Water Combined With Vocalise Improve the Immediate Effect on Voice?

This study aimed to analyze the immediate effect on a singer's voice of a flexible silicone tube immersed in water combined with ascending and descending vocalise scales compared with ascending and descending vocalise scales alone. A pre- and post-intervention quasi-experimental study was conducted. Thirty adult singers between 18 and 45 years old with no laryngeal disorders performed the two techniques for 3 min each on different days. Acoustic measurements of frequency, jitter, shimmer, glottal-to-noise excitation ratio, noise, smoothed cepstral peak prominence (CPPS), maximum phonation time (MPT), voice range profile, and self-perceived vocal effort (Borg Category Ratio 10-BR Scale adapted for vocal effort) were assessed before and after performing the techniques. The results indicated an increase in singers' CPPS and MPT values and a decrease in shimmer and noise when performing with a flexible silicone tube immersed in water combined with vocalise. The singers reported a perception of decreased vocal effort after both methods. However, the diminished perceived vocal effort became more pronounced with the tube phonation technique combined with vocalise. Phonation in tubes combined with vocalise improved the vocal acoustic parameters (including cepstral measurements), increased MPT, and diminished perceived vocal effort. Although using vocalise alone diminished perceived vocal effort, this decrease was more pronounced in the tube phonation technique combined with vocalise.

Does maxillary advancement alter vocal acoustic parameters in class III skeletal patients?

Any change in the maxillary position can affect the length of the vocal tract. This cross-sectional study aimed to assess the vocal acoustic parameters in 24 class III skeletal patients who underwent Le Fort I osteotomy for maxillary advancement. The vocal acoustic parameters (fundamental frequency, and jitter and shimmer perturbation indexes) were studied before, and at three, seven, and 10 months after maxillary advancement. The age and gender of the patients were the variables of the study. The amount of maxillary advancement was the predictive factor, and the changes in vocal acoustic parameters the study outcomes. Repeated-measures ANOVA were used to analyse the vocal acoustic parameters at different time points. Mean (SD) maxillary advancement was 3.5 (0.59) mm (range 3 - 6 mm). Data analysis did not demonstrate any significant correlation between the mean amount of maxillary advancement and changes in vocal acoustic parameters except for frequency of the ‘i’ sound. The results did not show a substantial change in the vocal acoustic parameters at 10 months after orthognathic surgery compared with baseline. These changed at three and seven months, but had returned to their baseline preoperative state 10 months after surgery.

Which teachers are most at risk for voice disorders? Individual factors predicting vocal acoustic parameters monitored in situ during a workweek.

To identify the factors affecting teachers' vocal acoustic parameters, with the aim of detecting individuals at risk of phonotrauma. The voicing time, voice sound pressure level [SPL] and fundamental frequency [fo] of 87 teachers were measured during one workweek using a voice dosimeter. We retrospectively investigated the impact of 10 factors (gender, age, teaching experience, teaching level, tobacco, gastro-esophageal problems, nonoccupational voice activity, voice education, past voice problems, and biopsychosocial impact of voice problems measured using the Voice Handicap Index [VHI]) on each voice parameter. None of the above factors affected voicing time or SPL. fo depended significantly on gender, teaching level, nonoccupational voice activity and VHI score. Specifically, fo was higher in women (Δ = 69Hz), in individuals without nonoccupational voice activities (Δ = 11Hz), and in individuals with a lower VHI score (increase of 0.7Hz for each additional point). For females, post hoc comparisons revealed a substantial impact of teaching level on fo: university instructors had deeper voices than kindergarten (Δ = 66Hz), elementary (Δ = 52Hz), or secondary teachers (Δ = 41Hz). Since higher fo increases the mechanical stress related to vocal fold vibration, the screening and prevention of phonotrauma should focus primarily on women, particularly those who teach at lower levels, and teachers with more self-rated voice problems. The lower fo of teachers who engage in nonprofessional voice activities may suggest acute inflammation or muscle fatigue due to voice overload.

Normative vocal acoustic parameters for preschool and elementary school Egyptian children

BackgroundA reliable acoustic analysis necessitates the availability of standard normative values at different ages. Normative values of vocal acoustic parameters are readily available for the adult population but not much data are available for the pediatric population. ObjectivesProviding a database for the normative vocal acoustic parameters in preschool and elementary school Egyptian children to lay out an objective model for the diagnosis and optimal treatment of childhood voice disorders. MethodsA total of 237 Egyptian children between the ages of 4 and 9 years from both genders were enrolled in the study. A Computer-assisted acoustic vocal analysis was done for all children. ResultsFundamental frequency values differed significantly according to gender with higher measures in girls. Mean values of the fundamental frequency were 258.57 Hz ± 39.69, jitter percentage 0.85% ± 0.67, shimmer percentage 1.59% ± 1.03, fundamental tremors 1.64HZ ± 0.421, maximum phonation time 4.81sec. ± 1.73 and harmonic/noise ratio were 15.34 dB ± 10.65. A decline of measures of the fundamental frequency and jitter percentage with increasing age and an increase of values of harmonic/noise ratio and shimmer percentage in children residing in rural areas are observed. ConclusionThis study provides an insight into the normative values of vocal acoustic parameters in preschool and elementary school Egyptian children. Comparable to other studies, both fundamental frequency and jitter percentage values show a decline with increasing age. Also, fundamental frequency values differ significantly among genders. The difference in socioeconomic environment seems to influence some of the vocal acoustic parameters in children.

Objective and Subjective Voice Examination in Turkish Imams

Imams are professional voice users and they are at high risk of developing voice problems. The aim of the present study was to investigate vocal acoustic parameters and voice handicap index (VHI) scores in Turkish imams and comparing these paramaters with a control group of male nonprofessional voice users. A total of 62 active working Turkish imams that never applied to our clinic with voice problems volunteered as subjects for the study and the control group consisted of 47 male nonprofessional voice users. Every participant completed a VHI questionnaire. A voice analysis was performed using computer program Dr.Speech Version 4 in an acoustically treated setting. Mean fundamental frequency, jitter, shimmer, harmonics to noise ratio values were recorded during the phonation and were analyzed. All imams were active working men aged 27-57 and the control group was comprised of male nonprofessional voice users of a similar age group. The measure of mean fundamental frequency, harmonics to noise ratio, jitter and shimmer rates were similar between two groups. In comparison of VHI between the groups no significant differences were found. Even though imams in the study group stated that they experienced voice problems in their professional lives, this did not cause any adverse changes in acoustic and subjective parameters (VHI) compared with control group.

Linking human male vocal parameters to perceptions, body morphology, strength and hormonal profiles in contexts of sexual selection

Sexual selection appears to have shaped the acoustic signals of diverse species, including humans. Deep, resonant vocalizations in particular may function in attracting mates and/or intimidating same-sex competitors. Evidence for these adaptive functions in human males derives predominantly from perception studies in which vocal acoustic parameters were manipulated using specialist software. This approach affords tight experimental control but provides little ecological validity, especially when the target acoustic parameters vary naturally with other parameters. Furthermore, such experimental studies provide no information about what acoustic variables indicate about the speaker—that is, why attention to vocal cues may be favored in intrasexual and intersexual contexts. Using voice recordings with high ecological validity from 160 male speakers and biomarkers of condition, including baseline cortisol and testosterone levels, body morphology and strength, we tested a series of pre-registered hypotheses relating to both perceptions and underlying condition of the speaker. We found negative curvilinear and negative linear relationships between male fundamental frequency (fo) and female perceptions of attractiveness and male perceptions of dominance. In addition, cortisol and testosterone negatively interacted in predicting fo, and strength and measures of body size negatively predicted formant frequencies (Pf). Meta-analyses of the present results and those from two previous samples confirmed that fonegatively predicted testosterone only among men with lower cortisol levels. This research offers empirical evidence of possible evolutionary functions for attention to men’s vocal characteristics in contexts of sexual selection.

Maximum vocal intensity as a primary outcome measure in unilateral vocal fold paralysis patients.

To evaluate voice intensity as the primary outcome measurement when treating unilateral vocal fold paralysis patients. This prospective observational study comprised 34 newly diagnosed unilateral vocal fold paralysis patients undergoing surgical interventions: injection laryngoplasty or medialisation thyroplasty. Voice assessments, including maximum vocal intensity and other acoustic parameters, were performed at baseline and at one and three months post-intervention. Maximum vocal intensity was also repeated within two weeks before any surgical interventions were performed. The results were compared between different time points and between the two intervention groups. Maximum vocal intensity showed high internal consistency. Statistically significant improvements were seen in maximum vocal intensity, Voice Handicap Index-10 and other acoustic analyses at one and three months post-intervention. A significant moderate negative correlation was demonstrated between maximum vocal intensity and Voice Handicap Index-10, shimmer and jitter. There were no significant differences in voice outcomes between injection laryngoplasty and medialisation thyroplasty patients at any time point. Maximum vocal intensity can be applied as a treatment outcome measure in unilateral vocal fold paralysis patients; it can demonstrate the effectiveness of treatment and moderately correlates with self-reported outcome measures.

Detection of major depressive disorder using vocal acoustic analysis and machine learning—an exploratory study

Diagnosis and treatment in psychiatry are still highly dependent on reports from patients and on clinician judgment. This fact makes them prone to memory and subjectivity biases. As for other medical fields, where objective biomarkers are available, there has been an increasing interest in the development of such tools in psychiatry. To this end, vocal acoustic parameters have been recently studied as possible objective biomarkers, instead of otherwise invasive and costly methods. Patients suffering from different mental disorders, such as major depressive disorder (MDD), may present with alterations of speech. These can be described as uninteresting, monotonous, and spiritless speech and low voice. Thirty-three individuals (11 males) over 18 years old were selected, 22 of which being previously diagnosed with MDD and 11 healthy controls. Their speech was recorded in naturalistic settings, during a routine medical evaluation for psychiatric patients, and in different environments for healthy controls. Voices from third parties were removed. The recordings were submitted to a vocal feature extraction algorithm, and to different machine learning classification techniques. The results showed that random tree models with 100 trees provided the greatest classification performances. It achieved mean accuracy of 87.5575% ± 1.9490, mean kappa index, sensitivity, and specificity of 0.7508 ± 0.0319, 0.9149 ± 0.0204, and 0.8354 ± 0.0254, respectively, for the detection of MDD. The use of machine learning classifiers with vocal acoustic features appears to be very promising for the detection of major depressive disorder in this exploratory study, but further experiments with a larger sample will be necessary to validate our findings.

Preliminary study on phonetic characteristics of patients with pulmonary nodules

ObjectivePulmonary nodules (PNs) are one of the imaging manifestations of early lung cancer screening, which should receive more attention. Traditional Chinese medicine believes that voice changes occur in patients with pulmonary diseases. The purpose of this study is to explore the differences in phonetic characteristics between patients with PNs and able-bodied persons. MethodsThis study explores the phonetic characteristics of patients with PNs in order to provide a simpler and cheaper method for PN screening. It is a case-control study to explore the differences in phonetic characteristics between individuals with and without PNs. This study performed non-parametric statistics on acoustic parameters of vocalizations, collected from January 2017 to March 2018 in Shanghai, China, from these two groups; it explores the differences in third and fourth acoustic parameters between patients with PNs and a normal control group. At the same time, computed tomography (CT) scans, course of disease, combined disease and other risk factors of the patients were collected in the form of questionnaire. According to the grouping of risk factors, the phonetic characteristics of the patients with PNs were analyzed. ResultsThis study was comprised of 200 patients with PNs, as confirmed by CT, and 86 healthy people that served as a control group. Among patients with PNs, 43% had ground glass opacity, 32% had nodules with a diameter ≥ 8 mm, 19% had a history of smoking and 31% had hyperlipidemia. Compared with the normal group, there were statistically significant differences in pitch, intensity and shimmer in patients with PNs. Among patients with PNs, patients with diameters ≥ 8 mm had a significantly higher third formant. There was a significant difference in intensity, fourth formant and harmonics-to-noise ratio (HNR) between smoking and non-smoking patients. Compared with non-hyperlipidemia patients, the pitch, jitter and shimmer of patients with PNs and hyperlipidemia were higher and the HNR was lower; these differences were statistically significant. ConclusionThis measurable changes in vocalizations can be in patients with PNs. Patients with PNs had lower and weaker voices. The size of PNs had an effect on the phonetic formant. Smoking may contribute to damage to the voice and formant changes. Voice damage is more pronounced in individuals who have PNs accompanied by hyperlipidemia.

Oropharyngeal Geometry and the Singing Voice: Immediate Effect of Two Semi-Occluded Vocal Tract Exercises

The aim of this study was to verify the immediate effect of a flexible resonance tube in water and of lip trill on oropharyngeal geometry and vocal acoustic parameters of singers without vocal symptoms. Twenty-two adult singers participated in the study. They had an average age of 27 (±4.8) years. Participants were split into two groups: a group composed of 12 singers who performed the flexible resonance tube (FRT) exercise and a group of 10 singers who performed the Lip Trill technique (LTT). Acoustic pharyngometry and acoustic analysis of the voice were used to assess oropharyngeal geometry before and after the exercises. After performing the techniques, the vocal tract length was longer in the group that performed the FRT, compared to the one that performed the LTT. In the acoustic evaluation, there was an improvement in the glottal to noise excitation ratio and a decrease in noise in the group of singers who performed the LTT. In the analysis by sex men had a longer oral cavity compared to women and after application of the techniques greater volume of the vocal tract. There was variation in the oropharyngeal geometry with the FRT, while the LTT had a positive effect on the vocal acoustic parameters related to glottal noise.

Vocal Fatigue in School Teachers and It's Relation to the Acoustic analysis of Voice.

Voice disorders are thought to be one of the major occupational hazards of school teaching. There is a need to study the prevalence of vocal fatigue in school teachers as it is unknown in Indian population and its awareness is at a very basic level. We aim to investigate percentage of school teachers reporting vocal fatigue and to find if there is any relationship between vocal fatigue and acoustic voice parameters. A total of 100 subjects (50-males and 50-females) in the age range of 25-35years participated in the study. Voice Sample was obtained from the subject using a digital tape recorder and was analyzed in Visi pitch and Dr.Speech softwares. The sample was taken twice in a day, that is, before teaching and after teaching. The mean values obtained on all the questions of the vocal fatigue questionnaire show a significant increase in mean values on all the questions at post teaching ratings. Results revealed a statistically significant difference in pre and post teaching values of F0 and shimmer in males. In females, statistical significant difference was obtained in Noise to Harmonic Ratio in /u/ production. No significant correlation between acoustic parameters and overall vocal fatigue was found except for Noise to Harmonic ratio in females for /u/.

Song variation in the Caatinga suboscine Silvery-cheeked Antshrike (Sakesphorus cristatus) suggests latitude and São Francisco River as drivers of geographic variation

Historical processes may result in patterns of differentiation among extant populations, which may lead to diversification and speciation. This is often expressed, and measured, as genetic and behavioral variation among populations. Suboscine birds acquire songs by innate mechanisms and are typically poorly studied relative to oscine birds, which may learn songs and thus develop unique dialects among populations. Behavioral features, including song, are extensively used to describe the structure and geographical variation in bird populations. In turn, this knowledge may shed light onto patterns of species diversification across ecoregions, which is particularly relevant in endemic species. Here we investigate for the first time song structure and variation in the Silvery-cheeked Antshrike, an endemic bird of a poorly studied South American dry forest, the Caatinga. We evaluate hypotheses for song diversification, correlating vocal acoustic parameters with geographic patterns and environmental variables. We measured temporal and spectral variables in the song of Sakesphorus cristatus across 14 localities spanning almost the entire range of the species’ distribution. The song presents a clear geographic pattern, and vocal variation was congruent with a barrier by the Sao Francisco River superimposed to a latitudinal clinal variation that was uncorrelated to climate variables. We argue that these regional differences may have a genetic basis since S. cristatus is a suboscine antbird that should not show song learning (social adaptation) and, apparently, does not have the song correlated to habitat features (acoustic adaptation). More detailed studies are required to test further hypotheses about the drivers of this potential genetic variation underlying the geographical variation in this suboscine bird song.

Acoustically advertising male harbour seals in southeast Alaska do not make biologically relevant acoustic adjustments in the presence of vessel noise.

Aquatically breeding harbour seal (Phoca vitulina) males use underwater vocalizations during the breeding season to establish underwater territories, defend territories against intruder males, and possibly to attract females. Vessel noise overlaps in frequency with these vocalizations and could negatively impact breeding success by limiting communication space. In this study, we investigated whether harbour seals employed anti-masking strategies to maintain communication in the presence of vessel noise in Glacier Bay National Park and Preserve, Alaska. Harbour seals in this location did not sufficiently adjust source levels or acoustic parameters of vocalizations to compensate for acoustic masking. Instead, for every 1 dB increase in ambient noise, signal excess decreased by 0.84 dB, indicating a reduction in communication space when vessels passed. We suggest that harbour seals may already be acoustically advertising at or near a biologically maximal sound level and therefore lack the ability to increase call amplitude to adjust to changes in their acoustic environment. This may have significant implications for this aquatically breeding pinniped, particularly for populations in high noise regions.