Comfortable effort level revisited

The purpose of this study was to measure the variability of frequency and intensity of speech, using multiple voice samples obtained over a period of time at a speaker's “comfortable effort level.” Variability in vocal output within and across several experimental sessions was assessed from measures of speaking fundamental frequency (SFF) and vocal intensity for utterances repeated three times a day over a 3-day period. Three distinct age groups of men and women—young, middle-aged and elderly—repeated the vowel /a/, read a standard passage, and spoke extemporaneously during each experimental session. Results indicated that variability in SFF and intensity were present across experimental sessions, age groups, gender, and speaking samples. Generally, group means indicated that ±1 semitone of variability for SFF and 2 db sound pressure level (SPL) variation in vocal intensity from any one experimental session to the next could be expected; individual variations within any group may reach two semitones and 6 db SPL.     

Intra- and intersubject variability in acoustic measures of normal voice

Twenty-four normal adult women read part of the Rainbow Passage and sustained vowels three trials each. Utterances were assessed for selected parameters measured by Visi-Pitch (average and SD of fundamental frequency (F₀), average and SD of dBA, perturbation, and percent voiced/unvoiced/pause). Assessment of each parameter included measures of central tendency, dispersion, and distribution characteristics (skewness and kurtosis) of the data and of the ranges of values that would include 95% of the scores (95% fiduciary limits). Generally, differences for the group between the three trials were not significant. Intersubject variability for only a few parameters was less than 20% of the parameter's mean. For vowels, variability of jitter was 30–48% of the mean. Eight subjects provided performances 2 months later to obtain an estimate of intrasubject variability over time. There were desirable intrasubject correlations between performances for mean F₀, jitter in reading and on vowels /i/ and /a/, and percent of voicing. Inter- and intrasubject variability seems restricted and the data appear to resemble a normally distributed function for mean F₀ on reading, jitter on /i/, and percent of voicing. Thus, these parameters may have statistical merit for use in vocal testing.     

Sound level variation findings for pianissimo and fortissimo phonations in repeated measurements

Ten vocally untrained female university students vocalized /a:/ at five given pitches within the average female speaking range (196, 220, 262, 330, and 396 Hz) as softly as possible (pianissimo) and as loudly as musically acceptable (fortissimo). To study the repeatability of voice range profile (sound level) measurement, the procedure was repeated 10 times in each of the five sample sessions during the day, in connection with vocal loading that included five oral readings (45 min each), 15-min pauses, and a lunch break (45 min). A sound level meter specially designed for voice range profile measurement was used. The effect of the loading was seen on the mean sound level changes and intraindividual variation on SDs. The difference between the first phonation and best performance indicates significance of the repetition of the measurement. The sound level averaged across the pitches rose significantly during loading. The intraindividual SD varied between 3 and 4 dBA according to pitch and loudness, and the sound level difference between the first phonation and best performance was 5 dBA in pianissimo and 7 dBA in fortissimo     

A modeling investigation of articulatory variability and acoustic stability during American English /r/ production

This paper investigates the functional relationship between articulatory variability and stability of acoustic cues during American English /r/ production. The analysis of articulatory movement data on seven subjects shows that the extent of intrasubject articulatory variability along any given articulatory direction is strongly and inversely related to a measure of acoustic stability (the extent of acoustic variation that displacing the articulators in this direction would produce). The presence and direction of this relationship is consistent with a speech motor control mechanism that uses a third formant frequency (F3) target; i.e., the final articulatory variability is lower for those articulatory directions most relevant to determining the F3 value. In contrast, no consistent relationship across speakers and phonetic contexts was found between hypothesized vocal-tract target variables and articulatory variability. Furthermore, simulations of two speakers' productions using the DIVA model of speech production, in conjunction with a novel speaker-specific vocal-tract model derived from magnetic resonance imaging data, mimic the observed range of articulatory gestures for each subject, while exhibiting the same articulatory/acoustic relations as those observed experimentally. Overall these results provide evidence for a common control scheme that utilizes an acoustic, rather than articulatory, target specification for American English /r/.     

A study of repeated measures of softest and loudest phonations

One common way to describe one's voice in an objective way is to measure the sound levels of the softest (pianissimo) and loudest possible (fortissimo) phonations at given pitches (voice range profile measurement). However, the reliability of the measurement has not been thoroughly investigated. The aim of the present study was to describe the repeatability and reproducibility of the sound level measurement in statistical terms, focusing on five target frequencies within the estimated speaking pitch range. Ten healthy female university students volunteered as test subjects. The voice range profiles within the speaking pitch range were defined 10 times in succession and in five sample sessions between 45-minute-long oral readings. Our study followed the ideas of the Gage repeatability and reproducibility design. The results showed that the method used was reliable in fortissimo phonations at four of the measured frequencies. Better reliability can be achieved by measuring three successive phonations at each pitch prior to the next target tone.     

Speaking fo and cepstral periodicity analysis of conversational speech in a 105-year-old woman: Variability of aging effects

We investigated speaking fundamental frequency and periodicity of voicing during conversational speech in a 105-year-old woman. Analyses revealed higher mean speaking fundamental frequency compared to previously published data obtained from elderly women. In the absence of normative data, the results of cepstrum analyses performed on vowels produced during connected speech revealed less periodicity for the 105-year-old woman's voice than for a 35-year-old woman's voice. The main finding of this study indicates that previously reported group trends regarding aging effects on mean speaking fundamental frequency of the female voice cannot simply be attributed to all elderly individuals. These results stress the importance, for clinical and research purposes, of recognizing the existence of considerable intra- as well as intersubject variability in the effects of aging on the voice.     

In situ TEM study of reversible and irreversible electroforming in Pt/Ti:NiO/Pt heterostructures

Experimental verification of the microscopic origin of resistance switching in metal/oxide/metal heterostructures is needed for applications in non‐volatile memory and neuromorphic computing. Numerous reports suggest that resistance switching in NiO is caused by local reduction of the oxide layer into nanoscale conducting filaments, but few reports have shown experimental evidence correlating electroforming with site‐specific changes in composition. We have investigated the mechanisms of reversible and irreversible electroforming in 250–500 nm wide pillars patterned from a single Ta/Ti/Pt/Ti‐doped NiO/Pt/Ta heterostructure and have shown that these can coexist within a single sample. We performed in situ transmission electron microscopy (TEM) electroform‐ ing and switching on each pillar to correlate the local electron transport behavior with microstructure and composition in each pillar. DFT calculations fitted to electron energy loss spectroscopy data showed that the Ti‐doped NiO layer is partially reduced after reversible electroforming, with the formation of oxygen vacancies ordered into lines in the 〈110〉 direction. However, under the same probing conditions, adjacent pillars show irreversible electroforming caused by electromigration of metallic Ta to form a single bridge across the oxide layer. We propose that the different electroforming behaviors are related to microstructural variations across the sample and may lead to switching variability. (© 2015 WILEY‐VCH Verlag GmbH &Co. KGaA, Weinheim)     

Qualitative and quantitative analysis of voice onset by means of a multidimensional voice analysis system (MVAS) using high-speed imaging

High-speed filming is one of the most informative methods for assessing voice physiology data. Tracing high-speed images of the glottis provides quantitative parameters such as the glottal area and the glottal width function. By way of example, a number of studies are discussed which extract quantitative data from high-speed images showing voice onsets. Furthermore, a new computer system (MVAS; multi-dimensional voice analysis system) is presented that synchronously displays a laryngoscopic high-speed film, the electroglottographical signal, and several acoustic analyses of the recorded voice sample. The automatic measurement of glottal width and glottal area from the laryngoscopic images is also provided. Looking at former studies and our analyses of voice onsets reveals a tremendous intersubject and even intrasubject variability (different prephonatory closure, different time span until full amplitude is reached, different open quotient).     

An acoustic analysis of fluctuations in the voices of normal adult speakers across three times of day

The purpose of this study was to determine the amount of variation for several vocal parameters across three times of the day (morning, noon, and afternoon). Connected speech samples from normal adult males (N = 10) and females (N = 10) were recorded during morning, early afternoon, and late afternoon. Results showed that males produced a statistically significant increase in speaking fundamental frequency (SFF) from morning to afternoon. Females did not demonstrate a statistically significant change in SFF across the three time periods. Vocal amplitude did not change significantly for either group. The SFF variability was higher for the females than for the males. Analysis of individual data revealed that the patterns of vocal change across the three times of day were not consistent among the subjects.     

Differential activity of the pars recta and pars oblique infundamental frequency control

This study was designed to determine if differences exist in parsrecta and pars oblique muscle activity during speech and singing. Hooked wire electrodes were implanted in the muscle bundles under direct vision during thyroid surgery in two men and three women. It was found that the pars recta and pars oblique do not function in a similar manner across fundamental frequencies (ƒ₀'s), tasks, or subjects. Large inter- and intrasubject variability wase evident in the contribution of the cricothyroid bundles to fundamental frequency (ƒ₀,) control. It is speculated that the effect of pars recta and pars oblique contraction may be a function of individual anatomic variations.     

Intraproduction variability in jitter measures from elderly speakers

This study examined intraproduction variability in jitter measures from elderly speakers' sustained vowel productions and tried to determine whether mean jitter levels (percent) and intraspeaker variability on jitter measures are affected significantly by the segment of the vowel selected for measurement. Twenty-eight healthy elderly men (mean age 75.6 years) and women (mean age 72.0 years) were tape recorded producing 25 repeat trials of the vowels /i/, /a/, and /u/, as steadily as possible. Jitter was analyzed from two segments of each vowel production: (a) the initial 100 cycles after 1 s of phonation, and (b) 100 cycles from the most stable-appearing portion of the production. Results indicated that the measurement point selected for jitter analysis was a significant factor both in the mean jitter level obtained and in the variability of jitter observed across repeat productions.     

Psychophysically based site selection coupled with dichotic stimulation improves speech recognition in noise with bilateral cochlear implants

The ability to perceive important features of electrical stimulation varies across stimulation sites within a multichannel implant. The aim of this study was to optimize speech processor MAPs for bilateral implant users by identifying and removing sites with poor psychophysical performance. The psychophysical assessment involved amplitude-modulation detection with and without a masker, and a channel interaction measure quantified as the elevation in modulation detection thresholds in the presence of the masker. Three experimental MAPs were created on an individual-subject basis using data from one of the three psychophysical measures. These experimental MAPs improved the mean psychophysical acuity across the electrode array and provided additional advantages such as increasing spatial separations between electrodes and/or preserving frequency resolution. All 8 subjects showed improved speech recognition in noise with one or more experimental MAPs over their everyday-use clinical MAP. For most subjects, phoneme and sentence recognition in noise were significantly improved by a dichotic experimental MAP that provided better mean psychophysical acuity, a balanced distribution of selected stimulation sites, and preserved frequency resolution. The site-selection strategies serve as useful tools for evaluating the importance of psychophysical acuities needed for good speech recognition in implant users.     

A deep learning–based method for improving reliability of multicenter diffusion kurtosis imaging with varied acquisition protocols

Multicenter magnetic resonance imaging is gaining more popularity in large-sample projects. Since both varying hardware and software across different centers cause unavoidable data heterogeneity across centers, its impact on reliability in study outcomes has also drawn much attention recently. One fundamental issue arises in how to derive model parameters reliably from image data of varying quality. This issue is even more challenging for advanced diffusion methods such as diffusion kurtosis imaging (DKI). Recently, deep learning–based methods have been demonstrated with their potential for robust and efficient computation of diffusion-derived measures. Inspired by these approaches, the current study specifically designed a framework based on a three-dimensional hierarchical convolutional neural network, to jointly reconstruct and harmonize DKI measures from multicenter acquisition to reformulate these to a state-of-the-art hardware using data from traveling subjects. The results from the harmonized data acquired with different protocols show that: 1) the inter-scanner variation of DKI measures within white matter was reduced by 51.5% in mean kurtosis, 65.9% in axial kurtosis, 53.7% in radial kurtosis, and 61.5% in kurtosis fractional anisotropy, respectively; 2) data reliability of each single scanner was enhanced and brought to the level of the reference scanner; and 3) the harmonization network was able to reconstruct reliable DKI values from high data variability. Overall the results demonstrate the feasibility of the proposed deep learning–based method for DKI harmonization and help to simplify the protocol setup procedure for multicenter scanners with different hardware and software configurations.     

Constancy of loudness of pipe organ sounds at different locations in an auditorium

Pipe organ sounds, as judged by ear, tend to remain constant across different locations in an auditorium, yet the SPL of line spectra may vary by a maximum of 26 dB (mean 8.98 dB, s.d. 2.5), and the overall level may vary, typically, 10 to 12 dB from location to location. However, organs are designed, listened to, and regulated using the psychophysical units of loudness and timbre, and it is possible that the heard sound constancy exists at the psychophysical level. The present work recorded the sound of the C's and G's of pipe organ stops at three different locations in a church. The sound pressure levels were transformed to loudness. Similarity of loudness across the locations was measured two ways. First, the bass to treble distribution of loudness across the compass was measured using cross-correlation functions across pairs of locations. Second, the degree of similarity of loudness at the different locations was quantified by calculating ratios of loudness between the different locations. By these measures, the bass to treble loudness distribution and absolute loudness of the reeds were found to be nearly identical at the three locations. Two psychophysical processes were shown to be responsible for the loudness constancy. The first depended upon the power summation of harmonics within each third octave band above band 9 which contain two or more harmonics. The power summation of these harmonics greatly reduced the effect of SPL variability of the line spectra contained within these higher numbered bands. The second depended upon interharmonic loudness summation and upward masking of the first six harmonics. Greater loudness variability at the different locations was found after transforming the SPL measurements of two 8-ft diapasons to loudness compared with the reeds. The larger loudness variability was due to the smaller number of harmonics above the third of the diapasons compared with the reeds. The psychoacoustic measures indicate what a listener will hear as he/she moves among the locations.     

基于平均吸收的太赫兹波振幅成像研究

提出了一种基于一定频率内平均吸收的太赫兹(THz)波振幅成像新方法。太赫兹波频率在0.1～10 THz之间,波段位于红外和微波之间。太赫兹波成像技术的一个显著特点是信息量大,如何对每个样品点的大量信息进行处理提取有用信息重构出样品的图像是一项关键技术。选用中间挖空有“THz”字样的白纸为样品作太赫兹波成像研究,首先探讨了时域和频域上几种常用太赫兹波振幅成像方法所反映的样品信息及其特点,进一步使用提出的基于一定频率内平均吸收的太赫兹波振幅成像新方法对样品进行图像重构。实验结果表明这种新方法可以很好的反映样品的真实信息,反映了样品在一定频率范围内由于吸收而引起的效果的综合,与吸收系数和厚度相关,离散效应得到了很好的消除,相对几种常用的太赫兹波振幅成像方法能够得到更清晰的图像。此新方法尤其适用于结构简单的样品,能够成为几种常用振幅成像方法的有力补充。     

The effect of intertalker speech rate variation on acoustic vowel space

The present study aimed to examine the size of the acoustic vowel space in talkers who had previously been identified as having slow and fast habitual speaking rates [Tsao, Y.-C. and Weismer, G. (1997) J. Speech Lang. Hear. Res. 40, 858-866]. Within talkers, it is fairly well known that faster speaking rates result in a compression of the vowel space relative to that measured for slower rates, so the current study was completed to determine if the same differences in the size of the vowel space occur across talkers who differ significantly in their habitual speaking rates. Results indicated that there was no difference in the average size of the vowel space for slow vs fast talkers, and no relationship across talkers between vowel duration and formant frequencies. One difference between the slow and fast talkers was in intertalker variability of the vowel spaces, which was clearly greater for the slow talkers, for both speaker sexes. Results are discussed relative to theories of speech production and vowel normalization in speech perception.     

A comparison of adaptive procedures for rapid and reliable threshold assessment and training in naive listeners

In psychoacoustic studies there is often a need to assess performance indices quickly and reliably. The aim of this study was to establish a quick and reliable procedure for evaluating thresholds in backward masking and frequency discrimination tasks. Based on simulations, four procedures likely to produce the best results were selected, and data collected from 20 naive adult listeners on each. Each procedure used one of two adaptive methods (staircase or maximum-likelihood estimation, each targeting the 79% correct point on the psychometric function) and two response paradigms (3-interval, 2-alternative forced-choice AXB or 3-interval; 3-alternative forced-choice oddball). All procedures yielded statistically equivalent threshold estimates in both backward masking and frequency discrimination, with a trend to lower thresholds for oddball procedures in frequency discrimination. Oddball procedures were both more efficient and more reliable (test-retest) in backward masking, but all four procedures were equally efficient and reliable in frequency discrimination. Fitted psychometric functions yielded similar thresholds to averaging over reversals in staircase procedures. Learning was observed across threshold-assessment blocks and experimental sessions. In four additional groups, each of ten listeners, trained on the different procedures, no differences in performance improvement or rate of learning were observed, suggesting that learning is independent of procedure.     

Automated measurement and classification of pulmonary blood-flow velocity patterns using phase-contrast MRI and correlation analysis

An automated method was evaluated to detect blood flow in small pulmonary arteries and classify each as artery or vein, based on a temporal correlation analysis of their blood-flow velocity patterns. The method was evaluated using velocity-sensitive phase-contrast magnetic resonance data collected in vitro with a pulsatile flow phantom and in vivo in 11 human volunteers. The accuracy of the method was validated in vitro, which showed relative velocity errors of 12% at low spatial resolution (four voxels per diameter), but was reduced to 5% at increased spatial resolution (16 voxels per diameter). The performance of the method was evaluated in vivo according to its reproducibility and agreement with manual velocity measurements by an experienced radiologist. In all volunteers, the correlation analysis was able to detect and segment peripheral pulmonary vessels and distinguish arterial from venous velocity patterns. The intrasubject variability of repeated measurements was approximately 10% of peak velocity, or 2.8 cm/s root-mean-variance, demonstrating the high reproducibility of the method. Excellent agreement was obtained between the correlation analysis and radiologist measurements of pulmonary velocities, with a correlation of R2=0.98 (P<.001) and a slope of 0.99+/-0.01.     

Intrasubject variability of objective voice measures

Recent advances in the diagnosis and treatment of voice disorders necessitate the need for accurate and reliable objective voice measurements. There are many instruments commonly used to analyze voice data. Many, if not most, of these instruments have not been adequately tested for reliability or consistency. This study evaluates the intrasubject variability of the objective voice measurements from two commonly used voice analysis instruments. The study also presents data correlating subjective mood states, room temperatures, sleep times of the subject, time since last meal, and hydration levels to the various acoustic measures. Several weak but significant correlations were obtained and are discussed. Guidelines for the appropriate use of these instruments are described.     

Sociodemographic variables of a german sample of patients with contact granuloma

We report 28 German patients with contact granuloma (27 male, 1 female). Their mean age was 52 years (ranging from 35 to 70). Thirty-two percent were retired. The occupations of the others represented a wide range of different jobs. The majority of the sample had a middle educational level. Most patients lived with their family or with a partner. According to self-assessments, 68% had average daily strain on their speaking voice. All patients were nonsmokers. The patients felt themselves more disturbed by somatic troubles as the general population. Heartburn was felt by nearly half of the patients. A little more than half of the patients suffered from globus sensation. Thus, it is not possible at present to explain the laryngeal contact granuloma by sociodemographic data, vocal stress, or special somatic complaints in this sample. Therefore a multifactorial etiology should be supposed.