Sustained Vowel Phonation Research Articles

Measuring Vocal Fatigue in Sports Coaches

Objective: This study explores the immediate impact of prolonged voice use by professional sports coaches. Method: Speech samples including sustained phonation of vowel /a/ and a short read passage were collected from two professional sports coaches. The audio recordings were made within an hour before and after a coaching session, over three sessions. Perceptual evaluation of voice quality was done using the GRBAS scale. The speech samples were subsequently analyzed using Praat. The acoustic measures included fundamental frequency (f0), jitter, shimmer, Harmonics-to-Noise ratio and Cepstral Peak Prominence. Main results: The results of perceptual and acoustic analysis suggest a slight shift towards a tenser phonation post-coaching session, which is a likely consequence of laryngeal muscle adaptation to prolonged voice use. This tendency was similar in sustained vowels and connected speech. Conclusion: Acoustic measures used in this study can be useful to capture the voice change post-coaching session. It is desirable, however, that more sophisticated and robust and at the same time intuitive and easy-to-use tools for voice assessment and monitoring be made available to clinicians and professional voice users.

Comparison of Acoustic Parameters According to the Section of Analysis in Sustained Vowel Phonation

Comparison of Acoustic Parameters According to the Section of Analysis in Sustained Vowel Phonation

Characteristics of Hypokinetic Dysarthria Patients' Speech based on Sustained Vowel Phonation and Connected Speech

This study investigated the characteristics of Parkinson's disease patients' speech through difference of measured cepstral values of speech assignment (sustained vowel phonation, connected speech) between normal adults and patient's with Parkinson's disease in Korea. Subjects of the study were 17 males with Parkinson's disease and control group was 28 healthy male adults without cranial nerve damage or disorder. Speech was collected in sustained vowel phonation and connected speech respectively. The cepstral analysis was used to Analysis of Dysphonia in Speech and Voice (ADSV) Model 5109 of KayPENTAX Corp. Difference of measured value between the groups was confirmed with independent t-test. As the result of independent t-test, there was significant difference in CPP, L/H ratio and CSID of sustained vowel phonation between groups. In contrast, in connected speech, all the measured values have no significant difference between the two groups except CPP. Parkinson's disease patients had difference in speech characteristics depending on speech assignment (sustained vowel phonation, connected speech). Based on the results of this study, analysis on connected speech other than sustained vowel phonation is essentially required in order to precisely identify the speech characteristics Parkinson's disease patients.

Measurement of vocal breathiness perception with a matching task for sustained phonation and running speech

Laboratory measurements of the perception of vocal breathiness typically employ recordings of sustained vowel phonations. Sustained vowels are thought to provide a good representation of the underlying vocal disorder and are relatively easy to produce, analyze, and synthesize. Clinical assessments of voice quality are sometimes based on the production of speech utterances that are more ecologically valid than sustained vowel phonation and that capture the dynamics of laryngeal function, breath support, and a variety of complex cognitive and neuromuscular challenges typically involved in natural speech. As a result, voice quality associated with running speech may correspond more closely with perceived handicap and may represent more relevant treatment targets than sustained vowels. In a listening experiment with naive listeners, breathy voice quality was evaluated for exemplars of sustained /a/ production as well as read speech from a selection of talkers that vary widely in terms of their vocal breathiness. A single-variable matching task was used to index perceived breathiness for both stimulus types. Listener reliability was high, and matching thresholds for the sustained phonation and speech stimuli were highly correlated, demonstrating the efficacy of the matching task for measuring vocal breathiness from speech utterances.

An insight to the automatic categorization of speakers according to sex and its application to the detection of voice pathologies: A comparative study

La hipotesis que se establece en este estudio es que una categorizacion automatica de hablantes de acuerdo con su sexo mejora el rendimiento de un detector automatico de patologias de voz. Esto se basa en hallazgos que demuestran diferencias perceptuales, acusticas y anatomicas en voces masculinas y femeninas. En particular, este trabajo persigue dos objetivos: 1) disenar un sistema que discrimine automaticamente el sexo de hablantes utilizando habla normal y patologica, 2) estudiar la influencia que este detector de sexo tiene sobre el acierto de un posterior detector de patologias de voz. La parametrizacion del detector automatico de sexo esta basada en MFCC aplicados sobre senales de voz; y MFCC aplicados a formas de onda glotal, junto a parametros que modelan el tracto vocal. Las formas de onda glotal se extraen de la voz a traves de un filtrado inverso iterativo en celosia. En cuanto al detector de patologias de voz, una parametrizacion MFCC se aplica sobre senales de voz. La clasificacion, tanto en los detectores de sexo como de patologia, se lleva a cabo con tecnicas del estado del arte basadas en modelos de base universal. Los experimentos se realizan sobre la base de datos Saarbrucken, empleando la fonacion sostenida de la vocal /a/. Los resultados indican que el sexo del hablante puede ser discriminado automaticamente utilizando habla normal y patologica, obteniendo una precision de hasta un 95%. Por otra parte, al incluir informacion a-priori sobre el sexo del hablante se produce una mejora en el rendimiento absoluto de alrededor de 2% en EER, en tareas de deteccion de patologia.

Screening for Voice Disorders in Older Adults (RAVI)—Part III: Cutoff Score and Clinical Consistency

The aim of the study was to determine the cutoff score and clinical consistency of "Screening for Voice Disorders in Older Adults" (RAVI-Rastreamento de Alterações Vocais em Idosos). This is a prospective, nonrandomized, cross-sectional diagnostic study. A sample of 301 subjects, including both sexes, aged 60 and more, and all of whom were living in either a community or an institution, was studied. To determine which subjects had or did not have voice problems, we used a composite reference standard (auditory-perceptual analysis of sustained vowel phonation, auditory-perceptual analysis of connected speech, and vocal self-assessment). The best cutoff score was identified using the receiver operating characteristic (ROC) curve analysis. The clinical consistency indicators were co-positivity, co-negativity, positive and negative predictive values, positive and negative likelihood ratio, and test efficiency. The significance level was 5%. The area under the ROC curve was 0.763 (95% confidence interval: 0.706-0.821), and the best cutoff score for determining which older adults had or did not have a voice disorder was 2. All clinical consistency indicators were satisfactory: co-positivity (79%), co-negativity (60%), predictive positive value (51%), negative predictive value (84%), positive likelihood ratio (2.01), negative likelihood ratio (0.34), and test efficiency (69%). RAVI has satisfactory indicators of clinical consistency and is able to determine which older adults have voice disorders by a cutoff score of 2. The use of RAVI as a screening tool is recommended to help determine the prevalence of voice disorders in older adults.

Voice Alterations in Patients With Spinocerebellar Ataxia Type 7 (SCA7): Clinical-Genetic Correlations

Spinocerebellar ataxia type 7 (SCA7) is an inherited neurodegenerative disease caused by the expansion of a cytosine-adenine-guanine triplet located in the coding region of the ATXN7 gene, which is characterized by cerebellar ataxia, pigmentary macular degeneration, and dysarthria. Although dysarthria is a common feature in various SCA, its clinical characterization has been barely approached. In this study, we report, to our knowledge for the first time, a detailed voice analysis in a large series of patients with SCA7, using different vocal parameters, including jitter, shimmer, and fundamental frequency. Patients were molecularly diagnosed using fluorescent-based polymerase chain reaction and capillary electrophoresis, and clinically characterized using the Scale for the Assessment and Rating of Ataxia and the Inventory of Non-Ataxia Symptoms. We found altered jitter, shimmer, and fundamental frequency measurements in patients with SCA7 compared with control subjects (P < 0.05). However, voice impairment was found unrelated with both age at disease onset and size of the cytosine-adenine-guanine triplet tract. Remarkably, jitter and shimmer measurements of patients were found to correlate with their Inventory of Non-Ataxia Symptoms, but not with their Scale for the Assessment and Rating of Ataxia scores, implying that voice impairment is the result of extra-cerebellar manifestations of the disease. We propose that deficiency of the extra-cerebellar component of SCA7 might lead to sudden changes in laryngeal muscle tone, producing instability in sustained vowel phonation. Clinical characterization of voice will help to discriminate SCA7 from other SCA and to guide vocal therapy treatments.

A Detailed Motion Analysis of the Angular Velocity Between the Vocal Folds During Throat Clearing Using High-speed Digital Imaging

To assess the angular velocity between the vocal folds just before the compression phase of throat clearing (TC) using high-speed digital imaging (HSDI) of the larynx. Twenty normal healthy adults (13 males and seven females) were enrolled in the study. Each participant underwent transnasal laryngo-fiberscopy, and was asked to perform weak/strong TC followed by a comfortable, sustained vowel phonation while recording an HSDI movie (4000 frames/s) of the larynx. Using a motion analysis, the changes in the vocal fold angle and angular velocity during vocal fold adduction were assessed. Subsequently, we calculated the average angular velocities in the ranges of 100-80%, 80-20%, and 20-0% from all of the angular changes. The motion analysis demonstrated that the changes in the angular velocity resulted in polynomial-like and sigmoid curves during TC and vowel phonation, respectively. The angular velocities during weak TC were significantly higher in the 20-0%, 80-20%, and 100-80% regions (in order); the 80-20% angular velocity in vocal fold adduction during phonation was highest. The 20-0% angular velocity during strong TC was more than twofold higher than 20-0% angular velocity during phonation. The present results confirmed that the closing motions of the vocal folds accelerate throughout the precompression closing phase of a TC episode, and decelerate just before the impact between the vocal folds at the onset of phonation, suggesting that the vocal fold velocity generated by TC is sufficient to damage the laryngeal tissues.

Comparison of Vowel and Text-Based Cepstral Analysis in Dysphonia Evaluation

Background Cepstral analysis which is obtained from Fourier transformation of spectrum has been known to be effective indicator to analyze the voice disorder. To evaluate the voice disorder, phonation of sustained vowel /a/ sound or continuous speech have been used but the former was limited to capture hoarseness properly. This study is aimed to compare the effectiveness in analysis of cepstrum between the sustained vowel /a/ sound and continuous speech. Methods From March 2012 to December 2014, total 72 patients was enrolled in this study, including 24 unilateral vocal cord palsy, vocal nodule and vocal polyp patients, respectively. The entire patient evaluated their voice quality by VHI (Voice Handicap Index) before and after treatment. Phonation of sustained vowel /a/ sample and continuous speech using the first sentence of autumn paragraph was subjected by cepstral analysis and compare the pre-treatment group and post-treatment group. Results The measured values of pre and post treatment in CPP-a (cepstral peak prominence in /a/ vowel sound) was 13.80, 13.91 in vocal cord palsy, 16.62, 17.99 in vocal cord nodule, 14.19, 18.50 in vocal cord polyp respectively. Values of CPP-s (cepstral peak prominence in text-based speech) in pre and post treatment was 11.11, 12.09 in vocal cord palsy, 12.11, 14.09 in vocal cord nodule, 12.63, 14.17 in vocal cord polyp. All 72 patients showed subjective improvement in VHI after treatment. CPP-a showed statistical improvement only in vocal polyp group, but CPP-s showed statistical improvement in all three groups (p<0.05). Conclusion In analysis of cepstrum, text-based analysis is more representative in voice disorder than vowel sound speech. So when the acoustic analysis of voice by cepstrum, both phonation of sustained vowel /a/ sound and text based speech should be performed to obtain more accurate result. Key words: Cepstrum ㆍ Dysphonia ㆍ Acoustic analysis ㆍ Voice 핵심용어: 켑스트럼 ㆍ ì–¸ì–´ìž¥ì• ã† 음성분석 ㆍ 음성

Speech task effects on acoustic measure of fundamental frequency in Cantonese-speaking children

ObjectivesSpeaking fundamental frequency (F0) is a voice measure frequently used to document changes in vocal performance over time. Knowing the intra-subject variability of speaking F0 has implications on its clinical usefulness. The present study examined the speaking F0 elicited from three speech tasks in Cantonese-speaking children. The study also compared the variability of speaking F0 elicited from different speech tasks. MethodsFifty-six vocally healthy Cantonese-speaking children (31 boys and 25 girls) aged between 7.0 and 10.11 years participated. For each child, speaking F0 was elicited using speech tasks at three linguistic levels (sustained vowel /a/ prolongation, reading aloud a sentence and passage). Two types of variability, within-session (trial-to-trial) and across-session (test–retest) variability, were compared across speech tasks. Results and conclusionsSignificant differences in mean speaking F0 values were found between speech tasks. Mean speaking F0 value elicited from sustained vowel phonations was significantly higher than those elicited from the connected speech tasks. The variability of speaking F0 was higher in sustained vowel prolongation than that in connected speech.

A Fast Semiautomatic Algorithm for Centerline-Based Vocal Tract Segmentation.

Vocal tract morphology is an important factor in voice production. Its analysis has potential implications for educational matters as well as medical issues like voice therapy. The knowledge of the complex adjustments in the spatial geometry of the vocal tract during phonation is still limited. For a major part, this is due to difficulties in acquiring geometry data of the vocal tract in the process of voice production. In this study, a centerline-based segmentation method using active contours was introduced to extract the geometry data of the vocal tract obtained with MRI during sustained vowel phonation. The applied semiautomatic algorithm was found to be time- and interaction-efficient and allowed performing various three-dimensional measurements on the resulting model. The method is suitable for an improved detailed analysis of the vocal tract morphology during speech or singing which might give some insights into the underlying mechanical processes.

Comparison of Tongue and Lip Trills with Phonation of the Sustained Vowel /&amp;lt;i&amp;gt;ε&amp;lt;/i&amp;gt;/ Regarding the Periodicity of the Electroglottographic Waveform and the Amplitude of the Electroglottographic Signal

Aim: The aim is to compare the vocal fold vibration seen during lip and tongue trills with that seen during phonation of the sustained vowel /ε/, in terms of the periodicity of the EGG waveform and the amplitude of the EGG signal, in professional voice users. Study design: This was a quasi-experimental study. Methods: We used electroglottography (EGG) to compare the vocal fold vibration seen during tongue and lip trills with that seen during phonation of the sustained vowel /ε/, in terms of the EGG waveform periodicity and signal amplitude, in 10 classically trained, professional singers. The participants produced the sustained vowel /ε/ and performed tongue and lip trills at the same frequency and intensity. The periodicity of the waveform and the amplitude of the signal were visually analyzed by three blinded, experienced readers. To confirm the visual analysis results, we measured the jitter and shimmer of the signal and the frequency of variation in vocal fold vibration during the trill exercises. Results: The EGG waveform was classified as periodic for the sustained vowel phonation task and as quasi-periodic for the trill exercises, the vibration pattern repeating at approximately 24 Hz. Conclusion: The vibration of the vocal folds was modified according to the supraglottic movement in trills exercises.

Objective Dysphonia Measures in the Program Praat: Smoothed Cepstral Peak Prominence and Acoustic Voice Quality Index

A version of the "smoothed cepstral peak prominence" (i.e., CPPS) has recently been implemented in the program Praat. The present study therefore estimated the correspondence between the original CPPS from the program SpeechTool and Praat's version of the CPPS. Because the CPPS is the main factor in the multivariate Acoustic Voice Quality Index (AVQI), this study also investigated the proportional relationship between the AVQI with the original and the second version of the CPPS. Comparative cohort study. Clinical recordings of sustained vowel phonation and continuous speech from 289 subjects with various voice disorders were analyzed with the two versions of the CPPS and the AVQI. Pearson correlation coefficients and coefficients of determination were calculated between both CPPS-methods and between both AVQI-methods. Quasi-perfect correlations and coefficients of determination approaching hundred percent were found. The findings of this study demonstrate that the outcomes of the two CPPS-methods and the two AVQI-methods are highly comparable, increasing the clinical feasibility of both methods as measures of dysphonia severity.

Computed tomographic assessment of the causal factors of unsuccessful medialization thyroplasty

Conclusion: The present results demonstrate that a small implant size, undercorrection of the vocal fold, antero-posterior implant malposition, and the use of expanded polytetrafluoroethylene (ePTFE) are the primary factors that cause a poor outcome of medialization thyroplasty (MT). Objectives: To assess the postoperative laryngeal condition using computed tomography (CT) in patients with unilateral vocal fold paralysis who underwent MT alone, and to identify the primary causal factors in terms of the surgical procedures that affect the outcomes of MT. Methods: Twenty-two patients who underwent MT alone were divided into two groups based on either the maximal phonation time or the perceived vocal breathiness. Two laryngologists assessed the postoperative laryngeal CT images during sustained vowel phonation and judged whether there were abnormalities of the arytenoid cartilage position, window position, implant size, and implant position, as well as the degree of correction of the vocal fold. As implant material, a silicone block, ePTFE, and hydroxyapatite had been inserted in 2, 9, and 11 patients, respectively. Comparisons of the prevalence of abnormalities in the abovementioned factors between the different outcomes and between the types of material used for the implant were performed. Results: Twelve patients with a poor outcome and 10 with a good outcome showed 36 and 18 abnormal findings identified by either of the two laryngologists, respectively. In the poor outcome group, a smaller implant size and undercorrection of the vocal fold showed both high kappa values and a significantly higher prevalence than those in the good outcome group (p < 0.001 and p < 0.05), respectively. The comparison between material types demonstrated that the sheet-like material (ePTFE) group exhibited a significantly higher prevalence of undercorrection than the block-like material group (p < 0.05).

Fundamental Frequency Changes of Persian Speakers Across the Life Span

This study was designed to investigate changes in fundamental frequency (F0) across the life span in Persian speakers. Four hundred children and adults were asked to produce a sustained phonation of vowel /a/ and their voice samples were studied in 10 age groups. F0 was analyzed using the software Praat (Version 5.1.17.). The results revealed that (1) the mean F0 in both sexes decreases from childhood to adulthood; (2) significant F0 differences between boys and girls begin at the age of 12 years; and (3) the range of F0 changes in the life span is greater in men (178.38 Hz) than in women (113.57 Hz). These findings provide new data for Persian-speaking children, women, and men and could be beneficial for Iranian speech and language pathologists.

Objective Acoustic Quantification of Phonatory Dysfunction in Huntington's Disease

PurposeAlthough speech motor changes are reported as a common sign of Huntington’s disease (HD), the most prominent signs of voice dysfunction remain unknown. The aim of the current study was to explore specific changes in phonatory function in subjects with HD.Method34 subjects with HD and 34 age- and sex-matched healthy controls were examined. Participants performed sustained vowel phonation for subsequent analyses of airflow insufficiency, aperiodicity, irregular vibrations of vocal folds, signal perturbations, increased noise, and articulation deficiency. In total, 272 phonations were collected and 12 voice parameters were extracted. Subsequently, a predictive model was built to find the most salient patterns of voice disorders in HD. The results were also correlated with disease severity according to the Unified HD Rating Scale (UHDRS) motor score.ResultsSubjects with HD showed deterioration in all investigated phonatory functions. Irregular pitch fluctuations, sudden phonation interruption, increased noise, and misplacement of articulators were found to be most significant patterns of phonatory dysfunction in HD (p<0.001). The combination of these four dysphonia aspects contributed to the best classification performance of 94.1% (sensitivity: 95.1%; specificity: 93.2%) in the separation of HD patients from healthy participants. Our results further indicated stronger associations between sudden phonation interruption and voluntary components of the UHDRS (r = −0.48, p<0.01) and between misplacement of articulators and involuntary components of the UHDRS (r = 0.52, p<0.01).ConclusionsOur configuration of phonatory features can detect subtle voice abnormalities in subjects with HD. As impairment of phonatory function in HD was found to parallel increasing motor involvement, a qualitative description of voice dysfunction may be helpful to gain better insight into the pathophysiology of the vocal mechanism.

Gender Classification in Children Based on Speech Characteristics: Using Fundamental and Formant Frequencies of Malay Vowels

Speech is one of the prevalent communication mediums for humans. Identifying the gender of a child speaker based on his/her speech is crucial in telecommunication and speech therapy. This article investigates the use of fundamental and formant frequencies from sustained vowel phonation to distinguish the gender of Malay children aged between 7 and 12 years. The Euclidean minimum distance and multilayer perceptron were used to classify the gender of 360 Malay children based on different combinations of fundamental and formant frequencies (F0, F1, F2, and F3). The Euclidean minimum distance with normalized frequency data achieved a classification accuracy of 79.44%, which was higher than that of the nonnormalized frequency data. Age-dependent modeling was used to improve the accuracy of gender classification. The Euclidean distance method obtained 84.17% based on the optimal classification accuracy for all age groups. The accuracy was further increased to 99.81% using multilayer perceptron based on mel-frequency cepstral coefficients.

Test-Retest-Variabilität und interne Konsistenz des Acoustic Voice Quality Index

The aim of this study was to determine the test-retest variability of the Acoustic Voice Quality Index (AVQI) and to investigate the weighting of the test's two components (sustained vowel and continuous speech) with regards to the final AVQI score. During this study, 43 test subjects with varying degrees of hoarseness were each assessed twice using the AVQI. No statistically significant differences were found between the end results of the two AVQI repetitions (t = 1.205; p = 0.235). The test-retest procedure outcome value of 0.54 confirms a low level of AVQI score variability. The end result of the AVQI assessment is most strongly influenced by sustained phonation of the vowel /a/ (r(2) = 0.88.). Although sustained phonation has a significantly greater influence on AVQI score than continuous speech (z = - 3.34; p < 0.01), the latter component also makes a substantial contribution to the final result (r(2) = 0.55). The results confirm a low level of test-retest variability within the AVQI. Combining the two speech elements showed a greater contribution of sustained vowel phonation to the final AVQI score.

Clinical Usefulness of Cepstral Analysis in Dysphonia Evaluation

Received June 12, 2013 Revised July 31, 2013 Accepted August 1, 2013 Address for correspondence Sang Hyuk Lee, MD Department of Otolaryngology Head and Neck Surgery, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, 29 Saemunan-ro, Jongno-gu, Seoul 110-746, Korea Tel +82-2-2001-1924 Fax +82-2-2001-2273 E-mail entlsh@hanmail.net Background and ObjectivesZZWith the present methods for assessing speech, there are procedures that make effective diagnostics possible for voice disorders. One such procedure is cepstrum. Spectrum is produced by Fourier transformation of sound waves, and if Fourier transformation is performed again about the spectrum, cepstrum is produced. This study compared cepstrum to jitter, shimmer, and noise-to-harmonic ratio (NHR) for assessment of its usefulness. Cepstrum was measured by Cepstral Peak Prominence (CPP) calculated by the Hillenbrand method and Cepstral Mean Values (CMV) calculated using the Computerized Speech Laboratory software. Subjects and MethodZZWe included in the study 30 patients with vocal nodule and unilateral vocal cord palsy who were diagnosed in Kangbuk Samsung Hospital between March 2010 and May 2011, and 30 normal controls. Phonation of sustained vowel /a/ sample and running speech was subjected to acoustic analysis using CMV and CPP. Then we compared the correlation of cepstrum with other acoustic methods. ResultsZZThe measured values of CPP-a were 14.16, 17.25, 20.00 and the age adjusted CPP-s values were 11.21, 12.85, 15.00 for vocal cord palsy, vocal nodule and normal group, respectively. There was significant correlation with perceptions of dysphonia (p<0.001), but in CMV-a, CMV-s, there was no significant correlation. When jitter, shimmer, and NHR were compared with cepstrum, the result showed negative correlation among the three groups but CPP values showed significant difference (p<0.001). ConclusionZZIn the assessment of voice disorders, cepstrum may be used as a reliable method for comparing other complementary analysis tools. For the acoustic analysis of voice by cepstrum, however, CPP has more reliable correlations with dysphonia than CMV. Korean J Otorhinolaryngol-Head Neck Surg 2013;56:574-8

Characterization of Dysphonic Voices by Means of a Filterbank-Based Spectral Analysis: Sustained Vowels and Running Speech

This article presents a comparative study of the spectral power distribution for normal and dysphonic voices, both for sustained vowels and running speech. The objective of this study was to find robust cues of dysphonia in spectral domain. For this purpose, recordings from two databases are processed, one of them including both sustained vowels and running speech. Additionally, a new measure of stability is introduced (decorrelation time). The application of this measure to the power spectrum is also tested as a cue of dysphonia. The spectral analysis is done having both an auditory model and the filterbank approach as references to the computation of discrete spectrograms. Results are obtained from three sets of recordings belonging to two different databases. The reported results indicate that only minor differences exist in the shape of the power spectrum of normal and dysphonic voices when performing sustained vowel phonation tasks. However, the calculated band power decorrelation times indicate that power in bands between 2000 and 6400Hz is significantly less stable in dysphonic voices. As for running speech, the stability of spectral power is not such a good indicator of dysphonia, but there is a significant difference between normal and dysphonic voices in the power level of high-frequency bands (above 5300Hz). In addition, this means that sampling rates above 10.6ksps are needed for assessing running speech in spectral domain. Also, the results involving decorrelation times indicate that for short-time spectral analysis, frame rates above 100 frames/s should be preferred.