On the use of pitch power spectrum in the evaluation of vocal tremor (original) (raw)
Related papers
Comparative Evaluation of Several Pitch Process Models in the Detection of Vocal Tremor
IEEE Transactions on Biomedical Engineering, 2000
Three models describing the speech excitation wave (denoted as pitch process) are suggested in order to detect vocal tremor in pathological speech. These models are compared, and the advantages and disadvantages of each of them are discussed. Comparison results for synthesized speech are presented, as well as spectral analysis results for real data of Parkinsonian speech, from which it turns out that the pitch process may serve as a powerful tool for detecting such tremor.
Discriminating Simulated Vocal Tremor Source Using Amplitude Modulation Spectra
Journal of voice : official journal of the Voice Foundation, 2014
Sources of vocal tremor are difficult to categorize perceptually and acoustically. This article describes a preliminary attempt to discriminate vocal tremor sources through the use of spectral measures of the amplitude envelope. The hypothesis is that different vocal tremor sources are associated with distinct patterns of acoustic amplitude modulations. Statistical categorization methods (discriminant function analysis) were used to discriminate signals from simulated vocal tremor with different sources using only acoustic measures derived from the amplitude envelopes. Simulations of vocal tremor were created by modulating parameters of a vocal fold model corresponding to oscillations of respiratory driving pressure (respiratory tremor), degree of vocal fold adduction (adductory tremor), and fundamental frequency of vocal fold vibration (F0 tremor). The acoustic measures were based on spectral analyses of the amplitude envelope computed across the entire signal and within select fre...
Interspeech 2015, 2015
The presentation concerns a method that obtains the size and frequency of vocal tremor in speech sounds sustained by normal speakers and patients suffering from neurological disorders. The glottal cycle lengths are tracked in the temporal domain via salience analysis and dynamic programming. The cycle length time series is then decomposed into a sum of oscillating components by empirical mode decomposition the instantaneous envelopes and frequencies of which are obtained via an AM-FM decomposition. Based on their average instantaneous frequencies, the empirical modes are then assigned to four categories (intonation, physiological tremor, neurological tremor as well as jitter) and added within each. The within-category size of the cycle length perturbations is estimated via the standard deviation of the empirical mode sum divided by the average cycle length. The tremor frequency within the neurological tremor category is obtained via a weighted instantaneous average of the mode frequencies followed by a weighted temporal average. The method is applied to two corpora of vowels sustained by 123 and 74 control and 456 and 205 Parkinson speakers respectively.
Analysis of vocal tremor by means of a complex wavelet transform
ulb.ac.be
A vocal frequency estimation method based on an analytical continuous wavelet transform is proposed, with a view to the study of vocal tremor. Vocal tremor designates a lowfrequency narrow-band perturbation of the vocal frequency. The vocal frequency estimate is the instantaneous frequency calculated in an automatically selected frequency-band of a wavelet transform of the speech signal. The analysis method is compared to an event-based method and a Hilbert-transform method for speech signals uttered by normal and Parkinsonian speakers. The results suggest that the ratio of the spectral energy of the vocal frequency trace in the intervals (1-5 Hz) and (5-20 Hz) differ for normophonic and Parkinsonian speakers.
Voice tremor detection using adaptive quasi-harmonic model
Speech along with hearing is the most important human ability. Voice does not only audibly represents us to the world, but also reveals our energy level, personality, and artistry. Possible disorders may lead to social isolation or may create problems on certain profession groups. Most singers seek professional voice help for vocal fatigue, anxiety, throat tension, and pain. All these symptoms must be quickly addressed to restore the voice and provide physical and emotional relief. Normophomic and dysphonic speakers have a mutual voice characteristic. Tremor, a rhythmic change in pitch and loudness, appears both in healthy subjects and in subjects with voice disorders. Physiological tremor or microtremor appears to be a derivative of natural processes. Pathological tremor, however, is distinguishable and characterized by strong periodical patterns of large amplitude that affect the quality of voice and influence the ability of patient's communication. However, researches examine...
Vocal tremors characterize many pathological voices, but acoustic-perceptual aspects of tremor are poorly understood. To investigate this relationship, 2 tremor models were implemented in a custom voice synthesizer. The first modulated fundamental frequency (F0) with a sine wave. The second provided irregular modulation. Control parameters in both models were the frequency and amplitude of the F0 modulating waveform. Thirty-two 1-s samples of /a/, produced by speakers with vocal pathology, were modeled in the synthesizer. Synthetic copies of each vowel were created by using tremor parameters derived from different features of F0 versus time plots of the natural stimuli or by using parameters chosen to match the original stimuli perceptually. Listeners compared synthetic and original stimuli in 3 experiments. Sine wave and irregular tremor models both provided excellent matches to subsets of the voices. The perceptual importance of the shape of the modulating waveform depended on the severity of the tremor, with the choice of tremor model increasing in importance as the tremor increased in severity. The average frequency deviation from the mean F0 proved a good predictor of the perceived amplitude of a tremor. Differences in tremor rats were easiest to hear when the tremor was sinusoidal and of small amplitude. Differences in tremor rate were difficult to judge for tremors of large amplitude or in the context of irregularities in the pattern of frequency modulation. These results suggest that difference limens are larger for modulation rates and amplitudes when the tremor pattern is complex. Further, tremor rate, regularity, and amplitude interact, so that the perceptual importance of any one dimension depends on values of the others.
Physiologic and Acoustic Patterns of Essential Vocal Tremor
Journal of Voice, 2013
Objectives/Hypothesis. This article describes a case study of physiologic and acoustic patterns of essential vocal tremor (EVT). Simulations of vocal tremor were used to test hypotheses regarding measured acoustic patterns and expected physiologic sources. Study Design. This is a case study of EVT using an analysis by synthesis approach. Methods. Oscillations of vocal tract and laryngeal structures were identified using rigid videostroboscopic examination. Acoustical analyses of sustained phonation were completed using the methods previously described in the literature and custom-written MATLAB functions. Simulations of the client's vocal tremor were created using a computational model. Results. The client exhibited vocal fold length changes and oscillation within the laryngeal vestibule during sustained phonation at a comfortable pitch and loudness. Despite the involvement of vocal fold length changes, a low average extent of fundamental frequency (F 0) modulation (ie, 5.3%) and high average extent of intensity modulation (ie, 23.0%) were measured. Simulations of vocal tremor involving modulation of F 0 demonstrated that this source of tremor contributes to frequency-induced intensity modulation, although there was a greater extent of F 0 modulation than intensity modulation. Conclusions. The greater extent of intensity than F 0 modulation in one client with EVT exhibiting predominant vocal fold length changes contrasted with the lower extent of intensity than F 0 modulation in simulated vocal tremor involving F 0 modulation. These findings demonstrate that other potential sources of intensity modulation outside the larynx should be determined during the evaluation of clients with vocal tremor.
Estimating Tremor in Vocal Fold Biomechanics for Neurological Disease Characterization
2013 18th International Conference on Digital Signal Processing (DSP), 2013
Neurological Diseases (ND) are affecting larger segments of aging population every year. Treatment is dependent on expensive accurate and frequent monitoring. It is well known that ND leave correlates in speech and phonation. The present work shows a method to detect alterations in vocal fold tension during phonation. These may appear either as hypertension or as cyclical tremor. Estimations of tremor may be produced by autoregressive modeling of the vocal fold tension series in sustained phonation. The correlates obtained are a set of cyclicality coefficients, the frequency and the root mean square amplitude of the tremor. Statistical distributions of these correlates obtained from a set of male and female subjects are presented. Results from five study cases of female voice are also given.
Acoustic Studies of Tremor in Pathological Voices
This work is focused on modeling the perception of tremor found in pathological voices. The main research objective is to automatically separate the different sources of tremor to estimate the magnitude of tremor perturbations using signal processing techniques. A new assessment algorithm is derived from speech recordings which combines non-linear filtering, amplitude demodulation and spectral estimation techniques. The algorithm is evaluated against the perceptual judgments provided by speech pathologists and other reported indexes. The results show that the algorithm is effective differentiating normal from pathological tremor and it is a reliable measurement of tremor perturbations with high correlation with perceptual judgments.
Phonatory characteristics of vocal fold tremor
Journal of Phonetics, 1986
To identify phonatory measures of vocal fold tremor, patients with benign essential tremor (BET) of the vocal folds were compared with normal controls and patients with phonatory tremor due to other neurological disorders. Measures included: the percent frequency and amplitude variation due to tremor, range, rate and regularity of tremor. Patients with neurological disorders (including BET) had greater frequency and amplitude range and percent variation due to tremor, but no increase in jitter and shimmer. The acoustic measures which specifically reflected vocal fold tremor in BET were the range in frequency variation and the variation in linear trend in frequency and amplitude. Tremor rate did not differ between BET, other neurological disorders and normal voices, but the regularity of the tremor rate did.