Assessment of Vocal Fold Stiffness by Means of High-Speed Videolaryngoscopy with Laryngotopography in Prediction of Early Glottic Malignancy: Preliminary Report.

One of the most important challenges in laryngological practice is the early diagnosis of laryngeal cancer. Detection of non-vibrating areas affected by neoplastic lesions of the vocal folds can be crucial in the recognition of early cancerogenous infiltration. Glottal pathologies associated with abnormal vibration patterns of the vocal folds can be detected and quantified using High-speed Videolaryngoscopy (HSV), also in subjects with severe voice disorders, and analyzed with the aid of computer image processing procedures. We present a method that enables the assessment of vocal fold pathologies with the use of HSV. The calculated laryngotopographic (LTG) maps of the vocal folds based on HSV allowed for a detailed characterization of vibration patterns and abnormalities in different regions of the vocal folds. We verified our methods with HSV recordings from 31 subjects with a normophonic voice and benign and malignant vocal fold lesions. We proposed the novel Stiffness Asymmetry Index (SAI) to differentiate between early glottis cancer (SAI = 0.65 ± 0.18) and benign vocal fold masses (SAI = 0.16 ± 0.13). Our results showed that these glottal pathologies might be noninvasively distinguished prior to histopathological examination. However, this needs to be confirmed by further research on larger groups of benign and malignant laryngeal lesions.

Segmentation of Glottal Images from High-Speed Videoendoscopy Optimized by Synchronous Acoustic Recordings.

Laryngeal high-speed videoendoscopy (LHSV) is an imaging technique offering novel visualization quality of the vibratory activity of the vocal folds. However, in most image analysis methods, the interaction of the medical personnel and access to ground truth annotations are required to achieve accurate detection of vocal folds edges. In our fully automatic method, we combine video and acoustic data that are synchronously recorded during the laryngeal endoscopy. We show that the image segmentation algorithm of the glottal area can be optimized by matching the Fourier spectra of the pre-processed video and the spectra of the acoustic recording during the phonation of sustained vowel /i:/. We verify our method on a set of LHSV recordings taken from subjects with normophonic voice and patients with voice disorders due to glottal insufficiency. We show that the computed geometric indices of the glottal area make it possible to discriminate between normal and pathologic voices. The median of the Open Quotient and Minimal Relative Glottal Area values for healthy subjects were 0.69 and 0.06, respectively, while for dysphonic subjects were 1 and 0.35, respectively. We also validate these results using independent phoniatrician experts.

Quantitative assessment of videolaryngostroboscopic images in patients with glottic pathologies.

INTRODUCTION: Digital imaging techniques enable exploration of novel visualization modalities of the vocal folds during phonation and definition of parameters, facilitating more precise diagnosis of voice disorders. AIM: Application of computer vision algorithms for analysis of videolaryngostroboscopic (VLS) images aimed at qualitative and quantitative description of phonatory vibrations. MATERIALS AND METHODS: VLS examinations were conducted for 45 females, including 15 subjects with vocal nodules, 15 subjects with glottal incompetence, and 15 normophonic females. The recorded VLS images were preprocessed, the glottis area was segmented out, and the glottal cycles were identified. The glottovibrograms were built, and then the glottal area waveforms (GAW) were quantitatively described by computing the following parameters: open quotient (OQ), closing quotient (CQ), speed quotient (SQ), minimal relative glottal area (MRGA), and a new parameter termed closure difference index (CDI). RESULTS: Profiles of the glottal widths assessed along the glottal length differentiated the study groups (P < 0.001). Moreover, it was shown that the OQ, CQ, CDI, and MRGA indices can be considered as viable parameters for quantifying kinematics of the vocal folds for normophonic subjects and patients with diagnosed vocal nodules and glottal incompetence (P < 0.001). CONCLUSIONS: Computer image processing and analysis methods applied to videolaryngostroboscopic images allow for their quantitative assessment. Computation of the size-related and time-related parameters characterizing glottic pathologies is of interest for evidence-based voice diagnostics. Results of the performed ROC curve analysis suggest that the evaluated parameters can distinguish patients with voice disorders from normophonic subjects.

[Nonlinear acoustic analysis in the evaluation of occupational voice disorders]. / Nieliniowa analiza akustyczna w ocenie zawodowych zaburzen glosu.

BACKGROUND: Over recent years numerous papers have stressed that production of voice is subjected to the nonlinear processes, which cause aperiodic vibrations of vocal folds. These vibrations cannot always be characterized by means of conventional acoustic parameters, such as measurements of frequency and amplitude perturbations. Thus, special attention has recently been paid to nonlinear acoustic methods. The aim of this study was to assess the applicability of nonlinear cepstral analysis, including the evaluation of mel cepstral coefficients (MFCC), in diagnosing occupational voice disorders. MATERIAL AND METHODS: The study involved 275 voice samples of pathologic voice (sustained vowel "a" and four standardized sentences) registered in female teachers with the occupation-related benign vocal fold masses (BVFM), such as vocal nodules, polyps, and 200 voice samples of normal voices from the control group of females. The mean age of patients and controls was similar (45 vs. 43 years). Voice samples from both groups were analyzed, including MFCC evaluation. RESULTS: MFCC classification using the Sammon Mapping and Support Vector Machines yielded a considerable accuracy of the test. Voice pathologies were detected in 475 registered voice samples: for vowel "a" with 86% sensitivity and 90% specificity, and for the examined sentences the corresponding values varied between 87% and 100%, respectively. CONCLUSIONS: Nonlinear voice analysis with application of mel cepstral coefficients could be a useful and objective tool for confirming occupational-related lesions of the glottis. Further studies addressing this problem are being carried out.

[Comparison of cepstral coefficients to other voice evaluation parameters in patients with occupational dysphonia]. / Porównanie wyników analizy cepstralnej z innymi parametrami oceny glosu u pacjentów z dysfoniami zawodowymi.

UNLABELLED: BACKGROUND Special consideration has recently been given to cepstral analysis with mel-frequency cepstral coefficients (MFCCs). The aim of this study was to assess the applicability of MFCCs in acoustic analysis for diagnosing occupational dysphonia in comparison to subjective and objective parameters of voice evaluation. MATERIALS AND METHODS: The study comprised 2 groups, one of 55 female teachers (mean age: 45 years) with occupational dysphonia confirmed by videostroboscopy and 40 female controls with normal voice (mean age: 43 years). The acoustic samples involving sustained vowels "a" and four standardized sentences were analyzed by computed analysis of MFCCs. The results were compared to acoustic parameters of jitter and shimmer groups, noise to harmonic ratio, Yanagihara index evaluating the grade of hoarseness, the aerodynamic parameter: maximum phonation time and also subjective parameters: GRBAS perceptual scale and Voice Handicap Index (VHI). RESULTS: The compared results revealed differences between the study and control groups, significant for MFCC2, MFCC3, MFCC5, MFCC6, MFCC8, MFCC10, particularly for MFCC6 (p < 0.001) and MFCC8 (p < 0.009), which may suggest their clinical applicability. In the study group, MFCC4, MFCC8 and MFCC10 correlated significantly with the major objective parameters of voice assessment. Moreover, MFCC8 coefficient, which in the female teachers correlated with all eight objective parameters, also showed the significant relation with perceptual voice feature A (asthenity) of subjective scale GRBAS, characteristic of weak tired voice. CONCLUSIONS: The cepstral analysis with mel frequency cepstral coefficients is a promising tool for evaluating occupational voice disorders, capable of reflecting the perceptual voice features better than other methods of acoustic analysis.

Computer software tool for heart rate variability (HRV), T-wave alternans (TWA) and heart rate turbulence (HRT) analysis from ECGs.

BACKGROUND: This paper presents a software package for quantitative evaluation of heart rate variability (HRV), heart rate turbulence (HRT), and T-wave alternans (TWA) from ECG recordings. The software has been developed for the purpose of scientific research rather than clinical diagnosis. MATERIAL/METHODS: The software is written in Matlab Mathematical Language. Procedures for evaluation of HRV, HRT and TWA were implemented. HRV analysis was carried out by applying statistical and spectral parametric and nonparametric methods. HRT parameters were derived using the Schmidt algorithm. TWA analysis was performed both in spectral and in time domain by applying Poincare mapping. A flexibility of choosing from a number of classical modelling approaches and their modifications was foreseen and implemented. The software underwent preliminary verification tests both on ECGs from the Physionet online ECG signal repository and recordings taken at the Department of Electrocardiology of the Medical University Hospital in Lodz. RESULTS: The result of the research is a program enabling simultaneous analysis of a number of parameters computed from ECG recordings with the use of the indicated analysis methods. The program offers options to preview the intermediate results and to alter the preprocessing steps. CONCLUSIONS: By offering the possibility to cross-validate the results of analyses obtained by several methods and to preview the intermediate analysis steps, the program can serve as a helpful aid for clinicians in comprehensive research studies. The software tool can also be utilized in training programs for students and medical personnel.