Models and analysis of vocal emissions for biomedical applications: 5th International Workshop: December 13-15, 2007, Firenze, Italy

The MAVEBA Workshop proceedings, held on a biannual basis, collect the scientific papers presented both as oral and poster contributions, during the conference. The main subjects are: development of theoretical and mechanical models as an aid to the study of main phonatory dysfunctions, as well as the biomedical engineering methods for the analysis of voice signals and images, as a support to clinical diagnosis and classification of vocal pathologies. The Workshop has the sponsorship of: Ente Cassa Risparmio di Firenze, COST Action 2103, Biomedical Signal Processing and Control Journal (Elsevier Eds.), IEEE Biomedical Engineering Soc. Special Issues of International Journals have been, and will be, published, collecting selected papers from the conference

Engineered Micro-Environments and Vibrational Culture Systems for Vocal Fold Tissue Engineering

Voice is produced by the conversion of aerodynamic energy from exhalation to acoustical energy for voice production by the vocal folds (membranous connective tissue) located in the larynx. The quality of voice depends on the biomechanical properties of the multi-layered vocal fold tissue which derive from its extracellular matrix (ECM) organization and composition. The wound healing response to vocal fold injuries is characterized by scarring and subsequent dysphonia due to alterations in the biomechanical properties of the tissue. The work presented here is motivated by the importance of voice in maintaining quality of life and the inability of current treatment techniques to restore long-term, normal phonatory voice following injury induced scarring. We hypothesize that vibration is the epigenetic stimulus regulating the unique extracellular matrix (ECM) composition of the human vocal fold tissue and that rapid restoration of the vibratory microenvironment using mechano-mimetic scaffolds will facilitate:- (a) inhibition of scarring and (b) stimulation of fibroblast regeneration of the normal vocal fold tissue architecture/ECM composition and thereby restore long-term, normal phonaory voice. Our objective was to create in situ photopolymerizable, degradable, mechano-mimetic hydrogels/semi-interpenetrating networks (semi-IPNs) which may be introduced into critical size vocal fold defects using minimally invasive methods. Towards this end, we created hyaluronic acid (HA) based hydrogels and polyethylene glycol (PEG)-diacrylate based hydrogels/semi-IPNs, which were found to approximate the viscoelastic mechanical properties of the native human vocal mucosa (vibratory component) and the vocal ligament (strain component), respectively. Cell culture studies indicated that these hydrogel/semi-IPN materials supported cell spreading, cell proliferation, and ECM deposition throughout the 3-dimensional crosslinked network. In an attempt to assess the ability of the HA-based hydrogels to support human fibroblast formation of vocal mucosa-specific matrix in response to physiologically relevant high frequency vibration, fibroblast encapsulated hydrogels were subjected to 2 hrs of vibration per day using a custom built vibrational bioreactor. Our results indicated that the exposure of HA hydrogel-encapsulated fibroblasts to physiologically relevant high frequency vibration stimulated a pattern of gene expression and ECM synthesis (upregulation of GAGs, downregulation of fibrous matrix proteins) consistent with the composition of the human vocal mucosa. In the future, these HA-based hydrogels introduced into the human vocal mucosa during the acute phase of wound healing by minimally invasive methods may bring about regeneration of the native human vocal mucosa ECM composition and thereby restore normal phonation

Using dysphonic voice to characterize speaker's biometry

Phonation distortion leaves relevant marks in a speaker's biometric profile. Dysphonic voice production may be used for biometrical speaker characterization. In the present paper phonation features derived from the glottal source (GS) parameterization, after vocal tract inversion, is proposed for dysphonic voice characterization in Speaker Verification tasks. The glottal source derived parameters are matched in a forensic evaluation framework defining a distance-based metric specification. The phonation segments used in the study are derived from fillers, long vowels, and other phonation segments produced in spontaneous telephone conversations. Phonated segments from a telephonic database of 100 male Spanish native speakers are combined in a 10-fold cross-validation task to produce the set of quality measurements outlined in the paper. Shimmer, mucosal wave correlate, vocal fold cover biomechanical parameter unbalance and a subset of the GS cepstral profile produce accuracy rates as high as 99.57 for a wide threshold interval (62.08-75.04%). An Equal Error Rate of 0.64 % can be granted. The proposed metric framework is shown to behave more fairly than classical likelihood ratios in supporting the hypothesis of the defense vs that of the prosecution, thus ofering a more reliable evaluation scoring. Possible applications are Speaker Verification and Dysphonic Voice Grading

Models and Analysis of Vocal Emissions for Biomedical Applications

The International Workshop on Models and Analysis of Vocal Emissions for Biomedical Applications (MAVEBA) came into being in 1999 from the particularly felt need of sharing know-how, objectives and results between areas that until then seemed quite distinct such as bioengineering, medicine and singing. MAVEBA deals with all aspects concerning the study of the human voice with applications ranging from the neonate to the adult and elderly. Over the years the initial issues have grown and spread also in other aspects of research such as occupational voice disorders, neurology, rehabilitation, image and video analysis. MAVEBA takes place every two years always in Firenze, Italy

Laryngeal preneoplastic lesions and cancer: challenging diagnosis. Qualitative literature review and meta-analysis

Background: The treatment of laryngeal cancer and its precursor lesions has a great impact on important laryngeal basic functions, thus, early detection and preoperative assessment are important for a curative and function-preserving therapy. Furthermore, delayed diagnosis, leads to loco-regional failure and a high incidence of second primary tumor, reasons for poor outcome. In this setting, there are two basic clinical problems in the management of premalignant and malignant laryngeal lesions. First, small and thin lesions are difficult to evaluate by the histopathologic examination and initial biopsies are often not sufficient for a conclusive diagnosis. Second, margins of the specimens from surgical excisions are difficult to evaluate due to tissue damage from the device, leaving us in doubt whether the excision is radical or not. From these observations, it is obvious that an instrument offering the possibility to detect pre-cancerous-early cancerous lesions, and satellite foci or second primaries would be the key to improving the survival rate in head and neck cancer. But, despite the high number of more advanced diagnostic techniques and methods, unfortunately, it is not uncommon for different clinicians to use different nomenclature or to identify different stage for the same laryngeal lesion. Object. Different modalities of diagnostic techniques of laryngeal lesions exist. Rather than difference between benign and obvious malignant diseases, more difficult is to detect the presence of precancerous epithelial alterations. Not all tests achieve the same diagnostic accuracy and that all tests must be considered against a gold standard, hence this meta-analysis of literature aimed to synthesise the validity of each single diagnostic technique in identifying and staging laryngeal diseases. Methods: A systematic review of literature was led searching for articles mentioning the following terms including their various combinations to maximize the yield: larynx, laryngeal cancer, white light (WL) endoscopy, contact endoscopy (CE), stroboscopy, autofluorescence (AF), ultrasound (US), narrow band imaging (NBI), computers assail tomography (CAT), magnetic resonance imaging (MRI), positron emission tomography (PET). A quantitative analysis was carried on for paper published after 2005 onward, reporting a minumun series of 10 patients each study, declaring sensitivity and specificity of each diagnostic system. Results: The search identified 7215 publications, of which 3616 published after 2005, with a final results of a total of 214 articles stratified and included by our selection criteria. 58 out of 214 articles were selected for quantitative synthesis. 35 out of 58 studies had a quality score of ≥ 6 (good), 15 presented a score between 4 and 5 (fair), the remaining 8 had a score between 2 and 3 (poor). While objections can be raised about the pooling of different diagnostic procedures under the same group and the high level of heterogeneity in the meta-analyses, the inclusion of over 2500 patients makes the results fairly robust. Conclusions: A comprehensive overview of the most recent advances in laryngeal imaging technology combined with all of the information needed to interpret findings and successfully manage patients with voice disorders can be found herein. With these data, clinicians can risk-stratify patients and select proper examination modalities in order to provide appropriate care. Moreover, study limitations, together with possible clinical and research implications have been counted, as well

Models and Analysis of Vocal Emissions for Biomedical Applications

The MAVEBA Workshop proceedings, held on a biannual basis, collect the scientific papers presented both as oral and poster contributions, during the conference. The main subjects are: development of theoretical and mechanical models as an aid to the study of main phonatory dysfunctions, as well as the biomedical engineering methods for the analysis of voice signals and images, as a support to clinical diagnosis and classification of vocal pathologies

Models and Analysis of Vocal Emissions for Biomedical Applications

The MAVEBA Workshop proceedings, held on a biannual basis, collect the scientific papers presented both as oral and poster contributions, during the conference. The main subjects are: development of theoretical and mechanical models as an aid to the study of main phonatory dysfunctions, as well as the biomedical engineering methods for the analysis of voice signals and images, as a support to clinical diagnosis and classification of vocal pathologies

MEMS-Based Endomicroscopes for High Resolution in vivo Imaging

Intravital microscopy is an emerging methodology for performing real time imaging in live animals. This technology is playing a greater role in the study of cellular and molecular biology because in vitro systems cannot adequately recapitulate the microenvironment of living tissues and systems. Conventional intravital microscopes use large, bulky objectives that require wide surgical exposure to image internal organs and result in terminal experiments. If these instruments can be reduced sufficiently in size, biological phenomena can be observed in a longitudinal fashion without animal sacrifice. The epithelium is a thin layer of tissue in hollow organs, and is the origin of many types of human diseases. In vivo assessment of biomarkers expressed in the epithelium in animal models can provide valuable information of disease development and drug efficacy. The overall goal of this work is to develop miniature imaging instruments capable of visualizing the epithelium in live animals with subcellular resolution. The dissertation is divided into four projects, where each contains an imaging system developed for small animal imaging. These systems are all designed using laser beam scanning technology with tiny mirrors developed with microelectromechanical systems (MEMS) technology. By using these miniature scanners, we are able to develop endomicroscopes small enough for hollow organs in small animals. The performance of these systems has been demonstrated by imaging either excised tissue or colon of live mice. The final version of the instrument can collect horizontal/oblique plane images in the mouse colon in real time (>10 frames/sec) with sub-micron resolution (<1 um), deep tissue penetration (~200 um) and large field of view (700 x 500 um). A novel side-viewing architecture with distal MEMS scanning was developed to create clear and stable image in the mouse colon. With the use of the instrument, it is convenient to pinpoint location of interest and create a map of the colon using image mosaicking. Multispectral fluorescence images can by collected at excitation wavelength ranging from 445 nm to 780 nm. The instruments have been used to 1) validate specific binding of a cancer targeting agent in the mouse colon and 2) study the tumor development in a mouse model with endogenous fluorescence protein expression. We use these studies to show that we have developed an enabling technology which will allow biologist to perform longitudinal imaging in animal models with subcellular resolution.PHDBiomedical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttps://deepblue.lib.umich.edu/bitstream/2027.42/136954/2/dxy_1.pd