Michael Doellinger

Variability of normal vocal fold dynamics for different vocal loading in one healthy subject investigated by phonovibrograms.

We investigate the potential of high-speed digital imaging technique (HSI) and the phonovibrogram (PVG) analysis in normal vocal fold dynamics by studying the effects of continuous voice use (vocal loading) during the workday. One healthy subject was recorded at sustained phonation 13 times within 2 consecutive days in the morning before and in the afternoon after vocal loading, respectively. Vocal fold dynamics were extracted and visualized by PVGs. The characteristic PVG patterns were extracted representing vocal fold vibration types. The parameter values were then analyzed by statistics regarding vocal load, left-right PVG asymmetries, anterior-posterior PVG asymmetries, and opening-closing differences. For the first time, the direct impact of vocal load could be determined by analyzing vocal fold dynamics. For same vocal loading conditions, equal dynamical behavior of the vocal folds were confirmed. Comparison of recordings performed in the morning with the recordings after work revealed significant changes in vibration behavior, indicating impact of occurring vocal load. Left-right asymmetries in vocal fold dynamics were found confirming earlier assumptions. Different dynamics between opening and closing procedure as well as for anterior and posterior parts were found. Constant voice usage stresses the vocal folds even in healthy subjects and can be detected by applying the PVG technique. Furthermore, left-right PVG asymmetries do occur in healthy voice to a certain extent. HSI in combination with PVG analysis seems to be a promising tool for investigation of vocal fold fatigue and pathologies resulting in small forms of dynamical changes.

Assessment of the variability of vocal fold dynamics within and between recordings with high-speed imaging and by phonovibrogram†‡§

The goal of the study was to assess the variability of healthy vocal fold dynamics. Quantitative parameters describing mean regularity and vibration characteristics of vocal fold dynamics along the entire glottal axis were analyzed.

Correlation between Psychometric Tests and Mismatch Negativity in Preschool Children

The objective was to determine whether mismatch negativity (MMN) is suitable to supplement subjective psychometric subtests of central hearing. We assessed 13 healthy children and 32 children with central auditory processing disorder (CAPD). Three different types of sound deviants were presented in a multi-deviant MMN design. At group level, the incidence of MMN was always higher in clinically diagnosed controls. Children with better results in the subtest Auditory Memory Span had a higher incidence of MMN. The controls also had peak latencies that occurred significantly earlier in frontal, central and temporal electrode sites. The area under the curve (AUC) displayed an asymmetric distribution in CAPD children, who tended to have a left-hemispheric dominance. AUC, peak latency, and the incidence of MMN reflected the discriminative ability of CAPD children. Hence, these characteristics could be used for investigating children with deficits in central hearing and can supplement psychometric tests.

Sentence repetition and digit span: potential markers of bilingual children with suspected SLI?

Abstract Purpose. Digit span and sentence repetition are identified as potential markers for specific language impairment (SLI). We investigated if language learning of bilingual children with suspected language impairment (biSLI) was also influenced and led by memory constraints. Method. In a retrospective study, 19 children with SLI and 25 controls (ages 4;9–5;9), as well as 15 biSLI children and 14 controls (ages 5;1–8;9) were compared with regard to their performance on a digit span and sentence repetition task. Results. Both groups with language impairment (SLI/biSLI) showed reduced performance on both tasks. Sentence repetition predicted language comprehension, and the digit span task predicted grammar abilities of the SLI, biSLI, and their controls. Conclusion. Sentence repetition and short-term memory provide information on language comprehension and grammar abilities in language-impaired mono- and bilingual children and confirm their function as SLI markers.

Effects of Consonant-Vowel Transitions in Speech Stimuli on Cortical Auditory Evoked Potentials in Adults

We examined the neural activation to consonant-vowel transitions by cortical auditory evoked potentials (AEPs). The aim was to show whether cortical response patterns to speech stimuli contain components due to one of the temporal features, the voice-onset time (VOT). In seven normal-hearing adults, the cortical responses to four different monosyllabic words were opposed to the cortical responses to noise stimuli with the same temporal envelope as the speech stimuli. Significant hemispheric asymmetries were found for speech but not in noise evoked potentials. The difference signals between the AEPs to speech and corresponding noise stimuli revealed a significant negative component, which correlated with the VOT. The hemispheric asymmetries can be referred to rapid spectral changes. The correlation with the VOT indicates that the significant component in the difference signal reflects the perception of the acoustic change within the consonant-vowel transition. Thus, at the level of automatic processing, the characteristics of speech evoked potentials appear to be determined primarily by temporal aspects of the eliciting stimuli.

Model‐based quantification of pathological voice production

Hoarseness, the primary symptom of voice disorders, results from irregular vocal fold vibrations. The oncological therapy of laryngeal cancer may even result in a total loss of voice if an excision of the larynx, and thus, the vocal folds, is necessary. State‐of‐the‐art voice rehabilitation technique in this case is the utilization of scarred tissue in the upper part of the esophagus for substitute voice production. The quality of laryngeal voice, as well as the substitute voice, primarily depends on the anatomy and the vibration patterns of the voice‐producing element. Using endoscopic high‐speed recordings, the voice generators are observed during voice production. In this work, a model‐based approach feasible for the analysis and objective quantification of vocal fold vibrations, as well as the PE dynamics, is presented. By means of an automatic parameter optimization, the dynamic of a biomechanical model of the considered voice‐producing element is fitted to the recorded vibration patterns. Thereby sp...

Automatic detection of anatomical landmarks on the knee joint using MRI data

To propose a new automated learning‐based scheme for locating anatomical landmarks on the knee joint using three‐dimensional (3D) MR image data.

Automatic model‐based semantic registration of multimodal MRI knee data

To propose a robust and automated model‐based semantic registration for the multimodal alignment of the knee bone and cartilage from three‐dimensional (3D) MR image data.

A wavelet-based approach for a continuous analysis of phonovibrograms

Recently, endoscopic high-speed laryngoscopy has been established for commercial use and constitutes a state-of-the-art technique to examine vocal fold dynamics. Despite overcoming many limitations of commonly applied stroboscopy it has not gained widespread clinical application, yet. A major drawback is a missing methodology of extracting valuable features to support visual assessment or computer-aided diagnosis. In this paper a compact and descriptive feature set is presented. The feature extraction routines are based on two-dimensional color graphs called phonovibrograms (PVG). These graphs contain the full spatio-temporal pattern of vocal fold dynamics and are therefore suited to derive features that comprehensively describe the vibration pattern of vocal folds. Within our approach, clinically relevant features such as glottal closure type, symmetry and periodicity are quantified in a set of 10 descriptive features. The suitability for classification tasks is shown using a clinical data set comprising 50 healthy and 50 paralytic subjects. A classification accuracy of 93.2% has been achieved.

Phonovibrography: The Fingerprint of Vocal Fold Vibrations

A new approach for quantitative and objective analysis of vibration patterns of the vocal folds is presented. Vocal fold vibrations are recorded during sustained phonation in real time using a digital high-speed system coupled to a rigid endoscope. Within these high-speed movies, the edges of the oscillating vocal folds are detected by an adapted region-growing algorithm. The used segmentation algorithm is evaluated regarding its stability and correctness within 372 recordings proofing its clinical applicability. From the segmented vocal fold edges, a two-dimensional color encoded matrix is performed, visualizing the oscillations of the entire vocal fold edges over time. These created so called phonovibrograms allow a direct and objective view on the occurring laryngeal dynamics. The phonovibrograms can be used for assessing therapy progress and as a basis for further classification of different types of dysphonia. Phonovibrograms have the potential to serve as the first standard in endoscopic high-speed evaluation of vocal fold dynamics.