[Reproducibility and reliability of phonovibrograms. Quantification of healthy vocal fold vibrations]. / Reproduzierbarkeit und Reliabilität des Phonovibrogramms. Quantifizierung gesunder Stimmlippenschwingungen.

BACKGROUND: Phonovibrography is capable of visualizing vocal fold vibrations in a static two-dimensional image, the so-called phonovibrogram (PVG). It allows quantification of the entire vocal fold vibration patterns. In this study we investigated the accuracy and reproducibility of PVG measures by analyzing high-speed laryngoscopy videos of healthy vocal fold vibrations. METHODS: High-speed laryngoscopy videos of 12 female speech therapists and 12 vocalists from the Regensburg Cathedral choir were analyzed. For evaluation purposes, PVG analysis was performed for two different sections of each video. RESULTS: The mean difference between the high-speed sections was 1.6 degrees +/-0.5 degrees for the female and 2.3 degrees +/-0.6 degrees for the male subjects. Within the sections, the mean variance of the PVG parameters was 3.5 degrees +/-0.7 degrees (therapists) and 3.7 degrees +/-1.0 degrees (vocalists). Likewise, a high left/right accordance of the PVG parameters, 5.3 degrees +/-0.5 degrees for therapists and 5.9 degrees +/-1.9 degrees for vocalists, was obtained. CONCLUSION: Vibrational patterns of normal vocal fold vibrations were very precisely quantified by the introduced PVG parameters. The high accuracy and reproducibility of PVG analysis provides a basis for prospective clinical trials dealing with precise characterization of pathological vibration patterns.

[Phonovibrogram: vocal fold dynamics integrated within a single image]. / Phonovibrogramm: Stimmlippendynamik in einem Bild.

BACKGROUND: Stroboscopy is widely used and is quite adequate for the examination of normal voices, but with increasing hoarseness its suitability declines, even when it is supplemented by video recordings and image evaluation. Real-time procedures such as videokymography or high-speed (HS) video imaging are more suitable methods of observing the movements of the vocal folds in such cases. A drawback of any video recording is the later time-consuming offline replay of the films in slow motion and our restricted pattern recognition for motion and other time-dependent processes. METHODS: The phonovibrogram (PVG) is an image-processing algorithm that extracts the vocal fold motions of a whole laryngoscopic HS video film and automatically compresses them into a single image. RESULTS: Simple patterns that vary from person to person are revealed by PVG; these can be categorized by means of simple geometric forms, which a human observer can more easily recognize and interpret than dynamic motion patterns. The PVG computation is described in detail and an extensive guide to interpretation is given, illustrated by reference to theoretical and real examples. CONCLUSION: In clinical conditions, HS laryngoscopic video recording is useful only in association with automatic image processing. The PVG procedure is a promising approach and tests should be performed with a view to further clinical validation.

[Basic research on vocal fold dynamics: three-dimensional vibration analysis of human and canine larynges]. / Grundlagenuntersuchungen für Stimmlippendynamik : 3D-Schwingungsanalyse menschlicher und caniner Kehlköpfe.

BACKGROUND: The understanding of normal and pathological vocal fold dynamics is the basis for a pathophysiological motivated voice therapy. Crucial vocal fold dynamics concerning voice production occur at the medial part of the vocal fold which is seen as the most critical region of mucosal wave propagation. Due to the limited size of the larynx the possibilities of laryngeal imaging by endoscopic techniques are limited. MATERIAL AND METHODS: This work describes an experimental set-up that enables quantification of the entire medial and superior vocal fold surface using excised human and in vivo canine larynges. RESULTS: The data obtained enable analysis of vocal fold deflections, velocities, and mucosal wave propagation. The reciprocal dependencies can be examined and different areas of vocal fold dynamics located. The vertical components obscured in clinical endoscopy can be visualized. This is not negligible. CONCLUSIONS: In particular it is shown that the vertical deflection, which cannot be observed by clinical examination, plays an important part in the dynamics and therefore cannot be omitted for therapeutic procedures. The theoretically assumed entrainment and influence of the two main vibration modes enabling normal phonation is confirmed.

Normal voice production: computation of driving parameters from endoscopic digital high speed images.

OBJECTIVES: A central point for quantitative evaluation of pathological and healthy voices is the analysis of vocal fold oscillations. By means of digital High Speed Glottography (HGG), vocal fold oscillations can be recorded in real time. Recently, a numerical inversion procedure was developed that allows the extraction of physiological parameters from digital high speed videos and a classification of voice disorders. The aim of this work was to validate the inversion procedure and to investigate the applicability to normal voices. METHODS: High speed recordings were performed during phonation within a group of five female and five male persons with normal voices. By using knowledge based image processing algorithms, motion curves of the vocal folds were extracted at three different positions (dorsal, medial, ventral). These curves were used to obtain physiological voice parameters, and in particular the degree of symmetry of the vocal folds based upon a biomechanical model of the vocal folds. RESULTS: The highest degree of symmetry was observed for the medial motion curves. While the dorsally and ventrally extracted motion curves exhibited similar results concerning the degree of symmetry the performance of the algorithm was less stable. CONCLUSIONS: The inversion algorithm provides reasonable results for all subjects when applied to the medial motion curves. However, for dorsal and ventral motion curves, correct performance is reduced to 85%.

The laryngectomee substitute voice: image processing of endoscopic recordings by fusion with acoustic signals.

OBJECTIVES: The most radical cancer therapy of the throat is the total excision of the larynx which post-operatively results in the loss of voice. A widely-used method of voice rehabilitation is the insertion of a silicone valve, which establishes an unidirectional connection between trachea and esophagus. Thus, during exhalation, air can be directed from the trachea into the esophagus. This air stream excites tissue vibrations of the esophagus and the hypo-pharynx which act as a substitute voice generator. Purpose of the current study is to present a technique for visualizing the dynamics of the substitute voice generating element. METHODS: Digital high speed videos of the vibrating tissue are simultaneously recorded with the emitted acoustic signal. The high speed sequences are directly evaluated by a three-step knowledge based algorithm. It considers correlation between image and acoustic data, information about the gray value of each pixel, and continuity of tissue vibration. The temporal properties of an image series are investigated by evaluating the time dependent gray value at each pixel position. RESULTS: The applicability of the algorithm is exemplarily demonstrated using the data of one male patient. It enables the identification of the regions within an image series which are mainly responsible for the acoustic signal. Additionally, the dynamics of tissue vibrations are visualized. The main propagation direction can be clearly identified. CONCLUSIONS: The new methodology summarizes the information about endoscopic and acoustic recordings of substitute voice into a single image. The results allow a first estimation of tissue velocity and elastic properties of oscillating tissue.

[The influence of conductive hearing loss on DPOAE-threshold. The effect of an individually optimized stimulation]. / Der Einfluss einer Schallleitungsstörung auf die DPOAE-Schwelle. Möglichkeiten einer individuell optimierten Auslösung.

BACKGROUND: The DPOAE-threshold, estimated from extrapolated I/O functions, allows an objective assessment of the mechanical sensitivity of the inner ear. In children, the specificity of this diagnostic tool is impaired by conductive hearing loss. METHODS: In this study, we propose an individual optimization of the primary tone level ratio. This procedure allows the detection of a conductive hearing loss that can be accounted for when estimating the DPOAE-threshold. By means of a simulation using DPOAE-data from 22 normally hearing subjects, the effects of this procedure on the estimation of the DPOAE-threshold are examined. RESULTS: An individually optimized DPOAE stimulation distinctly improves the signal-to-noise ratio of the DPOAE which enables an estimation of the DPOAE-threshold for sound conductive losses up to 15 dB. The DPOAE-threshold only worsens in individual cases. CONCLUSIONS: An individually optimized stimulation paradigm may improve the specificity of inner ear diagnostics with the DPOAE-threshold. A clinical evaluation of the method in children, however, is necessary.

[Quality of life and voice handicap of laryngectomees using tracheoesophageal substitute voice]. / Lebensqualität und Stimmbeeinträchtigung Laryngektomierter mit Stimmventilprothesen.

BACKGROUND: Health-related quality of life (QoL) and subjective health have become popular constructs for the evaluation of both efficacy and efficiency of diagnostic and therapeutic procedures in medicine. QoL is considered a multidimensional construct encompassing physical, mental and social facets of life. It is an accepted outcome parameter not only in international classification systems such as ICIDH and ICF, but as well in clinical guidelines and disease management programs. Measuring quality of life allows for comparison of different diseases though it certainly lacks disease specific aspects. Thus, it has to be assumed that in patients with distinct functional deficits QoL cannot cover all aspects that are important for the individual patient. This study focuses on laryngectomies and their self-evaluation of post-laryngectomy speech. It is well known that these patients experience a decreased QoL compared to patients after partial laryngectomy or healthy persons. In this study, the impact of voice restoration on the laryngectomies' QoL was evaluated. PATIENTS AND METHODS: In 20 male laryngectomies aged 62 +/- 8 years, relations between QoL and voice handicap were evaluated using two instruments as proposed in the international literature, i. e. the Short-Form Health Survey (SF-36) and the Voice Handicap Index (VHI). All patients had successfully been using tracheoesophageal substitute voice for at least one year. Complete data sets were available from all patients. Data were analysed using Microsoft Excel and Sigma Plot, Jandel Corp. software packages. RESULTS: Results of both the SF-36 and the VHI reveal wide interindividual ranges. There are statistically significant correlations (p < 0.05) between the SF-36's scales General Health and Vitality and the VHI, whereas no correlations were found between social and psychological scales and the voice handicap. DISCUSSION: Wide ranges of the data obtained reveal that obviously both health related quality of life and voice handicap are not affected in a group specific way. So, both tests are of clinical value to depict individual aspects of wellbeing after laryngectomy. The combination of VHI and SF-36 illuminates correlations between general and special subjective aspects. Strikingly, the laryngectomies' social and psychological status is not related to their voice handicap. Data allow for conclusion that laryngectomies' substitute voice problems do not affect social aspects of quality of life in a disease specific way, at least as long as voice restoration was successful at all.