Typing vocal fold vibratory patterns in excised larynx experiments via digital kymography.
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OBJECTIVES: Signal typing is central to the understanding of vocal fold vibratory patterns. Digital kymography (DKG) allows the direct observation of vocal fold vibratory patterns, and therefore, using DKG for vibratory signal typing may provide a useful complement to traditional signal typing techniques. METHODS: Video data collected from 20 larynges excised from mongrel dogs were observed with DKG in order to find examples of type 1 (nearly periodic), type 2 (subharmonic), and type 3 (aperiodic) vibratory patterns. The time series, frequency spectra, and correlation dimensions were calculated for each signal type. RESULTS: The type 1 pattern showed a periodic time series of glottal edges and a discrete frequency spectrum. The type 2 vibratory pattern displayed a time series of alternating high- and low-amplitude waves and a frequency spectrum that included a subharmonic (F0/2) frequency component. Regular and symmetric vibratory patterns were observed in the type 1 and type 2 patterns. The type 3 vibratory pattern was characterized by an aperiodic time series of glottal edges, a broadband frequency spectrum, and irregular and asymmetric vibratory patterns. The correlation dimension estimates increased from type 1 to type 2 to type 3. CONCLUSIONS: Imaging with DKG demonstrated an ability to assign a signal type to various laryngeal vibrations. Signal typing techniques utilizing direct observation of the vocal folds could be useful in determining valid methods for the analysis of vocal fold vibrations. (+info)
Intraflagellar transport particle size scales inversely with flagellar length: revisiting the balance-point length control model.
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Videokymographic analysis of patients after frontolateral laryngectomy with sternohyoid muscle flap reconstruction.
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A retrospective study was conducted to analyse videokymographic findings from patients who underwent vertical frontolateral laryngectomy with reconstruction using a sternohyoid muscle flap. Overall, 22 patients with T1b and T2 glottic tumours and more than one year of follow-up were studied. Two experienced observers analysed the recorded videokymographic data. A cross-sectional descriptive design was used. The images showed the vocal vibratory behaviour during sustained /i/ phonation. The vibratory source was supraglottic in 7/22 patients, glottic in 11 and mixed in 4. The mean duration of the glottic cycles extracted from the supraglottic, mixed and glottic vibratory sources was 6.4 ms, 5 ms and 4.6 ms, corresponding to the fundamental frequency (f0) of 188.7 Hz, 200 Hz and 215.7 Hz, respectively. Of the 11 patients with a glottic vibratory source, 4 did not present a closed phase in the glottic cycle. The mean open quotient was 79%, 40% and 63%, for the supraglottic, mixed and glottic vibratory sources, respectively. All 11 reconstructed vocal cords presented a rounded lateral peak. Of the 15 preserved vocal cords, 11 presented a rounded lateral peak and 4 had sharp peaks. All patients with a glottic vibratory source presented a rounded medial peak. All the vocal cords evaluated presented a mucosal wave, which was normal in 3 patients with a glottic source and clearly reduced in the others. Only one case presented phase asymmetry. The mean values for the amplitude asymmetry index were 0.92 and 0.68, for the mixed and supraglottic vibratory sources, respectively. (+info)