| 1. |
- Andrade, Pedro Amarante, et al.
(författare)
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The Flow and Pressure Relationships in Different Tubes Commonly Used for Semi-occluded Vocal Tract Exercises
- 2016
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Ingår i: Journal of Voice. - : Mosby-Elsevier. - 0892-1997 .- 1873-4588. ; 30:1, s. 36-41
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Tidskriftsartikel (refereegranskat)abstract
- This experimental study investigated the back pressure (Pback) versus flow (U) relationship for 10 different tubes commonly used for semi-occluded vocal tract exercises, that is, eight straws of different lengths and diameters, a resonance tube, and a silicone tube similar to a Lax Vox tube. All tubes were assessed with the free end in air. The resonance tube and silicone tube were further assessed with the free end under water at the depths from 1 to 7 cm in steps of 1 cm. The results showed that relative changes in the diameter of straws affect Pback considerably more compared with the same amount of relative change in length. Additionally, once tubes are submerged into water, Pback needs to overcome the pressure generated by the water depth before flow can start. Under this condition, only a small increase in Pback was observed as the flow was increased. Therefore, the wider tubes submerged into water produced an almost constant Pback determined by the water depth, whereas the thinner straws in air produced relatively large changes to Pback as flow was changed. These differences may be taken advantage of when customizing exercises for different users and diagnoses and optimizing the therapy outcome.
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| 4. |
- Geneid, A., et al.
(författare)
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Long-term follow-up of patients with spasmodic dysphonia and improved voice despite discontinuation of treatment
- 2017
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Ingår i: Folia Phoniatrica et Logopaedica. - : S. Karger. - 1021-7762 .- 1421-9972. ; 68:3, s. 144-151
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To evaluate voice function in patients with adductor spasmodic dysphonia (AdSD) who discontinued botulinum toxin (BTX) treatment because they felt that their voice had improved sufficiently. Patients and Methods: Twenty-eight patients quit treatment in 2004, of whom 20 fulfilled the inclusion criteria for the study, with 3 subsequently excluded because of return of symptoms, leaving 17 patients (11 males, 6 females) included in this follow-up study. A questionnaire concerning current voice function and the Voice Handicap Index were completed. Audio-perceptual voice assessments were done by 3 listeners. The inter- and intrarater reliabilities were r > 0.80. Results: All patients had a subjectively good stable voice, but with differences in their audio-perceptual voice assessment scores. Based on the pre-/posttreatment auditory scores on the overall degree of AdSD, patients were divided into 2 subgroups showing more and less improvement, with 10 and 7 patients, respectively. The subgroup with more improvement had shorter duration from the onset of symptoms until the start of BTX treatment, and included 7 males compared to only 4 males in the subgroup with less improvement. Conclusion: It seems plausible that the symptoms of spasmodic dysphonia may decrease over time. Early intervention and male gender seem to be important factors for long-term reduction of the voice symptoms of AdSD.
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| 5. |
- Gleiser, Julieta E., et al.
(författare)
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A method for extracting vibrato parameters applied to violin performance
- 1998
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Ingår i: TMH-QPSR. - Stockholm. ; 39:4, s. 039-044
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- A method is presented which semi-automatically extracts the fundamental frequency and displays as continuous signals vibrato rate, vibrato extent and sound level. The method is tested on specially made recordings of violin music with piano accompaniment, using a small microphone mounted directly on the violin. The fundamental frequency was successfully extracted by means of a waveform correlation program. Likewise, vibrato rate and extent were extracted separately for each tone from the fundamental frequency signal after elimination of its DC component. The results seem promising, offering the opportunity of visual examination and measurement of changes in vibrato characteristics during performances of entire pieces of music.
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| 6. |
- Granqvist, Svante, et al.
(författare)
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A method of applying Fourier analysis to high-speed laryngoscopy
- 2001
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Ingår i: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 110:6, s. 3193-3197
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Tidskriftsartikel (refereegranskat)abstract
- A new method for analysis of digital high-speed recordings of vocal-fold vibrations is presented. The method is based on the extraction of light-intensity time sequences from consecutive images, which in turn are Fourier transformed. The spectra thus acquired can be displayed in four different modes, each having its own benefits. When applied to the larynx, the method visualizes oscillations in the entire laryngeal area, not merely the glottal region. The method was applied to two laryngoscopic high-speed image sequences. Among these examples, covibrations in the ventricular folds and in the mucosa covering the arytenoid cartilages were found. In some cases the covibrations occurred at other frequencies than those of the glottis.
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| 9. |
- Granqvist, Svante, 1963-
(författare)
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Computer methods for voice analysis
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis consists of five articles and a summary. Thethesis deals with methods for measuring properties of thevoice. The methods are all computer-based, but utilisedifferent approaches for measuring different aspects of thevoice. Paper I introduces the Visual Sort and Rate (VSR) method forperceptual rating of voice quality. The method is based on theVisual Analogue Scale (VAS), but simultaneously shows allstimuli as icons along the VAS on the computer screen. As thelistener places similar-sounding stimuli close to each otherduring the rating process, comparing stimuli becomeseasier. Paper II introduces the correlogram. Fundamental frequencyF0 sometimes cannot be strictly defined, particularly forperturbed voice signals. The method displays multipleconsecutive correlation functions in a grey scale image. Thus,the correlogram avoids selecting a single F0 value. Rather itpresents an unbiased image of periodicity, allowing theinvestigator to select among several candidates, ifappropriate. PaperIII introduces a method for detection of phonation tobe utilised in voice accumulators. The method uses twomicrophones attached near the subject’s ears. Phase andamplitude relations of the microphone signals are used to forma phonation detector. The output of the method can be used tomeasure phonation time, speaking time and fundamental frequencyof the subject, as well as sound pressure level of both thesubject’s voicing and the ambient sounds. Paper IV introduces a method for Fourier analysis ofhigh-speed laryngoscopic imaging. The data from the consecutiveimages are re-arranged to form time-series that reflect thetime-variation of light intensity in each pixel. Each of thesetime series is then analysed by means of Fouriertransformation, such that a spectrum for each pixel isobtained. Several ways of displaying these spectra aredemonstrated. Paper V examines a test set-up for simultaneous recording ofairflow, intra-oral pressure, electro-glottography, audio andhigh-speed imaging. Data are analysed with particular focus onsynchronisation between glottal area and inverse filteredairflow. Several methodological aspects are also examined, suchas the difficulties in synchronising high-speed imaging datawith the other signals.
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| 10. |
- Granqvist, Svante, et al.
(författare)
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Paranasal sinus ventilation by humming
- 2006
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Ingår i: Journal of the Acoustical Society of America. - : Acoustical Society of America (ASA). - 0001-4966 .- 1520-8524. ; 119:5, s. 2611-2617
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Tidskriftsartikel (refereegranskat)abstract
- The gas nitric oxide (NO) is generated in the human paranasal sinuses and can be measured in nasally exhaled air. During humming, a marked increase in exhaled NO content has been observed. The acoustic phenomenon responsible for this evacuation of NO gas from the sinuses was analyzed. A tube model was constructed with a syringe containing NO gas attached radially. This tube was excited with an air stream modulated by a sine wave. Increased evacuation was observed whenever the syringe was not located at a pressure node of the exciting sine wave. A computer model of the system showed a good matching of observed pressure versus frequency data in the syringe resonator. The results thus suggest that the alternating pressure in the nasal cavity forces the air plug in the ostium of the paranasal sinus resonators to vibrate, thus expelling from the cavity NO gas, which is transported to free air by the exhalatory air stream.
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