Standardization of nasometry for normal Egyptian Arabic speakers.

OBJECTIVE: The aim of this study was to collect the normative values of nasalance for Egyptian Arabic speakers in different age groups, using Arabic speech samples in order to compare patients with disturbed nasality. MATERIAL AND METHODS: This study included 300 normal Egyptian volunteers divided into three groups according to their ages: group I = children (n = 92; age 3 years, 3 months to 9 years), group II = teenagers (n = 76; age 9-18 years) and group III = adults (n = 132; age above 18 years). The Nasometer II 6400 was used for the analysis of speech samples. All subjects were asked to perform four speech tasks that were based on the MacKay-Kummer SNAP Test-R and modified to be applicable to the Arabic language, especially to the Egyptian dialect. RESULTS: The normative values for nasometric assessment in the different age groups were studied. The results demonstrated nasalance score variations according to age and gender. Most of the nasalance score norms of the Egyptian children demonstrated statistically significant differences when compared with the norms of children for the MacKay-Kummer Test-R. CONCLUSION: The Egyptian Arabic SNAP test is an easy, noninvasive and objective procedure that is suitable for all age groups.

Tracking voice change after thyroidectomy: application of spectral/cepstral analyses.

This study evaluates the utility of perioperative spectral and cepstral acoustic analyses to monitor voice change after thyroidectomy. Perceptual and acoustic analyses were conducted on speech samples (sustained vowel /α/ and CAPE-V sentences) provided by 70 participants (36 women and 34 men) at four study time points: prior to thyroid surgery and 2 weeks, 3 months and 6 months after thyroidectomy. Repeated measures analyses of variance focused on the relative amplitude of the dominant harmonic in the voice signal (cepstral peak prominence, CPP), the ratio of low-to-high spectral energy, and their respective standard deviations (SD). Data were also examined for relationships between acoustic measures and perceptual ratings of overall severity of voice quality. Results showed that perceived overall severity and the acoustic measures of the CPP and its SD (CPPsd) computed from sentence productions were significantly reduced at 2-week post-thyroidectomy for 20 patients (29% of the sample) who had self-reported post-operative voice change. For this same group of patients, the CPP and CPPsd computed from sentence productions improved significantly from 2-weeks post-thyroidectomy to 6-months post-surgery. CPP and CPPsd also correlated well with perceived overall severity (r = -0.68 and -0.79, respectively). Measures of CPP from sustained vowel productions were not as effective as those from sentence productions in reflecting voice deterioration in the post-thyroidectomy patients at the 2-week post-surgery time period, were weaker correlates with perceived overall severity, and were not as effective in discriminating negative voice outcome (NegVO) from normal voice outcome (NormVO) patients as compared to the results from the sentence-level stimuli. Results indicate that spectral/cepstral analysis methods can be used with continuous speech samples to provide important objective data to document the effects of dysphonia in a post-thyroidectomy patient sample. When used in conjunction with patient's self-report and other general measures of vocal dysfunction, the acoustic measures employed in this study contribute to a complete profile of the patient's vocal condition.

[Standardised voice diagnostics--first experiences with a computer-aided voice strain test]. / Standardisierte Stimmdiagnostik--Erste Erfahrungen mit einem computergestützten Stimmbelastungstest.

INTRODUCTION: Vocal strain deficits are not yet standardised quantified. The investigation of vocal parameters in real professional requirements is still in experimental stage. Simulating these requirements in a shorter time with higher sound pressure levels is already possible by using a computer aided test. MATERIALS AND METHODS: 28 patients with voice disorders and 12 subjects without voice complaints attended a computer-aided voice strain test (reading a text 15 min, five minutes at 70 dB (A), 75 dB (A) and 70 dB (A); software and hardware: DiVAS, XION, Berlin). Before and after test they completed self assessment questionnaires and passed through an acoustic voice analysis. RESULTS: The presented voice strain test gives hints of reduced vocal load capacity in everyday life. The test was assessed by all participants, patients and volunteers, as "strenuous". For the analysis, the results will be graphically illustrated and documented. DISCUSSION: Due to the consistency of the anamnestic data with the results of the voice strain test, we assume that with the new voice strain test a total lack of voice resilience can be identified and documented by using a higher short-term vocal loading and analysing the effects on vocal sound and mood.

Directionality and maneuvering effects on a surface ship underwater acoustic signature.

This work examines underwater source spectra of a small (560 tons, 40 m length), single-screw oceanographic vessel, focusing on directionality and effects of maneuvers. The measurements utilized a set of four, self-contained buoys with GPS positioning, each recording two calibrated hydrophones with effective acoustic bandwidth from 150 Hz to 5 kHz. In straight, constant-speed runs at speeds up to 6.2 m s(-1), the ship source spectra showed spectral levels in reasonable agreement with reference spectra. The broadband source level was observed to increase as approximately speed to the fourth power over the range of 2.6-6.1 m s(-1), partially biased at low speeds by nonpropulsion machinery signals. Source directionality patterns were extracted from variations in source spectra while the ship transited past the buoy field. The observed spectral source levels exhibited a broadside maximum, with bow and stern aspect reduced by approximately 12-9 dB, respectively, independent of frequency. An empirical model is proposed assuming that spectral source levels exhibit simultaneous variations in aspect angle, speed, and turn rate. After correction for source directionality and speed during turning maneuvers, an excess of up to 18 dB in one-third octave source levels was observed.

Developing standards for distortion product otoacoustic emission measurements.

Characteristics of distortion product otoacoustic emission (DPOAE) measurements were investigated by comparing responses from two different emission measurement systems in 40 volunteers (78 ears) and making test-retest measurements of each system in 20 ears. For transformation of results between systems, it was shown that the minimum data set consisted of input-output (growth) functions obtained by stepping stimulus levels across a wide range, for each set of stimulus frequencies (1-8 kHz). Linear transformations were considered which involved either recalibration of the emission amplitude (vertical transformation) or of the stimulus levels (horizontal transformation). Horizontal transformations provided better agreement between growth functions from the two systems. For frequencies 4-8 kHz, the means of the horizontal shifts required ranged from 8 to 14 dB, clearly exceeding test-retest variability. The optimal horizontal transformation was derived and applied uniformly to all emission measurements; correlations r=0.81-0.89 were found between transformed emission amplitudes. To minimize the necessity for such transformations and to reduce the variability found both within and between systems, development of standardized equipment and methods is suggested for DPOAE measurements, including: (1) an optimized in-ear probe assembly; (2) use of intensity calibration; and (3) a focus on emission "threshold" measurement and analysis.

[Diagnostic value of nasometry--representative study of patients with cleft palate and normal subjects]. / Die diagnostische Wertigkeit der Nasometrie--eine reprasentative Studie fur Patienten mit Lippen-Kiefer-Gaumensegel-Spalten und Gesunde.

In the rehabilitation of cleft palate patients the quality of spoken language represents one of the most important aspects of successful social integration. It is therefore necessary to direct special attention to phoniatric care and speech therapy following operative reconstruction. One of the main problems is the comparison of subjective and objective measures of the degree and type of nasal disorder. In an interdisciplinary project at the University of Jena nasometry was assessed. Due to a lack of norm values for German a representative sample for the calibration of cleft palate patients and normal subjects was collected. Speech was elicited using standardized and phonetically validated reading materials. Nasalance measurements were compared with judgements made by a group of trained listeners who were asked to assess voice quality (RBH) and nasality. A database containing nasalance values and acoustic signals from 120 subjects was built up. The results generally exhibited highly significant correlations between instrumental measurements and auditory judgements. Profiles of norm values for a phonetically and statistically reliable standard for German were obtained, which in turn can be used as a comparative basis for further studies.

Detection of laryngeal function using speech and electroglottographic data.

The purpose of this research was to develop quantitative measures for the assessment of laryngeal function using speech and electroglottographic (EGG) data. We developed two procedures for the detection of laryngeal pathology: 1) a spectral distortion measure using pitch synchronous and asynchronous methods with linear predictive coding (LPC) vectors and vector quantization (VQ) and 2) analysis of the EGG signal using time interval and amplitude difference measures. The VQ procedure was conjectured to offer the possibility of circumventing the need to estimate the glottal volume velocity wave-form by inverse filtering techniques. The EGG procedure was to evaluate data that was "nearly" a direct measure of vocal fold vibratory motion and thus was conjectured to offer the potential for providing an excellent assessment of laryngeal function. A threshold based procedure gave 75.9 and 69.0% probability of pathological detection using procedures 1) and 2), respectively, for 29 patients with pathological voices and 52 normal subjects. The false alarm probability was 9.6% for the normal subjects.

Reproducibility of temporomandibular joint clicking.

AIMS: To investigate the stability of temporomandibular joint (TMJ) clicking over a 10-day period and the effect of different open/close velocities on sound amplitude and power spectra in a group of subjects with subjectively stable unilateral clicking during the 3 months preceding the recordings. METHODS: Ten volunteers were recorded with a self-developed microcomputer-based system used in a previous study on asymptomatic subjects. The recordings were performed during 4 different sessions at 3 different open/close rates in each session. The subjective sound intensity was measured with a 100-mm visual analog scale (VAS). The VAS scores, the maximum amplitudes, and the power spectra of the signals were tested for statistical differences among the different open/close rates and over the sessions. The reliability of measurements was also calculated. RESULTS: The maximum amplitude and the power spectra of the TMJ clicking varied between subjects in a broad range that differed from those reported for asymptomatic subjects. No statistically significant differences were found within subjects for the subjective VAS scores for the maximum signal amplitudes or for the power spectrum parameters among the open/close rates and over the 4 sessions. For all 3 open/close rates and for the 4 sessions, a good to excellent reliability of measurements was determined, the values of r being mostly over 0.75. CONCLUSION: Within the limits of the experiment, TMJ clicking was subjectively and objectively stable over a period of 10 days. Therefore, the constant subjective perception of sound intensity was supported by the objective measurements.

Computer aided evaluation of phonetograms.

The phonetogram represents an area limited by piano and forte contours of the sound pressure levels along the vocal range. Phonetograms are used in the diagnosis of voice status. Apart from reference phonetograms and the extraction of single parameters, phonetograms have not been evaluated quantitatively in medical practice. The present computer program divided the phonetogram into subareas which were approximated by simple patterns (ellipses). The ellipse parameters were used to evaluate voice efficiency, to recognize voice categories, and to derive diagnostic comments.

The application of fractal dimension to temporomandibular joint sounds.

Researchers have attempted to use mathematical analysis of the sounds produced by symptomatic temporomandibular joints (TMJ) as a diagnostic modality. However, previous studies have generally concluded that such analyses have little diagnostic utility. Previous studies using Fourier transforms and visual inspection were of limited success. This paper reports the results of a preliminary retrospective study using fractal analysis to analyze sounds produced by symptomatic temporomandibular joints previously diagnosed using other clinical modalities as having internal derangements with reducing discs. Multiple mandibular opening and closing cycles were recorded in four subjects. The study revealed that fractal analysis produced a high degree of reproducibility within, and similarity across subjects. The fractual dimension associated with joints having this pathology was found to be 1.266, revealing that fractal analysis shows promise as a noninvasive method for diagnosing interarticular TMJ pathology.

Estimation of analogue pre-filtering characteristics for CORSA standardisation.

This paper is concerned with devising a standard procedure for determining the gain and phase responses of the analogue filters used to pre-process pulmonary signals prior to their digitisation. The customary high-pass filtering, in particular, will strongly affect the time-domain wave-shapes of digitised signals and this must be taken into account when analysing the signals. Several means of determining the effect of the high-pass filtering are investigated and a measurement procedure is proposed which may be easily carried out using simple laboratory equipment.

Absolute determination of ultrasonic intensity in a diagnostic Doppler ultrasound equipment.

Absolute ultrasonic intensity from pencil type Doppler-shift probes has been measured using a radiation balance technique. Accuracy and repeatability of measurement have been considered and effects of using different absorbing materials and different liquids other than degassed water on intensity measured have also been discussed. The technique is recommended for routine monitoring of intensity levels from Doppler ultrasound equipment used by clinicians for in-vivo blood flow measurements in hospitals. In conclusion, basic requirements for accurate measurement of ultrasonic intensity using this technique have been suggested.

Development of a new clot formation protocol for standardized in vitro investigations of sonothrombolysis.

BACKGROUND: Agreement about the most suitable clot formation protocol for sonothrombolysis investigations is lacking. Lysis rates vary strongly owing to different test conditions and, thus, cannot be compared. We aim to establish a simple but physiologically grounded protocol for in vitro coagulation to enable standardized sonothrombolysis investigations. METHOD: Clots were generated from platelet-rich plasma (PRP) obtained by centrifugation (10 min, 180 × g) of human venous blood (VB). PRP was mixed with the boundary layer formed between the supernatant and the erythrocyte layer. To achieve clots with different platelet counts, PRP was gradually substituted with platelet-free plasma (PFP), harvested from the supernatant of VB after centrifugation (10 min, 2570 × g). Clot types were examined for histological appearance, hydrodynamic resistance under physiological flows, and lysis rate measured by weight loss after a 2-h treatment with recombinant tissue plasminogen activator (rt-PA) (60 kU/ml). Lysis rates of the most suitable clot were measured after a 1-h treatment with rt-PA (60 kU/ml), and combined treatment with rt-PA and 2-MHz transcranial color-coded sonography (TCCS) (0.179 W/cm(2)) or 2-MHz transcranial Doppler (TCD) (0.457 W/cm(2)). RESULTS: With increased platelet count, the hydrodynamic resistance of the artificial clots increased, their histological appearance became more physiological, and lysis rates decreased. The most suitable clots consisted of 1.5-ml PRP, 2.0-ml PFP, and 0.5-ml boundary layer. Their lysis rates were 36.7 ± 7.8% (rt-PA), 40.8 ± 8.6% (rt-PA+TCCS), and 40.4 ± 8.3% (rt-PA+TCD). COMPARISON WITH EXISTING METHODS: These systemic investigations were conducted for the first time. CONCLUSION: This protocol should be used for standardized sonothrombolysis investigations.

A flexible analysis tool for the quantitative acoustic assessment of infant cry.

PURPOSE: In this article, the authors describe and validate the performance of a modern acoustic analyzer specifically designed for infant cry analysis. METHOD: Utilizing known algorithms, the authors developed a method to extract acoustic parameters describing infant cries from standard digital audio files. They used a frame rate of 25 ms with a frame advance of 12.5 ms. Cepstral-based acoustic analysis proceeded in 2 phases, computing frame-level data and then organizing and summarizing this information within cry utterances. Using signal detection methods, the authors evaluated the accuracy of the automated system to determine voicing and to detect fundamental frequency (F 0) as compared to voiced segments and pitch periods manually coded from spectrogram displays. RESULTS: The system detected F 0 with 88% to 95% accuracy, depending on tolerances set at 10 to 20 Hz. Receiver operating characteristic analyses demonstrated very high accuracy at detecting voicing characteristics in the cry samples. CONCLUSIONS: This article describes an automated infant cry analyzer with high accuracy to detect important acoustic features of cry. A unique and important aspect of this work is the rigorous testing of the system's accuracy as compared to ground-truth manual coding. The resulting system has implications for basic and applied research on infant cry development.

Application of the envelope difference index to spectrally sparse speech.

PURPOSE: Amplitude compression is a common hearing aid processing strategy that can improve speech audibility and loudness comfort but also has the potential to alter important cues carried by the speech envelope. In previous work, a measure of envelope change, the Envelope Difference Index (EDI; Fortune, Woodruff, & Preves, 1994), was moderately related to recognition of spectrally robust consonants. This follow-up study investigated the relationship between the EDI and recognition of spectrally sparse consonants. METHOD: Stimuli were vowel-consonant-vowel tokens processed to reduce spectral cues. Compression parameters were chosen to achieve a range of EDI values. Recognition was measured for 20 listeners with normal hearing. RESULTS: Both overall recognition and perception of consonant features were reduced at higher EDI values. Similar effects were noted with noise-vocoded and sine-vocoded processing and regardless of whether periodicity cues were available. CONCLUSION: The data provide information about the acceptable limits of envelope distortion under constrained conditions. These limits can be used to consider the impact of envelope distortions in situations where other cues are available to varying extents.

Articulatory-to-acoustic relations in response to speaking rate and loudness manipulations.

PURPOSE: In this investigation, the authors determined the strength of association between tongue kinematic and speech acoustics changes in response to speaking rate and loudness manipulations. Performance changes in the kinematic and acoustic domains were measured using two aspects of speech production presumably affecting speech clarity: phonetic specification and variability. METHOD: Tongue movements for the vowels /ia/ were recorded in 10 healthy adults during habitual, fast, slow, and loud speech using three-dimensional electromagnetic articulography. To determine articulatory-to-acoustic relations for phonetic specification, the authors correlated changes in lingual displacement with changes in acoustic vowel distance. To determine articulatory-to-acoustic relations for phonetic variability, the authors correlated changes in lingual movement variability with changes in formant movement variability. RESULTS: A significant positive linear association was found for kinematic and acoustic specification but not for kinematic and acoustic variability. Several significant speaking task effects were also observed. CONCLUSION: Lingual displacement is a good predictor of acoustic vowel distance in healthy talkers. The weak association between kinematic and acoustic variability raises questions regarding the effects of articulatory variability on speech clarity and intelligibility, particularly in individuals with motor speech disorders.

[The voice evaluation protocol of the European Laryngological Society (ELS) -- first results of a multicenter study]. / Das Stimmdiagnostik-Protokoll der European Laryngological Society (ELS) -- erste Erfahrungen im Rahmen einer Multizenterstudie.

INTRODUCTION: A multidimensional protocol has been established by the ELS in order to reach better agreement and standardisation for functional assessment of pathologic voices. In order to evaluate the validity, practicability and applicability of this protocol the experiences of 6 european voice centres have been analysed in a retrospective study. MATERIAL AND METHODS: The ELS protocol comprises 5 dimensions: perceptual voice evaluation, videostroboscopy, acoustics, aerodynamics and subjective rating by the patient. Results obtained in 94 patients with benign voice disorders were evaluated retrospectively in a multicenter study. RESULTS: According to our results, the validity, practicability and applicability of the ELS protocol was largely satisfactory. This was true for all "common" voice disorders, but not for extreme voice alterations (e. g. spasmodic dysphonia, aphonia, substitution voices). The 5 dimension proofed to be not redundant and were able to selectively differentiate pre- post changes among various etiologies of voice disorders, various types of treatment and genders.

The accuracy of formant frequency measurements: a comparison of spectrographic analysis and linear prediction.

The accuracy of spectrographic techniques and of linear prediction analysis in measuring formant frequencies is compared. The first three formant frequencies of 90 synthetic speech tokens were measured by three experienced spectrographic readers and by linear prediction analysis. For fundamental frequencies between 100 and 300 Hz, both methods are accurate to within approximately +/- 60 Hz for both first and second formants. The third formant can be measured with the same degree of accuracy by linear prediction, but only to within +/- 110 Hz by spectrographic means. The accuracy of both methods decreases greatly when fundamental frequency is 350 Hz or greater. These limits of measurement appear to be within the range of the difference limens for formant frequencies.

Laryngeal perturbation analysis: minimum length of analysis window.

Laryngeal perturbation measures have been applied to the analysis of cycle-to-cycle changes in periodicity and amplitude of the acoustic voice signal for more than 25 years. Although such measures enjoy widespread clinical application, there is little agreement about basic methodology, including the length of signal to be analyzed. The purpose of this study was to examine changes in laryngeal perturbation measures as a function of length of signal analyzed in 18 subjects who complained of symptoms of possible laryngeal dysfunction. The results showed that as many as 190 cycles may be necessary before jitter asymptotes and as many as 130 cycles may be necessary before shimmer asymptotes. Pathological voices may require a longer analysis window for perturbation analysis than do nonpathological voices.