Soft Phonation Index Research Articles

Objective and Subjective Evaluation of Voice Quality in Multiple Sclerosis

The aim of this comparative, controlled, cross-sectional study is to evaluate the voice quality in patients with multiple sclerosis (MS) by subjective and objective methods. Female patients with MS (n=27) and age- and sex-matched healthy controls (n=27) were included in this study. Vocal functions were evaluated by a multidimensional set composed of videolaryngostroboscopic examination, acoustic analysis, and subjective measurements (GRBAS and "Voice Handicap Index"). Jitter percent, shimmer percent, and soft phonation index (SPI) values were higher in MS patients compared to controls (Jitt, P=0.001; Shim, P=0.033; SPI P<0.0001). Maximum phonation time was significantly shorter for MS patients compared to controls (P<0.0001). Stroboscopic examination revealed that 16 out of 27 MS patients have a "posterior chink" as glottic closure pattern with higher SPI values (40%). Noise to harmonic ratio (NHR) and mean fundamental frequency (F0) values were similar for MS and control groups (NHR, P=0.737; F0, P=0.976). In this study, most of the MS patients had dysphonia due to weakness of voice. MS tends to worsen acoustic parameters including fundamental frequency, SPI, and jitter values. These results are consistent with the more asthenic voice quality observed in MS group.

Acoustic Analysis of Snoring Sounds by a Multidimensional Voice Program

This prospective study aimed to determine whether the acoustic characteristics of snoring sounds differed between simple snorers and patients with obstructive sleep apnea syndrome (OSAS) by using a multidimensional voice program (MDVP) that analyzes various aspects of voice. Fifty-eight patients (48 men, 10 women) with a history of snoring were included in the study. All patients underwent conventional polysomnography (PSG). Twelve subjects were diagnosed as simple snorers and 46 subjects were diagnosed with OSAS. The mean body mass index (BMI) of simple snorers was 24.7 kg/m and that of patients with OSAS was 25.8 kg/m. Natural overnight snoring was recorded from each subject while they slept during PSG. Using the multiple token protocols of MDVP, 30 snores from each subject were analyzed automatically. For data analysis, four markers were used: peak frequency, soft phonation index (SPI), noise to harmonics ratio (NHR), and power ratio. The Mann-Whitney U test revealed significant differences between the SPI, NHR, and power ratio of simple snorers and patients with OSAS. Simple snorers had a high SPI value. OSAS-related snorers demonstrated a high NHR and low power ratio. MDVP can be used for snoring sound analysis as a noninvasive examination of sleep-related breathing disorders for differential diagnosis. However, a suitable option that is rapid and has an easy-to-use interface would be more advantageous for analyzing snoring sounds.

The clinical utility of the soft phonation index

This paper investigates the applicability of the soft phonation index (SPI) as an indicator of vocal fold adduction. The SPI is one of 33 acoustic parameters calculated and displayed from a single vocalization by the multi‐dimensional voice program (MDVP). A review of pertinent literature revealed that while increased values of SPI are presumed to be associated with incomplete adduction of the vocal folds, results should be interpreted cautiously as the index has not been sufficiently studied. The purpose of this pilot study was to determine how consistently SPI tracks systematic changes in vocal fold adduction. Samples of normal, breathy and pressed phonation produced by female speakers were analysed. As predicted, a significant increase in SPI for breathy productions was demonstrated. However, increases in SPI were also noted for pressed phonation. Possible explanations and implications for clinical application are discussed.

Perceptual evaluation of voice quality and its correlation with acoustic measurements

To determine whether a correlation exists between the Grade, Roughness, Breathiness, Aesthenia, Strain (GRBAS) scale (a subjective measure of voice) and the Multi-Dimensional Voice Program (MDVP) scale (an objective measure of voice). A retrospective review of 37 voice patients (12 male/25 female) was conducted. Each voice was perceptually evaluated using the GRBAS scale by an experienced speech pathologist and acoustically analyzed using the MDVP scale. Statistical analysis using a multivariate regression model identified a significant correlation between the noise-related parameters of MDVP and the components of the GRBAS scale. Grade correlated with voice turbulence index (VTI), noise harmonic ratio (NHR), and soft phonation index (SPI). Roughness correlated with NHR only. Breathiness correlated with SPI only. Aesthenia also correlated with SPI only. Of the 19 acoustic variables measured by the MDVP system, only three noise parameters significantly correlated with the GRBAS perceptual voice analysis. Perhaps “noise” is the perceived acoustical quality of the dysphonic voice. A voice quantifying measure such as a “voice index score” could be proposed using the GRBAS scoring and the three clinically relevant MDVP values following further studies.

Acoustic and Perceptual Indicators of Normal and Pathological Voice

The aim of this study was to obtain acoustic correlates to vocal quality of a group of men and women with and without voice disorders, based on evaluations of a group of judges experienced in the field of vocal rehabilitation. In male subjects, perceptual evaluation of normal, hoarse and rough voice qualities was related to the following acoustic features: frequency perturbation measures (JITA, RAP, and SPPQ), amplitude perturbation (SAPQ and VAM), soft phonation index (SPI) and fundamental frequency tremor intensity (FTRI). While these measures presented normal values for normal voice, hoarseness showed some deviations in perturbation frequency variables and very high SPI values, while rough voice showed deviations in all the measures. Qualities of female voices were perceived as normal, breathy and hoarse, but the acoustic correlates of these qualities were less conclusive.

Multidimensional voice program analysis (MDVP) and the diagnosis of pediatric vocal cord dysfunction

Vocal cord dysfunction (VCD) can present with signs and symptoms that mimic asthma. This may lead to unnecessary pharmacologic treatment or more invasive measures including intubation. Presently, the diagnosis of VCD can only be confirmed when a patient is symptomatic, via pulmonary function testing (PFT) or visualization of adduction of the vocal cords during inspiration by direct laryngoscopy. Multidimensional Voice Program (MDVP) analysis. a computer program which analyzes various aspects of voice, can detect abnormal voice patterns of patients with upper airway pathology. We determined whether MDVP analysis was useful in the diagnosis of VCD. We conducted chart reviews of patients referred to our department from 1995 to 1998 with the presumed diagnosis of VCD who had undergone MDVP analysis. The diagnosis of VCD was based on the presenting history, PFT results, laryngoscopy results, as well as voice evaluation conducted by a speech-language pathologist. We analyzed six consecutive patients referred for this investigation. We delineated common trends in the variables measured on MDVP analysis in VCD patients. and compared these with controls and other vocal cord pathology. Five cases of possible VCD had abnormalities in the MDVP variable of soft phonation index (SPI). All five also had abnormalities in the variation in fundamental frequency (vFo). In one case, MDVP analysis was conducted pre- and posttreatment for VCD, and SPI and vFo both normalized. In a sixth case of possible VCD. the diagnosis was not confirmed as the patient had normal PFTs and laryngoscopy. MDVP analysis was normal in this individual. The pattern of abnormal SPI and vFo was not seen in a group of normal controls or in patients with vocal cord nodules. MDVP analysis may be a useful tool when diagnosingVCD, as well as in evaluating response to treatment.

The effect of levodopa on vocal function in Parkinson's disease.

Phonatory and articulatory dysfunctions are frequent observations in Parkinson's disease. We have investigated, using acoustic measures, the effects of levodopa treatment on vocal function in 20 patients with Parkinson's disease before and after levodopa. These patients were also compared with a matched control group. The mean age was 63.5 +/- 9.66 years, Hoehn-Yahr stage was 2.38 +/- 0.45, and onset mean age was 56.5 +/- 10.36 years. Paired Wilcoxon tests were performed to compare measurements before and after levodopa. The acoustic analysis using Computerized Speech Lab and MultiDimensional Voice Program software programs (Kay Elemetrics, Lincoln Park, NJ, USA) showed that measurements of fundamental frequency (p < 0.017) were significantly increased after medication, whereas short-term frequency perturbation jitter (p < 0.033), soft phonation index (noise parameter) (p < 0.015 ), and frequency tremor intensity index (p < 0.018) were significantly decreased after medication. The objective measurements of acoustic analysis are useful in evaluating the dopaminergic pharmacologic response in Parkinson's disease. The improvement in fundamental frequency and other vocal parameters may be a result of decrease in laryngeal hypokinesia and rigidity.

EFFECTS OF RACE AND SEX ON ACOUSTIC FEATURES OF VOICE ANALYSIS

This study sought to provide preliminary normative data for the vocal productions of 44 Euro-American and 40 African-American elderly speakers and to test the hypotheses that (1) Euro-American elderly speakers do not have significantly different acoustic parameters of voice from African-American elderly speakers, and (2) elderly male speakers (both Euro-American and African-American) do not have significantly different acoustic parameters of voice from elderly female speakers (both Euro-American and African-American). Voice samples from groups of 44 Euro-American (21 men and 23 women) and 40 African-American (20 men and 20 women) elderly speakers (ages 70 to 80 years) from northeastern Arkansas were compared on measures of 15 selected multidimensional voice profile (KAY Elemetrics) acoustic parameters. Analysis show that Euro-American elderly speakers did not differ significantly from African-American elderly speakers on the measurements of all the selected acoustic parameters of voice, and elderly male speakers as a group differed from elderly female speakers on the measurements of absolute jitter, soft phonation index, and standard deviation of the fundamental frequency as well as fundamental frequency in Hz. The findings suggest it may not be necessary to establish separate acoustic norms of voice for Euro-American and African-American elderly speakers. However, some acoustic parameters of voice are highly sex-dependent, and different norms may be needed for male and female speakers regardless of their racial origins.

Voice signal analysis in laryngeal hyperreactivity

Increased reactions of the laryngeal mucosal membrane can appear after acetylcholine (ACH) inhalation. A red mucous membrane, vocal cord edema, mucus formation, changes in the glottic configuration and (rarely) subglottic edema are visible to laryngoscopic observations. The influence on various voice parameters in patients with and without laryngeal hyperreactivity was researched in order to decide the reliability of voice parameter measurements in clinical practice. Significant variations of the soft phonation index (SPI), the fundamental frequency variation (vFo), the noise-to-harmonic ratio (NHR) and the voice turbulence index (VTI) were examined for their correlations with the observable features of laryngeal hyperreactivity. A single diagnosis of hyperreactivity with voice parameter analysis failed in 50% of the patients examined because of functional voice instability and irregularities seen. Only with both laryngoscopy for reliable discrimination and voice parameter analysis for quantitative registration were findings sufficient for assessing laryngeal hyperreactivity.