Elina Kankare

Vocal Loading-Related Changes in Male Teachers’ Voices Investigated before and after a Working Day

Vocal loading-related changes have mainly been investigated in female voice users. The present study investigated male teachers’ voices before and after a working day. A questionnaire was used to select 22 male teachers as subjects from a larger group. Ten reported suffering often from symptoms of vocal fatigue (MC = multiple complaints group), 12 reported few vocal complaints (FC group). The subjects recorded a text reading sample at habitual loudness and loudly, and sustained vowel [a:] before and after an approximately 6-hour working day. Text samples were analyzed for total sound pressure level (SPL) and SPL at three frequency regions (50–1,000 Hz, 1–2 kHz, 2–5 kHz), fundamental frequency (F0) and alpha ratio [(SPL 1–5 kHz) – SPL (50 Hz–1 kHz)]. Jitter and shimmer were calculated from the vowel. The subjects filled in a questionnaire about vocal sensations. The MC group reported more symptoms of vocal fatigue, and the symptoms increased during the working day. F0 and SPL increased in both groups. Alpha ratio increased in the MC group but remained the same in the FC group. The MC group had higher values of jitter and shimmer. Jitter diminished in the FC group but did not change significantly in the MC group. The differences between the groups reflect either different strategies for coping with vocal loading or different loading-induced changes in the vocal organ.

Changes in Voice and Subjective Sensations during a 45-min Vocal Loading Test in Female Subjects with Vocal Training

Twenty-four females (mean age 38 years) with varying amounts of vocal training read aloud from a book for 45 min (70 dB at 40 cm distance). Symptoms of the throat and voice were ascertained with a questionnaire before, during and after the test. Fundamental frequency (F₀) and sound pressure level (SPL) were measured. The alpha ratio describing the spectrum slope was calculated: SPL in the range 1–5 kHz minus SPL in the range 50 Hz–1 kHz. All measurements were made for the 1st, 5th, 15th, 30th and the 45th min of loading and for text reading before and after it. F₀, SPL and alpha values rose during the test, which may indicate adaptation to loading. During the first 5 min, however, these parameters showed a decreasing tendency, possibly reflecting warm-up. Subjects with more vocal training had a lower F₀ in the loading test. SPL seemed to reflect variation of symptoms during loading. Changes in acoustic parameters did not distinguish between subjects with most and fewest symptoms of fatigue in this test.

Subjective Evaluation of Voice and Working Conditions and Phoniatric Examination in Kindergarten Teachers

Aims: This study evaluated the prevalence of voice problems in kindergarten teachers and investigated some background factors affecting vocal health. Methods: One hundred and nineteen female kindergarten teachers volunteered by responding to an Internet questionnaire on voice habits, voice symptoms, and the amount of negative impact various working conditions may have on their voices. Phoniatric examination was carried out with a rigid laryngoscope. Results: Of the subjects, 71.5% reported frequent strain on the voice (monthly or more often), and 56.3% reported hoarseness without infection. Eighty-six percent reported that when their voice got tired during the working day it recovered quite well, well or remarkably well by the next day. Noise at work was considered most detrimental to the voice. Clear organic findings were observed in 10.9% of the cases and did not correlate with subjective voice symptoms. Conclusions: The results confirmed earlier findings that a remarkable number of kindergarten teachers suffer from voice problems and consider noise in the environment especially to be harmful to their voices. However, the majority reported recovering well from vocal symptoms. Further studies are needed on individual speech habits, working day-related voice evaluation, recovery time and work-environmental factors. A follow-up is warranted to identify the main factors leading to voice problems.

Electroglottographic contact quotient in different phonation types using different amplitude threshold levels

Contact quotient (CQ), measured by electroglottogram (EGG), is a ratio which illustrates the duration of vocal fold contact during one vocal fold period. In the present study CQEGG was calculated from a sustained vowel phonation in three different phonation types (breathy, normal, pressed) at three amplitude threshold levels (25%, 35%, 50%). CQEGG values were compared with experts’ perceptual evaluation of the firmness of phonation. The contact time of the vocal folds differed significantly between the different phonation types at all threshold levels (P < 0.01). Perceptual evaluation correlated best with CQEGG at threshold levels 25% and 35%. The results of the linear regression model suggested that by using threshold level 25% the effect of F0 and SPL on CQEGG were not significant.

Acoustic and EGG analyses of emotional utterances

Abstract The aim of the present study was to investigate whether the glottal and filter variables of emotional expressions vary by emotion and valence expressed. Prolonged emotional vowels (n = 96) were produced by professional actors and actresses (n = 4) expressing joy, surprise, interest, sadness, fear, anger, disgust, and a neutral emotional state. Acoustic parameters and the contact quotient from the electroglottographic signal (CQEGG) were calculated. Statistics were calculated for the parameters. Vocal fold contact time differed significantly between the emotional expressions reflecting differences in phonation types. It was concluded that CQEGG may vary simultaneously and inversely with F3 and F4 in emotional expressions of positive emotions. Changes in the lower pharynx and larynx may affect the higher formant frequencies.

EGG and Acoustic Analyses of Different Voice Samples: Comparison between Perceptual Evaluation and Voice Activity and Participation Profile

Objective: This study investigated whether different electroglottographic (EGG) parameters may be used to estimate voice quality and loading related to it, and whether voice quality is related to self-estimation of voice problems and laryngeal status. The effect of sample type was also considered. Methods: EGG and acoustic signals of a sustained vowel [a:] (90 dB6 cm) and text reading during noise exposure were recorded from 93 female kindergarten teachers. Analyses were made from the sustained vowel and vowel [a:] from a stressed word. Contact quotient (CQ) was calculated. Maximum velocity of increase in contact area inferred from derivative (MDEGG) was examined. Fundamental frequency was calculated from the EGG signal. From the acoustic signal sound pressure level (SPL) was computed and pressedness in voice quality was evaluated perceptually. Self-evaluation was made with Voice Activity and Participation Profile (VAPP). Indirect laryngoscopy was also performed. Results: Pressedness in voice correlated with EGG results only for the sustained vowel, and better with MDEGG than CQ values. VAPP and laryngeal evaluation did not correlate with the acoustic or EGG parameters or with perception. Conclusions: MDEGG is worth testing as an indicator of impact stress. Sustained vowel at a controlled SPL is more suitable for voice quality evaluation than a long stressed vowel from connected speech.

Vocal Fatigue Symptoms and Laryngeal Status in Relation to Vocal Activity Limitation and Participation Restriction

OBJECTIVES The study aims to investigate the vocal fatigue symptoms and laryngeal status in relation to vocal activity limitations and vocal participation restrictions. STUDY DESIGN This is a case-control study. METHODS Two hundred six teachers were divided into two groups based on the frequency of their self-reported vocal symptoms being more or less than the mean of reported frequency. The study compared odds for activity limitation and participation restriction in relation to frequency of vocal symptoms, number of vocal symptoms recurring weekly, and organic laryngeal changes. Activity limitation and participation restriction were studied using the Voice Activity and Participation Profile questionnaire. RESULTS Increased odds were found for teachers with frequent vocal symptoms and especially those with one or more vocal symptom recurring weekly. Odds were found to be 2.6-8.5 times more likely in teachers with more frequent vocal symptoms. The odds increased dramatically with increase of the number of vocal symptoms recurring weekly. Laryngeal organic changes were found to increase the odds but insignificantly. CONCLUSIONS Teachers with frequent vocal symptoms, especially those with vocal symptoms recurring weekly, have increased odds ratio for vocal activity limitation and vocal participation restrictions. High scores or frequent occurrence of self-reported vocal fatigue symptoms must be taken seriously in the evaluation of vocal working ability.

Quasi-output-cost-ratio, perceived voice quality, and subjective evaluation in female kindergarten teachers.

Abstract This study estimated vocal economy and investigated its relation to perceived voice quality and self-reported symptoms of vocal fatigue in kindergarten teachers. Quasi-output-cost ratio (QOCR) was calculated for sustained vowel [a:] at habitual loudness and at sound pressure level (SPL) of 90 dB6cm. QOCR was calculated as (SPL/CQEGG) × T/T0, where CQEGG is the contact quotient measured from the electroglottogram, T is the period length, and T0 is arbitrarily set mean period length (0.005 s in females). QOCR correlated negatively with perceived firmness at standard SPL and with the evaluation of too high pitch for the subject at both SPLs. QOCR did not predict self-reported vocal fatigue. Further studies with connected speech and objectively stated loading symptoms are warranted.

Emotions in freely varying and mono-pitched vowels, acoustic and EGG analyses

Vocal emotions are expressed either by speech or singing. The difference is that in singing the pitch is predetermined while in speech it may vary freely. It was of interest to study whether there were voice quality differences between freely varying and mono-pitched vowels expressed by professional actors. Given their profession, actors have to be able to express emotions both by speech and singing. Electroglottogram and acoustic analyses of emotional utterances embedded in expressions of freely varying vowels [a:], [i:], [u:] (96 samples) and mono-pitched protracted vowels (96 samples) were studied. Contact quotient (CQEGG) was calculated using 35%, 55%, and 80% threshold levels. Three different threshold levels were used in order to evaluate their effects on emotions. Genders were studied separately. The results suggested significant gender differences for CQEGG 80% threshold level. SPL, CQEGG, and F4 were used to convey emotions, but to a lesser degree, when F0 was predetermined. Moreover, females showed fewer significant variations than males. Both genders used more hypofunctional phonation type in mono-pitched utterances than in the expressions with freely varying pitch. The present material warrants further study of the interplay between CQEGG threshold levels and formant frequencies, and listening tests to investigate the perceptual value of the mono-pitched vowels in the communication of emotions.

Cepstral and Perceptual Investigations in Female Teachers With Functionally Healthy Voice

PURPOSE The present study aimed at measuring the smoothed and non-smoothed cepstral peak prominence (CPPS and CPP) in teachers who considered themselves to have normal voice but some of them had laryngeal pathology. The changes of CPP, CPPS, sound pressure level (SPL) and perceptual ratings with different voice tasks were investigated and the influence of vocal pathology on these measures was studied. METHOD Eighty-four Finnish female primary school teachers volunteered as participants. Laryngoscopically, 52.4% of these had laryngeal changes (39.3% mild, 13.1% disordered). Sound recordings were made for phonations of comfortable sustained vowel, comfortable speech, and speech produced at increased loudness level as used during teaching. CPP, CPPS and SPL values were extracted using Praat software for all three voice samples. Sound samples were also perceptually evaluated by five voice experts for overall voice quality (10 point scale from poor to excellent) and vocal firmness (10 point scale from breathy to pressed, with normal in the middle). RESULTS The CPP, CPPS and SPL values were significantly higher for vowels than for comfortable speech and for loud speech compared to comfortable speech (P < 0.001). Significant correlations were found between SPL and cepstral measures. The loud speech was perceived to be firmer and have a better voice quality than comfortable speech. No significant relationships of the laryngeal pathology status with cepstral values, perceptual ratings, or voice SPLs were found (P > 0.05). CONCLUSION Neither the acoustic measures (CPP, CPPS, and SPL) nor the perceptual evaluations could clearly distinguish teachers with laryngeal changes from laryngeally healthy teachers. Considering no vocal complaints of the subjects, the data could be considered representative of teachers with functionally healthy voice.