Voicing quantification is more relevant than period perturbation in substitution voices: an advanced acoustical study.

Quality of substitution voicing-i.e., phonation with a voice that is not generated by the vibration of two vocal folds-cannot be adequately evaluated with routinely used software for acoustic voice analysis that is aimed at 'common' dysphonias and nearly periodic voice signals. The AMPEX analysis program (Van Immerseel and Martens) has been shown previously to be able to detect periodicity in irregular signals with background noise, and to be suited for running speech. The validity of this analysis program is first tested using realistic synthesized voice signals with known levels of cycle-to-cycle perturbations and additive noise. Second, exhaustive acoustic analysis is performed of the voices of 116 patients surgically treated for advanced laryngeal cancer and recorded in seven European academic centers. All of them read out a short phonetically balanced passage. Patients were divided into six groups according to the oscillating structures they used to phonate. Results show that features related to quantification of voicing enable a distinction between the different groups, while the features reporting F(0)-instability fail to do so. Acoustic evaluation of voice quality in substitution voices thus best relies upon voicing quantification.

Tridimensional assessment of adductor spasmodic dysphonia pre- and post-treatment with Botulinum toxin.

Spasmodic dysphonia voices form, in the same way as substitution voices, a particular category of dysphonia that seems not suited for a standardized basic multidimensional assessment protocol, like the one proposed by the European Laryngological Society. Thirty-three exhaustive analyses were performed on voices of 19 patients diagnosed with adductor spasmodic dysphonia (SD), before and after treatment with Botulinum toxin. The speech material consisted of 40 short sentences phonetically selected for constant voicing. Seven perceptual parameters (traditional and dedicated) were blindly rated by a panel of experienced clinicians. Nine acoustic measures (mainly based on voicing evidence and periodicity) were achieved by a special analysis program suited for strongly irregular signals and validated with synthesized deviant voices. Patients also filled in a VHI-questionnaire. Significant improvement is shown by all three approaches. The traditional GRB perceptual parameters appear to be adequate for these patients. Conversely, the special acoustic analysis program is successful in objectivating the improved regularity of vocal fold vibration: the basic jitter remains the most valuable parameter, when reliably quantified. The VHI is well suited for the voice-related quality of life. Nevertheless, when considering pre-therapy and post-therapy changes, the current study illustrates a complete lack of correlation between the perceptual, acoustic, and self-assessment dimensions. Assessment of SD-voices needs to be tridimensional.

The comparison of auditory behavioral and evoked potential responses (steady state and cortical) in subjects with occupational noise-induced hearing loss.

OBJECTIVE: To define difference scores between PTA, ASSR and CERA thresholds in subjects with occupational NIHL. DESIGN: 44 subjects undergoing a medico-legal expert assessment for occupational NIHL and fulfilling criteria of reliability were considered. Assessment included: PTA, 40 Hz binaural multiple ASSR and CERA (1-2-3 kHz). RESULTS: The respective average difference scores (ASSR - PTA) for 1, 2 and 3 kHz are 13.01 (SD 10.19) dB, 12.72 (SD 8.81) dB and 10.38 (SD 8.19) dB. The average (CERA - ASSR) difference scores are 1.25 (SD 14.63) dB for 1 kHz (NS), 2.73 (SD 13.03) dB for 2 kHz (NS) and 4.51 (SD 12.18) dB for 3 kHz. The correlation between PTA and ASSR (0.82) is significantly stronger than that between PTA and CERA (0.71). In a given subject, PTA thresholds are nearly always lower (i.e., better) than ASSR thresholds, whatever the frequency (1-2-3 kHz) and the side (right - left). A significant negative correlation is found between the difference score (ASSR - PTA) and the degree of hearing loss. CONCLUSION: ASSR outperforms CERA in a medicolegal context, although overestimating the behavioral thresholds by 10-13 dB.

Objective frequency-specific hearing thresholds definition for medicolegal purposes in case of occupational NIHL: ASSR outperforms CERA.

Audiological use of the 40 Hz-ASSR (auditory steady state responses) could be valuable for objectively estimating the frequency-specific threshold in adults undergoing an expertise examination for medicolegal and/or compensation purposes. The present prospective study was set up to clarify the relationship between the thresholds obtained by cortical evoked response audiometry (CERA) and by 40 Hz-ASSR, in the same ears, within a large homogeneous sample of 164 subjects (328 ears) with NIHL and well documented exposure to noise. All these subjects claimed financial compensation for occupational NIHL, and there was a suspicion of exaggeration of the reported NIHLs. ASSR thresholds show a good correlation with the CERA thresholds. However, a systematic shift is noticed, ASSR thresholds being on average (1-2 - 3 kHz) 4.38 dB lower (i.e. showing less hearing loss) than CERA thresholds. Moreover, the binaural multiple ASSR technique allows a considerable time gain when compared to the CERA.

Neurovegetative symptoms and complaints before and after voice therapy for nonorganic habitual dysphonia.

In a previous study, female patients in all age categories with a nonorganic dysphonia were found to report significantly more autonomic symptoms and complaints than healthy controls. This could not be confirmed for the male subgroup. The present study is to corroborate and nuance this observation by investigating larger groups, and to determine if, after voice therapy, the number of autonomic symptoms and complaints-particularly those ones that have no obvious relation to voice function-decreases. It is a prospective study with a matched control group; 184 patients with nonorganic dysphonia and 126 normal controls answered a questionnaire of 46 questions with 3 subsets and a consistency control. One hundred and one patients received functional voice therapy and completed the questionnaire before and after treatment. A matched control group of 42 normal subjects also filled in the questionnaire two times, with an interval of about 6 months. Neurovegetative symptoms and complaints-voice related and not related-are reported in highly significant excess by patients (especially but not exclusively females) with habitual nonorganic voice disorder. After therapy, there is a highly significant reduction in the number of autonomic symptoms and complaints (related or not related to voice), to such an extent that patients report on average no more general neurovegetative symptoms and complaints than healthy controls (even less). The number of neurovegetative symptoms and complaints connected with voice function is also strongly reduced in patients after therapy, but remains in significant excess when compared with controls.

Smartphones Offer New Opportunities in Clinical Voice Research.

Smartphone technology provides new opportunities for recording standardized voice samples of patients and sending the files by e-mail to the voice laboratory. This drastically improves the collection of baseline data, as used in research on efficiency of voice treatments. However, the basic requirement is the suitability of smartphones for recording and digitizing pathologic voices (mainly characterized by period perturbations and noise) without significant distortion. In this experiment, two smartphones (a very inexpensive one and a high-level one) were tested and compared with direct microphone recordings in a soundproof room. The voice stimuli consisted in synthesized deviant voice samples (median of fundamental frequency: 120 and 200 Hz) with three levels of jitter and three levels of added noise. All voice samples were analyzed using PRAAT software. The results show high correlations between jitter, shimmer, and noise-to-harmonics ratio measured on the recordings via both smartphones, the microphone, and measured directly on the sound files from the synthesizer. Smartphones thus appear adequate for reliable recording and digitizing of pathologic voices.

Functional tubal therapy for persistent otitis media with effusion in children: myth or evidence?

Otitis media with effusion (OME), a form of inflammatory middle ear disease, is a common reason for young children to visit their family doctor and to have surgery. Tubal dysfunction plays a major role in the pathogenesis. In case of persistent OME, there seems to be a logical rationale for a favourable effect on the tubal dysfunction of a functional active motoric approach combined with behavioral changes (hygiene), and as a consequence for a therapeutic effect on the middle ear disease. The basic principles of this functional treatment are: active ventilation of the middle ear, correction of immature and undesirable deviant mouth habits, increasing swallowing frequency, activating jaw and palate movements, and encouraging the use of chewing gum. The bases for this functional therapy are critically analysed, and it may be concluded that all of these principles rely upon evidence based physiological mechanisms. However, the limited available clinical data from the literature are reviewed, and appear as methodologically weak. The results of an own prospective randomized pilot study comparing functional treatment with watchful waiting may be considered encouraging, since a borderline significance level was reached with a small amount of subjects.

Retropharyngeal autologous fat transplantation for congenital short palate: a nasometric assessment of functional results.

Seventeen patients (4 to 24 years old; mean, 9.7 years) with mild velopharyngeal insufficiency were treated in our department during the period 1996 to 1999 with augmentation of the posterior pharyngeal wall with autologous fat. The main disorder was a congenital short palate without a cleft, in most cases revealed by adenoidectomy. Four patients had previously undergone pharyngoplasty, and 1 had already been injected in the posterior pharyngeal wall with Teflon paste. All patients had been exhaustively treated with speech therapy, and the result remained unsatisfactory. The functional outcome of the surgical procedure was quantified by acoustic nasometry. The decrease of the nasalance percentage for a standardized spoken passage was significant 1 to 3 months after the fat transplantation, and there was a slight tendency to further reduction of nasality at the late follow-up visit, more than 6 months (average, 9.4 months) after the intervention. The mean value of the nasalance score for the "normal passage" (running speech) then reached the limit of normal values. A long-term follow-up (average, 24.3 months) by telephone questionnaire confirmed the persistence of the beneficial results. Autologous fat seems an excellent alternative for Teflon in this indication. Acoustic nasometry allows a precise quantitative assessment of functional velopharyngeal surgery.

Perceptual and laboratory assessment of dysphonia.

The voice laboratory is an essential tool in the voice clinic. It provides a functional diagnosis of disturbed voice production, demonstrating the deviant characteristics, limitations, and possibilities for change. As voice is multidimensional, several aspects need to be documented, quantified, and analyzed: perception, stroboscopy, aerodynamics, acoustics, self-evaluation by the patient, and in specific cases, physiologic signals, such as electroglottography, flow glottography, nasometry, and electromyography. Effectiveness and outcome studies rely on such data.

Voice problems in children: pathogenesis and diagnosis.

Voice problems seem to concern more than one child out of twenty, and may concern quality (hoarseness), resonance (nasality), pitch (mutation) and loudness. The main etiological categories are defined as organic (congenital/acquired), functional/habitual (especially due to voice abuse and misuse), and psychogenic (especially mutation disorders). Flexible transnasal endoscopes of small diameter (2.3 mm) are optimally suited for accurate endoscopic diagnosis, especially if combined with video-recording and stroboscopy.

Fundamental voice frequency and jitter in girls and boys measured with electroglottography: influence of age and height.

The fundamental frequency and jitter of the voice was measured by electroglottography in 71 children between the age of 7 and 15 years. In this series of children the fundamental frequency and jitter did not depend on the gender. The median (range) fundamental frequency was 244 (182-331) Hz in girls and 250 (205-293) Hz in boys. It decreased with increasing height (r = -0.59; P < 0.0005) and age (r = -0.57; P < 0.001). The median jitter ratio was 9.7 (1.6-33.3) in girls and 10.3 (2.0-4.3) in boys. The jitter ratio was negatively related to height (r = -0.31; P < 0.05), but not to age.

Fo-perturbation and Fo/loudness dynamics in voices of normal children, with and without education in singing.

Sustained phonations were compared in two groups of children (aged 7-12), one with special artistic voice education and one from a normal school, without voice complaints or problems. The hypothesis of specific (better) biomechanical vocal fold properties in the first group is confronted with the hypothesis of differences solely related to training of voice control. In both groups, Fo-aperiodicity was measured in a sustained phonation at 3 different SPL levels. As a general rule, aperiodicity clearly decreases when the voice becomes louder. Aperiodicity is highly significantly lower, at all SPL-levels, in children with trained singing voices: this implies better mechanical properties of the vocal oscillator. The Fo/SPL relation on a sustained /a:/ does not differ in trained and untrained children's voices: out of singing context, trained children do not spontaneously control the Fo/SPL dynamics differently from untrained children. The higher regularity of vocal fold pulses is not related to the duration of training.

Voice disorders in children.

The pediatric otolaryngologist has an especially important role in the differential diagnosis and treatment of two voice disorders; these are the voice quality problems (dysphony) and the resonance problems (rhinophony). The first step in the examination is to preclude the organic causes. The functional dysphonia is mostly related to voice abuse/misuse, but may be present on a psychosomatic basis; environmental factors can also play a role in the etiology and the personality structure has been found to be very relevant. The perceptual evaluation of voice is of obvious importance. Endoscopy with a transnasal flexible scope makes it possible, in practically all cases, to identify the morphodynamic changes. Stroboscopy and phonetography can be carried out only in older children, sometimes a 'trial treatment' is of valuable help. The therapy can be divided into five groups (counselling, voice re-education, drug treatment, psychotherapy, surgery), but should be always individual. An open question: how to choose the preferable treatment of vocal nodules: surgery, conservative or wait-and-see? According to a detailed survey in Kurume University Hospital the following can be stated: if the patient is in trouble due to hoarseness, and immediate improvement of his voice is necessary, surgery should be indicated; if they need the improvement but do not need it urgently, voice therapy is recommended; without motivation vocal hygiene is proposed. No matter what treatment patients receive, their voices improve in the majority after puberty, but 15% of the patients do not show any improvement. In cases of hoarseness due to long-term postintubational glottic lesions logopedic treatment is the only therapeutic possibility. The delay of speech development of tracheotomized children can and should be avoided by applying proper cannula technique and by logopedic training. The physiological nasality which depends upon the undisturbed activity of the velopharyngeal closure, can become pathologic in four forms: closed, open, mixed and alternating nasality (rhinophonolalia). In the diagnosis of hyperrhinophony due to VPI X-ray procedures, supplemented with nasendoscopy, proved to be the most informative methods, the etiology (neuromyogen processes) may be revealed by electrophysiological methods; the voice and speech can be assessed and visualized by nasometry, but the detailed speech evaluation is indispensable. The basic possibilities of treatment are as follows: speech therapy, surgery, speech bulb, electrotherapy and medicines. The basis of operative treatment is flap surgery. The anatomical result of 1000 (velo) pharyngoplasties carried out in Madarász and Heim Pál Children's Hospital (Budapest) is good in 98%, the hyperrhinophony ceased or became minimal in 90% after surgery. The ideal age for operation is 4.5 years.

Plasticity of voice quality: a prognostic factor for outcome of voice therapy?

Plasticity of voice quality is defined here as the degree of improvement in deviant voice quality that can be achieved immediately or quasi-immediately by changing basic voicing conditions, posture, articulation or resonance, breathing mechanics, laryngeal position, or auditory feedback. Thirty-two adult patients with various benign organic voice pathologies, and who had a (preoperative) functional voice therapy, were scored before therapy using a weighted multidimensional Index of Voice Plasticity (IVP). The hypothesis is that IVP could be a predictor of the final outcome of functional voice therapy, and therefore a correlation with a comparable quantification of the actual results of the therapy was investigated. The IVP shows a satisfactory correlation (Spearman's rho = 0.68) with the efficacy of (preoperative) voice therapy. The IVP also significantly differs between diagnostic categories. Although its predictive value remains limited, the Index of Voice Plasticity seems helpful in decision making for indication of (presurgical) voice therapy.

Documentation of progress in voice therapy: perceptual, acoustic, and laryngostroboscopic findings pretherapy and posttherapy.

The effect of voice therapy in a group of chronically dysphonic patients with diverse diagnoses was studied according to the normal clinical procedure. The results were evaluated by perceptual rating, acoustic analysis, and the assessment of laryngostroboscopic recordings. Although the group effects for the differences between posttherapy and pretherapy data were clearly significant, the effects of voice therapy for the individual patients were divergent. For each of the three evaluation methods, a significant improvement was found for about 40% to 50% of the patients. The diversity of the therapy outcome among the patients could not be explained by the pretherapy status nor by age, gender, or diagnosis groups. In general, the perceptual ratings and the acoustic parameters from the baseline data were clearly correlated. However, these characterizations of the voice were only moderately correlated with the visual evaluation of the vocal fold vibrations. Relations among the three evaluation tools for the changes caused by voice therapy were very weak. The low correlation among the three methods suggests that a multidimensional evaluation of the voice is necessary to give a complete picture of the therapy outcome.

Clinical relevance of the fractal dimension of F0 perturbations computed by the box-counting method.

The box-counting method for determining the fractal dimension (Dfj) was applied to the fundamental frequency (F0) perturbations in normal and pathological voices in order to assess its clinical value. The upper limit of these Dfj values was similar for both groups, but the distribution for pathological voices extended to lower values than for the normal voices. However, these lower values were most probably the result of one or a few outlying frequency points due to incorrect determination of the vocal period. The Dfj of normal voices were within the range of values found for randomly varying F0 values. It was concluded, that the vocal perturbations in pathological voices are also more or less randomly distributed. So, the Dfj, at that least determined with the box-counting method, do not contain clinically relevant information in addition to the traditional measures for the extent of the vocal period perturbations. An exception is special perturbation types like diplophonia. The result of the computation is very sensitive for voice breaks and vibrato and depends on the number of periods.

The effect of relative humidity of inhaled air on acoustic parameters of voice in normal subjects.

The hypothesis that relative humidity (RH) of air exerts an effect on voice has been widely accepted. The aim of this study has been to assess whether this can be demonstrated. Eight healthy subjects inhaled during ten minutes three different air conditions: dry, standard room, and humidified air. After inhalation, the subjects produced repeatedly a sustained /a/ of controlled pitch and loudness, which was analyzed for perturbation and noise-to-harmonic parameters. Perturbation measures increased after inhalation of dry air. No significant differences existed between standard and humidified air. No significant difference in the noise-to-harmonic ratio was found among the three conditions. We conclude that the human voice is very sensitive to decreases in RH of inhaled air, because even after a short provocation with dry air, a significant increase in perturbation measures was found.

A comparison between middle latency responses and late auditory evoked potentials for approximating frequency-specific hearing levels in medicolegal patients with occupational hearing loss.

To evaluate the medicolegal relevance of middle latency responses for objectively approximating frequency-specific hearing levels in subjects with occupational hearing loss, we compared the middle latency response with the cortical response in 22 reliable subjects who had noise-induced hearing loss and were submitting claims for compensation and 21 subjects who had noise-induced hearing loss but were exaggerating the level of this loss and also were submitting claims for compensation. Middle latency components of auditory evoked potentials, especially the time-saving 40-Hz response, seem efficient and reliable for evaluating the true pure-tone thresholds (1, 2, and 3 kHz). A good correlation exists between the 40-Hz response threshold and the slow vertex response (SVR) threshold (long latency). Both also show a fairly close correlation with behavioral thresholds in cooperating subjects. However, in most cases, the 40-Hz response is less sensitive (mode of difference, 10 dB) than is the SVR. As middle latency response audiometry is not actually a time-saving procedure in comparison with cortical evoked response audiometry and as it seems less sensitive than the SVR for approximating the true threshold, the use of middle latency response audiometry seems best limited to situations in which a control or a confirmation of the SVR is wanted. Further information about the sensitivity of middle latency response to drug effects and to subject wakefulness (specifically, whether the patient is more or less sleepy) is expected.

Acute tinnitus and permanent audiovestibular damage after hepatitis B vaccination.

Yeast-derived recombinant DNA hepatitis B vaccine usage has been widely accepted since the early 1990s, especially for high-risk patients. Severe adverse effects have been reported infrequently. Certain neurological complications raise concern for hepatitis B vaccine: central nervous system demyelination, acute myelitis, acute cerebellar ataxia, and various peripheral mononeuropathies. Case reports on tinnitus, hearing loss, and vestibular damage are extremely scarce. The case presented here concerns a professionally active nurse, born in 1953, with a medical history of progressive renal failure and hemodialysis. Eleven hours after a second injection of the hepatitis B vaccine Engerix B, an acute left-sided tinnitus occurred and, a few hours later, severe left hearing loss and intense vertigo. Tinnitus and the sensation of vertigo regressed fairly quickly, but the hearing loss and the vestibular paresis were permanent. Increased interpeak intervals on auditory brain responses and lack of recruitment suggested that the lesion probably is located at the level of cranial nerve VIII. From a medicolegal point of view, this audiovestibular damage had to be considered an accident at work and not as an occupational disease.

Cortical evoked response audiometry thresholds and neuroleptic, sedative, hypnotic drugs.

Cortical evoked response audiometry is adequate for approximating hearing threshold levels with frequency specificity when the psychoacoustic responses lack reliability and reproducibility (compensation claim). It is well-known that control of wakefulness is essential for the reliability of slow vertex responses (SVR). Therefore, sedative, hypnotic, and neuroleptic drugs are supposed to have possible adverse effects on the detection of SVR. In contrast, brainstem evoked responses (BER) have proved not to be significantly affected by therapeutic doses of these compounds. The purpose of our study was to assess the reliability of SVR-threshold definition in subjects taking neuroleptic, sedative, and hypnotic drugs. Fifteen subjects examined for occupational hearing loss at the Fund for Occupational Diseases in Brussels and regularly taking one or several of these drugs were compared with 27 comparable controls. In each subject the auditory thresholds were defined with both techniques: SVR (1, 2, and 3 kHz) and BER (clicks). A highly significant difference is observed between the two groups: In the group receiving drugs, the SVR threshold for 3 kHz is 12.1 dB (average) higher than the BER threshold, whereas in the group without drugs, the SVR threshold for 3 kHz is 7.77 dB (average) lower than the BER threshold. In the drug group, large interindividual differences are observed. It may be concluded that the use of neuroleptics, sedatives, and hypnotics renders the auditory threshold definition with SVR completely unreliable. In using SVR for medicolegal threshold definition, controlling the 3-kHz threshold with BER always is necessary.