Improvement In Maximum Phonation Time Research Articles

The Effect of Adding Cricothyroid Visor Maneuver to Voice Facilitating Techniques on Improving Voice in Individuals With Primary Muscle Tension Dysphonia: A Pilot Randomized Clinical Trial

The purpose of the present study was to examine the effect of adding a cricothyroid visor maneuver to conventional voice-facilitating techniques on voice quality and reported symptoms in patients with primary muscle tension dysphonia. This was a double-blind two parallel-group clinical trial in which 20 adult patients participated through convenience sampling. Participants were allocated to intervention (combined treatment) and control (conventional treatment) groups. The intervention was performed for both groups for five sessions, twice a week. The two groups were compared after the intervention for primary outcome measures including maximum phonation time, jitter, shimmer, harmonic-to-noise ratio, and consensus auditory-perceptual evaluation of voice, and for secondary outcome measures including the voice handicap index, the voice activity and participation profile, the voice-related pain scale, and the vocal tract discomfort scale. Within-group primary outcome comparison showed that both groups showed significant improvement in maximum phonation time and consensus auditory-perceptual evaluation of voice indices after treatment. the between-group comparison showed that the maximum phonation time increased significantly in the intervention group after the treatment (P=0.03) and the effect size was large (es=1.05). within-group secondary outcome comparison showed that all indices improved significantly in both groups except for the voice-related pain scale frequency. The between-group comparison showed that except for voice-related pain scale frequency, the intervention group reported significantly more improvement in all other self-reporting indices with a large effect size. The study showed that adding cricothyroid visor maneuver to conventional voice-facilitating techniques, compared to conventional treatment alone, resulted in a significant increase in maximum phonation time, reduction in pain and vocal tract discomfort, increase in activity and participation, and improvement in voice-handicapped index in primary muscle tension dysphonia patients. Therefore adding cricothyroid visor maneuver to other treatments can be an effective method in improving primary muscle tension dysphonia which needs more studies in the future.

Vocal Outcomes Following Laser-Assisted Sulcus Release for Superficial and Deep Vocal Fold Sulcus

The objective is to study vocal outcomes following laser-assisted sulcus release (LASR), having documented the length and depth of the sulcus intraoperatively. LASR performed for superficial and deep sulci were included. Retrospective, observational. The preoperative and 3-month postoperative and post voice-therapy Voice Handicap Index 10 (VHI), Grade-Roughness-Breathiness-Asthenia-Strain of the voice (GRBAS), Maximum Phonation Time (MPT), Fundamental Frequency (FO), and stroboscopy findings were noted retrospectively from our voice clinic records of LASR patients. Intraoperative sulci length and depth details were noted from records. Patients with coexisting lesions, surgically tackled, were excluded. In a total of 14 patients, 21 superficial sulci and eight deep sulci were operated by LASR. The average preoperative VHI improved from 25.3 to 9.9, GRBAS from 10.6 to 3.5, and MPT from 7.6 to 12.3seconds. The preoperative average FO was 235.9Hz in 12 patients (no pick-up in two) with a postoperative 248.4Hz. Using the Mann-Whitney U test, we found a statistically significant improvement in MPT, VHI, and GRBAS of the patients. There was no significant improvement in the FO of the patients. There was no postoperative voice deterioration in any patient. A preoperative phonatory gap was found in all patients, which postoperatively was absent in 10, markedly decreased in three, present in one with stroboscopy revealing an improvement in mucosal wave amplitude in 13 patients. In four patients with deep bilateral sulci where the LASR had been ligament deep, VHI improved from 26 to 13.3, GRBAS from 12 to 6.5, and MPT from 4.3 to 9.5seconds. Using the Mann-Whitney U test, all three parameters were significantly improved. A statistically significant vocal improvement in VHI, GRBAS, and MPT was observed at 3months, in superficial and deep sulci, operated by LASR. LASR is a simple, quick, and easily replicable surgery. Larger multi-centric studies with long-term follow-up are recommended.

Combined treatment of muscle tension dysphonia: voice therapy with instrumental postural rehabilitation.

This investigation aimed to propose a new rehabilitation technique that combines voice exercises and instrumental postural rehabilitation for patients with muscle tension dysphonia (MTD). We enrolled nine dysphonic patients (8 women and 1 man, aged 22-55 years). Voice assessment included strobovideolaryngoscopy, Maximum Phonation Time (MPT), perceptual evaluation by GRBAS scale and patient's self-rating by Italian version of the Voice Handicap Index (VHI). Vestibular function was evaluated by the Bed Side Examination and Video Head Impulse test (VHIT). Postural control was evaluated by Dynamic Posturography (DP) using the Sensory Organization Test (SOT) and analysing the Equilibrium Score (ES) and balance subsystems (somatosensorial, visual, vestibular). All cases underwent different types of voice exercises combined with balance training based on NeuroCom Balance Master Protocols, once a week for six 35-minutes sessions. After therapy, an improvement in MPT, VHI, GRBAS scores and endoscopic laryngeal features was obtained. DP results at baseline were normal and after therapy we showed a slight improvement of ES (somatosensorial and visual components). A combined rehabilitation technique for MTD, by improving the attention to postural control, allows for significant improvement in vocal symptoms.

The use of basic fibroblast growth factor to improve vocal function: A systematic review and meta-analysis.

This systematic review and meta-analysis examines if intralaryngeal injection of basic fibroblast growth factor 2 (FGF2) can improve voice outcomes in those with vocal disability. A Systematic review of original human studies reporting voice outcomes following intra-laryngeal injection of basic fibroblast growth factor 2 in those with vocal dysfunction. Databases searched were Medline (1946-July 2022), Embase (1947-July 2022), Cochrane database and Google Scholar. Secondary or tertiary care centres that undertook the management of voice pathology Hospital. Inclusion criteria were original human studies reporting voice outcome measurements following intralaryngeal injection of FGF2 to treat vocal fold atrophy, vocal fold scarring, vocal fold sulcus or vocal fold palsy. Articles not written in English, studies that did not include human subjects and studies where voice outcome measures were not recorded before and after FGF2 injection were excluded from the review. The primary outcome measure was maximum phonation time. Secondary outcome measures included acoustic analysis, glottic closure, mucosal wave formation, voice handicap index and GRBAS scale. Fourteen articles were included out of a search of 1023 and one article was included from scanning reference lists. All studies had a single arm design without control groups. Conditions treated were vocal fold atrophy (n = 186), vocal cord paralysis (n = 74), vocal fold fibrosis (n = 74) and vocal fold sulcus (n = 56). A meta-analysis of six articles reporting on the use of FGF2 in patients with vocal fold atrophy showed a significant increase of mean maximum phonation time of 5.2 s (95% CI: 3.4-7.0) at 3-6 months following injection. A significant improvement in maximum phonation time, voice handicap index and glottic closure was found following injection in most studies assessed. No major adverse events were reported following injection. To date, intralaryngeal injection of basic FGF2 appears to be safe and it may be able to improve voice outcomes in those with vocal dysfunction, especially vocal fold atrophy. Randomised controlled trials are needed to further evaluate efficacy and support the wider use of this therapy.

Comparison of Short and Long-Term Results after Injection Laryngoplasty with Radiesse® Voice and Thyroplasty Type I in Unilateral Vocal Fold Palsy.

Unilateral vocal fold palsy independently of etiology results in glottic insufficiency leading to unfavorable short or long-term impact on voice quality. Our aim was to evaluate the effect of injection laryngoplasty using Radiesse® Voice and thyroplasty type I on glottic closure, voice quality and aerodynamics by comparing preoperative, short- and long-term results. Data of 32 consent patients were reviewed between 2012 and 2023. All patients underwent either injection laryngoplasty (14 patients) or thyroplasty type I (18 patients) under local anesthesia. Maximum phonation time, glottic closure based on videolaryngostroboscopy, VHI-30 values and GRBAS scale were recorded prior, short-term (3 month) and long-term (12 months) after procedures for statistical comparison. Friedman test, Mann-Whitney test and Wilcoxon signed rank tests were used for statistical analysis. In injection laryngoplasty group, we found significant improvement in maximum phonation time (p = 0.002), grade of hoarseness (p = 0.002) and breathiness (p = 0.000) when comparing results before and short-term after procedure. In thyroplasty type I group we saw significant improvement of maximum phonation time (p = 0.000), glottic insufficiency (p = 0.000), all three VHI-30 components (p = 0.000), as well as grade of hoarseness, breathiness (both p = 0.000) and roughness (p = 0.011) of GRBAS scale when comparing voice outcome before and short-term after procedure. There was no significant difference in voice outcome results neither between short and long-term results nor between the two groups in any parameter. These results demonstrate both short and long-term efficiency of injection laryngoplasty and thyroplasty type I in the improvement of voice quality and glottic closure.

Effects of Diaphragmatic Breathing Exercise on Respiratory Functions and Vocal Sustenance in Apparently Healthy Vocalists

Effective vocalization is dependent on breathing efficiency. Previous studies have reported the efficacy of Diaphragmatic Breathing Exercise (DBE) on the respiratory muscles and breath control of vocalists. There is a paucity of data on the effects of DBE on their vocal sustenance (VS), which is determined as Maximum Phonation Time (MPT). No known published study has considered physiotherapy as influencing voice dynamics amongst vocalists; evaluated the relationship between respiratory functions (Forced Vital Capacity - FVC, Forced Expiratory Volume in one second - FEV1, FEV1/FVC, and Peak Expiratory Flow - PEF) and VS in apparently healthy vocalists. Moreover, literature on the benefits of DBE to vocalists has not considered explicitly this aspect of vocalization skill, VS. This is a pre-test - post-test experimental study involving a total of 37 participants (17 males and 20 females) selected by purposive and convenience sampling techniques. The subjects were grouped into DBE and control groups. Spirobank MIR spirometer was used to assess the respiratory function of the singers, while a stopwatch and keyboard were used in assessing the MPT. Statistical analysis was done with SPSS version 21.0. Alpha level set at 0.05. Significant improvement was found in respiratory functions (FVC, FEV1, FEV1/FVC, PEF) of the DBE group when pre- and post-test results were compared. The DBE and control groups differed significantly. Respiratory values correlated significantly with the MPT values (FVC - r[p] - 0.416[0.011]; FEV1 - r[p] - 0.416[0.010]; PEF - r[p] - 0.566[0.000]), except for FEV1/FVC - r(p) - 0.248(0.138). Voice category did not correlate with respiratory parameters or MPT. While male singers showed more changes in respiratory function the female singers showed more improvement in MPT. DBE can improve respiration and VS (increased MPT). Therefore, it can be recommended for vocalists, and Physiotherapy can be relevant in trainings to improve vocal dynamics.

Intracordal injection therapy for vocal fold scarring: Steroid versus basic fibroblast growth factor.

ObjectivesVocal fold scarring is caused by replacement of vocal fold mucosa with fibrous tissue due to repeated inflammation or trauma. It can lead to severe dysphonia. It is currently treated conservatively and with phonosurgery and intracordal injections. Intracordal injection of steroid or basic fibroblast growth factor (bFGF) has been recently found to be useful for treating vocal fold scarring that does not respond to voice therapy.MethodsThis retrospective study involved the administration of steroid injection and bFGF injection bilaterally under local anesthesia in 16 patients each. Laboratory measurements of voice parameters were performed before and 3–6 months after injection.ResultsIn the steroid injection group, the Voice Handicap Index (VHI) score significantly improved from 57.1 to 40.5, total Grade, Roughness, Breathiness, Asthenia, Strain (tGRBAS) score significantly improved from 4.2 to 2.6, and mean speech fundamental frequency (SFF) increased from 192.5 to 211.4 dB, but there was no improvement in maximum phonation time (MPT) and mean airflow rate (MFR). In the bFGF injection group, significant improvements in the VHI score (from 53.3 to 35.7), MPT (from 16.9 to 21.8 s) and MFR (from 314.6 to 210.5 ml/s) were seen; however, the tGRBAS score did not improve. In addition, the SFF significantly decreased from 178.1 to 160.5 Hz.ConclusionThese results suggest that both steroid and bFGF injections are effective for treating vocal fold scarring, with steroids improving voice quality and bFGF improving glottic closure, thereby contributing to improvements in VHI scores.Level of Evidence4.

Does Abrupt Weight Loss Caused by Bariatric Surgery Compromise the Voice in Women?

To evaluate vocal symptoms, voice characteristics and videolaryngoscopy in obese women before and after bariatric surgery. Obese patients (18 to 59 years old), candidates for bariatric surgery were recruited. Evaluation times: T1 (preoperative), T2 (after six months), T3 (after 12 months). Evaluated parameters: weight, height, body mass index, abdominal and neck circumference, vocal self-assessment, perceptual and acoustic vocal assessment, and videolaryngoscopy. A total of 37 obese women were included, average age 40.8 years. There was a decrease in anthropometric measurements between the preoperative assessment and after 12 months: weight (121.18 ± 15.4 kg; 77.1 ± 11.6 kg), BMI (46.6 ± 6.95 kg/m2; 30 ± kg/m2), abdominal circumference (128 ± 16.1; 99.1 ± 12.1), and neck circumference (41.1 ± 5.85; 36.6 ± 3.02). Gastroesophageal (21.6%) and vocal symptoms (27%) prevailed. No difference was identified in vocal self-assessment between the evaluations. In the acoustic analysis, f0 increased and the soft phonation index decreased. The perceptual analysis registered lower scores for the degree of dysphonia (G) and voice instability (I). The maximum phonation time values increased without changing the s/z ratio. Videolaryngoscopies showed a posterior middle cleft and improvement in the signs of reflux. Bariatric surgery led to an important and gradual decrease in anthropometric parameters. The voice became less hoarse, with higher pitch and more stable, with an improvement in maximum phonation time, however with slight breathiness. Such changes were not noticed by the patients.

Surgical effects of type-I thyroplasty and fat injection laryngoplasty on voice recovery

ObjectiveType-I thryroplasty, also known as medialization thyroplasty (MT) and autologous fat injection laryngoplasty (FIL) are one of the main surgical treatments for unilateral vocal fold paralysis (UVFP). Both procedures have the same concept of completing the glottal closure by medializing the vocal fold, although the surgical approaches are quite different. In order to assess these surgical effects, we examined the treatment outcomes and benefits of the two surgeries. MethodsWe collected data from the 135 phonosurgeries that we performed out of 375 patients with UVFP at Osaka Voice Center, Osaka Kaisei Hospital from January 2009 to February 2013. After excluding cases with glottal level differences on phonation, either MT or FIL were performed on 80 cases. The inclusion criteria for the present study were: (1) patients had no history of previous phonosurgery, and (2) functional evaluations were available before/after surgery. Consequently, 43 participants (12 for MT and 31 for FIL) were enrolled in this study. Surgical effects were evaluated by means of the maximum phonation time (MPT), pitch period perturbation quotient (PPQ), amplitude perturbation quotient (APQ), and harmonic to noise ratio (HNR) just before, one month, and 6 months after surgery. ResultsBoth MT and FIL showed significant improvement in MPT (MT, p = 0.005; FIL, p < 0.001) and PPQ (MT, p = 0.047; FIL, p = 0.041) at 1 month postoperation. We also compared the variation of each variable between the two procedures, but there were no significant differences in these parameters. However, MPT, APQ, and HNR at the post-MT after 6 months worsened compared to those at 1 month posttreatment, whereas MPT showed only a slight decrease from the 1st month to the 6th month in those with FIL. ConclusionBoth MT and FIL were effective for the voice recovery in patients with UVFP. Our findings suggest that surgical results in FIL might be better than those in MT 6 months after surgery, although there were no significant differences between these two procedures 1 month postoperation.

Early Injection Laryngoplasty With a Long-Lasting Material in Patients With Potentially Recoverable Unilateral Vocal Fold Paralysis.

Objectives.Injection laryngoplasty (IL) is one of the major options for treatment of unilateral vocal fold paralysis (UVFP). Early IL in patients with abrupt-onset UVFP can reduce hoarseness and aspiration-related discomfort and complications. Temporary or short-lasting materials are recommended for the early IL since permanent or long-lasting materials may negatively affect the voice quality when vocal fold motion is spontaneously recovered.Methods.Patients who received IL with a long-lasting material (ArteSense) within 1 month following development of postoperative UVFP were enrolled for this study. They were categorized into a spontaneously recovered group (n=30) and unrecovered group (n=276) from UVFP. The subjective and objective voice parameters were collected before and 6 months after IL. Patients’ demographics and collected voice parameters were compared between the two groups.Results.Age and sex distributions were not different between the two groups. Aspiration symptom, maximum phonation time (MPT), jitter, shimmer, noise to harmonic ratio (NHR), overall grade (G) and breathiness (B) of GRBAS (grade of dysphonia, roughness, breathiness, asthenia, strain) scale score, and voice handicap index (VHI) were significantly improved after IL in both groups. The amounts of improvement in MPT, jitter, shimmer, NHR and VHI were significantly greater in the recovered group. There was no IL-related complication including granuloma formation, hypersensitivity to injection material, or worsening of hoarseness.Conclusion.Early IL with a long-lasting material can be safely performed to improve voice quality and to reduce aspiration episode for the patients with postoperative UVFP, regardless of recovery from the paralysis. The amounts of improvement in the subjective and objective voice parameters were significantly greater in patients who showed spontaneous recovery from UVFP when compared with those in patients who did not.

Vocal fold medialization—A 5‐year series of single surgeon consecutive medialization with review of literature

ENT UK released guidelines in 2010 detailing the requisite structure for the creation of a laryngeal intervention clinic. The senior author's practice is the only one regionally that offers this service, and our objective was to review this to determine whether vocal cord medialization injections were showing an improvement in quality of voice for patients. Patients were reviewed in a specialist voice clinic prior to being offered vocal cord injection under local anaesthetic in a separate dedicated weekly clinic. They would be assessed by the senior author and a dedicated voice specialist speech and language therapist (SALT). This would include a preinjection grade, roughness, breathiness, asthenia, and strain (GRBAS), Voice Handicap Index (VHI)-10, and the measuring of maximum phonation time (MPT) with the aid of Opera Vox Apple iPad application. Data were available for 186 injections, on patients with a median age of 66years (interquartile range [IQR]: 51-75), of whom 61% were male. VHI-10 score improved significantly, from a mean of 26.7 to 12.5 (P<.001). A significant improvement in MPT was also observed, from a median of 3.0 to 6.3 (N=66, P<.001). Improvements in all components of the GRBAS score were also observed (all P<.001), with between 43% and 88% of cases reporting reductions after the procedure. Patients receiving a repeat procedure saw a significantly smaller improvement in VHI-10 than those where it was the primary treatment (mean reduction: 9.8 vs 15.5, P=.018). Analysis of MPT found a significant correlation between the quantity of injection material used and the degree of improvement observed (rho=0.355, P=.004). Vocal Cord local anaesthetic medialization injection is a swift, safe, and effective short-term method of improving dysphonia.

Vocal function exercises for normal voice: The effects of varying dosage

Purpose: This study examined the effect of varying dosage of vocal function exercise (VFE) home practice on attainment of pre-established maximum phonation time (MPT) goals in individuals with normal voice. High dosage VFE practice was expected to result in greatest MPT. The overarching goal of this study was to contribute to a VFE dosage-response curve, potentially including a point of observable toxicity.Method: Twenty-eight females ages 18–25 with normal voice participated in this pre-post longitudinal group study. Participants were randomly assigned to one of three experimental groups and completed a six-week VFE protocol with practice twice daily. The low dosage group performed each exercise once, the traditional group twice, and the high dosage group four times. The primary outcome measure was MPT as performed on the fourth VFE using the prescribed semi-occluded vocal tract posture.Result: No toxic effects were observed. MPT increased for all participants, with significant improvement for traditional and high dosage groups.Conclusion: High dosage VFEs may yield more rapid improvement in MPT, however benefits must be weighed against the risk of increased attrition. Low dosage VFEs insufficiently improved MPT. Further research on dosage is warranted, and should include individuals with disordered voice.

Long-term Results of 18 Fat Injections in Unilateral Vocal Fold Paralysis

The purposes of this study were to assess the long-term efficacy of medialization laryngoplasty via injection of autologous fat in patients with unilateral laryngeal paralysis, and to discuss the results based on the volume of fat injected and the size of the initial glottic gap. This was a retrospective study with clinical reevaluation of 18 patients treated for unilateral laryngeal paralysis at Liège University Hospital between April 1, 2011, and December 1, 2014. The voice examination included subjective scales (GRBAS and the Voice Handicap Index), a report on acoustic and aerodynamic voice parameters, and laryngostroboscopic assessment of glottic closure and mucosal wave (T0: preoperative; T1: immediate postoperative; T2: >1 year). The median follow-up duration was 19 months. We observed a significant improvement in maximum phonation time; mean flow rate; jitter; the Voice Handicap Index; the G, R, B, and A subscales of the GRBAS-I; and glottic closure at T1. These parameters remained stable over time, without any significant difference except for shimmer and glottic closure between T1 and T2. Regardless of the volume of fat injected and the magnitude of the initial glottic gap, we did not see any significant difference from one assessment time to another. Medialization laryngoplasty by means of the injection of autologous fat is a safe, effective surgical technique for patients with unilateral laryngeal paralysis regardless of the size of the initial glottic gap. The results are maintained longer than 1 year, and no evidence of significant resorption of the fat was found in our study over a period of 12-58 months. The volume of fat injected does not seem to affect the functional results.

The Effect of Voice Rest on the Outcome of Phonosurgery for Benign Laryngeal Lesions

According to the literature, voice rest following phonosurgery, as recommended in clinical practice, varies between 3 and 7 days. However, up until now, no randomized trials have been published comparing voice rest of short versus long duration. This is an ongoing prospective randomized study, comparing strict voice rest of 5 versus 10 days on the voice following phonosurgery. Thirty-one elective patients operated on for benign laryngeal lesions were randomized. They completed pre- and postoperative assessments, including perceptual voice quality (Grade, Roughness, Breathiness, Asthenia, Strain, Instability scale), Voice Handicap Index total score, and voice analysis with both acoustic and aerodynamic measurements. Additional factors such as smoking, vocal abuse, reflux, and preoperative speech therapy were also taken into account. Sixteen patients were randomized to follow 5 days' voice rest and 15 patients were randomized to 10 days' voice rest. Statistical analysis showed no significant differences in pre- or postoperative measurements between the 2 groups. However, multilinear regression analysis for the effect of voice rest duration on postoperative values showed a significant improvement in maximum phonation time (MPT) with 10 days' voice rest. Preliminary results show a benefit of prolonged voice rest (10 days' duration) on MPT.

Outcome with immediate direct anastomosis of recurrent laryngeal nerves injured during thyroidectomy

Management of unrecognized recurrent laryngeal nerve injury typically entails delayed phonosurgical intervention and laryngeal reinnervation, but in cases of recognized injury, nerve anastomosis has been considered standard management. However, the well-organized outcome analysis of nerve anastomosis has been insufficient. We performed immediate direct anastomosis of recurrent laryngeal nerves injured during surgery for thyroid cancer, and subsequent patient outcomes were analyzed. A total 14 patients sustaining recurrent laryngeal nerve injury during thyroidectomy were recruited for the study. Patients undergoing immediate direct reparative anastomosis of the injured nerves constituted the test group, whereas the controls of group 2 (n = 4) did not. At follow-up, all patients submitted to rigid laryngoscopy at 3, 6, and 12 months postoperatively. Subjective and objective outcomes of the two groups were then compared. At 12 months postoperatively, group 1 showed greater improvement in maximum phonation time, glottic gap scores, GRBAS (grade, roughness, breathiness, asthenia, and strain) scales, aspiration scoring, and Voice Handicap Index than controls of group 2. Moreover, group 1 showed an improvement in all five categories at 12 months postoperatively, compared with status at 3 months. None of the patients in group 1 showed laryngoscopic evidence of vocal cord atrophy. In this study, patients undergoing immediate direct recurrent laryngeal nerve anastomosis demonstrated better phonation and perceptually rated voice quality than those who did not undergo repair. 3b.

Interventions for preventing voice disorders in adults

Poor voice quality due to a voice disorder can lead to a reduced quality of life. In occupations where voice use is substantial it can lead to periods of absence from work. To evaluate the effectiveness of interventions to prevent voice disorders in adults. We searched MEDLINE (PubMed, 1950 to 2006), EMBASE (1974 to 2006), CENTRAL (The Cochrane Library, Issue 2 2006), CINAHL (1983 to 2006), PsychINFO (1967 to 2006), Science Citation Index (1986 to 2006) and the Occupational Health databases OSH-ROM (to 2006). The date of the last search was 05/04/06. Randomised controlled clinical trials (RCTs) of interventions evaluating the effectiveness of treatments to prevent voice disorders in adults. For work-directed interventions interrupted time series and prospective cohort studies were also eligible. Two authors independently extracted data and assessed trial quality. Meta-analysis was performed where appropriate. We identified two randomised controlled trials including a total of 53 participants in intervention groups and 43 controls. One study was conducted with teachers and the other with student teachers. Both trials were poor quality. Interventions were grouped into 1) direct voice training, 2) indirect voice training and 3) direct and indirect voice training combined.1) Direct voice training: One study did not find a significant decrease of the Voice Handicap Index for direct voice training compared to no intervention.2) Indirect voice training: One study did not find a significant decrease of the Voice Handicap Index for indirect voice training when compared to no intervention.3) Direct and indirect voice training combined: One study did not find a decrease of the Voice Handicap Index for direct and indirect voice training combined when compared to no intervention. The same study did however find an improvement in maximum phonation time (Mean Difference -3.18 sec; 95 % CI -4.43 to -1.93) for direct and indirect voice training combined when compared to no intervention. No work-directed studies were found. None of the studies found evaluated the effectiveness of prevention in terms of sick leave or number of diagnosed voice disorders. We found no evidence that either direct or indirect voice training or the two combined are effective in improving self-reported vocal functioning when compared to no intervention. The current practice of giving training to at-risk populations for preventing the development of voice disorders is therefore not supported by definitive evidence of effectiveness. Larger and methodologically better trials are needed with outcome measures that better reflect the aims of interventions.

Vocal cord medialisation by transcutaneous injection of calcium hydroxyapatite

Objectives: Various techniques of vocal cord medialization have been described. The 2 most commonly used procedures are medialization thyroplasty and injection augmentation of the vocal cord. Translaryngeal injection of agents to cause cord medialization has increasingly become the route of choice as it is quick, simple and does not require general anaesthesia. Various agents have been injected but none are without problems. Calcium hydroxyapatite has recently been advocated as a potentially superior alternative. The aims of this study were to investigate the short and medium term patient benefits of calcium hydroxyapatite for vocal cord medialization via trancutaneous injection. Methods: A retrospective analysis of 24 patients undergoing transcutaneous vocal cord injection with calcium hydroxyapatite was performed. The primary diagnosis was vocal cord paralysis in 20 patients and vocal cord scarring in the remaining 4. Results: The mean age of the patient group was 66.7 years (SD 15.7). Due to various factors including patient death and distance to travel, follow-up is incomplete. Maximum phonation time (MPT) was taken as the performance measure. Twenty-two patients had a preinjection MPT (average 4, SD 1.7); 12 patients had follow-up at 3 months (mean MPT 10.3, SD 6.5). The mean preinjection MPT of this group was 4.25 (SD 1.8); 5 patients had follow-up at 6 months (mean MPT 10.6, SD 3.0). The mean preinjection MPT of this group was 4.5 (SD 1.7). In 2 patients the injection of calcium hydroxyapatite entered the submucosal space of the vocal cord but only 1 patient required surgical removal of the substance. Conclusion: Transcutaneous injection of calcium hydroxyapatite gives satisfactory improvement in maximum phonation time for glottic insufficiency due to vocal cord paralysis in the short and medium term. Longer term follow-up studies are in progress and these will further evaluate the outcome and safety of calcium hydroxyapatite as a substance for vocal cord medialization.

Aerodynamic and stroboscopic findings before and after microlaryngeal phonosurgery

Acoustic, aerodynamic, and laryngo-video-stroboscopy (LVS) studies were done on 50 patients before and after microlaryngeal surgery for benign vocal fold lesions. Perceptual pre- and postratings were also obtained. After microlaryngeal surgery, statistically significant differences between pre- and posttreatment conditions included postoperative findings of (a) a lowering of mean flow rate, (b) an increase in glottal efficiency, and (c) an increase in maximum sound pressure level. There was no significant improvement in maximum phonation time. Stroboscopy findings showed changes of glottal configuration, linearity of the vocal fold edge, amplitude of vocal fold vibration, excursion of the mucosal wave, and periodicity. Acceptable perceptual voice quality appeared to depend on a straight vocal fold edge, good vibratory amplitude, and good mucosal wave. Improved understanding of vocal function after phonosurgery should help us refine surgical principles and techniques. The combined use of LVS and phonatory function measures is advocated.