Reinhardt J. Heuer

Cepstral Peak Prominence: A More Reliable Measure of Dysphonia

Quantification of perceptual voice characteristics allows the assessment of voice changes. Acoustic measures of jitter, shimmer, and noise-to-harmonic ratio (NHR) are often unreliable. Measures of cepstral peak prominence (CPP) may be more reliable predictors of dysphonia. Trained listeners analyzed voice samples from 281 patients. The NHR, amplitude perturbation quotient, smoothed pitch perturbation quotient, percent jitter, and CPP were obtained from sustained vowel phonation, and the CPP was obtained from running speech. For the first time, normal and abnormal values of CPP were defined, and they were compared with other acoustic measures used to predict dysphonia. The CPP for running speech is a good predictor and a more reliable measure of dysphonia than are acoustic measures of jitter, shimmer, and NHR.

Autologous fat implantation for vocal fold scar: a preliminary report.

New insights into the anatomy and physiology of phonation, along with technological advances in voice assessment and quantification, have led to dramatic improvements in medical voice care. Techniques to prevent vocal fold scar have been among the most important, especially scarring and hoarseness associated with voice surgery. Nevertheless, dysphonia due to vocal fold scar is still encountered all too frequently. Although it is not generally possible to restore such injured voices to normal, patients with scar-induced dysphonia can usually be helped. Voice improvement is optimized through a team approach. Treatment may include sophisticated voice therapy and vocal fold surgery. Although experience with collagen injection has been encouraging in selected cases (particularly in those involving limited areas of vocal fold scar), there is no consistently successful surgical technique. Attempts to treat massive vocal fold scar, such as may be seen following vocal fold stripping, have been particularly unsuccessful. This paper reports preliminary experience with the implantation of autologous fat into the vibratory margin of the vocal fold of patients with severe, extensive scarring. Using this technique, it appears possible to recreate a mucosal wave and improve voice quality. Additional research is needed.

Unilateral recurrent laryngeal nerve paralysis:The importance of “preoperative” voice therapy

This preliminary retrospective study of 19 female patients and 22 male patients with unilateral recurrent nerve lesions demonstrated the promise of objective measurements in predicting the need for surgery, the efficacy of voice therapy in ameliorating vocal symptoms, and the effects of therapy in conjunction with surgery. Sixty-eight percent (68%) of the female patients and 64% of the male patients did not elect to have surgery. Outcome satisfaction of nonsurgical and surgical patients appeared to be similar. The data from this study support the importance of preoperative therapy for patients with unilateral vocal fold paralysis.

Intrasubject variability of objective voice measures.

Recent advances in the diagnosis and treatment of voice disorders necessitate the need for accurate and reliable objective voice measurements. There are many instruments commonly used to analyze voice data. Many, if not most, of these instruments have not been adequately tested for reliability or consistency. This study evaluates the intrasubject variability of the objective voice measurements from two commonly used voice analysis instruments. The study also presents data correlating subjective mood states, room temperatures, sleep times of the subject, time since last meal, and hydration levels to the various acoustic measures. Several weak but significant correlations were obtained and are discussed. Guidelines for the appropriate use of these instruments are described.

Laryngeal Electromyography: Clinical Application

Laryngeal electromyography (LEMG) is a valuable adjunct in clinical management of patients with voice disorders. LEMG is valuable in differentiating vocal fold paresis/paralysis from cricoarytenoid joint fixation. Our data indicate that visual assessment alone is inadequate to diagnose neuromuscular dysfunction in the larynx and that diagnoses based on vocal dynamics assessment and strobovideolaryngoscopy are wrong in nearly one-third of cases, based on LEMG results. LEMG has also proven valuable in diagnosing neuromuscular dysfunction in some dysphonic patients with no obvious vocal fold movement abnormalities observed during strobovideolaryngoscopy. Review of 751 patients suggests that there is a correlation between the severity of paresis and treatment required to achieve satisfactory outcomes; that is, LEMG allows us to predict whether patients will probably require therapy alone or therapy combined with surgery. Additional evidence-based research should be encouraged to evaluate efficacy further.

Laryngeal myasthenia gravis: report of 40 cases.

Myasthenia gravis, an autoimmune disorder of the neuromuscular junction, is usually recognized because of ocular complaints or generalized weakness. We report a series of 40 patients who presented with dysphonia as their initial and primary complaint. Diagnostic testing included strobovideolaryngoscopy, electromyography (EMG) with repetitive stimulation and Tensilon testing, and laboratory and radiographic evaluation. Strobovideolaryngoscopy most commonly revealed fluctuating impairment of vocal fold mobility, either unilateral or bilateral. EMG detected evidence of neuromuscular junction abnormalities in all patients. Only one patient had evidence of antiacetylcholine receptor (ACh-R) antibodies, but many other abnormalities suggestive of autoimmune dysfunction were present. Pyridostigmine therapy was initiated in 34 patients but was not tolerated in 4. Of the remaining 30 patients, 23 reported improvement of symptoms. We conclude that myasthenia gravis can present with symptoms confined primarily to the larynx and should be included in the differential diagnosis of dysphonia.

Respiratory and glottal efficiency measures in normal classically trained singers

Respiratory and glottal efficiency measures were collected from a pool of 40 classically trained singers with normal larynges. All singers had > or = 3 years of formal classical voice training and were active professional solo classical singers. Mean flow rates were obtained from all subjects to assess glottal efficiency. Additionally, maximum phonation times and phonation quotients were obtained from a subset of the singers. Pulmonary function test data on forced expiratory volume, forced vital capacity, and forced expiratory flow were obtained for all subjects. Results were compared with published normal values, not specifically derived from trained singers, used commonly in voice laboratories. Differences were found, suggesting the need for separate normative data to be used for evaluation of the vocal athlete.

Male soprano voice : a rare complication of thyroidectomy

A soprano voice from cricothyroid fusion is a rare complication following thyroidectomy. Thyroid surgeons should be aware of this possibility and recognize it early if voice pitch rises following thyroid surgery. This patients unfortunate complication may prove fortuitous for phonosurgeons and their patients. Cricothyroid fusion may provide a better long-term retention of frequency elevation than traditional cricothyroid approximation. It is also a reversible procedure. Cricothyroid fusion should be investigated as an alternative to cricothyroid approximation for pitch modification.

Vocal tremor reduction with deep brain stimulation: a preliminary report.

Abstract Vocal tremor has been a challenging problem for patients and their physicians. In some cases, it has been possible to lesson the symptoms tremor through medications and/or voice therapy. However, in most cases no good treatment has been availabe. Chronic stimulation of the thalamus has been successful in controlling tremors of the upper limb and other portions of the body. Our preliminary experience suggests that it may also be helpful in controlling vocal tremor.

Vocal Tremor Reduction withDeep Brain Stimulation

We present a case illustration of the significant effect that deep brain stimulation (DBS) of the thalamus can have on vocal tremor. A 72-year-old female with a history of essential tremor was noted preoperatively to have a moderate vocal tremor (3 on a scale of 1–5). Following bilateral DBS of the thalamus, the vocal tremor rating improved to 1. Acoustic analysis demonstrated her vocal tremor to be affecting the amplitude of her voice at 5.58 Hz preoperatively, at 1.93 Hz postoperatively with both leads on and at 1.54 Hz with only the left lead on. A videotaped endoscopic view of the patient’s vocal cords (presented at the 1999 ASSFN meeting) clearly illustrated the dramatic changes apparent in the vocal tremor when the stimulators were turned on and off.