Research Interests - James P. Thomas, MD

Research: Vocal weakness study: Consent

Background & Purpose

Much about the conditions of vocal weakness due to nerve injury remains speculative. Some physicians speculate that the nerves to the voice box, when injured, will cause the vocal folds to be non-moveable and floppy and later stiffen into a single position. Others believe that after the original floppiness, the nerve regrows but only poorly or that the nerve regrows but is misdirected in its growth.

Based on experience and testing of clinical conditions of vocal fold weakness, Dr. Thomas has some additional thoughts. The testing done has been with 1) a listening examination of the patient’s vocal capabilities, 2) a visual examination of the position and the movement of the vocal folds by video recording and 3) with an EMG of the muscles of the larynx. An EMG is an abbreviation for a test called ElectroMyoGraphy. This is a measurement of the signals generated by a muscle when it contracts. The findings in actual patients have suggested that there are even more variations of weakness of the vocal folds than proposed above.

When the vocal fold doesn’t move, that would be called paralysis and when it moves slowly or incompletely this would be called paresis. However, even these assumptions may prove to be not completely accurate. For example, there are probably times when a vocal fold does not move because two muscles are pulling in opposite directions at the same time in an uncoordinated fashion. So visually, it may appear to be a paralysis, yet on EMG testing, something different is revealed to be closer to the truth.

Probably the hardest determination to make is when only one of the ten vocal fold muscles has been weakened or paralyzed. The vocal folds still move because the other muscles are working. Thus on a typical office examination, the patient might be told that all is well, when in fact the patient’s voice is still poor. Recent advances in video technology now allow the vocal folds to be viewed in very slow motion and even more recently to be viewed in ultra-slow motion.

A condition called spasmodic dysphonia is treated by injecting the vocal fold muscles with a muscle-weakening agent. Typically, the muscle injected is the thyroarytenoid. It is the muscle that lies within the vocal fold or cord as opposed to the other muscles that move the vocal fold, but are outside the actual vocal fold.

In this study, different individual muscles will be selectively and temporarily weakened and the change in response will be measured with 1) vocal capabilities and 2) video appearance of the vocal folds and their movement. The EMG will be utilized to find the individual muscles. A local anesthetic, lidocaine, will be injected in a small quantity into the muscle creating a temporary weakness of that muscle that should last for about an hour.

Lidocaine is a local anesthetic that blocks the conduction of nerve impulses. It is approved by the FDA for this usage.

Purpose

The purpose of this study is to correlate visual and auditory findings of weakness induced by lidocaine with 1) vocal capabilities and 2) visual laryngeal examination.

You are invited to participate in this study knowing that the principle benefit you will receive is the satisfaction of a contribution to medical knowledge and an increase in your own knowledge about your vocal fold structure and function.

The study would consist of 20 subjects, with a 50:50 mix of males and females. The study will be limited to adults.

Procedures and Treatment

The subject will be asked to fill out a voice history questionnaire. After an interview with the physician, the subject will be asked to read a passage, sing their highest and lowest notes, sing the first line of Happy Birthday, yell, cough and other vocal tasks as appropriate.

Topical anesthesia (lidocaine) may be sprayed on the back of the mouth or in the nose and a video recording of the larynx will be obtained which the subject will be able to view.

After this baseline documentation lidocaine will be injected in or near the voice box with the intent of weakening one portion of the vocal musculature. An electromyographic (EMG) needle will be utilized to locate the muscle to be injected. The medication effect should be complete within five minutes and the above listening and visual exam will be repeated with attention paid to any differences. Depending on the initial results, an additional injection may be placed. Then, the patient’s voice will be allowed to recover, perhaps over 30 to 60 minutes. A third listen and look exam will be performed to document a return to normal. This exam should take about two hours to complete.

This entire exam will take place in an office setting as an outpatient. It is likely that the subject should be able to return to work within four hours.

Possible risks

There is a temporary risk of aspiration (food or liquid going down the breathing tube) during the effect of the medication. Depending on the muscle or nerve injected there may be noisy breathing or shortness of breath. The patient may have a poor cough. These effects should typically be limited to 20 minutes to an hour. There may be discomfort or pain at the site of the injection for one to several days. There is the possibility of infection at the site of the injection. Side effects are generally dose related and the dosage used in this study will be very small. The most common allergic reaction is a skin rash and that is extremely rare. Lidocaine is a pregnancy category B medication Ð meaning studies in rats at doses 6.6 times that of humans have failed to produce cancer.

Possible benefits

There is no expected benefit to participation in this study other than an increase in medical knowledge.

Other treatments

None applicable

Costs and Compensation

You will be paid $50 to take part in this study.

Your are responsible for and must pay for the costs of your routine medical care; however, these costs may be covered, at least in part, by most major insurance companies or Medicare.

Liability for Injury

Should you suffer any injury as a result of taking part in this research activity, all of the necessary medical facilities are available for treatment, insofar as is reasonably possible. You are responsible for the costs of your medical care for injury resulting from treatment in this study; however, these costs may be covered, at least in part, by most major insurance companies or Medicare. Providence Health System is not the sponsoring institution of this research study and will not assume financial responsibility for such treatment or provide financial compensation for such injury.

You do not waive any of your legal rights by signing this consent form and agreeing to take part in this study.

Confidentiality

The confidentiality of records and the subject’s identity will be maintained as much as possible. Individuals with access to these records will be Dr. Thomas and his employee Jody Coale and any temporary employees that may need to be employed by Dr. Thomas for the purpose of maintaining records. The Providence Health System Institutional Review Board (PHS IRB) and the Health Care Finance Administration (HCFA) may have access to this data. The subject’s medical record will not be accessed for this study. All information to be used in the study will be obtained directly from the history and from physical findings during the study. Any publication of findings will not identify the subject. Videotaped findings will remain confidential and if used in publication, either in print or on the internet will not identify the subject.

New Findings

The subject will be provided with any new information, either good or bad, that may be obtained in the course of this study.

General Information

There should be no consequences to an early withdrawal from this study. The medication used during the study should have an effect for several hours at most. A decision not to take part in the study or to withdrawal from the study will not affect the subject’s continuing medical care. Participation in the study is voluntary.

Questions

If you have questions regarding the study please contact Investigator: James P. Thomas, MD Ð (503) 478-1845

If you have questions about your rights as a research subject or a research related injury please contact: Providence Health System Institutional Review Board (503) 215-6560 Reference name: Visual analysis of laryngeal paresis Number: 00-109

Methods

I have read and understand the contents of this consent form. I have had the opportunity to ask and have answered all of my questions regarding the procedure. I understand that my participation is voluntary and that I may stop my participation at any time. I will receive a signed copy of this consent form.

Updated - 23 April 2001