Treatment Efficacy for Voice Disorders
1. Substitution of Alternative Behaviors in the Treatment of Chronic Cough
- 95% of persons with hyperfunctional voice disorders chronically cough and throat clear.
- Chronic coughing and throat clearing impedes the treatment of voice disorders. These behaviors can greatly impact the outcomes of behavioral voice treatment and surgical interventions.
- SLPs and ENTs spend time in most patient visits discussing coughing and throat clearing. Despite the prevalence of these conditions and their role in voice disorders, there is not good evidence for how chronic coughing and throat clearing associated with voice disorders should be managed.
- This research investigates aspects of coughing, throat clearing, and the ameliorative substitute behaviors promoted in treatment in terms of efficacy of removing the irritating laryngeal sensation that caused them and removing the laryngeal mucus aggregation which is the most commonly reported cause of the irritating laryngeal sensation.
2. Use of Stroboscopy as a Treatment Outcome Measure
The use of stroboscopy as a treatment outcome measure is hindered by:
- Low rater reliability of diagnostically important features from stroboscopy
- Variability in the use of and reporting of features from stroboscopy in treatment studies
Combined this lack of standardization, reliability, and validity of stroboscopy diminish its value as a treatment outcome measure. Without being able to use the gold-standard of evaluating vocal fold vibration, stroboscopy, as a treatment outcome measure, the ability to test and prove the efficacy of treatments is greatly reduced. It is necessary to prove the efficacy of treatments for 2 main reasons:
- To have strong evidence for clinical practices
- To be able to provide such evidence to insurance companies and other medical policy as a rationale for the ability to bill for diagnostic and treatment methods
Dr. Bonilha is currently working on improving the rater reliability of vocal fold vibratory features from stroboscopy as detailed in the section on Rater Reliability from Laryngeal Endoscopy in Diagnostic Accuracy in Voice and Swallowing above.
She and her team are evaluating the use and reporting of stroboscopy as a treatment outcome measure in the literature across all etiologies of voice disorders and separately for specific areas of high impact.
Reporting of Parameters from Stroboscopy in the Treatment of Head and Neck Cancer: One such study is a systematic review of stroboscopy parameters as an intervention outcome measure in patients with head and neck cancer. The review found that literature is inconsistent in reporting parameters identified on stroboscopic examinations, defining parameters used, and the scales used to objectively quantify parameters. The lack of a standardized measurement tool to interpret stroboscopic findings hinders comparison across treatment studies. Future research should focus on development of a valid and reliable tool to standardize the measurement and reporting of stroboscopic findings.
3. Methods to Improve Self-Efficacy of Persons with Voice Disorders
When working with patients, specifically those with voice disorders, treatment adherence is a major hindrance to successful treatment outcomes. Dr. Bonilha believes that patients have difficulty adhering to treatments if 1) they do not believe the treatment will help and/or 2) they do not believe they can personally be successful with the treatment. As a clinician, she feels she has a responsibility of providing evidence that a specific treatment will work for a specific patient. Generally, she is able to complete this during the voice evaluation. It is more difficult to convince the patient that they have the ability to complete the steps of the treatment that will help them improve their voice. That step involves improving the patient’s self-efficacy.
One study that Dr. Bonilha has accomplished on this topic is an investigation into a method to improve patients’ self-efficacy through a mastery experience. This is important as it is known that persons with high self-efficacy have better treatment adherence than those with low self-efficacy. An ideal mastery experience gives early and quick evidence that the patient will be successful with the treatment and works for a broad range of patients. This study sought to test whether a brief stimulability trial of forward focused voice could produce sufficient change in acoustic analysis measures to provide visibly improved objective results and, thus, be a potentially useful mastery experience. Results demonstrated that pairing a trial therapy with acoustic analysis during a voice evaluation is a possible mastery experience. Dr. Bonilha’s future research in this line will be to determine if this mastery experience improves self-efficacy, treatment adherence, and treatment outcomes.
4. Symptom Reduction in Persons with Vocal Tremor with and without Spasmodic Dysphonia
Vocal tremor is a repetitive changing in the pitch and/or loudness of voice at a rate of 4-6 times per second. Tremor may be focal to the larynx or diffuse. There is no known cause, but it has been related to aging, occlusive arterial disease, and cerebellar, basal ganglion, and brain lesions. As many as 66.7% of patients with Adductor Spasmodic Dysphonia have vocal tremor.
Vocal tremor has been treated using: drug therapy, surgery, and voice therapy. None of these treatments are ideal. Drug therapy has dosing issues, side effects and inconsistent results across patients. Surgery is not used often enough or in standard methods to judge the treatment efficacy. Voice therapy focusing on easing muscle tension is often tried, but with no established method or clear proof of treatment efficacy it is difficult to promote. Additionally, voice treatment often requires the patient to consistently use fatiguing techniques to produce speech with less tremor. Dr. Bonilha was interested in studying techniques that could be used infrequently, as needed, to reduce tremor in situations where greater clarity of communication was needed for a short period.
She and her team investigated 4 techniques: 1) speaking with better breath support, 2) speaking quickly, 3) speaking at a high pitch, and 4) speaking quietly. In 100% of patients, at least one technique was rated as having better vocal quality than the patient’s normal speech. When analyzed for the frequency of tremor cycles, 60% of the participants demonstrated a reduction in the frequency of tremor when using their best tremor reduction technique.
While there is not yet a perfect treatment for vocal tremor, perhaps there is a role for voice therapy sessions for patient education and the teaching of these temporary tremor reduction techniques.
5. Role of Hydration in the Prevention and Treatment of Voice Disorders
Advising patients to increase their water intake and decrease dehydrating behaviors is a frequent practice of SLPs and ENTs who treat patients with voice disorders. This is especially so with patients who present with chronic coughing and throat clearing.
While hydration has been related to improving some characteristics of vocal fold physiology, the relationship between systemic hydration, reported water and fluid intake, laryngeal sensations, coughing and throat clearing is not known.
Dr. Bonilha investigated this relationship by asking personswith and without voice disorders about their hydration and clearing behaviors. This data was evaluated against urine specific gravity measures for systemic hydration and in clinic reports of laryngeal sensation.
She found that persons with voice disorders were more likely to report coughing and throat clearing, but not irritating laryngeal sensations, than persons without voice disorders.
She did not find that persons with voice disorders had a lower water or fluid intake than persons without voice disorders. However, persons who drank more 8 or more cups of water a day were statistically less likely to report an irritating laryngeal sensation than persons who drank less than 8 cups of water daily.
In the future, Dr. Bonilha would like to approach this topic in a prospective study that addresses the role of hydration in chronic coughing and voice disorders.