**Comparison Among Phonation of the Sustained Vowel /ε/, Lip Trills, and Tongue Trills: The Amplitude of Vocal Fold Vibration and the Closed Quotient**

Gislaine Ferro Cordeiro, Arlindo Neto Montagnoli and Domingos Hiroshi Tsuji *University of São Paulo School of Medicine Brasil* 

#### **1. Introduction**

128 Otolaryngology

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Trill exercises are traditionally used in the clinical practice of speech-language pathology as vocal warm-ups in the treatment of dysphonia (Behlau & Pontes, 1995; Sataloff, 1991). They are also used by voice coaches (Aydos & Hanayama, 2004; Scarpel & Pinho, 2001) in the training of professional voice users, such as singers, actors (including voice actors), teachers, and lawyers. Although there are various types of trill exercises, including gargling, voiced fricatives, and simultaneous tongue/lip trills, the most commonly used exercises are tongue trills and lip trills (Scwarz & Cielo, 2009; Menezes *et al.*, 2005).

In the literature, the first reports of trill exercises date from the 1970s, at which time the tongue trill was already considered a "universal technique," i.e., a technique that can change the overall quality of the voice (Linklater, 1976). Trills are among the so-called facilitating sounds (Behlau & Pontes, 1995), and trill exercises can be used in the treatment of hyperkinetic and hypokinetic disorders (Schneider & Sataloff, 2007; Speyer, 2008); they can also be used as vocal warm-ups (Aydos & Hanayama, 2004; Speyer, 2008). Trill exercises are therefore widely disseminated among voice coaches, including speech-language pathologists, singing teachers, and drama teachers (Aydos & Hanayama, 2004). In individuals with a normal voice, tongue trills increase the amplitude of vocal fold vibration, reduce the glottal gap (Rodrigues, 2001), and improve the results of auditory-perceptual and acoustic analyses, resulting in less shimmer, a higher harmonics-to-noise ratio, increased amplitude of the harmonics, and decreased noise (Schwarz & Cielo, 2009; Rodrigues, 1995). During tongue trills, the entire laryngeal framework vibrates and there is anteroposterior constriction of the pharynx (Bueno, 2006). After the performance of tongue trills, the fundamental frequency increases, broad- and narrow-band spectrograms become clearer, and glottic closure increases, as do the amplitude and symmetry of vocal fold vibration, all of which demonstrate that tongue trills change the glottal source and vocal tract filter (Scwarz & Cielo, 2009).

Speech-language pathologists also use tongue trills, principally in individuals diagnosed with vocal nodules (Bueno, 2006). In addition, tongue trills can be used in individuals with

Comparison Among Phonation of the Sustained Vowel /ε/, Lip Trills,

users (Aydos & Hanayama, 2004; Nix, 1999).

vocal tract (Story, 1998; Gregio, 2006).

**2. Study sample and method** 

**2.1 Ethical aspects** 

written informed consent.

**2.2 Study sample** 

following criteria:

and Tongue Trills: The Amplitude of Vocal Fold Vibration and the Closed Quotient 131

address a wide range of issues, from breathing to voice articulation and projection. Trill exercises involve a functional balance among the vibrating organ (the tongue, the lips, or a combination of the two), the vocal tract, the larynx, and the exhaled air. Therefore, they constitute one of the principal tools for vocal warm-up and training in professional voice

Studies involving electroglottography (EGG) and comparing the closed quotient during lip trills with that during phonation of the vowel /a/ before and after the exercise showed a reduction of approximately 50% in the closed quotient during the performance of lip trills (Gaskill & Erickson, 2008) and an increase in the value when the exercise was performed at high intensity by singers (Cordeiro *et al.*, in prelo). The change is more evident in untrained individuals. The mechanical interaction between the source and the filter plus a lower adduction of the vocal process were reported to be responsible for the results obtained(15).

Recent studies have attempted to determine the best exercise prescription (the most effective duration and number of repetitions per session) for each case. Menezes *et al.*. (2005) suggested that, for individuals with no complaints or dysphonia, trill exercises be performed for a maximum of three and five minutes by females and males, respectively. For females with nodules, the ideal exercise duration is five minutes, the exercise leading to signs of vocal fatigue if performed for seven minutes or more (Menezes, 2011). , According to Schwarz (2009), when prescribing the exercise, the vocal resistance of the individual should be taken into consideration. In the study conducted by Schwarz (2009), the individuals performed three series of fifteen trills with a 30-second interval of passive rest between each series, and the author reported that voice quality improved after the exercise. In this chapter, we determine whether there are differences among tongue trills, lip trills, and phonation of the sustained vowel /ε/ in classically trained singers in terms of the maximum amplitude of vocal fold vibration, mean closed quotient, and standard deviation of the closed quotient, as assessed by EGG. We chose to compare the vocal fold vibration seen during lip and tongue trills with that seen during phonation of the sustained vowel /ε/ because that vowel is considered an open vowel, produced with minimal constriction of the

The present study was approved by the Research Ethics Committee of the *Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo* (HCFMUSP, University of São Paulo School of Medicine *Hospital das Clínicas*; Protocol no. 907/06, February 14, 2007; Appendix 1), located in the city of São Paulo, Brazil. All participating individuals gave

In the present study, we evaluated 14 individuals (7 males and 7 females). We applied the

The closed quotient varies widely during trill exercises (Cordeiro *et al.*, in prelo).

chronic edema and in those with hyperfunctional dysphonia (Pinho & Pontes, 2008). Some authors also recommend tongue trills in cases of hypofunctional dysphonia (Behlau e Pontes, 1995). Manieka-Aleksandrovix (2006) collected data regarding 500 patients with aphonia due to psychogenic dysphonia and found that gargling is one of the exercises used on the first day of therapy for voice rehabilitation.

Casper *et al.* (1992) employed tongue trills as a therapeutic resource in individuals with vocal fold paralysis and in those having undergone laryngeal surgery (Woo *et al.*, 1994). The tongue trill is contraindicated for individuals with recent-onset acute inflammation, because the exercise can aggravate the inflammatory phase. In the immediate postoperative period, tongue trills can delay healing (Pinho & Pontes, 2008) and, in cases of papillomatosis, stimulate the dissemination of the disease (Pinho & Tsuji, 2006).

When performing trill exercises, individuals should keep the tongue (or lips) and the mandible relaxed, coordinating the airflow so that vibration can occur (Scneider & Sataloff, 2007). The tongue trill is maintained by the interaction among the firmness of the body of tongue, control of the tip of the tongue, glottic closure, and control of the exhaled air. The exercise should be performed with the sides of the body of tongue firmly pressed against the dental alveoli and the tip of the tongue positioned in the region of the incisive papilla, free to vibrate (McGowan, 1992). As a result, the entire vocal tract vibrates (Scwarz & Cielo, 2009). For lip vibration (lip trill) to occur, the lips should be held together tightly enough to promote airway occlusion and relaxed enough for air pressure to overcome the resistance (Gaskill e Erickson, 2008). During lip trills, as during tongue trills, there is interaction among the vocal tract, glottal vibration, and the exhaled air during lip trills (Titze, 2006). During all trill exercises, the vibrating organ acts as a valve and creates oscillatory differences in external pressure and in the pressure in the cavity behind the constriction. This produces differences in the pressure, speed, and volume of air in the oral cavity, causing changes in the pharyngeal wall. Therefore, for vocal fold vibration to occur concomitantly with the point of oscillation of the oral cavity, subglottic air pressure must be greater than is that during normal phonation (McGowan, 1992).

Tongue and lip vibration follow the same principle as does the vocal fold mass effect: the anterior part of the vocal tract is occluded by the tip of the tongue or the lips. Intraoral pressure becomes greater than the atmospheric pressure and therefore greater than the force that maintains the anterior part of the vocal tract closed. Therefore, the anterior part of the vocal tract opens and is subsequently "sucked out" by the speed of the airflow (McGowan, 1992).

According to Gaskill and Erickison (2008), the difference between lip trills and other exercises that focus on the anterior part of the vocal tract is that the lip trill is the only exercise that promotes lip occlusion and non-occlusion (without loss of muscle tone). This causes the lips to vibrate, although at a frequency lower than that of vocal fold vibration. Therefore, airflow and subglottic pressure must adjust in order to allow the lips and the vocal folds to vibrate, overloading the vocal folds. The variations that occur in the pharynx during lip trills can increase the force of mucosal vibration during the wavelike motion of the vocal folds (McGowan, 1992).

Because of high vocal demand, professional voice users should maintain the fitness of all of the structures involved in phonation. For professional voice users, voice training should address a wide range of issues, from breathing to voice articulation and projection. Trill exercises involve a functional balance among the vibrating organ (the tongue, the lips, or a combination of the two), the vocal tract, the larynx, and the exhaled air. Therefore, they constitute one of the principal tools for vocal warm-up and training in professional voice users (Aydos & Hanayama, 2004; Nix, 1999).

Studies involving electroglottography (EGG) and comparing the closed quotient during lip trills with that during phonation of the vowel /a/ before and after the exercise showed a reduction of approximately 50% in the closed quotient during the performance of lip trills (Gaskill & Erickson, 2008) and an increase in the value when the exercise was performed at high intensity by singers (Cordeiro *et al.*, in prelo). The change is more evident in untrained individuals. The mechanical interaction between the source and the filter plus a lower adduction of the vocal process were reported to be responsible for the results obtained(15). The closed quotient varies widely during trill exercises (Cordeiro *et al.*, in prelo).

Recent studies have attempted to determine the best exercise prescription (the most effective duration and number of repetitions per session) for each case. Menezes *et al.*. (2005) suggested that, for individuals with no complaints or dysphonia, trill exercises be performed for a maximum of three and five minutes by females and males, respectively. For females with nodules, the ideal exercise duration is five minutes, the exercise leading to signs of vocal fatigue if performed for seven minutes or more (Menezes, 2011). , According to Schwarz (2009), when prescribing the exercise, the vocal resistance of the individual should be taken into consideration. In the study conducted by Schwarz (2009), the individuals performed three series of fifteen trills with a 30-second interval of passive rest between each series, and the author reported that voice quality improved after the exercise.

In this chapter, we determine whether there are differences among tongue trills, lip trills, and phonation of the sustained vowel /ε/ in classically trained singers in terms of the maximum amplitude of vocal fold vibration, mean closed quotient, and standard deviation of the closed quotient, as assessed by EGG. We chose to compare the vocal fold vibration seen during lip and tongue trills with that seen during phonation of the sustained vowel /ε/ because that vowel is considered an open vowel, produced with minimal constriction of the vocal tract (Story, 1998; Gregio, 2006).
