45.Voice and Speech Training

Explanation

This module explains voice and speech training exercises that can be used in indirect training. Speech therapists primarily conduct rehabilitation for voice and speech disorders, but people with those disorders often have impaired eating and swallowing function as well, because the same structures are used for both. Therefore, voice and speech assessments or exercises are sometimes used to screen for dysphagia or as indirect training exercises for dysphagia.

Because of this, professionals other than speech therapists should also have a proper understanding of the mechanisms of voice and speech production and know how these mechanisms differ from those of eating and swallowing. Then, they can adopt voice and speech exercises suited to the goals they set for dysphagia.

Explanation

Voice and speech production occur through 4 processes: (1) respiration, (2) phonation, (3) resonance, and (4) articulation. In (1) and (2), the passage of air exhaled from the lungs through the glottis in the larynx causes the mucous membranes of the vocal folds to vibrate. This vibration generates fluctuations in air, otherwise known as sound waves. This process requires proper glottic closure. If there is insufficient glottic closure due to, for example, recurrent laryngeal nerve palsy, air escapes and causes the voice to become hoarse (breathy hoarseness). Conversely, if there is excessively strong glottic closure, this produces a breathless state that makes voice production difficult. In (3), the sound waves generated by the larynx cause various reverberations as they pass through the airspaces above the larynx (ie, the pharyngeal, oral, and nasal cavities), also known as the vocal tract. Velopharyngeal closure plays a particularly important role in this process. The nasopharyngeal cavity is the passageway between the oral cavity and the nasal cavity. During relaxed breathing, the nasopharyngeal cavity stays open and serves as a passageway for air from the nose. However, when sounds other than nasal consonants ("m" and "n" sounds) are produced, the muscles of the soft palate and pharyngeal wall constrict to tightly close the nasopharyngeal cavity and direct the flow of exhaled air through the mouth. Lastly, in (4), various sounds are produced by cutting off the flow of exhaled air using the lips or tongue.

Explanation

Here we see the places where different sounds in the Japanese language are produced. The "pa" and "ba" sounds are produced by closing the lips, the "ta" and "da" sounds by touching the tongue to the alveolar ridge, and the "ka" and "ga" sounds by touching the back of the tongue with the soft palate.

Explanation

Voice and speech are produced using the same structures used for eating and swallowing, but these structures function in very different ways for each activity. The first difference is that the movements are in opposite directions. In eating and swallowing, food enters through the mouth, passes through the pharynx into the esophagus, and then is carried to the stomach. In contrast, in voice and speech production, air exhaled from the lungs passes through the trachea, larynx, and pharynx and then exits through the oral or nasal cavity.

The intensity of each movement also differs: voice and speech movements are very slight, whereas eating and swallowing require strong and firmly executed movements.

Other differences are the speed of movements and changes in movements: voice and speech require fast and accurate movements with high variability, whereas eating and swallowing movements are relatively slow and regular.

Yet another difference is how movement is induced: voice and speech are voluntary, whereas eating and swallowing involve a mix of voluntary movements in the preparatory and oral stages and reflexive movements in the pharyngeal stage.

Explanation

Here we see speech production captured on videofluorography. During vowel phonation (left), the tongue does not touch the palate and the lips are open. The nasopharyngeal cavity closes and exhaled air exits through the oral cavity. Depending on the vowel, the positions of the lips, jaw, and tongue change. With the "ee" sound, the tongue is in a high-front position, and with the "ah" sound the tongue is in the lowest position, which expands intraoral space.

In continuous speech (right), the tongue and soft palate execute rapid coordinated movements. Depending on the sound, the lips may close or the tongue and palate may touch. All of these movements are slight and brief. They look different from movements in the oral stage of swallowing observed on videofluorography.

Explanation

Voice production occurs with the passage of exhaled air through the glottis. It is possible to infer information about laryngeal function and problems during swallowing from the quality of a patient's voice.

Gurgling phlegm-like sounds while eating suggests retention of sputum or food or drink near the glottis. It is a good idea to have the patient say "ah" after coughing or suctioning to see if the gurgling voice sounds have disappeared.

A hoarse voice suggests glottic insufficiency (eg, recurrent laryngeal nerve palsy). Eating training should be conducted carefully if patients are suspected to be at risk of aspiration.

Patients who cannot sustain their voice who has short intermittent speech have problems with respiratory function or glottic closure. So, these patients have difficulty forcefully expelling sputum if they experience laryngeal penetration or aspiration. To measure maximum phonation time (MPT), tell them to take a deep breath and then say "ah" for as long as they can, repeat this measurement 3 times, and take the longest of the 3 measurements as the result. Average times are 30 s for men and 14 s for women; times of ≤ 14 s for men and ≤ 9 s for women are considered abnormal.

Difficulty controlling vocal pitch suggests problem in the superior laryngeal nerve. It is important to look out for reduced laryngeal sensitivity in such patients.

Voice resonance in the nose (hypernasal speech) occurs due to velopharyngeal insufficiency. These patients may regurgitate food or drink into the nasopharyngeal cavity. Causes of a voice that sounds like the nose is congested (hyponasal speech) include rhinitis and adenoid hypertrophy. These cause mouth breathing and olfactory impairment.

Explanation

We can infer information about oral and pharyngeal function from the quality of patients' articulation (speech production). Intelligibility is reduced by incomplete lip closure (affecting "p" and "b" sounds) and with poor lifting of the tip of the tongue ("t" and "d" sounds). The sounds "k" and "g" are difficult to distinguish when the back of the tongue and the soft palate do not meet. This is a sign to look out for because this problem makes it more difficult to hold food in the mouth and may lead the premature spillage into the pharynx too quickly. Velopharyngeal closure insufficiency can mean "b" sounds like "m" and "d" sounds like "n". Velopharyngeal closure insufficiency can lead to regurgitation into the nasopharyngeal cavity. An "eh" vowel sound instead of an "ee" is believed to occur through poor lifting of the tongue or inadequate tongue volume. Inadequate contact between the tongue and palate makes food propulsion difficult and can cause retention of food inside the oral cavity.

Explanation

Articulation (speech) exercises are an important part of indirect training for dysphagia because they aim at improving movement of the lips and tongue, as well as oral function primarily during the preparatory and oral stages. They should also help to invigorate eating movements when performed as pre-meal warm-up exercises. They can be performed as early training with any patient. However, as mentioned earlier, various aspects differ between voice/speech movements and eating/swallowing movements. Therefore, we must be aware of what movements are necessary for eating and swallowing, and instruct patients to slowly and accurately produce each sound with good effort. Articulation exercises or drills to read aloud, which include the "p/b," "t/d," and "k/g" sounds, may be used for the purpose of early training.

Explanation

In falsetto, making a high-pitched voice causes the larynx to rise. This principle is used to promote opening of the esophageal sphincter (UES) during swallowing and reduce pharyngeal residue (pooling) by increasing elevation of the larynx. This approach is used for patients with reduced laryngeal lifting and impaired opening of the UES due to prior resection of the floor of the mouth or the root of the tongue. Patients are instructed to sustain a high-pitched voice for a few seconds. The fingers can also be used to further elevate the larynx during this exercise.

Explanation

The Lee Silverman Voice Treatment (LSVT® LOUD) aims at improving volume and intelligibility of speech by improving the function of all voice and speech-related structures through exercises made with a loud voice. It is used for patients with voice and speech disorders or dysphagia associated with neuromuscular disorders such as Parkinson's disease. Intensive training to increase vocal effort is performed in four 50- to 60-min sessions per week for 4 weeks. The instructions are simple and clear, and include the followings: (1) sustain a loud sound (vowel) for a long time, (2) make loud high-pitched and low-pitched vowel, and (3) speak in a loud voice. First, we need to provide an enthusiastic example to motivate our patients. They should understand that the goal is to make their voice loud to the degree that they feel it's too loud. Becoming accustomed to speaking in a loud voice will invigorate both their voice and speech abilities as well as their eating and swallowing abilities.

However, anyone who wishes to use the LSVT® LOUD method must be certified by participating in a 2-day certification workshop held by LSVT GLOBAL. In recent years, computer-based remote online therapy and self-training software for this treatment have also been developed and implemented.

Reference

1. Fujiu-Kurachi, M:LSVT® LSVTRLOUD - Voice Treatment for Parkinson Disease. The Japanese journal of communication disorders 30: 103-109, 2013.