**3. Dysphagia and ALS**

With the clinical progression of ALS, manifestations such as dysarthria (speech impairment), dyspnoea (breathing alteration), dysphonia (voice alteration) and dysphagia (swallowing alteration) are common. These manifestations occur as a result of progressive respiratory muscle dysfunction, caused by motor neuron degeneration of corticobulbar tract (Chiappetta; Oda, 2004).

In 17 to 30% of ALS patients, bulbar muscles, especially the muscle groups of the velum and tongue are the first ones affected, resulting in progressive dysphagia, and therefore difficulty in swallowing food and liquids (Calia; Annes, 2003; Mitsumoto; Norris, 1994; Gubbay et al., 1985).

The oro-laryngo-pharyngeal weakness affects the survival of subjects with ALS, especially because of the continuous risk of aspiration pneumonia and sepsis, and the inadequate food intake, which can result in malnutrition (Karsarkis et al., 1996).

Malnutrition due to dysphagia, or other factors associated, such as muscle atrophy and diaphragm weakness, increases the relative risk of death almost eight times in ALS patients (Mitsumoto et al., 2003; Desport et al., 1999).

The involvement of the tongue muscles and lip orbicular muscles, upon ALS progression, triggers a decrease in pressure wave, pharyngeal peristalsis, and elevation and anteriorization of larynx, causing choking, even with saliva (Watts; Vanryckeghem, 2001; Strand et al., 1996).

In ALS, dysphagia for liquids is more common than for solids. The early escape, that is, when the food reaches the vallecula prior to initiation of pharyngeal swallowing, is more frequent with thin liquids and is the leading cause of tracheal aspiration. Pharyngeal residues are more commonly observed throughout the course of the disease. The pasty and solid consistencies may cause laryngeal penetration and tracheal aspiration after swallowing. Swallowing disorders occur due to the influence of oral transit, decreased movement of the tongue base, decreased elevation and anteriorization of the larynx and decreased pharyngeal contraction (Chiappetta; Oda, 2004; Logeman, 1998; Campbel; Enderby, 1984; apud Chiappetta, 2005).

In order to minimize respiratory and nutritional complications in the treatment of dysphagia, interdisciplinary assessment is extremely important, and the modification of the texture of foods is an alternative for the maintenance of the oral route.
