**3.1 Influence of viscosity**

600 Amyotrophic Lateral Sclerosis

very expensive, and the fact that the patient remains in a horizontal position with his/her arms extended along the body for more than 10 minutes can be a problem for subjects

In a study conducted by Rio and Cawadias (2007), it was discussed the main techniques adopted by nutritionists of some centers for the treatment of ALS in Europe and Canada for nutritional assessment of ALS subjects. The researchers found only 22% of nutritionists had more than 4 years of experience in ALS. Amongst the most used nutritional assessment methods were weight, % WL, BMI and arm circumference, used by 100%, 96%, 83%, and 9% of the professionals, respectively. The bioelectrical impedance, validated by Desport et al. in 2003, as well as DEXA, were not reported by the professionals from the centers investigated

Analyzing the measures adopted by the relevant literature, in ALS, as well as in other diseases, the use of parameters such as weight, % WL and BMI, as well as skinfolds, BIA, DEXA and indirect calorimetry can also be observed (Rio; Cawadias 2007; Desport et al.,

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

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;

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

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

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;

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;

2003; Desport et al., 2001; Silani; Kasarkis, Yanagisawa, 1998).

intake, which can result in malnutrition (Karsarkis et al., 1996).

(Mitsumoto et al., 2003; Desport et al., 1999).

Enderby, 1984; apud Chiappetta, 2005).

with ALS.

by Rio and Cawadias.

**3. Dysphagia and ALS** 

(Chiappetta; Oda, 2004).

Gubbay et al., 1985).

Strand et al., 1996).

Food viscosity is one of the most important variables of swallowing. Thin liquids make difficult swallowing by patients with reduced laryngeal control, since they are quickly swallowed and do not maintain their shape inside the oral cavity, which can prematurely leak into the pharynx and, thus, penetrate the airways still open. To avoid such effect, the optimal viscosity must be determined so the swallowing may occur safety (Macedo & Furkim, 2000).

Viscosity influences many aspects of the assessment and management of dysphagia. It can be defined as the fluid resistance to the flow and is measured in Centipoise (ctps or cPs) (Silva et al, 2010).

There are different types of viscosity that can be easily achieved using commercial thickeners. These types can be classified in centipoise (cP) values (Table 1) as thin (1-50 cP), nectar (51-350 cP), honey (351-1750 cP) and pudding (> 1750 cP).


*Source: ADA, 2002.* 

Table 2. Classification of viscosity, in centipoise (cP) values, according to the ADA (2002), for the nutritional care of subjects with dysphagia.
