Assessment and Management of Respiratory Dysfunction in Patients with Amyotrophic Lateral Sclerosis

Amyotrophic Lateral Sclerosis (ALS) is a relatively rare neurodegenerative disorder that causes progressive dysfunction of voluntary muscle groups secondary to motor neurons death. The relentless involvement of all skeletal muscles of the body, characterized by weakness and atrophy to complete paralysis, invariably involves respiratory muscles (particularly the diaphragm) resulting in a failure to deliver adequate amounts of oxygen to, and remove carbon dioxide from blood. As a result, respiratory failure, frequently complicated by pneumonia related to respiratory muscle weakness and ineffective cough, is the most frequent cause of death in these patients (Lo Coco et al., 2008). Considering the natural history of ALS, only a few number of patients shows respiratory muscle dysfunction at the onset of the disease (Marti-Fabregas et al., 1995; De Carvalho et al., 1996), and the majority of patients maintains an almost normal pulmonary function for months or years. Patients thus need to be regularly and progressively evaluated to identify early signs of respiratory muscle weakness so that adequate treatment can be implemented. Indeed, in the last few years it has been repeatedly shown that non-invasive positivepressure ventilation (NIPPV), the treatment of choice for chronic hypoventilation and respiratory failure in ALS, allows a significant improvement in survival and quality of life (Heiman-Patterson & Miller, 2006). Many tests are available to objectively assess the performances of the respiratory system, and there is increasing interest toward those able to sensitively detect mild impairment. Moreover, great attention has to be put on monitoring of cough effectiveness, management of respiratory secretions and prevention of respiratory infections. For all these reasons the management of respiratory dysfunction has become a