Amyotrophic Lateral Sclerosis: Pathophysiology and Implications for Physical Therapy
This work will provide a basic overview of the pathophysiology for amyotrophic lateral sclerosis (ALS) as well as the medical interventions used in treatment of the disease. Physical therapy interventions for ALS and therapeutic exercise recommendations are the major focus of this study, and will be discussed in greater detail in the later portion.
Amyotrophic lateral sclerosis, or Lou Gehrig's disease as it is commonly called, is described by the ALS association (ALSA, 2010) as “a progressive neurodegenerative disease that affects nerve cells in the brain and the spinal cord.” Amyotrophic is described by Porth and Matfin (2009) as muscle wasting or atrophy as a result of the death of lower motor neurons which is the most easily observed result of the disease process. Lateral sclerosis refers to the degradation of nervous tissue in the lateral columns of the spinal cord due to scarring.
ALS presents with the following signs and symptoms (S&S). Early stages involve muscle weakness, involuntary movements, spasticity, twitching and cramping; these usually begin in the distal extremities (Lescher, 2011). Progressive S&S include atrophy and paralysis of muscles of the limbs, trunk, and face as well as fatigue, dysarthria, dysphagia, and hyperreflexia (i.e. highly sensitive gag reflex and positive Babinski reflex). As a result of weakness and paralysis in the muscles of the face and throat, feeding and respiration are affected. Most people with ALS are eventually dependent on mechanical ventilation.
ALS most commonly affects people between the ages of 40 and 70; the average age is 55, most are Caucasian (93%) and it is 20% more common in males (ALSA, 2010). Of those diagnosed with ALS, 20% live five or more years, up to 10% live more than 10 years, and 5% will live for 20 years or more. In very few cases, ALS progression has ceased and, in still fewer, it has reversed. Military veterans are a unique population who show a higher risk of developing ALS, and those deployed during the Gulf War are twice as likely to develop the disease.
In and of itself, ALS should not be described as a single disease. ALS is a clinical diagnosis which includes many different pathologies that lead to the same physiological conditions. There are many different forms of this disease which can be generally categorized as familial (hereditary) or spontaneous (caused by unknown factors); benign and juvenile forms are rare. This collection of pathologies follows the same general sequence of systematic destruction to motor neurons. ALS degrades motor neurons in three locations: the lower motor neuron cells of the anterior horn, the motor nuclei of the brainstem (hypoglossal in particular), and the upper motor neurons of the cerebral cortex (Porth & Matfin, 2009). ALS most often progresses by first affecting peripheral muscles and eventually, those...