Amyotrophic lateral sclerosis, or ALS, is a progressive and eventually fatal neurological disease characterized by loss of the nerve cells that control muscle movement, the motor neurons. Common symptoms of ALS include muscle weakness, spasms and wasting, which leads to paralysis. Other diseases that adversely affect the motor neurons or muscle function may mimic ALS. Physical examination, diagnostic tests and the clustering of signs and symptoms help doctors distinguish ALS from other diseases.
Primary Lateral Sclerosis
Primary lateral sclerosis and ALS belong to the same disease group, the motor neuron diseases. Similar to ALS, primary lateral sclerosis typically causes muscle weakness, spasms and awkward movement, commonly involving the legs and hands. Both diseases can also adversely affect speech. Onset after age 40 is another similarity, reports the National Institute of Neurological Disorders and Stroke. Amyotrophic lateral sclerosis and primary lateral sclerosis, however, are distinctly different illnesses.
Amyotrophic lateral sclerosis involves degeneration of both the upper motor neurons of the brain and the lower motor neurons of the spinal cord. Primary lateral sclerosis, in contrast, affects only the upper motor neurons. Whereas patients with ALS typically exhibit muscle wasting, or shrinkage, those with primary lateral sclerosis generally do not exhibit this symptom. The disease of ALS is fatal, with most patients succumbing within five years after symptom onset, according to the National Institute of Neurological Disorders and Stroke. In contrast, primary lateral sclerosis usually progresses slowly over 15 to 20 years and rarely proves life threatening, according to MayoClinic.com.
Multiple Sclerosis
Multiple sclerosis is an inflammatory nervous system condition, which can affect nerves of the brain, spinal cord and body. Inflammation associated with multiple sclerosis damages the covering of the nerves, causing disrupted signal transmission. Because multiple sclerosis can affect any nerve, the disease may cause symptoms similar to ALS, such as leg muscle weakness, stiffness and spasticity, reports the National Multiple Sclerosis Society.
Amyotrophic lateral sclerosis and multiple sclerosis differ in many ways. The disease course with ALS usually proves to be rapidly and relentlessly progressive. With multiple sclerosis, the disease often follows a remitting and relapsing course over many years. Multiple sclerosis typically involves both sensory and motor nerves. With ALS, the sensory nerves are characteristically spared. Approximately 50 percent of patients with multiple sclerosis have cognitive, or thinking, difficulties, reports the National Institute of Neurological Disorders and Stroke. Intellectual functions typically remain unaffected by ALS.
Parkinson's Disease
Parkinson's disease is a progressive neurological disorder caused by the loss of brain cells that control the initiation and coordination of voluntary movement, explains the National Institute of Neurological Disorders and Stroke. Early-stage Parkinson's disease and ALS may present similarly. Involvement of the legs with both conditions typically causes slow, awkward movements and a tendency to stumble. Muscle stiffness also frequently occurs with both conditions. Features of Parkinson's disease that distinguish it from ALS include the presence of tremors, difficulty initiating movement and postural changes, such as leaning forward or to the side without recognizing the odd body position.
References
- National Institute of Neurological Disorders and Stroke: Amyotrophic Lateral Sclerosis Fact Sheet
- National Institute of Neurological Disorders and Stroke: NINDS Primary Lateral Sclerosis Information Page
- MayoClinic.com: Primary Lateral Sclerosis
- National Multiple Sclerosis Society: Walking (Gait), Balance, & Coordination Problems
- National Institute of Neurological Disorders and Stroke: Multiple Sclerosis: Hope Through Research
