What Are the Symptoms of Motor Neuron Disease?

As motor neuron disease is a collection of related medical conditions, the symptoms of motor neuron disease are similar no matter which condition a patient has. Motor neuron disease has five forms, some more severe and life-threatening that others. All of the conditions affect the body's ability to perform voluntary movement. Symptoms generally worsen over time despite palliative care. Initial symptoms cannot predict a patient's short- and long-term prognosis.

Motor neuron disease has five forms: ALS (amyotrophic lateral sclerosis), PLS (primary lateral sclerosis), PMA (progressive muscular atrophy), pseudobulbar palsy and progressive bulbar palsy. The symptoms of motor neuron disease are generally associated with ALS, also known as Lou Gehrig's disease in the United States. The initial neuron degeneration can begin in any part of the body; loss of coordination and weakness usually present wherever the symptoms begin. The symptoms quickly spread to the rest of the body, in most cases causing complete immobility. Ninety percent of patients die within six years of diagnosis.

In many ways, PLS is a less severe form of ALS. Like ALS, it generally appears when an individual is middle aged. Though initial symptoms are nearly identical to those of ALS, PLS does not affect spinal neurons. Thus, the disease progresses very slowly, and the majority of patients do not die from it. In some cases, though, PLS can develop into ALS. A few medications have shown promise in relieving the muscle spasms associated with PLS.

The symptoms of motor neuron disease in PMA are similar to those of ALS and PLS. Muscle atrophy is the most common symptom. Whether the atrophy is confined to a single limb or spread across the body depends on a patient's particular physiology. As atrophy is common to all forms of motor neuron disease, the lack of muscle spasms and emotional changes allow physicians to rule out the presence of ALS and PMS. The five-year survival rate for PMA is between that of ALS and PLS.

The visible symptoms of motor neuron disease for pseudobulbar palsy are confined to a patient's speech and ability to swallow. In a patient's mind, wild and sudden mood swings can occur as well. This palsy can have a number of causes from ALS to cancer. Prognosis depends on the root cause.

Finally, the symptoms of motor neuron disease can indicate the presence of progressive bulbar palsy. As of 2011, there is no consensus in the medical community whether progressive bulbar palsy is a separate condition or a part of ALS. Like pseudobulbar palsy, the condition quickly compromises a patient's ability to speak and swallow. There is no treatment, and death generally occurs within one to three years.