Medically reviewed by Brigid Dwyer, MD Key Takeaways Clonus causes involuntary, rhythmic muscle contractions when a muscle is stretched.It is often observed in conditions like multiple sclerosis, ...

Medically reviewed by Nicholas R. Metrus, MD Key Takeaways Neurons are cells that transmit electrical signals through the ...

Primary lateral sclerosis (PLS) is a rare neurological disorder that affects the motor neurons in the brain and spinal cord, which control movement. It is a form of motor neuron disease (MND). PLS ...

Amyotrophic lateral sclerosis (ALS) is a degenerative neurological disorder that involves the death of nerve cells in the brain and spinal cord. This, over time, leads to the brain losing its ability ...

Progressive muscular atrophy (PMA) is a rare adult-onset motor neuron disease. Although there’s no cure, treatments may slow down nerve damage and reduce symptoms. Progressive muscular atrophy (PMA) ...