Lou Gehrig's disease is different for every person who has it. In general, muscle weakness, especially in the arms and legs, is an early symptom for more than half of people with ALS. Other early signs are tripping or falling a lot, dropping things, having difficulty speaking, and cramping or twitching of the muscles. As the disease gets worse over time, eating, swallowing, and even breathing may become difficult.
It may take several months to know for sure that someone has Lou Gehrig's disease. The illness can cause symptoms similar to other diseases that affect nerves and muscles, including Parkinson's disease and stroke. A doctor will examine the patient and do special tests to see if it might be one of those other disorders.
One of the tests, an electromyogram, or EMG, can show that muscles are not working because of damaged nerves. Other tests include X-rays, magnetic resonance imaging (MRI), a spinal tap, and blood and urine evaluations.
Sometimes a muscle or nerve biopsy is needed. A biopsy is when a doctor takes a tiny sample of tissue from the body to study under a microscope. Examining this tissue can help the doctor figure out what's making someone sick.