Amyotrophic lateral sclerosis (ALS) is also known as ‘motor neurone disease’ (MND) and ‘Lou Gehrig’s Disease’. In ALS, the nerve cells in the brain and spinal cord that control movement, or ‘motor neurons’, gradually shrink and disappear. Motor neurons reach from the brain to the spinal cord and from the spinal cord to the muscles throughout the body. When the motor neurons die the brain is no longer able to trigger and control muscle movement, meaning that the muscles become paralysed.
‘A-myo-trophic’ comes from the Greek language. ‘A’ means no, ‘myo’ refers to muscle, and ‘trophic’ means nourishment: ‘No muscle nourishment.’ Without nourishment, a muscle atrophies, or wastes away. ‘Lateral’ describes the areas in a person’s spinal cord where portions of the nerve cells that signal and control the muscles are located. As this area degenerates there is scarring or hardening, called ‘sclerosis’, in the region.
The muscles affected by ALS are voluntary muscles. They are the muscles we use to pick up a book or walk across a room. Muscles such as our hearts or the ones controlling digestion are involuntary. These are not involved with ALS. Breathing is a voluntary action and can be impacted by ALS.
Similarly, there are many kinds of nerves and not all are affected by ALS, only those that control the movement of voluntary muscles. Even when a person with ALS has lost the ability to move a part of his or her body, healthy sensory neurons remain in that area allowing him or her to feel heat, cold, pressure, and pain there. Because vision, hearing, and some other bodily functions are controlled by yet other kinds of nerves, they are also safe from ALS. In some cases, memory or thinking may be affected, but this is uncommon.
The cause of ALS is not fully known. The majority of people live for 3 to 5 years after they are diagnosed with the illness. There are extremely rare medically documented cases in which the disease stops progressing, or slows nearly to a stop. The progress of the illness is different for every person.
Research for a drug that halts and reverses ALS is ongoing. Devices and therapies exist and are continually being developed to extend independence and life.