What is Motor Neurone Disease (MND)?
Motor neurone disease (MND) is a neurological condition caused by the damage and death of specific nerve cells called motor neurons in the brain and spinal cord. Electrical signals travel from the brain to the muscles via the motor neurones. Damage and destruction of motor neurones results in a failure of signals to the muscles. This causes progressive weakness and wasting of muscles. Motor neurones of any part of the body can be affected resulting in a wide variety of symptoms.
Motor neurones are divided into upper and lower types
Upper motor neurones:
These begin in the brain and travel down into the spinal cord where they communicate with the lower motor neurones.
Lower motor neurones:
These begin at the spinal cord. They receive information from upper motor neurones. They extend out of the spinal cord and travel to the muscles of the body.
For example, when our hand touches a hot object, the painful sensation is carried by the sensory nerves to the brain. The brain then decides that the hand should be moved away to avoid pain. It then sends a signal to the spinal cord in the neck. This signal will then pass from the upper motor neurones to lower motor neurones down the right arm to the muscles involved in moving the hand. Thus the signal ultimately results in a muscle contraction which causes the hand to move away from the painful stimulus.
There are different subtypes of Motor Neurone Diseases. Sometimes, particularly in America, Motor Neurone Disease is referred to as Amyotrophic Lateral Slerosis (ALS) or Lou Gehrig’s disease. In the UK, ALS is a term used primarily by doctors to describe the most common form of MND.
The cause of MND is unknown and is the focus of on-going research. In the vast majority of cases, MND occurs randomly and is called ‘sporadic MND’. In a much smaller number of cases, MND can be inherited and is called ‘familial’.
MND can present at any age. The only established risk factors for developing MND are age (the condition is more common as age increases), being male and having a family history of MND.
At present, there is no cure for MND and it remains a progressive condition. Management is therefore based around controlling symptoms and maintaining quality of life.
The prognosis in MND is varied and depends upon many different factors. Every person who develops MND is different and therefore the length of survival with MND is different too.