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What is Motor Neurone Disease (MND)?

MND is a group of rare neurological disorders caused by the progressive deterioration of neurones (nerves) in the brain and spinal cord. These motor neurones breakdown and die, so muscles are unable to move, causing them to weaken and waste.

MND is a fatal, rapidly progressing disease that affects the brain and spinal cord.

MND attacks the nerves that control movement so muscles no longer work. It does not usually affect the senses such as sight, sound, touch etc.

MND can leave people locked in a failing body, unable to move, talk, swallow and eventually breathe.

Causes and Symptoms

The cause of MND is still unknown till today although 5-10% of people with MND have a family history of the condition. Approximately 300-400 people are living with MND in Singapore at any one time, predominantly in people who are aged above 50 years and slightly more common in males than females. Every year, there are 30-50 new cases.

The initial symptoms differ between patients, it could be an onset of weakness in the arms and/or hands, foot drop, loss of voice, breathing difficulties, loss of muscular and motor controls.

Around 35% experience mild cognitive change causing difficulties with planning, decision-making and language.

A further 15% show signs of a form of dementia resulting in more pronounced behavioural change.

MND affects people from all communities.

Main Types of MND

Amyotrophic Lateral Sclerosis
(ALS)

Amyotrophic lateral sclerosis (ALS) is a degenerative neurological disorder that damages nerve cells and causes impairment.

It is also known as Lou Gehrig's disease. Motor neurones, the nerve cells that regulate voluntary movements, are particularly vulnerable to the disease, which causes them to atrophy and die. Lower motor neurones convey messages from the spinal cord to the muscles. In contrast, upper motor neurones send messages from the brain to the spinal cord.

The brain can no longer move muscles or govern muscular movement due to the absence of these nerve cells. As a result, the muscles shrink and become weaker. Patients with ALS lose their ability to walk upstairs, reach for things, and dress themselves within a few years of being diagnosed. A variety of factors causes ALS. The specific aetiology of ALS is unknown; however, it is thought that genetic, environmental, and lifestyle factors may have a role.

ALS symptoms include tight muscles, muscle twitching, and a gradual decrease of muscle strength in the early stages of the disease. Muscles gradually become paralyzed as the disease develops, and patients have trouble speaking, swallowing, and finally breathing. ALS first affects the muscles in the arms, hands, and legs in roughly two-thirds of patients, causing tripping, stumbling, or clumsiness when running.

Foot drop and a "slapping" gait are additional symptoms of ALS. The term "foot drop" refers to the difficulty in elevating the front half of the foot. Reduced finger dexterity, cramping, stiffness, and weakness or wasting of intrinsic hand muscles, as well as a wrist drop that interferes with task performance, are all early indications.

Slurred voice, hoarseness, and reduced speech volume are other common ALS symptoms. Aspiration of food, which occurs when food is breathed into the airways, and choking during a meal are two other alarming early symptoms. Emotional and cognitive issues can occur in people with ALS, including involuntary and inappropriate laughter or sobbing, depression, decreased critical thinking, and odd social behaviours.

Muscle atrophy (shrinkage) becomes increasingly noticeable as the condition advances, and muscle cramps become more common. Patients' voices often fluctuate as the disease progresses, and speech may be lost eventually. Drooling and swallowing issues are common in patients.

Progressive Bulbar Palsy
(PBP)

Many persons with this illness will get ALS in the future. PBP causes motor neuron damage in the brain stem, which is located towards the base of the brain.

Motor neurones in the stem help you chew, swallow, and speak. You may slur your speech and have difficulty eating and swallowing if you have PBP. It also makes it difficult to maintain emotional control. You may laugh or cry unintentionally. The brain stem is involved in progressive bulbar palsy. The brain stem is a region of the brain that helps you swallow, speak, chew, and perform other tasks. Difficulty swallowing, weak jaw and face muscles, progressive loss of speech, and tongue weakness are signs and symptoms of progressive bulbar palsy.

Other signs and symptoms include less noticeable weakness in the arms and legs and bursts of laughter or tears (called emotional lability). A variant form of amyotrophic lateral sclerosis is progressive bulbar palsy (ALS). Many patients who have progressive bulbar palsy go on to acquire ALS later in life. While neither progressive bulbar palsy nor ALS have a cure, doctors can treat the symptoms.

Progressive Muscular Atrophy (PMA)

This type of ALS is far less common than PBP or ALS. It might be sporadic or inherited. Lower motor neurones are primarily affected by progressive muscular atrophy.

Weakness commonly begins in the hands and subsequently spreads across the body. Your muscles may get weak and spasm. This condition has the potential to progress to ALS.

PMA is an extremely rare variant of motor neuron disease (MND) that only affects the lower motor neurones. PMA is considered to be responsible for about 4% of all MND cases. This contrasts to amyotrophic lateral sclerosis (ALS), which affects both the upper and lower motor neurones, and primary lateral sclerosis, a rare MND variety that affects just the upper motor neurones. The distinction is significant since PMA has a better prognosis than traditional ALS.

Primary Lateral Sclerosis
(PLS)

PLS resembles ALS in that it affects just the top motor neurones. It causes arm and leg weakness and stiffness and slower walking and impaired coordination and balance.

Speech becomes garbled and slow. It commonly begins in persons between the ages of 40 and 60, just like ALS. Over time, the muscles get stiffer and weaker. People do not die from it, unlike ALS.

Legs are usually the first to be affected, followed by the body, trunk, arms, hands, and eventually the bulbar muscles (muscles that control speech, swallowing, and chewing). Some of the symptoms are weakness, muscle stiffness and spasticity, clumsiness, slowness of movement, and issues with balance and speech. PLS is more common in males than in women, and it manifests itself in a variety of ways between the ages of 40 and 60.

Sensory nerves which control sight, hearing, taste, touch and smell are not affected. Many people with MND continue to think clearly and are fully aware of what is going on throughout their illness.

There is no cure for MND and many survive an average of up to five years from diagnosis.

The most famous MND/ALS patient was Stephen Hawking, scientist from United Kingdom, who survived more than 50 years after diagnosis.

MND/ALS gained wider public attention in Singapore with the 2014 ALS Ice Bucket Challenge.

ALS Staging

According to King's College staging system, ALS staging was based on the presence of wasting, weakness, spasticity, dysphagia, or dysarthria in different central nervous system (CNS) regions defined as bulbar, upper limb, lower limb or diaphragmatic.