Understanding Motor Neurone Disease: Types & Management

Motor neurone diseases (also called motor neuron diseases or MNDs) are a group of neuromuscular disorders in which there is progressive damage to parts of the brain and spinal cord. 

Specifically, the damage in MND disease occurs in motor neurons, which are nerve cells that control skeletal muscle function (muscles used for moving, speaking, breathing, swallowing, gripping, etc.). In healthy people, signals from the upper motor neurons in the brain are transmitted to the lower motor neurons in the brain-stem and spinal cord, and from there to muscles throughout the body, causing them to be divided into upper motor neurone or lower motor neurone diseases.

When signals from the lower motor neurons to the upper motor neurons are disrupted, it leads to muscle weakness, muscle atrophy (wasting or shrinking in size), and fasciculations (muscle twitches). When signals to the lower motor neurons from the upper motor neurons are disrupted, it leads to spasticity (muscle stiffness), slowed movements, and overactive reflexes.

What Is The Difference Between ALS and Motor Neuron Disease?

Amyotrophic lateral sclerosis (ALS), formerly known as Lou Gehrig’s disease, is one type of motor neurone disease. It is a rare neurological condition that can affect both upper and lower motor neurons. ALS is the most common form of motor neurone disease (MND). There are other motor neuron diseases (see table below), some of which affect lower motor neurons or upper motor neurons only.

Causes of Motor Neurone Disease  

Genetic Factors  

Some motor neuron diseases occur due to a genetic mutation (change in DNA), usually involving a single specific gene. These types of motor neurone diseases are inherited and run in families. For example, people with certain gene mutations can develop ALS (amyotrophic lateral sclerosis).

However, having a gene mutation and a family history of MND does not mean a person will definitely get MND—it means they have a higher risk of getting it. Symptoms of inherited motor neurone diseases can be present at birth or appear during early childhood. 

Environmental Triggers  

When there is no family history of motor neurone disease and no identifiable gene mutation, it is called sporadic MND. Some genes may still play a role, but environmental factors such as viral infections and exposure to toxins play a bigger role in the development of sporadic motor neurone disease. 

Research is underway to identify the exact causes of why people develop MND that is not inherited. Symptoms of non-inherited motor neuron disorders are adult-onset (they typically appear after the age of 50), although they can appear at any age.

Save On Your MND Treatments

Early Symptoms of Motor Neurone Disease  

There can be three types of symptoms in the early stages of motor neuron disease:

Limb-Onset MND

This is the most common presentation of MND, where symptoms first appear in the limbs, affecting about 65% of people with motor neuron disorders. The symptoms first appear in the limbs (arms or legs) and may include:

• A weakened grip (problems picking up or holding objects, opening jars, etc.)

• Weakened shoulder muscles (trouble lifting the arms above head level)

• Weakened hip and ankle muscles (frequent tripping)

Bulbar-Onset MND

Bulbar-onset MND is caused by damage to motor neurons in the bulbar region of the brainstem. This occurs in about 25% of people with the condition, affecting the muscles of the face, throat, and tongue, leading to problems of swallowing and speaking. The first symptom is usually dysarthria (slurred speech), which can be mistaken as a sign of stroke. As the disease progresses, it can cause dysphagia (difficulty swallowing), which can be mistaken for a blockage in the throat.

Respiratory-Onset MND

This is a rare type of MND in which the respiratory (breathing) muscles are affected first. Usually, these muscles are affected in the advanced stages of motor neurone disease. Symptoms may include morning headaches due to lack of sleep and proper oxygen exchange in the lungs. Symptoms may also include shortness of breath or trouble breathing with daily activities like climbing stairs.

Progressive Symptoms of Motor Neurone Disease 

As a motor neurone disease progresses, it causes more severe symptoms, including:

Muscle Symptoms

• Muscle weakness

• Muscle atrophy (wasting, shrinking, or thinning)

• Muscle spasticity (stiffness)

• Muscle cramps

• Trouble with movements

• Joint aches and pains and stiff joints

Speech, Swallowing, and Other Symptoms

• Increasing difficulty with speaking (slurred speech)

• Trouble swallowing, including choking episodes

• Excessive saliva and drooling due to reduced swallowing function

• Difficulty clearing mucus from the throat and chest due to weak cough muscles

• Excessive yawning and jaw pain

Psychological and Cognitive Symptoms

• Emotionality, also called emotional lability (trouble controlling emotions with episodes of uncontrolled crying or laughing)

• Problems with concentration, communication, and planning

• Behavioral changes

• Around 15% of people with motor neurone disease develop dementia, usually a type called frontotemporal dementia

Respiratory Insufficiency Symptoms

• Shortness of breath with activities, and over time, breathlessness at rest

• Difficulty breathing, especially when lying down

• Nighttime awakenings due to breathlessness

• Daytime drowsiness

• Need for non-invasive breathing support

Diagnosis of Motor Neurone Disease (MND)

Clinical Assessment  

There is no specific test to diagnose motor neurone diseases. Many of the signs and symptoms in the early stages can be due to other diseases, which makes diagnosing MND challenging. 

Clinical assessment for motor neurone disease includes a thorough medical history and physical examination. This includes a neurological examination to assess sensory and motor function, including vision, hearing, speech, swallowing, muscle strength, balance, coordination, mental abilities, mood, and behavior.

Diagnostic Tests  

Some of the tests that can help to diagnose motor neurone disease include: 

• Electromyography (EMG) to assess electrical activity in the muscles. This test can help to diagnose muscle disease, problems with peripheral nerves, and lower motor neuron disorders. 

• Nerve conduction studies to measure the strength and speed of nerve signals. A nerve conduction test can help to identify muscle and nerve conditions that can cause similar symptoms as MND.

• Laboratory tests, including blood tests, urine tests, and cerebrospinal fluid tests to rule out other diseases.

• Imaging tests such as magnetic resonance imaging (MRI). There are usually no specific changes seen on MRI in people with MND. However, brain imaging can help to rule out other conditions that can cause similar symptoms. MR spectroscopy may be done to measure levels of certain chemicals in the brain that indicate if the upper motor neurons are healthy.

• Biopsy (muscle or nerve biopsies) to diagnose muscle or nerve disease, although many MND experts consider this invasive procedure unnecessary.

Genetic Testing for MND

There are genetic tests available for some types of motor neurone diseases, such as familial ALS, spinal muscular atrophy (SMA), and Kennedy's disease.

Types of Motor Neurone Disease  

Available Treatments and Therapies  

There is no known cure for motor neurone diseases. Clinical trials and research are underway to try and find new treatments and cures. 

Management of motor neurone disease depends on the type of MND disease, age at symptom onset and diagnosis, and type and severity of symptoms. Some types of MNDs, such as Kennedy's disease and primary lateral sclerosis (PLS), are slowly progressive and not usually fatal. Other types, such as severe spinal muscular atrophy (SMA) and amyotrophic lateral sclerosis (ALS) are fatal.

Management of MND consists of treating symptoms, providing emotional support, and helping to maintain independent living and quality of life for as long as possible. A multidisciplinary team of healthcare professionals provides care to people with MND, including a neurologist, physical therapist, occupational therapist, respiratory therapist, speech and language therapist, social worker, and others. 

Medications for MNDs

The U.S. Food and Drug Administration (FDA) has approved the following medications to treat MNDs. They work by targeting the gene mutations in the genetic forms of MNS and/or slowing the progression of the disease. 

• Riluzole (Rilutek, Tiglutik, Exservan).

• Tofersen (Qalsody).

• Edaravone (Radicava).

• Dextromethorphan HBr and quinidine sulfate (Nuedexta).

Other medications that healthcare providers may prescribe to people with motor neurone disease include:

• Muscle relaxers for muscle stiffness and muscle spasms.

• Botulinum toxin injections for muscle stiffness or drooling.

• Medications such as glycopyrrolate (oral tablets), amitriptyline (oral tablets), atropine (drops placed under the tongue), and scopolamine (topical patch) for excessive saliva.

Support Services for Motor Neurone Diseases

Some of the supportive therapies that can benefit people with MNDs include:

• Assistive devices to maintain muscle strength.

• Mobility and communication devices to maintain independent functioning.

• Physical and occupational therapy to improve balance, posture, and mobility, and slow muscle wasting.

• Speech and language therapy to improve speech, chewing, and swallowing.

• Stretching and strengthening exercises to reduce muscle stiffness and improve range of motion and blood circulation.

• Heating pads for muscle pain. 

• Nutritional counseling to develop a balanced diet and maintain a healthy weight. 

• In the advanced stages, a feeding tube and ventilatory support for nutrition and breathing support.

Resources and Support for Motor Neurone Disease  

Support for Patients and Caregivers  

• Motor Neurone Disease Association (MNDA)

• MND/ALS Support Group

• International Alliance of ALS/MND Associations (ALS-MND)

Research and Clinical Trials 

Research on motor neurone disease (MND) is focused on identifying the causes of MNDs, including genetic mutations, as well as finding new treatments, and, eventually, ways to prevent and cure these disorders. 

Frequently Asked Questions

What Are The First Signs of Motor Neurone Disease?

In many people with motor neurone disease, the first signs are muscle weakness in the limb muscles. Initial  symptoms may include a weak grip, trouble holding or picking up objects, difficulty raising arms above the head, and frequent tripping. In addition, there can be speech, chewing, swallowing, and saliva problems.

What Can Be Mistaken For MND?

Many neurological disorders can cause similar symptoms and be mistaken for MND, especially in the early stage. For example, stroke, brain and spinal cord tumors, infection and inflammation in the brain and spinal cord, vascular abnormalities, multiple sclerosis, and myasthenia gravis.

What Is The Main Cause of Motor Neurone Disease? 

For some types of motor neurone disease, the main cause is a gene mutation (change in DNA) that is inherited from parent to child. For other types of MND that are not inherited, the exact cause is unknown, but scientists believe it is a combination of genetic and environmental factors such as viral infections and exposure to toxins.

What is the New Treatment for MND in 2024?

Methylcobalamin (the biologically active form of vitamin B12) has been approved as a treatment for MND in Japan in 2024. A new novel drug for MND disease, Ellorarxine, is being researched and early results are promising.

What is the Life Expectancy of a Person with Motor Neurone Disease?

The life expectancy of a person with motor neurone disease depends on the type and age at diagnosis. Some forms of MND disease are slowly progressive and non-fatal. Others are severe and have a life expectancy of 1 to 5 years after diagnosis. The cause of death is usually a severe infection or respiratory failure in the later stages.