Types of Brain Disease

Neurodegenerative diseases

Neurodegenerative disease is a broad category including any condition in which neurons lose function and eventually die. Neurons are the information messengers of the brain, and are essential in everything we do. Depending on which neurons are affected, neurodegenerative diseases can affect your mobility, coordination, strength, sensation, and cognition.

Neurodegenerative diseases are ones where the primary insult affects the cell body in the “grey matter”. This differs from “white matter diseases” in which the primary insult affects the axon and prevents the message being passed from one neuron to the next, e.g., multiple sclerosis, spinal cord injury. However few diseases affect just the cell body or just the axon.

Neuronal disease encompasses many other conditions that also fall into other categories. Alzheimer’s disease and other dementias are neurodegenerative, as are many neuromuscular or movement disorders.

Motor neurone disease (MND) and amyotrophic lateral sclerosis (ALS) are also in this category.

Examples: Motor neurone disease, amyotrophic lateral sclerosis.

Alzheimer’s disease & other dementias

Dementia is a type of neurodegenerative disease that causes the loss of cognitive function to the point that it interferes with daily life. It affects skills such as memory, problem-solving, language, and other thinking abilities. Dementia usually affects people later in life but is not a normal part of ageing. It is caused by damage to brain cells, and many people live well into old age without getting dementia.

Early symptoms might be mild (i.e. forgetting keys, confusion, short term memory loss) but most forms of dementia are slowly progressive. Symptoms will often develop to a point that the person is unable to function independently. There is no cure for dementia, but some treatments can help alleviate symptoms and improve the person’s quality of life.

Examples: Alzheimer’s disease, fronto-temporal dementia, lewy body disease

Brain tumours

A brain tumour is any abnormal tissue growth inside the brain. There are many types of brain tumours which vary in cause and severity. 

Some form in the brain originally (primary tumours), and others develop when cancer spreads from one part of the body to the brain (secondary tumours). They can either be malignant (cancerous) or benign (non-cancerous). Even benign tumours can cause problems because of the pressure they exert upon the brain.

Symptoms can include headache, seizures, nausea and vomiting, numbness, and difficulty with movement, amongst other symptoms. The treatment will depend on the type & severity, but could involve surgery, chemotherapy, or radiation therapy.

Examples: Gliomas, meningiomas, acoustic neuroma.

Cerebrovascular disease

Cerebrovascular diseases are any conditions that affect blood flow or the blood vessels in your brain. They can cause problems such as narrowed blood vessels, clots, artery blockage, or blood vessel rupture. This can prevent the brain from getting enough blood and oxygen (ischemia), which can result in brain damage or stroke.

The cause, symptoms, severity, and treatment for cerebrovascular disease will depend on the type of disease and location of the affected blood vessels. Some general symptoms might include a sudden and severe headache, weakness or paralysis on one side of the body, and difficulty speaking. If you experience these symptoms you should seek emergency medical help as soon as possible.

Examples: Stroke, aneurysm, arteriovenous malformations (AVM).

Concussion & traumatic brain injury

A traumatic brain injury (TBI) is caused by external injuries. They vary greatly in severity, ranging from a concussion (essentially ‘bruising’ of the brain) to bleeding inside the brain and coma. However, even mild TBIs can lead to more severe injury. Repeated blows to the head and repeated concussion can cause brain scarring and neurodegenerative disease (chronic traumatic encephalopathy, “punch-drunk” syndrome, the condition that probably affected Muhammad Ali & many well-known sportsmen).

TBI can be caused by falls, car crashes, sports injuries, or domestic violence incidents. Symptoms include loss of consciousness, headache, nausea/vomiting, dizziness, drowsiness, difficulty concentrating, or other cognitive problems. If you experience any of these symptoms after a head injury you should seek medical treatment. 

Examples: Concussion, traumatic brain injury.

Epilepsy

Epilepsy is a long-term neurological disorder in which groups of neurons discharge spontaneously, leading to seizures or ‘fits’. A seizure usually lasts between 1 and 3 minutes. People can have seizures for many other reasons (e.g. febrile seizures in children), and epilepsy is diagnosed only when someone has repeated seizures.

The most recognised form of seizure (tonic-clonic) can involve loss of consciousness and full body convulsions. Other types can cause briefly clouded consciousness, or uncontrolled movement in only one part of the body.

Example: Epilepsy.

Migraine & headache disorders

Headache is one of the most common symptoms experienced by humans. It can be a symptom of an underlying medical condition, but headache disorders (or primary headache) can occur without a definable brain disease. These are presumably due to neurochemical and neurovascular changes in regions of the brain. Some common headache disorders include migraine, tension-type headache, and cluster headache.

Head pain is the main symptom of any headache disorder but, particularly in migraine, this can be accompanied by other symptoms such as nausea, vomiting, sensitivity to light, or irritated eyes. There are many treatments available for headache, ranging from over-the-counter painkillers to prescription preventive treatments for chronic disorders.

You can find detailed information about headache on the Migraine & Headache Australia website. Migraine & Headache Australia is a division of the Brain Foundation.

Examples: Migraine, tension-type headache, cluster headache.

Infections

Neurological infections occur when viruses or bacteria get into your brain or spinal cord. Meningitis is the infection of the outer covering of your brain and spinal cord, while encephalitis is infection of the brain itself.

Symptoms can include a high fever and headache, neck stiffness, vomiting, convulsions, and drowsiness. The severity and treatment options depend on whether the infection is bacterial or viral. Encephalitis can be very dangerous to infants or elderly people.

Examples: Meningitis, encephalitis.

Inflammatory diseases

Neuroinflammatory diseases happen when the immune system misfires and attacks healthy cells. This can occur in various parts of the central nervous system, including the brain, spinal cord, and optic nerves (e.g. MS) or peripheral nerves (e.g. Guillain-Barré syndrome). 

Symptoms will depend on which nerves are affected, and vary from mild impairment to permanent disability. There is no known cure for these diseases, but there are now many treatments to slow or stop the progress of the immune attacks. Symptomatic treatment is also used to improve the person’s quality of life.

Examples: Multiple sclerosis, transverse myelitis, Guillain-Barré syndrome.

Movement disorders

This category includes brain disorders that impair your ability to move in some way. A movement disorder could impair voluntary movements (hypermobility, reduced, or slowed movement) or cause involuntary movements.

The most well-known movement disorder is Parkinson’s disease, which causes tremor, muscle stiffness, slowed movement and loss of balance. Other common movement disorders include writer’s cramp and the “yips” in golfers. Some disorders such as dystonia cause uncontrollable twisting, repetitive movements or abnormal postures. Symptoms, severity, and treatment vary greatly between different movement disorders.

Examples: Parkinson’s disease, dystonia, Huntington’s disease.

Neuromuscular disorders

Neuromuscular disorders are disorders that affect sensory and motor fibres in peripheral nerves or muscle, causing loss of feeling and/or muscle weakness and wasting. 

Symptoms vary depending on the severity of the disease and how many nerves are affected. Sensory nerve disorders may produce numbness, tingling, or weakness. Motor nerve involvement may result in muscle wastage and disability due to weakness. Muscle diseases can be hereditary (e.g. Duchenne muscular dystrophy) or acquired (e.g. polymyositis), and can be fatal if the heart or breathing muscles are affected.

Examples: Muscular dystrophies, peripheral neuropathy, Charcot-Marie-Tooth disorder.

Paediatric neurology

Diseases in children are very different to those in adults (e.g. epilepsy, aneurysms, genetic disorders) and may require specialist paediatric neurologists. Paediatric neurology is the study of diseases of the brain, spinal cord, peripheral nerves and muscle in children and adolescents. These conditions could also fall into other categories, along with the comparable disease in adults, but the causes, symptoms and treatments are often different for children.

Sometimes children are born with these disorders (i.e. cerebral palsy, neurodevelopmental disorders), which could be caused by genetics, fetal brain injuries, or birth complications. Others are acquired during childhood (i.e. brain tumours, head injuries).

Neurodevelopmental disorders affect the development of your brain. This is most obvious in young children as parents or teachers might notice they aren’t keeping up with their peers. Symptoms usually involve impairment of memory, speech/language, behaviour, motor skills, learning, social skills, and/or emotions.

Examples: Cerebral palsy, autism, dyslexia.

Other ways to classify types of brain disease

The Brain Foundation’s Scientific Committee has chosen these twelve types of brain disease to direct research funding. Some categories are more specific than others to help our supporters direct their donations towards the condition that they want to fund. However, there are some broader ways of understanding brain disease.

Type of onset or progression

• Sudden onset conditions. These types of brain disease commonly occur as a result of stroke or traumatic brain injury.
• Intermittent and/or unpredictable conditions. These are disorders that have phases with and without symptoms. Multiple sclerosis is one example, with periods of relapse and remission, and epilepsy is another example. Even though there are periods without symptoms, these conditions often continue to affect people while asymptomatic (i.e. avoiding triggers for epilepsy).
• Progressive conditions. These diseases continually get worse over time and may be fatal. Motor neurone disease and Alzheimer’s disease are two examples.
• Stable neurological conditions. Stable conditions remain the same from onset throughout someone’s life. People might have different care needs as they age, but the disease does not progress. Cerebral palsy is a common stable neurological condition.

Other ways to classify types of brain disease could include the cause of disease (e.g. genetic, external causes, or spontaneous).

Further information & resources

If you want to learn more about brain disorders, diseases, and injuries, you can view the following resources:

• A-Z of Brain Disorders – our directory of articles with information on over 70 neurological conditions
• Brain Foundation Research Grants – see the project summaries of research we have funded from 2003 onwards
• Newsletters – sign up to our newsletter and access past editions
• Healthy Brain – resources about maintaining brain health

Support for people living with brain disorders, diseases or injuries:

• Finding a neurologist – our article with advice on how to find a neurologist
• Brain Injury Australia (support for brain injuries including traumatic brain injuries, stroke, infection, and degenerative diseases)
• Brain Tumour Alliance Australia (support groups for people with brain tumours)
• MND Australia (support for motor neurone disease)
• MS Australia (support for multiple sclerosis)

If you found this article helpful, please consider donating to support Australian neurological research. Your donation, no matter how small, is greatly appreciated and will help so many. Donate today >