Epilepsy Ireland Essential Research Glossary

A type of seizure characterised by a brief loss and return of consciousness, often referred to as 'blanking out' for a few seconds.

Adjustments or supports provided to help people with disabilities or medical conditions take part fully in education, work, or community life.

A chemical messenger (neurotransmitter) that helps nerve cells communicate, especially for muscle movement and memory.

A rapid electrical impulse that travels along a nerve cell, sending signals across the brain or body.

A type of study that involves working directly with people or communities to find practical solutions to real problems.

Symptoms that come on suddenly and last a short time, often needing immediate care.

Additional treatment used alongside a main therapy to improve results or manage symptoms.

An unwanted or harmful effect that happens during or after taking a treatment or medication.

Speaking up or taking action to support the rights, needs, or interests of individuals or groups.

The cause or origin of a disease or condition.

The inability to process sensory information, such as the inability to recognise people, shapes, sounds, or smells.

Treatments used instead of conventional medical care, such as herbal remedies, acupuncture, or homeopathy.

A type of brainwave recording done while a person moves around in their normal environment, often over 24 hours or more.

A small brain structure in the temporal lobe, involved in processing memory and emotions like fear and anxiety.

a non-human model, such as rodents, zebrafish, or primates, used in scientific research to study human diseases.

Medication used to prevent or reduce seizures.

Difficulty speaking, understanding, reading, or writing, usually due to stroke, brain injury, or neurological conditions.

A seizure that causes a sudden and temporary loss of muscle tone, leading a person to go limp or fall. Also known as 'drop attacks' or 'drop seizures'.

A warning sign or feeling that happens before a seizure, such as a strange sensation in the stomach, a weird smell, or a feeling of déjà vu.

A network of nerves controlling our body's involuntary functions, such as heart rate, digestion, and breathing. It is categorised into 2 branches – the sympathetic nervous system ('fight or flight') and the parasympathetic nervous system ('rest and digest').

An inherited genetic trait or condition that occurs when a person inherits just one copy of a faulty gene for the trait or condition to appear. It can be passed from an affected parent to their child with a 50% chance.

An inherited genetic trait or condition that occurs when a person inherits two copies of a faulty gene – one from each parent. People with only one copy are 'carriers', and usually do not have symptoms.

The long, thin projection of a nerve cell, down which action potentials travel for cell-to-cell communication.

A group of structures in the brain, that control movement.

Describes a condition that is not harmful, or not likely to get worse.

On both sides of the body or brain.

A biological substance that can be measured, such as proteins, hormones or chemicals in the blood or other bodily tissues.

A protective layer of cells between the blood vessels and the brain, which acts as a filter. It allows nutrients like oxygen to pass through the blood to the brain, but blocks harmful substances like pathogens.

The structure below the brain, that connects the brain to the spinal cord. It controls basic functions like breathing, heart rate and blood pressure. It is comprised of the midbrain, pons, and medulla.

A seizure that happens despite ongoing treatment with antiseizure medication.

A region of the brain involved in producing and planning speech.

A method of administering medicine inside the cheek so it's absorbed through the lining of the mouth.

A class of chemical compounds found in cannabis plants (or created synthetically), sometimes used to treat epilepsy.

The smallest, basic building unit of all living things, including the brain and nervous system.

The brain and spinal cord.

A region of the brain located at the back of the head, responsible for coordinating movements, balance and posture.

The main and largest area of the brain. The cerebrum is the largest part of the brain; the cerebral cortex is its outer layer responsible for higher thinking, sensation, and voluntary movement.

The protective liquid surrounding the brain and spinal cord.

A long thread-like structure inside the nucleus of cells, containing genetic information in the form of packaged DNA. Humans have 23 pairs of chromosomes (46 total), inheriting 23 from the mother and 23 from the father.

A research study that tests new treatments or interventions in humans to see if they are safe and effective. They are conducted in 'phases'.

The rhythmic jerking movements of muscles during a seizure.

The mental processes involved in thinking, learning, remembering, and understanding.

Two or more diseases or conditions that exist in one person at the same time.

A medical imaging test that uses many X-rays from differing angles to create detailed pictures of the brain or body.

From birth – meaning a disease or condition with which someone was born.

A specific situation in which a particular medical treatment, procedure, or drug should not be used because it could be harmful to the patient.

Uncontrolled shaking or jerking of the body, often caused by a seizure.

A surgical procedure where the fibres of the corpus callosum are cut, which prevents communication from the left to the right brain hemisphere, and vice versa. This is a surgery which can reduce the number or severity of seizures in some patients.

A bundle of nerve fibres that connect the left and right hemispheres of the brain together.

A brain abnormality where nerve cells in an area of the cortex develop incorrectly, which can cause seizures.

A treatment that uses small electrical pulses from implanted electrodes to help control seizures or movement problems.

A branch like structure projecting from a nerve cell, that acts like an antenna – receiving signals from other nerve cells.

A region of the brain within the hippocampus, important for learning and memory.

A change in a nerve cell's electrical charge, that triggers it to send an action potential.

Severe forms of neurological disorders that begin in infancy or childhood and can cause seizures, and affect development and learning. They are often caused by genetic mutations, and are often treatment resistant.

When a child takes longer than expected to reach milestones such as walking, talking, or learning.

A list of all the possible causes of medical symptoms - the process of comparing symptoms to decide which of several possible conditions is the correct diagnosis.

A rare childhood epilepsy syndrome that causes atonic (sudden drops) and/or myoclonic (jerk) seizures, often beginning between ages 1 and 5.

A severe epilepsy that starts in infancy, often linked to a gene change (SCN1A), and includes prolonged and difficult-to-control seizures.

Epilepsy that is not controlled/seizures still continue despite trying two or more antiseizure medicines.

The tough, protective outer layer covering the brain and spinal cord.

A test that records electrical brain activity through small electrodes placed on the scalp.

How well a treatment works under ideal or controlled conditions.

A small metal disc or wire used to detect or deliver electrical signals in the brain.

The study of how electrical signals work in the body, especially in the brain or heart.

Inflammation (swelling) of the brain, usually caused by infection.

The study of how often diseases occur (incidence) and who they affect in a population (distribution).

The study of how genes can be temporarily turned on or off by environmental, behavioural, or lifestyle factors, without changing the DNA itself.

A neurological condition that causes repeated seizures due to abnormal electrical activity in the brain.

The specific area within the brain where seizures begin.

A neurologist who specialises in epilepsy.

The principles that guide what is right and fair in research and medical practice.

A seizure that happens in a young child with a high fever, usually harmless and short-lasting.

A seizure that starts in one specific area of the brain. The person may remain aware or lose awareness, depending on where it occurs.

Small group discussions used in research to gather people's opinions or experiences.

A genetic neurodevelopmental condition that can cause learning difficulties, behavioural issues, and sometimes seizures. Males are usually more affected than females.

The region of the brain at the front of the head. It is the largest of the four brain lobes, and is responsible for higher functions like problem solving and decision making.

A type of epilepsy where seizures begin in the brain's frontal lobe (behind the forehead). These seizures are often brief and nocturnal.

A condition presenting with neurological symptoms that occurs due to a problem with how the brain and body send and receive signals, resulting in abnormal neurological function.

Episodes that look like epileptic seizures but are not caused by abnormal electrical activity in the brain, and instead are caused by stress or psychological factors.

A medical technique that aims to treat or prevent disease by changing, correcting, or replacing faulty genes.

A seizure that affects both sides of the brain at once, unlike focal seizures which affect one specific region. Generalised seizures can be nonmotor (absence seizures) or motor (tonic clonic, myoclonic, atonic).

The study of how traits and conditions are passed through genes from parents to children.

Cells in the central and peripheral nervous systems that act as support cells. They protect and nourish neurons (brain cells) by performing activities such as insulating them, clearing debris, and providing nutrients to them. Examples of glial cells include astrocytes, microglia, and oligodendrocytes.

The activation of glial cells in response to injury or damage to the brain or spinal cord.

Money given to support scientific studies, medical research, or community projects.

The time it takes for half the amount of a drug in the body to be broken down or removed. Drugs are not eliminated by the body at a steady rate, as the rate slows down as the amount decreases – so measuring in halves gives a more accurate and consistent way to track how drugs behave over time.

An injury to the head or brain that can cause temporary or permanent problems, including seizures.

One of the two halves of the brain (left and right).

A rare brain surgery where one hemisphere (half of the brain) is removed or disconnected to control severe seizures.

A region in the brain vital for learning and memory. It is located in the temporal lobe.

A region of the brain located below the thalamus, that is involved in temperature, sleep, thirst, hunger, and hormone release.

The period during a seizure (the active seizure event).

Epilepsy with no clear cause.

The global organization that promotes epilepsy research, education, and improved care.

A serious type of seizure seen in babies, causing sudden jerks or bending movements, often linked to developmental delay.

A deep region of the brain involved in emotion, sensory experience, and self-awareness.

A common form of epilepsy starting in the teenage years, with brief jerks of the arms or body, often soon after waking up.

A special high-fat, low-carbohydrate diet that can help reduce seizures in some people with epilepsy, especially children.

A severe childhood epilepsy that causes multiple types of seizures and can affect learning and development.

An area of damaged or abnormal brain tissue/the surgery to remove an area of damaged or abnormal brain tissue, often to help stop seizures.

A group of brain regions involved in emotions, behaviour, motivation and many other functions.

A procedure where a needle is inserted into the lower back to collect cerebrospinal fluid for testing or to relieve pressure. Also known as a 'spinal tap'.

The lowest part of the brainstem. It controls vital functions such as breathing, heart rate, swallowing, and blood pressure.

Scarring or damage and severe nerve cell death in the inner (mesial) part of the temporal lobe, often linked to temporal lobe epilepsy.

Small molecules that regulate genes by turning them on and off.

The uppermost part of the brainstem. It is involved in visual and auditory signals, coordinating motor information, and eye movement.

A group of atoms bonded together, making the smallest unit possible of a chemical compound.

Monotherapy means using one medication to treat a condition; polytherapy means using more than one.

The region of the brain responsible for voluntary muscle movement, like kicking a ball or waving your hand.

Magnetic Resonance Imaging; a type of medical scan that uses strong magnetic fields and radio waves to create detailed images of the body or brain.

Messenger ribonucleic acid; a small molecule that carries genetic information from DNA to make proteins in the body.

A change in someone's DNA sequence. Mutations play a part in normal biological processes, such as evolution, but can also cause or increase risk of disease.

The protective coating around nerve fibres that helps electrical signals travel quickly and efficiently, like insulation on a wire. Myelination is the process by which a myelin sheath is formed around nerve fibres, whereas demyelination is the process by which myelin is lost, like in Multiple Sclerosis.

A sudden, quick, involuntary jerking of a muscle or group of muscles.

During the growth and development of the brain and nervous system, especially in children.

Methods of scanning and observing the brain or body in a medical setting. These imaging techniques show the structure or function of the brain.

Treatments that use gentle electrical stimulation of the brain or nerves, and can be used to help control seizures.

A nerve cell; the fundamental unit of the nervous system. They send and receive signals to and from the brain through electrical and chemical signals.

The study of how the nervous system works and communicates through electrical and chemical signals.

The brain's ability to change and adapt by forming new connections between nerve cells, which occurs during learning new skills, forming new memories, and after injury. The brain is especially 'plastic' during infancy and childhood.

A specialist health care professional who studies how brain function affects thinking, emotions, and behaviour.

A chemical messenger that carries signals between nerve cells in the brain and body.

Seizures that happen during sleep, at nighttime.

The central 'command centre' of every cell. It contains and protects the cell's DNA.

The region of the brain at the back of the head that processes vision.

The region of the brain that processes smells, located above the nose.

Activities that connect with the community to raise awareness, provide education, or support fundraising for a cause.

A doctor who specialises in the health and medical care of babies, children, and teenagers.

The region of the brain at the upper and back of the head. It is involved in sensory processing.

The study of diseases; what causes them and how they affect the body.

The study of how diseases affect the normal function of the body or brain.

The process through which scientific or medical experts evaluate research studies or proposals before publication/funding, to ensure scientific accuracy, quality and merit.

The network of nerves outside the brain and spinal cord, that connects them to the rest of the body.

Positron Emission Tomography. A medical imaging test that shows how the brain or body is working by tracking a small amount of radioactive material.

The observable traits or characteristics of a person or animal, such as appearance or behaviour, as influenced by genes and environment.

A type of epilepsy where seizures are triggered by flashing or flickering lights, or contrasting light and dark patterns. Around 5% of people with epilepsy are photosensitive.

A harmless, inactive substance such as a sugar pill used in research to compare against real treatments.

The largest part of the brainstem, located between the midbrain and the medulla. It is involved in sleep-wake cycles, facial movements, and facilitating communication between the cerebrum and cerebellum.

Epilepsy that develops after a head injury.

Public and Patient Involvement. The active collaboration of members of the public or patients with researchers and clinicians in the planning and execution of research. This means that research is carried out with or by members of the public or patients, rather than to/about/for them.

The lead researcher responsible for managing a study or clinical trial.

A seizure caused by a temporary event such as fever, low blood sugar, head injury, or alcohol withdrawal.

A professional who helps people understand and manage thoughts, emotions, and behaviour through therapy.

Emotional, practical, or social help for people and families affected by illness.

A person's overall wellbeing, including their physical health, emotional state, relationships, and daily functioning.

A condition, like epilepsy, that does not respond to standard treatments. Also referred to as Drug Resistant Epilepsy.

Therapy and support to help someone recover skills and independence after illness, injury, or surgery.

Scientific study aimed at discovering new knowledge, improving treatments, or understanding conditions better.

A type of study that looks back at existing data or past patient records to find patterns or outcomes.

A detailed brain recording method using electrodes placed inside the skull and brain to locate where seizures begin.

Brief and sudden bursts of abnormal electrical activity in the brain.

A record kept by a person or caregiver to track seizures, medications, and possible triggers.

Steps taken to keep someone safe during a seizure, such as timing the seizure, making the person safe, and staying with them during and after the seizure. TIME, SAFE, STAY.

The level of resistance a person's brain has to seizures – a lower threshold means seizures are more easily triggered.

A type of childhood epilepsy that usually goes away on its own as the child grows older. Also referred to as benign epilepsy.

The description of seizure symptoms and how they appear.

An unwanted or unexpected reaction to a medicine or treatment.

A statistical term showing whether a research result is likely to be real or due to chance.

The main body of a nerve cell, containing the nucleus.

A brainwave pattern seen on EEGs, of brain cells firing. A 'spike' is a sudden, sharp burst of electrical activity, and a 'wave' is a slower rhythm that follows it.

A medical emergency that occurs when a seizure lasts more than five minutes, or a series of seizures without recovery between them.

SUDEP is confirmed when someone with epilepsy dies and no other cause of death can be found during the post-mortem.

A gathering (in person or online) where people with shared experiences provide emotional and practical support to one another.

The tiny gap between nerve cells where chemical signals are passed.

A small bubble-like structure within nerve cells that stores and releases neurotransmitters.

Fainting caused by a temporary drop in blood flow to the brain.

A group of symptoms that occur together and define a specific condition or disorder.

Short forms for 'tonic-clonic' and 'generalised tonic-clonic seizures'.

The region of the brain near the temples, that is responsible for memory, understanding and emotion.

A surgical procedure to remove all or part of the temporal lobe to help control seizures.

A deep region in the brain that acts as a relay station for sensory information and plays a role in consciousness and alertness.

A seizure with two phases – stiffening of the muscles (tonic) followed by rhythmic jerking of the muscles (clonic).

A seizure that causes sudden muscle stiffness.

Damage to the brain from a blow or hit to the head, sometimes leading to epilepsy.

A condition that does not respond well to standard medications or therapies.

Something that increases the chance of a seizure, such as lack of sleep, stress, fever, or flashing lights.

Seizures where the starting point in the brain is not known.

A seizure that occurs without an immediate or obvious trigger.

A long nerve that runs from the brain to the body, helping control heart rate, digestion, and mood.

A therapy that uses a small implanted device to send mild electrical signals to the vagus nerve to help prevent seizures.

A fluid-filled hole-like space inside the brain that helps circulate cerebrospinal fluid.

The ability to remember things we see, such as faces or places.

How we understand where objects are in space and how we move around them.

A severe epilepsy that begins in infancy, marked by clusters of spasms and often linked to developmental delay. Now referred to as infantile spasms.

Advanced genetic tests that analyse a person's genes to find causes of medical conditions. DNA can be sequenced (read) from the areas in the genome that write the instructions for how to create proteins (exons, whole exome sequencing) or can be sequenced from the entire genome (whole genome sequencing).

Gradually stopping a medication, often under medical supervision, to reduce side effects or dependence.

A genetic pattern where a condition is passed down through genes on the X chromosome, often affecting males more than females.