Epilepsy is a neurological condition that makes people susceptible to seizures.
A seizure is a change in sensation (vision, hearing, touch, smell, taste), behaviour or abnormal movement involving a part of or entire body with or without losing awareness. It is brought about by a brief electrical disturbance in the brain. Seizures are sometimes called convulsions or fits. However, many seizures do not involve convulsions and can go unnoticed by bystanders.
Approximately 75% – 90% of individuals with TSC (Tuberous Sclerosis Complex) will have Epilepsy at some point. Epilepsy can start at any age, but many babies with TSC have a specific type of seizure called infantile spasms. Infantile spasms present with head bobbing, head and eye turning or whole body stiffening. They peak during the first 4-6 months of life but can occur anytime in the first two years.
Here is a glossary of some of the health care professionals who may be involved in managing epilepsy:
Neurologist – a doctor who specialises in brain and nerve-related conditions
Epileptologist – a neurologist who specialises in treating epilepsy
Epilepsy specialist nurse – may assist with epilepsy management and education
Neurosurgeon – a doctor who is involved with brain surgery. An individual with TSC with medically uncontrolled epilepsy is considered for epilepsy surgery.
For more general epilepsy information, please visit Epilepsy Action Australia.
Why do seizures occur in TSC?
Seizures occur in TSC because the areas of abnormal brain development cause abnormal electrical activity. However, it is unknown which specific changes in the brain with TSC lead to seizures. Therefore, it is not possible to predict whether an individual with TSC will have seizures, what type or how severe they will be.
Why are seizures different from one person to another?
Billions of nerve cells make up the part of the brain called the cerebral cortex. The cerebral cortex makes up the two sides of the brain, the cerebral hemispheres. Each hemisphere is made up of four areas of the brain, called the lobes. These four lobes are the frontal, temporal, parietal and occipital lobes. Each lobe is divided by many clefts into smaller regions. Each region is responsible for specific functions like vision, hearing, touch, taste, smell, movement, judgement or memory. TSC brain lesions can involve any part of the brain, and the number, size and location of the lesions are variable in different people. Therefore, seizures are completely different from one person to another.
Signs, Symptoms and
Signs and Symptoms
What type of seizures occur in TSC?
The distinct type of seizures that infants develop during the first 3-6 months of their life are called called infantile spasms. Otherwise, the seizures that occur in in TSC are focal seizures, which means they arise from a small abnormal region of the brain. These types of seizures were known as partial seizures in the past. A seizure may remain focal or spread to the nearby regions or the whole brain, causing generalised seizures.
Symptoms of focal seizures vary depending on the region of brain they start in and the regions they spread to. Patients can be completely aware during the seizure and can talk about their feelings during the seizures. Seizures can stop at this point or progress to a more intense type of seizure with movement of arms, legs, head or face in isolation or sequence, uncontrolled behavioural disturbance, extreme fear and falls with or without loss of awareness. Focal seizures may rapidly progress to convulsive seizures. Seizures progressing to convulsions are called bilateral tonic clonic seizures.
The types of seizures experienced may change throughout the life of someone with TSC and epilepsy.
The different changes that occur in the brain due to TSC are covered here. Impacts of TSC and epilepsy on learning, behaviour and mental health are covered here.
More on the different types of epileptic seizures
Though seizures in TSC start from a small abnormal area in the brain and therefore should cause focal seizures, some seizures rapidly or simultaneously involve multiple areas in the brain and cause bilateral/generalised seizures.
Some of the more common types of seizures experienced by people with TSC are described below. For more information on seizure types, visit this information page from Epilepsy Action Australia.
Monitoring, Tests and Diagnosis
Seizures are diagnosed based on clinical history. Repetition of similar neurological symptoms lasting for seconds to minutes are a clue for diagnosis.
Home video is valuable for doctors to confirm a diagnosis of clinical seizures and behavioural disturbance, and to decide what further tests needed to be done.
EEG (Electroencephalogram) is helpful for diagnosing electrographic seizures and figuring out what part of the brain the seizures are coming from, as well as performing pre-surgery screening in patients whose seizures are not controlled with medicine. EEG is also useful for diagnosing non-convulsive status epilepticus. It is a painless test that records the brain’s electrical activity, sometimes called brain waves.
There are several clinical trials investigating whether babies with TSC should have an EEG before having any clinical seizures to identify epileptiform activity and electrographic seizures. Early EEG may allow for treatment to prevent seizures or infantile spasms. It may also make them easier to treat. This in turn may eventually reduce risk of neurodevelopmental delay and autism spectrum disorder. However, more studies need to be done in this field.
For more information on EEG and the different types of EEGs, visit this page from Melbourne’s Royal Children’s Hospital.
The 2021 guidelines for the surveillance and management of TSC recommend:
• When an individual is first diagnosed with TSC, obtain a baseline routine EEG during wakefulness and sleep; if EEG is abnormal, and particularly if features of TAND are present, follow this with 8-24-hour video EEG to look for subtle seizure activity.
• In infants with TSC who have not had any seizures, obtain routine EEG every 6 weeks up to age 12 months and every 3 months up to age 24 months, as abnormal EEG frequently precedes the onset of clinical seizures.
• When a child under 3 years old is newly diagnosed with TSC, teach parents and other caregivers how to recognize infantile spasms and what to do if they suspect the child is having infantile spasms. A description and video are available at tscalliance.org/infantilespasms.
• The duration and frequency of EEG monitoring should be determined by clinical need.
• Video EEG should be obtained if a diagnosis of seizure is unclear or challenging to differentiate from behavioural or neurological changes.
Some individuals who have regular seizures (or their parents/carers) find it helpful to track seizures on a computer or mobile phone using an app called Seizure Tracker, developed by a TSC family in the USA, is one tool that can be used for this.
There are several different ways to treat epilepsy in individuals with TSC (Tuberous Sclerosis Complex).
The 2021 guidelines for the surveillance and management of TSC recommend:
• Treat infantile spasms with Vigabatrin as first-line therapy. Adrenocorticotropic hormone (ACTH) can be used as second-line therapy if Vigabatrin treatment is unsuccessful.
Last updated: 8 February 2023
Reviewed by: Dr Denise Chan, Paediatric Neurologist, Sydney Children’s Hospital; Dr John Lawson, Neurologist and Rural, Regional and Remote Clinical Trial Enabling Program, NSW Ministry of Health; Prof. Lakshmi Nagarajan, Neurologist and Epileptologist, Perth Children’s Hospital; Dr Zebunnessa Rahman, Neurologist and Epileptologist, Westmead Hospital, Sydney
- Kwiatkowski D.J., Whittemore V.H. & Thiele E.A. (2010) Tuberous Sclerosis Complex: Genes, Clinical Features, and Therapeutics. Weinheim: Wiley-Blackwell
- Anti-epileptic drugs: how they treat seizures and their unwanted side-effects, Tuberous Sclerosis Association, viewed 9th April 2012
- Epilepsy in Adults with TSC, TSC Alliance, viewed 9th April 2012
- Epilepsy Surgery for Individuals with TSC, TSC Alliance, viewed 9th April 2012
- Infantile Spasms and TSC, TSC Alliance, viewed 9th April 2012
- Types of Seizures Affecting Individuals with TSC, TSC Alliance, viewed 29th April 2012
- Epilepsy Explained, Epilepsy Australia, viewed 29th April 2012 h
- Vagal Nerve Stimulation, The Royal Children’s Hospital Melbourne, viewed 9th April 2012, https://rch.org.au/cep/treatments/index.cfm?doc_id=3245
- French, J. A. et al. Adjunctive everolimus therapy for treatment-resistant focal-onset seizures associated with tuberous sclerosis (EXIST-3): a phase 3, randomised, double-blind, placebo-controlled study. Lancet, doi:10.1016/s0140-6736(16)31419-2 (2016).
- Capal J.K et al., Influence of Seizures on Early Development in Tuberous Sclerosis Complex. Epilepsy Behav. 2017 May; 70(Pt A): 245–252.