Focal onset aware seizures can take many different forms, depending on which area of the brain is affected. They include:
- Motor seizures involve a change in muscle activity (such as jerking or twitching).
- Sensory seizures involve a change in sensation such as tingling, numbness or prickling in a body part, or seeing or hearing things that are not there.
- Autonomic seizures involve a change in the autonomic functions of the body. A child may blush, sweat or feel nausea or a “rising” sensation in their stomach.
- Cognitive seizures involve a change in thinking, feeling such as fear or sadness or experience such as déjà vu.
Focal aware seizures may spread to other areas of the brain. If the seizure progresses and the child has loss of awareness, this is sometimes called a focal seizure with impaired awareness. If they spread to the entire brain, this is known as a secondarily generalized seizure. It may become a focal impaired awareness seizure or a focal to bilateral tonic-clonic seizure.
What are other terms for focal aware seizures?
Other terms for focal aware seizures include:
- simple partial seizures
- localized onset seizures
- focal motor seizures
- sensory seizures, tactile seizures, somatosensory seizures
How can you tell if your child has focal aware seizures?
A health-care provider will diagnose focal aware seizures by looking at the child’s medical history, their physical and neurological exam and their EEG.
Focal aware seizures appear different from person to person, depending on the seizure focus (the affected area of the brain). An individual child will usually have the same seizure pattern every time. Some of the seizures may remain as a focal onset aware seizure, and some may progress to a focal to bilateral tonic-clonic seizure. A common feature of focal aware seizures is that the child remains conscious and alert and can remember what happened.
It can be hard to identify focal aware seizures in a baby or a young child up to five or six years old, because their nervous systems are less developed than those of older children and adults. A child of this age may:
- suddenly stop what they are doing
- jerk their hand or arm rhythmically; holding the arm will not stop the jerking
- raise one or both arms or move their head to one side
- look to one side (rare)
Motor seizures
A child having a motor seizure will have brief muscle contractions (twitching, jerking, or stiffening), often beginning in the face, finger, or toe on one side of the body. This twitching or jerking then spreads to other parts of the body on the same side, near the initial site. This is called motor march or Jacksonian march, and it happens because the seizure spreads out to neighbouring parts of the motor strip of the brain.
Alternatively, the child’s head may turn to one side and they may raise one arm. This is called posturing.
The seizure begins in the same way each time. When the seizure is over, the child may feel weakness or paralysis in the affected body part, usually for less than two hours, although it may last for up to 24 hours. This is called Todd paralysis.
Simple motor seizures often progress to generalized or focal impaired awareness seizures or focal to bilateral tonic-clonic seizures.
Sensory seizures
Sensory seizures may also be called “auras” especially when they precede the motor manifestations of the seizure.
Possible symptoms of a sensory seizure include:
- a feeling of pins and needles or numbness in part of the body (these may spread to nearby parts of the body in the same way that motor seizures do)
- hearing ringing, buzzing, or voices that are not there, or experiencing normal sounds as muffled or distorted
- seeing lights or objects that are not there, seeing distortions or movement in objects that are there, or seeing objects as smaller or larger than they really are
- smelling or tasting something that is not there (often something unpleasant)
Autonomic seizures A child having an autonomic seizure may experience any of the following:
- changes in heart rate
- changes in breathing
- sweating
- goose bumps
- flushing or turning pale
- a strange or unpleasant sensation in the stomach, chest, or head
Cognitive seizures
A child having a cognitive seizure may experience problems with memory or garbled speech. They may feel as though they are outside their own body, or have feelings of déjà vu, jamais vu or knowledge of the future. They may feel sudden emotions, such as fear, depression or happiness, for no apparent reason. Children who are not old enough to talk may run to a parent and hold on.
Secondarily generalized seizures
A secondarily generalized seizure begins as a focal aware seizure then spreads to the whole brain. This leads to a focal impaired awareness seizure or a focal to bilateral tonic-clonic seizure. This can happen very quickly, so it is not always obvious the child is having a focal aware seizure.
What causes focal aware seizures?
Focal aware seizures are often caused by an injury, tumour or congenital malformation in a part of the brain. The source of the seizures may be very small, so that it is not always possible to find the cause.
How many other children have focal aware seizures?
Focal aware seizures are quite common. Between 2% and 12% of all children with epilepsy have this type of seizure.
How are focal aware seizures treated?
The treatment for focal aware seizures depends on the underlying cause. In some cases, such as a brain tumour, surgery may be advised as the first course of treatment. In other cases, the doctor will prescribe an anti-seizure medication.
If the child continues to have seizures while taking medication, it may be possible to surgically remove the affected area of the brain. This option depends on how close the seizure focus is to essential areas of the brain, such as the speech and language areas.
In some rare cases, the brain imaging may appear normal, but if seizures continue despite a child receiving good doses of anti-epileptic medications, the doctor may refer the child for evaluation for epilepsy surgery to remove the area of the brain where the seizures are coming from.
What should I do when my child has a focal aware seizure?
A focal aware seizure affects only part of the brain, and the child is usually conscious and aware the whole time. If your child is having this type of seizure, keep them safe; no other intervention is usually needed.
What is the outlook for a child with focal aware seizures?
As with most seizure types, the outlook for a child with focal aware seizures depends on the underlying cause. Some epilepsy syndromes with focal aware seizures, for example, self-limited epilepsy with centro-temporal spikes, may be age-dependent and the child may outgrow the seizures.
If the child has surgery, the outlook is often good. The outcome of surgery depends on the following.
- The cause of the seizures. For example, surgery for low-grade tumours may be more successful than surgery for brain malformations which are a type of brain problem that a person is born with.
- Whether the surgeon was able to remove the entire seizure focus.