A seizure is defined as a massive influx of electrical signals across the specialised nerve cells known as neurons, which impairs brain functions. While a seizure can at once hamper the entire area of the brain, a focal onset seizure is one where an abrupt flow of nerve signals occurs in just one segment of the brain.

Also termed partial seizures, these sudden malfunctions in the nerve signalling mechanism of the brain develop due to numerous reasons, including heat stroke, tumour growth or infection in the brain and epilepsy. Since a focal onset seizure invariably leads to many disabling signs such as complete blackouts, hazy vision and painful muscle spasms, it is advised to promptly report the symptoms to a doctor to ensure timely treatment.

Also Read: Heat Stroke: Causes, Symptoms And Treatment
Focal seizure

Types Of Focal Onset Seizures:

There are two types of focal onset seizures depending upon the nature of physical indications that manifest from the passage of vast concentrations of electrical impulses in the nerve cells in the brain. These are known as focal onset aware seizure and focal onset impaired awareness.

Focal Onset Aware Seizure:

Also known as a simple partial seizure, a focal onset aware seizure implies that the affected individual is still conscious while the electric signal disturbances are taking place in the brain. They happen in very short spurts, usually for one minute or less and though they trigger panic and anxiety, focal onset aware seizures do not impede memory.

Focal Onset Impaired Awareness:

In the instance of a focal onset impaired awareness, otherwise referred to as a complex partial seizure, the afflicted person experiences a few warning signals like nausea and bodily discomfort prior to the onset of the abnormal nerve signalling. This type of focal onset seizure lasts for at least 1 – 2 minutes, with an inability to recollect the event along with drowsiness and mental confusion.

Also Read: Seizures: Signs, First Aid And Safety Precautions


Several factors lead to a focal onset seizure, including:

  • Heat stroke
  • Injury in the brain/skull
  • Low blood sugar levels
  • High blood pressure/hypertension
  • Epilepsy
  • Stroke
  • Infections in the brain, for example, meningitis
  • Congenital disorders affecting the brain of a newborn child during foetal/embryonic development
  • Damage and malfunctioning of the liver, kidneys

In certain situations, the exact cause of a focal onset seizure cannot be ascertained and the condition is called an idiopathic seizure.


The distinguishing signs of a focal onset seizure comprise:

  • Abrupt muscle contractions and relaxations, like sudden jerking of arms, legs
  • Irregular muscular motions along one side of the body, such as rolling the eyes or turning the head in an awkward manner
  • Obstructed vision with blurry images, hallucinations
  • Fast-paced heartbeats and pulse, arrhythmia
  • Numb and tingling sensations in the body
  • Excessive sweating
  • Stomach ache with nausea, vomiting
  • Erratic mood swings
  • Loss of consciousness leading to a blackout


The physician requests the patient to convey the exact attributes experienced before, during and after the seizure. Based on the symptoms reported by the patient as well as their medical history, the doctor then carries out various diagnostic assays.

These consist of an MRI scan of the brain, blood test and profiling to look for infection, inflammatory markers, as well as a spinal tap, to determine the cause of the focal onset seizure.


In general, the majority of cases of focal onset seizures only last for a small period of time and do not result in life-threatening consequences. While the patient is experiencing a seizure at home, it is advised that their family members maintain a distance and place all objects far away so as to prevent any severe injury to the patient.

If the focal onset seizures occur repeatedly, then the doctor prescribes medications to be taken at a specific time and at the right dose, which help control nerve signalling activity in the brain. Furthermore, basic lifestyle modifications such as adhering to a wholesome, balanced diet, regular physical exercise, proper uninterrupted sleep schedules and avoiding stressful situations significantly reduces the risk of focal onset seizures in the patient and prevents their recurrence.

Only in rare instances do focal onset seizures present grave complications such as breathlessness, chest pain, choking and in these circumstances, the patient needs to be hospitalized and given emergency medical care to ensure their full recovery.