Focal seizures
Encyclopedia
Partial seizures are seizure
Seizure
An epileptic seizure, occasionally referred to as a fit, is defined as a transient symptom of "abnormal excessive or synchronous neuronal activity in the brain". The outward effect can be as dramatic as a wild thrashing movement or as mild as a brief loss of awareness...

s which affect only a part of the brain at onset. The brain is divided into two hemispheres, each consisting of four lobes - the frontal, temporal, parietal and occipital lobes. In partial seizures the seizure is generated in and affects just one part of the brain - the whole hemisphere or part of a lobe. Symptoms will vary according to where the seizure occurs. In the frontal lobe symptoms may include a wave-like sensation in the head; in the temporal lobe, a feeling of déja vu; in the parietal lobe, a numbness or tingling; and in the occipital lobe, visual disturbance or hallucination.

Partial seizures are split into two main categories; simple partial seizure
Simple partial seizure
Simple partial seizures are seizures which affect only a small region of the brain, often the temporal lobes and/or hippocampi. People who have simple partial seizures retain consciousness...

s and complex partial seizures. A new classification system for partial seizures has been described in the 18th Edition of Harrison's Principles of Internal Medicine (released July 2011). The new classification splits partial seizures into "partial seizures with dyscognitive features" and "partial seizures without dyscognitive features".

In simple partial seizures a small part of one of the lobes may be affected and the person remains conscious. This will often be a precursor to a larger seizure such as a complex partial seizure. When this is the case, the simple partial seizure is usually called an aura
Aura (symptom)
An aura is a perceptual disturbance experienced by some migraine sufferers before a migraine headache, and the telltale sensation experienced by some people with epilepsy before a seizure. It often manifests as the perception of a strange light, an unpleasant smell or confusing thoughts or...

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A complex partial seizure affects a larger part of the hemisphere than a simple complex seizure and the person may lose consciousness.

If a partial seizure spreads from one hemisphere to the other side of the brain this will give rise to a secondarily generalised seizure. The person will become unconscious and may well have a tonic clonic seizure.

Partial seizures are common in temporal lobe epilepsy
Temporal lobe epilepsy
Temporal lobe epilepsy a.k.a. Psychomotor epilepsy, is a form of focal epilepsy, a chronic neurological condition characterized by recurrent seizures. Over 40 types of epilepsies are known. They fall into two main categories: partial-onset epilepsies and generalized-onset epilepsies...

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See also

  • Temporal lobe epilepsy
    Temporal lobe epilepsy
    Temporal lobe epilepsy a.k.a. Psychomotor epilepsy, is a form of focal epilepsy, a chronic neurological condition characterized by recurrent seizures. Over 40 types of epilepsies are known. They fall into two main categories: partial-onset epilepsies and generalized-onset epilepsies...

  • Simple partial seizure
    Simple partial seizure
    Simple partial seizures are seizures which affect only a small region of the brain, often the temporal lobes and/or hippocampi. People who have simple partial seizures retain consciousness...

  • Complex partial seizure
    Complex partial seizure
    A complex partial seizure is an epileptic seizure that is associated with bilateral cerebral hemisphere involvement and causes impairment of awareness or responsiveness, i.e. loss of consciousness.-Presentation:...

  • God helmet
    God helmet
    God Helmet refers to an experimental apparatus used in neuroscience, primarily in the field of neurotheology. Originally called the "Koren helmet" after its inventor Stanley Koren, it was conceived to study creativity and the effects of subtle stimulation of the mesiobasal temporal lobes...

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