A complex partial seizure is an epileptic

Epilepsy

Epilepsy is a common chronic neurological disorder characterized by seizures. These seizures are transient signs and/or symptoms of abnormal, excessive or hypersynchronous neuronal activity in the brain.About 50 million people worldwide have epilepsy, and nearly two out of every three new cases...

 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...

 that is associated with bilateral cerebral hemisphere

Cerebral hemisphere

A cerebral hemisphere is one of the two regions of the eutherian brain that are delineated by the median plane, . The brain can thus be described as being divided into left and right cerebral hemispheres. Each of these hemispheres has an outer layer of grey matter called the cerebral cortex that is...

 involvement and causes impairment

Impairment

Impairment may refer to:* A medical condition that leads to disability* In accounting, a downward revaluation of fixed assets* In health, any loss or abnormality of physiological, psychological, or anatomical structure or function, whether permanent or temporary...

 of awareness

Awareness

Awareness is the state or ability to perceive, to feel, or to be conscious of events, objects or sensory patterns. In this level of consciousness, sense data can be confirmed by an observer without necessarily implying understanding. More broadly, it is the state or quality of being aware of...

 or responsiveness

Responsiveness

Responsiveness as a concept of computer science refers to the specific ability of a functional unit to complete assigned tasks within a given time, but also may incorporate the ability of an artificial intelligence system to understand and carry out its tasks in a timely fashion. It is one of the...

, i.e. loss of consciousness.

Presentation

Complex partial seizures are often preceded by a 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...

 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...

. The seizure aura is a 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...

. The 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...

 may manifest itself as a feeling of déjà vu

Déjà vu

Déjà vu is the experience of feeling sure that one has already witnessed or experienced a current situation, even though the exact circumstances of the prior encounter are uncertain and were perhaps imagined...

, jamais vu

Jamais vu

In psychology, jamais vu is the phenomenon of experiencing a situation that one recognises but that nonetheless seems very unfamiliar.-Linguistics:...

, fear, euphoria

Euphoria

Euphoria is an emotional and mental state defined as a sense of great elation and well being.Euphoria may also refer to:* Euphoria , a genus of scarab beetles* Euphoria, a genus name previously used for the longan and other trees...

, or depersonalization

Depersonalization

Depersonalization is an anomaly of the mechanism by which an individual has self-awareness. It is a feeling of watching oneself act, while having no control over a situation. Sufferers feel they have changed, and the world has become less real, vague, dreamlike, or lacking in significance...

. The seizure 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...

 might also occur as a visual disturbance, such as tunnel vision

Tunnel vision

Tunnel vision is the loss of peripheral vision with retention of central vision, resulting in a constricted circular tunnel-like field of vision.- Medical / biological causes :Tunnel vision can be caused by:...

 or a change in the size of objects (macropsia

Macropsia

Macropsia is a neurological condition affecting human visual perception, in which objects within an affected section of the visual field appear larger than normal, causing the subject to feel smaller. Macropsia, along with its opposite condition, micropsia, can be categorized under dysmetropsia...

 or micropsia

Micropsia

Micropsia is a condition affecting human visual perception in which objects are perceived to be smaller than they actually are. Micropsia can be caused by either optical distortion of images in the eye or by a neurological dysfunction. The condition of micropsia can be caused by more factors than...

). Once consciousness is impaired, the person may display automatism

Automatic behavior

Automatic behavior, from the Greek automatos or self-acting, is the spontaneous production of often purposeless verbal or motor behavior without conscious self-control or self-censorship...

s such as lip smacking, chewing, or swallowing. There may also be loss of memory (amnesia

Amnesia

Amnesia is a condition in which one's memory is lost. The causes of amnesia have traditionally been divided into categories. Memory appears to be stored in several parts of the limbic system of the brain, and any condition that interferes with the function of this system can cause amnesia...

) surrounding the seizure event. The person may still be able to perform routine tasks such as walking. Witnesses may not recognize that anything is wrong.

Complex partial seizures might arise from any lobe

Lobe (anatomy)

In anatomy, a lobe is a clear anatomical division or extension that can be determined without the use of a microscope This is in contrast to a lobule, which is a clear division only visible histologically....

 of the brain. Complex partial seizures most commonly arise from the mesial temporal lobe

Temporal lobe

The temporal lobe is a region of the cerebral cortex that is located beneath the Sylvian fissure on both cerebral hemispheres of the mammalian brain....

, particularly the amygdala

Amygdala

The ' are almond-shaped groups of nuclei located deep within the medial temporal lobes of the brain in complex vertebrates, including humans. Shown in research to perform a primary role in the processing and memory of emotional reactions, the amygdalae are considered part of the limbic system.-...

, hippocampus

Hippocampus

The hippocampus is a major component of the brains of humans and other vertebrates. It belongs to the limbic system and plays important roles in the consolidation of information from short-term memory to long-term memory and spatial navigation. Humans and other mammals have two hippocampi, one in...

 and neocortical regions. A common associated brain abnormality is mesial temporal sclerosis

Mesial temporal sclerosis

Mesial temporal sclerosis is a specific pattern of hippocampal neuron cell loss . There are 3 specific patterns of cell loss; Cell loss might involve sectors CA1 and CA4, CA4 alone, or CA1 to CA4 . Associated hippocampal atrophy and gliosis is common...

. Mesial temporal sclerosis is a specific pattern of hippocampal neuronal loss accompanied by hippocampal gliosis

Gliosis

Gliosis is a proliferation of astrocytes in damaged areas of the central nervous system . This proliferation usually leads to the formation of a glial scar....

 and atrophy. Complex partial seizures occur when excessive and synchronous electrical brain activity causes impaired awareness and responsiveness. The abnormal electrical activity might spread to the rest of the brain and cause a secondary generalized tonic-clonic seizure

Tonic-clonic seizure

Tonic–clonic seizures are a type of generalized seizure that affects the entire brain...

.