The "aura" experienced before a seizure, while frequently thought-of as a primarily visual experience, can include disturbances in taste or smell, bodily sensations such as stomach ache or tingling, anxiety, or a sense that everything is oddly familiar (déjà vu) or unfamiliar (jamais vu). 

A generalized seizure is one which involves both sides of the brain simultaneously from onset and results in loss of consciousness. This is contrasted with complex and simple partial seizures, in which only one area of the brain is involved and the individual may or may not lose consciousness (in complex and simple partial seizures, respectively). Seizure activity that lasts for 30 or more minutes is a rare and serious condition known as status epilepticus. Any seizure that lasts for over five minutes is considered a medical emergency and requires emergency assistance.

Currently there are over 40 distinct types of seizures recognized by the medical community. Some of the most common seizure types are generalized tonic-clonic, absence, myoclonic, clonic, tonic, febrile, and atonic. Some other less common types include refractory seizures, gelastic seizures, and dacrystic seizures.

Absence seizures are typified by a brief, 2-30 second loss of consciousness in the absence of other symptoms. Individuals with this condition generally will not experience muscle rigidity (as in a tonic seizure) or jerking (as in clonic or myoclonic seizures), nor do they experience a loss of muscle tone, as seen in atonic seizures. Absence seizures present frequently in young children as "staring spells" and may cause issues with learning or appear as inattentive behavior in school until correctly diagnosed by a medical professional.

While CT and MRI may aid in discovering structural abnormalities associated with certain seizure disorders, the correct tool for diagnosis of seizures is electroencephalography (EEG). An EEG can show abnormal surges in brain activity responsible for temporary loss of consciousness in absence seizures.

While epilepsy may certainly be hereditary, the diagnosis of epilepsy requires the occurrence of at least two seizures during two separate incidents, regardless of positive family history. These must occur in the absence of provocative factors such as fever, head trauma, or medication. 

Generalized seizures are defined as seizures in which both hemispheres of the brain are affected by seizure activity from the onset. There are four main types of generalized seizures: tonic-clonic, myoclonic, atonic, and absence. All of these result in loss of consciousness and may or may not cause spasm or clonus. Complex partial seizures, while also resulting in a loss of consciousness, are restricted to one hemisphere of the brain.

The most common type of seizure in adults is the tonic clonic seizure, also known as grand-mal. These seizures have two stages: a tonic stage, characterized by muscle stiffening and rigidity, followed by a clonic phase, characterized by jerking and twitching of the muscles and the face. Some individuals may have a tendency to have more tonic symptoms or more clonic symptoms, or may go in a tonic-clonic-tonic pattern of alternating rigidity and jerking motions. Individuals in a tonic clonic seizure experience loss of consciousness and may experience headache, lethargy, confusion, or may want to go to sleep on recovery of consciousness.

A total loss or absence of sense of smell is called anosmia. It may be caused by a wide variety of medical conditions, including trauma to the head, stroke, nasal blockage, various dementias, viral infection, toxic exposure, autoimmune disease, or zinc deficiency.

Hyposmia is a state in which sense of smell is reduced but not absent, while hyperosmia is an increased sensitivity to smell. Dysosmia is an alteration in the perception of smell which may include olfactory hallucinations or distortions.

Hypogeusia is a condition of reduced sensitivity to taste. This may be due to various causes, including brain injury, viral infection, zinc deficiency, certain medications such as chemotherapeutic agents or antibiotics. 

Dysgeusia and parageusia both describe alterations in the perception of taste. These conditions can have similar etiologies to hypogeusia. Ageusia is the total absence of taste perception.