Atonic seizures are a type of 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...

. They consist of a brief lapse in muscle tone

Muscle tone

In physiology, medicine, and anatomy, muscle tone is the continuous and passive partial contraction of the muscles, or the muscle’s resistance to passive stretch during resting state. It helps maintain posture, and it declines during REM sleep.-Purpose:Unconscious nerve impulses maintain the...

 that are caused by temporary alterations in brain

Brain

The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...

 function. The seizures are brief - usually less than fifteen seconds. They begin in child

Child

Biologically, a child is generally a human between the stages of birth and puberty. Some vernacular definitions of a child include the fetus, as being an unborn child. The legal definition of "child" generally refers to a minor, otherwise known as a person younger than the age of majority...

hood and may persist into adult

Adult

An adult is a human being or living organism that is of relatively mature age, typically associated with sexual maturity and the attainment of reproductive age....

hood. The seizure itself causes no damage, but the loss of muscle control can result in indirect damage from falling

Falling (accident)

Falling is a major cause of personal injury, especially for the elderly. Builders, electricians, miners, and painters represent worker categories representing high rates of fall injuries. The WHO estimate that 392,000 people die in falls every year...

. Electroencephalography

Electroencephalography

Electroencephalography is the recording of electrical activity along the scalp. EEG measures voltage fluctuations resulting from ionic current flows within the neurons of the brain...

 can be used to confirm diagnosis. It is minor and relatively common, and can be indicative of Lennox-Gastaut syndrome

Lennox-Gastaut syndrome

Lennox–Gastaut syndrome , also known as Lennox syndrome, is a difficult-to-treat form of childhood-onset epilepsy that most often appears between the second and sixth year of life, and is characterized by frequent seizures and different seizure types; it is often accompanied by developmental delay...

 (see Henri Gastaut

Henri Gastaut

Henri Gastaut was a French neurologist.Henri Gastaut was educated in neurology and neuroanatomy at the University of Marseille, graduating M.D. in 1945. In 1953 he became head of the neurobiological laboratories. He was appointed professor of anatomical pathology in 1954 and director of the...

).

Atonic seizures can occur while standing, walking or sitting, and are often noticeable by a head drop (the neck muscles releasing) and damage sometimes results from hitting the face or head. As with common epileptic occurrences, no first aid is needed post-seizure, except in the instances where falling injuries have occurred. In some cases, a person may become temporarily paralyzed in part of his or her body. This usually does not last longer than 3 minutes.