An atonic seizure (also called drop seizure, akinetic seizure, astatic seizure, or
drop attack A drop attack is a sudden fall without loss of consciousness. Drop attacks stem from diverse mechanisms, including orthopedic causes (for example, leg weakness and knee instability), hemodynamic causes (for example, transient vertebrobasilar insuf ...
) is a type of
seizure
An epileptic seizure, informally known as a seizure, is a period of symptoms due to abnormally excessive or synchronous neuronal activity in the brain. Outward effects vary from uncontrolled shaking movements involving much of the body with l ...
that consists of partial or complete loss of
muscle tone that is caused by temporary alterations in
brain
A brain is an organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It is located in the head, usually close to the sensory organs for senses such as vision. It is the most complex organ in a ve ...
function. These seizures are brief – usually less than fifteen seconds. They usually begin in
childhood and may persist into
adulthood. The seizure itself causes no physical
injury, but the loss of control, predominantly in trunk muscles, can result in direct
injury from
falling.
Electroencephalography can be used to confirm diagnosis. It is rare and can be indicative of
Lennox–Gastaut syndrome
Lennox–Gastaut syndrome (LGS) is a complex, rare, and severe childhood-onset epilepsy. It is characterized by multiple and concurrent seizure types, cognitive dysfunction, and slow spike waves on electroencephalogram (EEG). Typically, it presents ...
(''see''
Henri Gastaut).
Atonic seizures can occur while standing, walking, or sitting, and are often noticeable by a head drop (relaxing of the neck muscles). Fall injuries may result in impact to 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.
Treatment
There is no general treatment for patients with a seizure disorder. Each treatment plan is specifically tailored to the individual patient based on their diagnosis and symptoms. Treatment options may include medical therapy, nerve stimulation, dietary therapy, or surgery, as appropriate. Clinical trials may also be a valuable treatment alternative.
Usually, anticonvulsants are given based on other symptoms and / or associated problems.
Because the areas of the cerebellum which determine increases and decreases in muscle tone are close together, people experiencing atonic seizures are most likely experiencing myoclonic ones too, at some point. This may play a role in therapy and diagnostic.
One surgical approach, selective posterior
callostomy, can greatly decrease instances of drop attacks and improve function and behavior in patients with intellectual disability.
References
External links
{{Seizures and epilepsy
Pediatrics
Seizure types