Atonic Seizures

Atonic seizure is one of a variety of seizure types including myoclonic, myoclonic-atonic, and tonic that can cause sudden falls. The exact delineation of the seizure type in the patient with drop seizures will often require polygraphic recordings. In the past, they have gone by a variety of different names including static, akinetic, and astatic. Atonia is meant to designate a pure loss of tone.

Definition

The ILAE glossary defines atonic seizures as a "sudden loss or diminution of muscle tone without apparent preceding myoclonic or tonic event lasing ≥1-2 seconds, involving head, runk, jaw, or limb musculature." Astatic seizures are a "loss of erect posture that results from atonic, myoclonic or tonic mechanism." Drop attacks are synonymous (Blume et al. 2001).

Classification

Atonic seizures are classified among the generalized seizures even though there is a clear clinical evidence of