Tonic seizures are less common in Doose Syndrome and may suggest the need to re-evaluate the diagnosis with your neurologist. However, parents anecdotally tell us that sometimes after medication is initiated what looks like Tonic seizures may actually be other seizure types that have been altered by the effects of the medication. This can be a bit confusing. If you can catch one on video and have your neurologist evaluate it this could be helpful in differentiating between other types.
The unique nature of Tonic seizures come in the fact that they exhibit only stiffening and not a following clonic phase of a tonic-clonic. They are different from myoclonic seizures in that they exhibit stiffening for at least a few seconds as opposed to myoclonic which are quick jerks and don’t persist beyond a fraction of a second. Both tonic and atonic seizures can cause falls, though atonic seizures are the loss of all muscle tone where tonic is the sudden stiffening of the muscles.
Tonic seizures are brief seizures (usually < 60 seconds) consisting of the sudden onset of increased tone in the extensor muscles. If standing, the patient typically falls to the ground. These seizures are invariably longer than myoclonic seizures. The degree to which consciousness is impaired is often difficult to assess. In seizures lasting longer than a few seconds, impairment of consciousness is usually apparent. Postictal impairment with confusion, tiredness, and headache is common. The degree of postictal impairment is usually related to the duration of the seizure activity and is dramatically increased in tonic seizures.