Seizures are exclusively induced by reading and can start minutes to hours after reading. Myoclonic jerks of the masticatory, perioral and oral muscles are the commonest seizure seen in this syndrome, resulting in a clicking sensation. If reading continues, the jerks may increase and spread or a generalized tonic-clonic seizure may occur. Seizures with inability to read or possibly dysphasia may occur and may be prolonged. Absence seizures may occasionally occur. Seizures are typically well controlled once the stimulus is recognized. Seizures may be precipitated by talking, writing or chewing in some patients.
Seizures are exclusively induced by startle with a sudden brief focal tonic seizure typically affecting the trunk and causing a fall. Other seizure types may occur, including focal atonic and focal myoclonic seizures. Seizures are typically frequent.