Non-convulsive status epilepticus: a practical approach to diagnosis in confused older people

Non-convulsive status epilepticus (NCSE) presents with minimal seizure activity clinically, but with evidence on EEG. It is a recognised cause of delirium in older people, but prevalence estimates vary widely. As delirium is a common presentation in older people and because NCSE is potentially reversible, an improved diagnostic ability in this group could be highly beneficial. EEG testing is required to make a definitive diagnosis, but this may be difficult due to access to testing, patient adherence and result interpretation. NCSE has two commonly recognised forms: complex partial status epilepticus (CPSE) and absence status epilepticus (ASE). Clinical features associated with NCSE in older people presenting with confusion include a reduction in level of arousal; aphasia or interrupted speech; myoclonus or subtle jerking; staring; automatisms; perseveration or echolalia; increased tone; nystagmus or eye deviation; emotional lability; disinhibition and anosagnosia. Risk factors include female sex, a history of epilepsy or a tonic–clonic seizure around the time of onset, and recent discontinuation of benzodiazepines. A practical approach to the diagnosis of NCSE in older people is suggested based upon the presence of clinical features suggestive of NCSE and local access to EEG testing.