Complex Partial Seizure

Definition and current terminology. A seizure arising in one hemisphere with impairment of awareness or consciousness. The ILAE 2017 classification renamed “complex partial seizure” as focal seizure with impaired awareness (focal impaired-awareness seizure) — both terms should be written in the answer. It is the commonest seizure type in older adults.

Site of origin and causes. Most arise from the temporal lobe (mesial temporal structures — hippocampus and amygdala), fewer from the frontal lobe. Causes in the elderly: stroke and small-vessel disease, tumour, hippocampal sclerosis, head trauma and subdural haematoma, Alzheimer’s disease, and in India neurocysticercosis and tuberculoma.

Clinical sequence (temporal lobe type). Aura — rising epigastric sensation, déjà vu or jamais vu, sudden fear, olfactory or gustatory hallucination → motionless stare and behavioural arrest → automatisms: oro-alimentary (lip smacking, chewing, swallowing) and manual (picking, fumbling) → post-ictal confusion and amnesia. Attacks last 30 seconds to 2–3 minutes, with post-ictal confusion of 5–30 minutes, often much longer in the elderly.

Frontal lobe variant. Brief, frequently nocturnal, occurring in clusters, with bizarre hypermotor, bicycling or thrashing movements, vocalisation and minimal or absent post-ictal confusion — commonly mislabelled as psychogenic non-epileptic attacks or a sleep disorder.

Differential diagnosis. Absence seizure (no aura, seconds only, no post-ictal confusion, 3 Hz generalised spike-and-wave, a disorder of childhood), TIA, transient global amnesia, syncope, hypoglycaemia, delirium and psychogenic non-epileptic seizures. In older adults the prolonged post-ictal state readily mimics delirium or dementia, and repeated brief attacks may be dismissed as “absent-mindedness”.

Investigations and treatment. EEG — anterior temporal spikes or sharp waves; yield improves with sleep-deprived or prolonged recording. MRI brain for hippocampal sclerosis, tumour or infarct. Treatment: focal-onset agents — levetiracetam or lamotrigine are preferred in older adults; lacosamide, oxcarbazepine and carbamazepine are alternatives. In drug-resistant cases (failure of two appropriate drugs), refer for pre-surgical evaluation — anterior temporal lobectomy gives seizure freedom in about two-thirds of selected patients.

Focal impaired-awareness seizures in Alzheimer’s disease. Work published from 2023 onward has established that subclinical epileptiform activity and unrecognised focal impaired-awareness seizures are common in Alzheimer’s disease and are associated with earlier onset and faster cognitive decline. The practical implication is that an older patient with dementia and fluctuating cognition, unexplained confusional episodes, staring spells or amnestic gaps should have a prolonged or sleep EEG, since these episodes are treatable — a diagnosis routinely missed when they are attributed to the dementia itself.