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Hallucinations or illusions can occur in the context of loss of a primary sense. This is well
recognised in limb amputees, with phantom limb pain and sensory disturbance. Similarly,
patients with visual impairment may develop Charles Bonnet syndrome, with visual
hallucinations in the area of visual field loss. This results from damage to the visual system
due to, for example, age-related macular degeneration or glaucoma, but it may also arise in
patients with intracranial pathology and secondary deafferentation of the visual cortex78.

Aggressive or vocal outbursts

Episodic dyscontrol syndrome (EDS) and its counterpart, intermittent explosive disorder
(IED), are patterns of abnormal, episodic, and frequently violent and uncontrollable social
behaviour often in the absence of significant provocation. These events are frequently
attributed to epilepsy as they often arise seemingly out of character. Uncontrolled rage
occurring in the context of epileptic seizures is also unprovoked, however the anger is usually
undirected or reactive, the episodes occur in isolation and other manifestations of a seizure
disorder are frequently present. Additionally, routine inter-ictal EEG recordings in EDS have
not shown epileptiform activity79. Interestingly, however, a significant proportion of patients
demonstrate non-specific diffuse or focal slowing not attributable to drowsiness or the effects
of medication. There is neuroimaging evidence of frontolimbic involvement in the
pathogenesis of EDS and IED and co-existent neurological and psychiatric conditions are
frequently seen80. So although the rage attacks themselves may not have an epileptic basis,
the two conditions may be pathogenetically linked.

Prolonged confusional or fugue states

Acute neurological conditions, such as non-convulsive status epilepticus, intracranial
infections, head injuries, ischaemic events and drug intoxication or withdrawal may result in
an acute confusional state. Systemic disorders may also give rise to episodes of acute
encephalopathy and transient loss of consciousness such as renal or hepatic failure and
endocrine and metabolic abnormalities, the most common of which is hypoglycaemia related
to insulin therapy in diabetes mellitus. Other precipitants of hypoglycaemia include alcohol,
insulinomas, rare inborn metabolic abnormalities, such as congenital deficiencies of
gluconeogenic enzymes, and renal or hepatic disease. The symptoms of hypoglycaemia are
protean, and include visual disturbance, diaphoresis, confusion, unconsciousness, and altered
behaviour including irritability and aggression. Peri-oral and acral paraesthesias, ataxia,
tremor and dysarthria are common features, leading to diagnostic confusion unless an
accurate history and appropriate laboratory investigations are performed. The rare disorders
of phaeochromocytoma, carcinoid syndrome and hypocalcaemia may also present with
confusion, presyncope or syncope and the hypocalcaemic sensory disturbance may be
mistaken as an epileptic aura81.

Transient global amnesia (TGA) usually occurs in middle-aged or elderly people and is
characterised by the abrupt onset of anterograde amnesia, accompanied by repetitive
questioning82. With the exception of the amnesia, there are no neurological deficits. There is
neither clouding of consciousness nor loss of personal identity. Attacks last between minutes
and hours, with six hours being the average duration. The ability to lay down new memories
gradually recovers, leaving only a dense amnesic gap for the duration of the episode and a
variable degree of retrograde amnesia. The attacks are often associated with headache,
dizziness and nausea. The duration and number of attacks are important in distinguishing
TGA from transient epileptic amnesia and transient ischaemic events affecting mesial
temporal lobe structures. Unlike the epileptic form of amnesia, TGA rarely lasts less than one
hour, and recurrences occur in less than 10% of patients. The aetiological basis of TGA is
uncertain. Possible underlying mechanisms include cortical spreading depression or venous