23 August 2007

People with auras may be good candidates for surgery

People with epilepsy who experience multiple auras – sensations such as feeling a cold breeze or seeing a bright light – before they have a seizure may be good candidates for epilepsy surgery because their seizures seem to be generated in one area of the brain, according to a study published in the August 21, 2007, issue of Neurology, the medical journal of the American Academy of Neurology.

For the study, researchers examined 31 people with epilepsy who experienced multiple types of auras, such as a bad smell, psychic experience, or abdominal pain.

The study found 90 per cent of patients with at least two types of aura and 100 per cent of patients with at least three aura types had seizures arising from the non-dominant side of their brain.

"Epilepsy surgery may be effective for people with multiple auras since most of the seizures seem to arise from one area of the brain rather than multiple regions," said the study's author Dr. Prakash Kotagal, from Cleveland Clinic Epilepsy Center in Cleveland USA.

The study also found that more than half of the 19 study participants who went on to have epilepsy surgery stopped having seizures.

Before now, researchers say little has been known about the significance of having multiple auras since most of the attention has been focused on people with single auras.

"Multiple auras may be underestimated since auras are often difficult and time-consuming to elicit from a patient, particularly if their importance is not appreciated by the patient's doctor," said study co-author Dr Peter Widdess-Walsh with Saint Barnabas Institute of Neurology in West Orange, New Jersey. "However, our findings show multiple auras should be recognised by doctors as a significant finding and should be used in deciding whether to proceed with epilepsy surgery."

'Mahjong epilepsy'

A study by doctors in Hong Kong has concluded that the Chinese tile game of mahjong can cause seizures.

The findings, published in the Hong Kong Medical Journal, were based on 23 cases of people who had suffered mahjong-induced seizures.

The report's four authors, from Queen Mary Hospital, said the best prevention was to avoid playing the game.

The study led the doctors to define mahjong epilepsy as a unique syndrome. The game, played by four people around a table, can involve gambling and can quickly become compulsive.

The game, which is intensely social and sometimes played in crowded mahjong parlours, involves the rapid movement of tiles in marathon sessions.

The doctors concluded that the syndrome affects far more men than women; that their average age is 54; and that seizures can happen any time between one to 11 hours into a mahjong game.

They said the attacks were not just caused by sleep deprivation or gambling stress.

The cognitive demands of the game, which draws on memory, fast calculations, concentration, reasoning and sequencing, along with the design of the tiles and sound of them hitting the table, may contribute to the syndrome.

Transient amnesia can be a form of epilepsy

Episodes of transient amnesia, which frequently occur on awakening and are associated with other memory problems, may be a symptom of a distinct type of epilepsy. A British team describes this condition they call "transient epileptic amnesia" in a study published in the Annals of Neurology.

Dr. Adam Z. J. Zeman described transient epileptic amnesia as "repeated short episodes of transient amnesia, occurring about once a month, usually lasting about half an hour, often occurring on waking, typically in middle-aged people around the age of 60."

Dr. Zeman and colleagues, from the Peninsula Medical School in Exeter, recruited 50 patients who had had recurrent episodes of amnesia and evidence of epilepsy, including EEG abnormalities, response to anticonvulsant therapy; or clinical features, such as hallucinations involving the sense of smell.

"There can be other manifestations of epilepsy during the attack, like a hallucination of a smell, or a brief period of loss of awareness, but often the amnesia is the sole manifestation of the seizure."

Zeman's team found that the condition was often misdiagnosed: only 12 of the 50 patients in the study had received an initial diagnosis of epilepsy.

Anti-epileptic medication was effective in 44 of the 47 patients treated. "Most of our patients were treated with carbamazepine, sodium valproate or lamotrigine and the response to treatment was generally excellent," Zeman said.

Among the 50 patients, 40 described persistent memory difficulties. Patients demonstrated a "loss of autobiographical memory for events extending back over 40 years." They had a normal performance on standard memory tests, but they exhibited "accelerated forgetting of verbal and visual material over three weeks by comparison with matched control subjects," the researchers report.

"We propose that transient amnesic epilepsy is a distinctive epilepsy syndrome, typically misdiagnosed... and associated with accelerated long-term forgetting and autobiographical amnesia," Zeman and his colleagues concluded.

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