Seizures that
damage memory: transient epileptic amnesia
Grant round winners 2007
24 April 2007
Many people with epilepsy complain of having
problems with their memory. Seizures themselves,
anti-epileptic medicines, mood changes and
any underlying brain condition can all disrupt
memory, especially if they affect the temporal
lobe, the part of the brain which coordinates
the storing of new memories and the retrieval
of old ones.
Disruption to the temporal lobe can affect
either short or long term memory, or both.
It can affect particular types of memory
but not others. One person with epilepsy
may not remember what happened last week,
but clearly recall their schooldays; another
may often forget specific words, but remember
events well; another may keep forgetting
where they're going and why.
There is a form of temporal lobe epilepsy
where the main sign of a seizure is a 15-
to 30-minute period of forgetting. This
is called transient epileptic amnesia (TEA).
This type of epilepsy mainly affects middle-aged
adults. Seizures occur about once a month.
People with TEA often find they forget recent
memories quickly, but they also forget important
episodes in their own lives, often from
years before they developed epilepsy. This
is called autobiographical amnesia and is
an especially upsetting aspect of this form
of epilepsy, affecting patients' sense of
personal identity.
Researchers at the Peninsula Medical School,
University of Exeter, have already carried
out a series of clinical and imaging studies
of 50 patients with TEA, to establish the
nature of their epilepsy and the way it
affects their memory. In this project, Professor
Adam Zeman, Dr Catherine Haslam and
Ms Dominika Pindus will now focus on
autobiographical memory loss, in about twenty
patients with TEA and twenty comparison
patients who do not have TEA.
They will look at the underlying biology
of the brain that contributes to this effect,
and the exact nature of what gets forgotten,
for example:
Which sorts of episodes are forgotten,
e.g., public or personal; dating from
childhood, adolescence or adulthood?
How quickly does this memory loss occur?
Does the age of onset of epilepsy make
any difference?
Do any psychological or social factors
predict this form of memory loss?
Why are some memories spared?
They will also look at the effect of autobiographical
amnesia on social interactions and psychological
health, how TEA should be treated and how
it might be prevented.
This project, entitled "The impairment
of memory in epilepsy: the significance
of autobiographical amnesia" is
funded in collaboration with the Economic
and Social Research Council
(CASE Studentships programme). Epilepsy
Research UK will contribute £18,000
over three years and the ESRC will contribute
approximately £60,000.
We would like to thank everyone who responded
to our appeal last year enabling us to support
this project.
