EPILEPSY AND LEARNING
DISABILITY
by National Society for Epilepsy
The frequency of epilepsy occurring in people with learning disability is
higher than in the average population, and increases in proportion with the
severity of their disability. About 30% of people with a learning disability
also have some form of epilepsy. However, in those people with a severe
learning disability, the number of people who also have epilepsy increases to
80%.
Learning disability and epilepsy
Both epilepsy and learning disability are outward symptoms of underlying
brain dysfunction or damage. Generally, this damage has existed from birth. If
the mother has an infection such as rubella or abuses drugs or alcohol, the
developing brain of the baby may be damaged. Some learning disabilities are
genetic, such as Down's Syndrome or Tuberous Sclerosis. Head injuries from
accidents, high fevers, brain infections, or tumours can also cause brain
damage. Treatment of these seizures is more difficult and they are often more
severe, more frequent and harder to control.
Identifying seizures
There are many types of seizure, and some take the form of quite strange
behaviour sequences. Seizures may be particularly unusual in people with
learning disability, and can easily go unrecognised. This may be more likely
for people who have poor communication skills. Any strange behaviour such as
long periods of confusion or unusual physical activity may be the sign of a
seizure. If any unusual behaviour occurs which you think might be a seizure, it
is important to observe it closely and write down what you see.
Many people with. a learning disability show unusual behaviour which might
not be a seizure but another sign of brain damage. Tests such as the EEG (if
done whilst this activity is occurring) will determine whether or not this is
seizure activity. Sometimes people will need special assessment to determine
this.
Anti-epileptic medication
Anti-epileptic medication may make people feel drowsy or sick and it may
affect their vision, but it seldom causes behaviour problems. The damaged brain
is more vulnerable to the side-effects of anti-epileptic medication and
obviously, if someone is not able to communicate what they are feeling, then
this may result in withdrawn or sometimes aggressive behaviour. Sometimes
side-effects of medication such as slowing, inattention, restlessness, and
unsteadiness when walking, may be difficult to distinguish from the signs of
underlying neurological disorder.
Testing serum levels
It is probably not good practise to rely heavily on drug levels for
anti-epileptic drugs, with possibly the exception of phenytoin. They provide a
rough guide to dosing, but should not be overemphasised. The main reasons for
checking blood levels are for testing compliance, to document over doses, and
suspected drug interactions. They should be used when there is a clinical need,
rather than on a routine basis. The rules about testing serum levels should be
the same for people with a learning disability as for anybody else.
Cognitive functioning
Cognitive difficulties in individuals with learning disabilities are
invariably due to the underlying brain damage which gives rise to the epilepsy.
If the seizures are under optimal control, then further cognitive difficulties
are unlikely. Seizures, however, if poorly controlled (and particularly if
undetected) may result in additional impairments of cognitive function.
Improvements may then occur if seizure control improves, although high levels
of medication are to be avoided, since this also would have a negative impact
on mental alertness.
Neurosurgery
At one time people with learning disabilities were not considered good
candidates for surgical treatment of seizures. More recently, a more positive
view is taken. However, as for individuals without learning disabilities, not
everyone is suitable for surgery. Each case requires close examination with
careful consideration of the potential benefits and possible adverse effects of
the surgery.
Reference
1. A Textbook of Epilepsy. Edited by J Laidlaw, A Richens, D
Chadwick. Churchill Livingstone, 4th Edition 1993
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