EPILEPSY
Jane Bernal (UK)

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• Epidemiology
• Diagnosis
• Classification
• Aetiology
• Treatment
• Psychological impact
• Social impact
• Risk Management
• References

People who have epilepsy show a tendency to have recurrent seizures or fits that are associated with changes in the electrical activity of the brain.

Epilepsy in people with intellectual disabilities:

Most people with epilepsy do not have intellectual disabilities, but a substantial minority of people with intellectual disabilities have epilepsy.

It is important to be aware of the epidemiology of epilepsy.

Epilepsy is often caused by the same brain damage or maldevelopment that caused the intellectual disability. It is much more common in some conditions, particularly Tuberous Sclerosis. In people with Down's Syndrome, the onset of epilepsy may form part of the onset of Alzheimer's.

Epilepsy is classified according to the International Classification of Epilepsy (1).

International Classification of Seizures

People with intellectual disabilities and epilepsy may be forbidden to do all kinds of things because those caring for them are afraid they will have a fit. For example they may not be allowed to use computers, travel, go to pubs or the swimming pool. This secondary handicap can be minimised by sensible risk management (2)

Epilepsy is diagnosed on a good history taken from someone who has witnessed a seizure. Investigations help with classification and aetiology, but cannot substitute for good history taking.

Epilepsy, especially if it is uncontrolled, may prove fatal. Treatment with anti-epileptic drugs reduces the severity and frequency of seizures, and prevents seizures altogether in up to 70% of people with epilepsy (3).

Good first aid reduces the injuries and mortality from seizures.

Epilepsy affects the brain. Not surprisingly, psychological and psychiatric phenomena may be observed before, during or after seizures. The social impact of epilepsy may lead to over-protection or low self esteem.

Finally, epilepsy can have a considerable social impact, potentially leading to stigmatisation and secondary handicap and low self esteem, and compounding the social exclusion of people with intellectual disabilities.

EPIDEMIOLOGY

The prevalence of epilepsy in the general population has been estimated to be 5-10 per 1000 people. This figure does not include those with febrile convulsions, inactive epilepsy or who have had a single seizure. Among people known to Learning Disability services in the UK it is 20-30% and possibly higher in the residual populations of long-stay institutions. Supporting people with poorly controlled epilepsy, especially if they are liable to episodes of status epilepticus, requires high levels of competence and confidence in staff in community settings. Where this is not available it can be difficult to discharge people with epilepsy. The prevalence of epilepsy increases with the severity of the intellectual disability. Among those with milder intellectual disabilities, who may not be known to specialist services, the prevalence rate of 6% is 10 times higher than that for the general population.(19)

DIAGNOSIS

With the patient's consent, take a history from someone who has actually seen a seizure. Pay particular attention to the events leading up to, during and after the episode. Was there any warning? What was the first thing they noted? Were there abnormalities of tone? Were there abnormal movements? It can help to encourage the witness to mime what happened. Did the person change colour? Was there incontinence? How long did the episode last? What happened at the end of the episode?

Staff in day and residential services commonly attempt to classify seizures rather than describing them. They often use the outdated terms 'grand mal' and 'petit mal'. Though 'petit mal' is technically an earlier name for 'absences' it is all too often misused to cover any seizure or event that is not a typical tonic clonic seizure.

Remember - not all that shakes is epilepsy! (7) Simple faints, cardiac dysrhythmias, panic attacks, tremors, stereotypes and mannerisms may all resemble epilepsy. The distinction is usually made on history (8). Where the person cannot give a history themselves it is easy to mis-diagnose epilepsy. .

An EEG is performed to spot the location of any epileptic focus. A normal EEG between seizures does not rule out epilepsy. Most people with intellectual disability will be able to co-operate with EEG. MRI Brain Scanning may be done to rule out a tumour or to see if there is a surgically treatable lesion. It may contribute to the diagnosis of Alzheimer's or Tuberous Sclerosis. With careful preparation many people with intellectual disabilities can have an MRI scan, but some will need heavy sedation or a general anaesthetic. Video telemetry which combines EEG and video recording is valuable in seeing whether an identified behaviour is epileptic or not.

CLASSIFICATION

Epilepsy is classified according to the International Classification of Epilepsy. There is a broad division between location related (partial or focal) and generalised epilepsy syndromes together with a group for whom localisation cannot be determined. Partial seizures are further subdivided into simple where consciousness is unaffected and partial where it is altered. Partial seizures may secondarily generalise. Some seizure syndromes with an origin in childhood, particularly West's Syndrome and Lennox-Gastaut Syndrome are associated with severe intellectual disabilities and difficult-to-treat seizures.

AETIOLOGY

Intellectual disabilities, especially more severe intellectual disabilities, are mainly caused by brain pathology, that is maldevelopment of or damage to the brain. Usually we assume that the brain problem gives rise to both the intellectual disabilities and the epilepsy (4):

In a few people, prolonged seizures or epilepsy lead to a cognitive decline:

Both processes can occur in the same person. Some single gene disorders have strong associations with both intellectual disabilities and epilepsy.

Specific genetic syndromes and epilepsy: (9)

The aim of treatment is for the patient to be seizure-free, preferably on a single anti-epileptic drug (AED) and to be free of adverse drug effects. Though some AEDs work best against particular seizure types, several AEDs may need to be tried (3,10,11). It is dangerous to stop AEDs suddenly, because this may precipitate status epilepticus. AEDs should be introduced and withdrawn slowly with the aim of achieving the lowest effective dose. People with intellectual disabilities and their carers may not understand the importance of adhering to a treatment regime. A simple regime, the use of pictures and close liaison with the pharmacist all help. Click here to see related articles on Clinical Communication or the use of pictures to communicate with people with intellectual disabilities.

All anti-epileptic drugs cross the blood brain barrier. All therefore have the potential to produce adverse effects on alertness, cognition and mental state. These effects may be particularly pronounced in people with intellectual disabilities who can do without further iatrogenic cognitive impairment (12).

In addition, people with intellectual disabilities may be less likely to complain of side effects, or to have their complaints recognised.

The table below lists the main AEDS and some of their more common side effects; more detail is given in the BNF.

Phenobarbitone and Phenytoin cannot be recommended as first line drugs in the treatment of epilepsy in people with intellectual disabilities. Both can worsen cognitive deficits and Phenytoin toxicity can cause permanent brain damage. Phenytoin has a narrow therapeutic range and non-linear kinetics. This means that what appears to be a small change in dosage can radically alter the serum level. The symptoms of toxicity are insidious, especially in people who cannot complain of side effects.

The management approach must be centred on the needs and wishes of the person with epilepsy and take into account their experiences and social context. Nobody who is unconscious during or after a seizure, whether or not they have intellectual disabilities, can give informed consent to treatment. However most people with intellectual disabilities can express a view about how they want to be treated during the next seizure. It may be difficult for people, again not just those with intellectual disabilities, to share the doctor's belief that medication must be taken regularly to prevent rare episodic events. Education about epilepsy is particularly important for people with intellectual disabilities, who often have a very high level of knowledge of the condition. Their understanding may be limited, but they have often witnessed more seizures than most neurologists, because of the places in which they live and work. Video, pictures and photographs can be used to support education, which should be directed towards families and care staff as well as the person with epilepsy. Language, sequencing and memory difficulties may contribute to poor adherence to a treatment regime. People with intellectual disabilities and epilepsy have typically experienced very little control of their own lives. Resentment over this may also lead to difficulties.

Cognitive activity is affected by the underlying brain pathology, by the effects of repeated interruptions in consciousness and by anti-epileptic drugs. All tend to reduce cognitive function. This may lead to sedation and poor motivation, or it may be expressed as irritability, impulsiveness and disinhibition (16).

Repeated disruption of consciousness interrupts memory and learning. This is a particular problem in 'absence' seizures, where the seizures are brief and may be unrecognised, but are often frequent, especially in children. A person with undiagnosed partial status epilepticus may resemble someone with severe intellectual disabilities or autism. When their epilepsy is treated, their whole demeanour changes dramatically.

Children with epilepsy are often seen as very precious and vulnerable by their families. This may lead to few demands being placed on them, or infantilisation. Epilepsy can have a negative effect on self esteem. It is a hidden disability, but one that can be internally stigmatising (17).

Some anti-epileptic drugs, particularly but not exclusively Vigabatrine can produce behaviour problems and even psychosis.

Psychological disturbance may be pre-, peri- or post-ictal, that is it may occur before, during or after a seizure:

• Pre-ictal: People with complex partial seizures commonly experience a warning or aura which may take the form of a particular emotional state or a hallucinatory experience.
• Peri-ictal: Some seizures, particularly complex partial seizures affecting the temporal or frontal lobes, result in the person behaving in a bizarre and stereotyped way, though they are partly conscious.
• Post-ictal: After a seizure many people sleep, some have headaches and many are irritable or confused. (18)
  

SOCIAL IMPACT

Watching your own child have a convulsive seizure is terrifying. People unfamiliar with epilepsy usually think the child is dying. For some parents, and some people with epilepsy, this fear persists. There are also real risks of serious injury, for example by falling under a bus, or into deep water. Services are afraid of litigation. It is not surprising that people with epilepsy and intellectual disabilities are sometimes offered more protection than they need.

People with epilepsy can only drive if they have been free of seizures for a year (14). Most people with intellectual disabilities do not drive. However, transport can still be a problem - they may not be allowed to use public transport or taxis without an escort, and sometimes no escort is available.

Seizures further limit access to employment, leisure and sporting activities (15) . They therefore contribute to poverty and social isolation. This in turn contributes to a sense of powerlessness and low self-esteem. In some cultures, epileptic seizures are seen as evidence of demonic possession or of infection. This can mean that people are reluctant to touch or share cutlery with anyone who has seizures.

Rescue medication, in the form of rectal diazepam can pose particular difficulties. It is useful in the prevention of status epilepticus in vulnerable individuals and can be given by specially trained, but otherwise unqualified people. It can enable people with intellectual disabilities avoid frequent in-patient admissions or even to live at home rather than in hospital. However staff may be reluctant to use it. They may fear injuring the person; that there could be accusations of sexual abuse; or simply find rectal administration distasteful.

An individually based assessment of the real risks of particular activities an treatments will often allow the person to lead a much fuller life. An epilepsy care plan, centred on the person with epilepsy and involving everyone with a responsibility to care for them, is helpful. Such a plan should form part of the Health Action Plan recommended by the 2001 UK White paper, Valuing People.

RISK MANAGEMENT

The British Epilepsy Association issue excellent leaflets on Epilepsy and Sport, Leisure, Employment and Computers for example. The emphasis should be on having strategies in place to prevent injury from occurring if the person has a seizure, rather than restricting their activities. For example, 'swim only when there is a life guard. It is safer if you also swim alongside a friend.' 'Stand well back from the platform until the train has stopped'.(2, 5)

Try writing the advice for the other potentially risky situations shown here:

References

1. Commission of Classification of the International League Against Epilepsy. Proposal for revised clinical and electroencephalographic classification of epileptic seizures. Epilepsia 1981; 22:489-501.
   
2. Forjuoh SN, Guyer B. Injury prevention in people
   with disabilities. BMJ 2001; 322:940-941.
3. Feely M. Drug treatment of epilepsy. BMJ 1999; 318( ( 9 January )):106-109.
4. Bowley C, Kerr M. Epilepsy and intellectual disability. J Intellect Disabil Res 2000; 44 (Pt 5):529-543.
5. Besag F. Lesson of the week: Tonic seizures are a particular risk factor for drowning in people
   with epilepsy. BMJ 2001; 322:975-976.
6. Hollins S, Bernal J, Thacker A. Getting on with Epilepsy. 1 ed. London: Gaskell/St George's, University of London, 1999.
7. Rothner AD. 'Not everything that shakes is epilepsy'. The differential diagnosis of paroxysmal nonepileptiform disorders. [Review]. Cleveland Clinic Journal of Medicine 1989; 56 Suppl Pt 2:S206-S213.
8. Epilepsy. 2 ed. London: Chapman & Hall, 1995.
9. Shepherd C, Hoskings G. Epilepsy in school children with intellectual impairments in Sheffield: the size and nature of the problem and the implications for service provision. Journal of Mental Deficiency Research 1989; 33:511-514.
10. Kerr M, Bowley C. Evidence-based prescribing in adults with learning disability and epilepsy. Epilepsia 2001; 42 Suppl 1:44-45.
11. Iivanainen M, Alvarez N. Drug treatment of epilepsy in people with intellectual disability. JIDR 1998; 42 Suppl 1:iv.
12. Espie CA, Gillies JB, Montgomery JM. Antiepileptic polypharmacy, psychosocial behaviour and locus of control orientation among mentally handicapped adults living in the community. Journal of Mental Deficiency Research 1990; 34:351-360.
13. Iivanainen M. Phenytoin: effective but insidious therapy for epilepsy in people with intellectuall disability. JIDR 1998; 42(S1):24-31.
14. Shorvon SD. Epilepsy and driving. BMJ 1995; 310:885-886.
15. Scambler G, Hopkins A. Generating a model of epileptic stigma: the role of qualitative analysis. Soc Sci Med 1990; 30(11):1187-1194.
16. Espie CA, Pashley AS, Bonham KG, Sourindhrin I, O'Donovan M. The mentally handicapped person with epilepsy: a comparative study investigating psychosocial functioning. Journal of Mental Deficiency Research 1989; 33:123-135.
17. Scambler G. Stigma and disease: changing paradigms. Lancet 1998; 352(9133):1054-1055.
    
18. Fenwick P. Psychiatric Disorder and Epilepsy. In: Hopkins A, Shorvon SD, Cascino G, editors. Epilepsy. London: Chapman Hall, 1995: 453-502.
19. Bell GS, Sander JW. The epidemiology of epilepsy: the size of the problem. Seizure 2001; 10(4):306-314.
20. Brown SW. Managing severe epilepsy in the community. APT 1998; 4(6):345-355.
    

Textbooks

Epilepsy. 2 ed. London: Chapman & Hall, 1995.
The Clinical Psychologists' Handbook of Epilepsy. London: Routledge, 2003.

This article first appeared on the site in 2003.

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