Brendan Mclean; Rohit Shankar; Jane Hanna; Caryn Jory; Craig
Newman. Sudden Unexpected Death in Epilepsy: Measures
to Reduce Risk. Pract Neurol.
2017;17(1):13-20.
Abstract
This review looks at the strategies that may help to reduce
the risk of sudden unexpected death in epilepsy beyond that of trying to
achieve seizure cessation, which is not possible for up to 30% of patients with
epilepsy. These strategies include seizure safety checklists, mobile phone
technology, telehealth and various devices currently available or in
development. We highlight interventions where there is evidence of benefit, and
draw attention for the need both to involve patients with epilepsy in risk
reduction and to improve communication with those at risk…
Strategies to reduce the risk of SUDEP must involve not only
people with epilepsy but also their general practitioners. General
practitioners have the most medical contact with people with epilepsy, not just
for their epilepsy but also for other conditions that may also influence risk,
such as depression and substance misuse. The UK's National Institute for Health
and Care Excellence epilepsy guidelines from 2004 to 2012 clearly state that
the risk of death in epilepsy, in particular SUDEP, should be discussed as a
priority at the time of diagnosis. Its
equivalent in Scotland, the Scottish Intercollegiate Guidelines Network
epilepsy guidelines 2015, suggests discussion about SUDEP at an 'appropriate
time'. Despite this risk, there is a tacit avoidance of discussing the risk of
death both in primary and secondary care, while the patient organisations and
SUDEP Action (formerly Epilepsy Bereaved) vociferously support the patients'
view that such should be made transparent. This article sets out
strategies that may help clinicians to improve person-centred communication
when dealing with epilepsy, to reduce this risk.
Discussing SUDEP has been controversial and some countries
still advocate a paternalistic approach on a 'need to know basis'. A recent court judgement in Scotland supported
the view that people with epilepsy and their families were entitled to be provided
with such information at an early stage. The timing of such a discussion should
be tailored to individual needs. Sometimes an early discussion is not
appropriate; for example, if there is active psychiatric comorbidity or epilepsy
has occurred in the setting of a malignant cerebral tumour. In patients with
intellectual disability, the family and carers usually wish to know as early as
possible. In our practice, we have this discussion using a structured approach
and aided by the SUDEP and seizure safety checklist at diagnosis in people with
intellectual disability, and at the first follow-up in those without…
There are numerous studies looking at the risk factors for
SUDEP. An in-depth review of the literature identified 18 risk factors, leading
to our development of a safety checklist. Of the 18 factors, 11 were
potentially modifiable, particularly non-adherence to antiepileptic
medications, substance misuse, mood disorders and sleep disruption (see
https://www.sudep.org/checklist to register, see training videos and access a
copy). There is no absolute risk assigned to each item, nor to the sum of the
items, but completing the list allows a discussion around risk modification.
Detailed analysis and stratification of the risk factors show that some are more
significant than others. Despite initial fears that raising the issues might
cause unnecessary alarm, patients tend to receive it positively and using the
checklist can modify behaviours…
Device Technology
A recent systemic review into available commercial seizure
detection devices showed no suitable robust seizure detection and safety
technology though some were clearly promising.[26] Most available devices
detect movement and/or physiological changes that occur before or during a
seizure such as altered blood oxygen levels, heart rate changes, electrical
activity in muscles and changes in galvanic skin resistance. Whether we can
call seizure-alert dogs a 'device' is debatable.
Movement Sensors
These comprise a pressure sensor map placed under the
mattress or sheets to detect an abnormal movement and absence of movement.
While weight and sleep movement adjustments can be made, seizure detection
rates are variable, with the most successful devices picking up 89% of tonic–clonic
seizures, although one study failed to detect any seizures. Specificity is
poor, with frequent false positives, so disrupting sleep of both carers and
patients. As with all sensor devices for epilepsy, they also raise issues of
individual privacy. Nonetheless, these remain the most popular among parents
because of their simplicity.
Accelerometers
These detect motion and change in velocity in two or three
dimensions. Smartphones are particularly good for this. Sensitivity can be as
high as 95%, but again specificity is lower. Speed of detection in one study
was a median of 17 s with all detected within 30 s. The use of two
accelerometers may improve nocturnal seizure detection.
Physiological Changes
Seizure onset is associated with altered autonomic activity,
including decreased skin resistance. When combined with an accelerometer, a
galvanic device detected 94% of seizures, but with a significant false positive
rate.
Heart rate monitors in one study were 100% sensitive for
tonic–clonic convulsions, and almost good for myoclonic seizures, but attempts
to refine by adding breathing detectors or electromyographic analysis provided
no advantage.
Apnoea devices combined with heart rate monitors are
attractive in theory, but studies have not yet shown any benefits.
Electromyography
There are no devices for home use, but when combined with
video electroencephalogram (EEG), there was 100% sensitivity within 30 s for
tonic–clonic convulsions. Thus, the assessment of a more suitable device is in
progress.
Video and Infrared Devices
Video monitoring is feasible, but has not been validated by
EEG support. Infrared movement monitors reliably correlate with carer-reported
activity, which did not necessarily confirm seizures.[ Using infrared
spectroscopy to measure blood oxygen changes failed to detect seizures.
Seizure-alert Dogs
There are numerous anecdotal reports of dogs successfully
detecting seizures, but no rigorous studies. Dogs may alert to the seizure
itself but not to its onset. Dogs may also react both to non-epileptic seizures
and epileptic seizures, and so are not specific. One study reported seizure
reduction but our group experienced the tragedy of a patient being killed by
her dog that was responding to a seizure.
Antisuffocation Pillows
These are often purchased by families, and are advertised on
epilepsy support websites, with one study on carbon dioxide retention
properties showing theoretical benefits. There is also the advantage that they
are cheap and harmless…
Only long-term studies will determine whether safety
checklists, telehealth interventions and mobile technologies have an impact. We
have used these approaches for several years, and have seen SUDEP in our region
fall in the intellectually disabled community from 4–5/year to nil, and in the
non-intellectually disabled community from 6 to 1–2/year. How much of this is
from the checklist, and how much from increased awareness among clinicians, the
media and people with epilepsy or from improved services in general is
difficult to determine. However, these interventions do raise the profile of
epilepsy mortality and may contribute to enhanced awareness. Device technology
is still in its infancy, and we cannot recommend any single device particularly
as none has been shown to prevent SUDEP. The ideal drug—one that suppresses all
seizure activity and is free from side effects—may not be developed in our
lifetime. Furthermore, clinically based interventions will not capture those
individuals at high risk. Self-monitoring by people with epilepsy or carers
remains important, although there will still be those whose lifestyles put them
at risk. Good communication is essential, but current services are not
structured with that in mind. Professionals can only do so much, leaving a
service gap between the epilepsy professionals, who see a snapshot of a
patient's life, and the day-to-day experiences of people with epilepsy.
Empowering people with epilepsy to take responsibility for their condition
would do much to bridge that gap.
http://www.medscape.com/viewarticle/875311
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