Introduction
Epilepsy is a condition that affects 0.6-0.8% of the
world population, rendering it the most common
neurological disorder after stroke. It is characterized by
recurrent unprovoked seizures, due to abnormal, excessive
or synchronous neuronal activity in the brain and by a
vast range of causes, triggering events, symptoms and
brain locations where the seizures originate. In 25% of
the affected population, seizures cannot be controlled by
antiepileptic drugs or surgery. However, it has been
suggested, that at least some types of seizures are
predictable.
Seizures compromise the quality of life of patients with
epilepsy to a great extent and may result in serious
self-injuries from various causes. Epilepsy has been also
associated with a sudden death rate that is at least 10
times of the same rate for the general population (sudden
unexplained death in epilepsy - SUDEP). Therefore, the
importance and usefulness of seizure prediction cannot be
overstated, as it would increase epileptic patients’
autonomy, drastically reduce accidents and self-injuries
related to epileptic seizures and, as a whole, improve the
patients’ quality of life dramatically. Upon successful
completion, we envision using these algorithms in compact,
wearable predictor systems that will take full advantage
of the state-of-the-art in personalized monitoring
systems, further improving the quality of life of people
with epilepsy.
General Objectives
The general objectives of the present project are in
accordance with the objectives of the program and the
specific action (ΥΓΕΙΑ/ΔΥΓΕΙΑ), as it concerns a
neurological disorder - epilepsy - that affects millions
of people worldwide (second only to stroke). Epilepsy
greatly compromises quality of life, both physically and
psychologically, and it increases mortality rate. Βy
developing novel, improved strategies for predicting
epileptic seizures, the proposed approach has the
potential of elucidating some of the implicated mechanisms
and dramatically improving the quality of life of patients
with epilepsy. The results could be also used in
personalized monitoring systems, which are becoming more
portable and discreet, improving quality of life and
self-autonomy further. State-of-the art signal processing
techniques will be used in order to achieve the stated
goals, and as a result the researchers to be employed will
acquire skills that will enable them to compete in
research on an international level. The acquired expertise
and results will be also important for the research and
technological development of Cyprus, as Bioengineering is
a key priority area. Finally, the acquisition of a wealth
of data from PA1 will lead to the availability of a large
database of epilepsy data in Cyprus, which will be very
important in driving relevant future studies. Other
objectives include the publication of the research results
in high-impact refereed journals.
Scientific and Technological Objectives
In the context of the present project we aim to: (i)
collect long-term video-EEG and ECG data simultaneously in
patients with epilepsy (the anticipated number is around
50 for the project duration) (ii) record the occurrence of
subjective prodromal symptoms and identify their
neural/cardiac correlates (iii) evaluate the performance
of different EEG prediction algorithms, placing emphasis
on multivariate, patient-specific approaches. We will also
consider novel and emerging concepts in EEG signal
analysis, such as the assessment of Granger causality with
multivariate autoregressive linear and nonlinear models,
mutual information and nonlinear “black-box” models, in
order to identify changes in functional connectivity
during the pre-ictal phase (4) extract complementary
information from simultaneous ECG measurements (5) design
appropriate data fusion schemes that will utilize the
aforementioned multimodal information efficiently and (6)
extensively evaluate the performance of the
multimodalalgorithms in a rigorous statistical manner, by
assessing both their specificity and sensitivity. In this
context, we will place emphasis on using well-suited
methods for assessing statistical significance, such as
surrogate data. The availability of long recordings of
experimental data for each subject is particularly
important to this end.
Added Value and Benefit
Epilepsy is a widespread disease - up to 5% of people in
the world may have at least one seizure in their lives
(http://www.who.int) - that has significant personal,
social and economic consequences. These include profound
physical and psychological impact on the patients, which
in turn have a profound social and economical impact,
affecting a significant portion of the population and
especially sensitive population age groups, the young and
the aged. Based on the age-specific incidence rates in
European studies, the estimated number of new cases per
year amongst European children and adolescents is 130 000
(incidence rate 70 per 100 000), 96 000 in adults 20–64
years (30 per 100 000) and 85 000 in the elderly 65 years
and older (100 per 100 000). It is estimated that around
7,000-8,000 people with epilepsy exist in Cyprus, of which
about 30% are drug-resistant.
Epilepsy is also associated with an increased risk of
mortality. Death may be related to an underlying brain
disease, such as a tumour or infection, seizures in
dangerous circumstances, leading to life-threatening
injuries. Epilepsy-related deaths in young adults in the
UK, for example, are 3 times higher than standard
age-related mortality rates. Very importantly, people with
epilepsy are at least 10 times more probable to suffer
sudden death (sudden unexplained death in epilepsy –
SUDEP) compared to the general population,with probable
causes including cardiac or respiratory arrest.
Controlling seizures is considered to be the most
important preventive measure against SUDEP; hence, seizure
prediction would contribute in this direction. From the
social point of view, people with epilepsy experience
problems in the areas of personal relationships and even
sometimes legislation. For example, people with epilepsy
were prevented from marrying in the United Kingdom or the
U until recently, while they can only drive if they have
been free of seizures for a year. In the 25 European Union
member countries, Iceland, Norway, and Switzerland the
estimated total cost of the disease in Europe was €15.5
billion in 2004, indirect costs being the single most
dominant cost category (€8.6 billion).
The socioeconomic burdens of epilepsy are obviousfrom the
abovementioned facts. Therefore, successful completion of
the proposed project will not only lead to the production
of new scientific knowledge, but also to a vast
improvement in the quality of life of the patients as well
as a decrease in the related social and economic
costs.Furthermore, the scientific outcomes of the project
could be further used in portable, personalized monitoring
systems, i.e., portable EEG and ECG, which will take
advantage of the recent advances in body sensor network
and mobile communications technology. This would further
improve the quality of life by decreasing the frequency of
hospital admissions (by self-managing the seizures where
possible and avoiding accidents and self injuries).
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