Seizure Signatures Study
Research type
Research Study
Full title
Electrophysiological, Cognitive and Psychiatric Signatures of Epileptic and Psychogenic Non-Epileptic Seizures
IRAS ID
265164
Contact name
Irene Faiman
Contact email
Sponsor organisation
King's College London
Clinicaltrials.gov Identifier
N/A, N/A
Duration of Study in the UK
1 years, 6 months, 1 days
Research summary
Research Summary
Epilepsy is a serious neurological condition affecting 65 million people worldwide. Psychogenic non-epileptic seizures (PNES) are episodes of observable abrupt change in behaviour or consciousness in the absence of the electrophysiological changes in the brain that accompany an epileptic seizure. The differential diagnosis between PNES and epileptic seizures (ES) is a prominent problem in clinical practice, resulting in diagnostic delays of 7 years, on average. This imposes health and economic burdens at the individual and population levels.
Early diagnosis is crucial to ensure appropriate and timely treatment, and to reduce unnecessary health costs. Observing a non-epileptic seizure event whilst recording normal electroencephalographic (EEG) activity is the gold standard method supporting the diagnosis of PNES. However, recordings may require prolonged periods of time and events are not always observed.
The aim of the proposed cross-sectional observational study is to identify factors that can differentiate ES from PNES based on measures that are easier to obtain, such as EEG recorded in the absence of seizures, electrocardiogram (ECG), and a combination of cognitive and psychiatric measures.
Additionally, the proposed study will investigate rates of suicidal ideation, suicidal attempts and self-harm behaviour, and their relationship with dissociation in epilepsy.We will recruit people with ES and people with PNES from King's College Hospital and South London and Maudsley Hospital. They will be asked permission to access their clinical data, including EEG and ECG recordings. They will undergo assessment of mood, cognition and seizure severity, and a suicide risk assessment.
The identification discriminative markers is an unmet clinical need that would contribute to improved patient care, and reduced psychological and economical burden.
Summary of Results
RESULTS OF THE SEIZURE SIGNATURES STUDY Electrophysiological, Cognitive and Psychiatric Signatures of Epileptic and Psychogenic Non-epileptic Seizures
In this study we aimed to identify markers that are specific to people with epilepsy or people with psychogenic non-epileptic seizures (PNES) and can be used to support clinicians in diagnostic decision-making. We looked for specific characteristics in the cognitive and psychological profiles, as well as clinical electroencephalogram (EEG) data if these were available.
PART 1 – COGNITIVE AND PSYCHOLOGICAL CHARACTERISTICS
In this study, we recruited 81 participants with confirmed or suspected epilepsy or PNES. Participants completed a series of tests measuring different aspects of thinking such as attention, language, thinking speed and mental flexibility. They also completed questionnaires on depression, anxiety, dissociation, medically unexplained physical symptoms, trauma history and suicidality.
Results indicated that people with PNES and people with epilepsy are equally good at completing cognitive (thinking) tasks. However, people with PNES experience more symptoms of depression, more medically unexplained physical symptoms and report having been exposed to a higher number of traumatic experiences in their lives.
Results also indicated that there are some differences in the way cognitive and emotional factors interact in people with epilepsy as compared to people with PNES.
In people with epilepsy, better verbal expression abilities were associated with a lower number of medically unexplained physical symptoms. One interpretation of these findings might be that physical symptoms that are medically unexplained arise due to distress or other emotion-related factors. An ability to express and articulate verbal information might provide relief from physical symptoms as it “translates” them to verbal entities. Whilst this mechanism might be at work for the majority of people with epilepsy, it was not consistently observed in the group with PNES. It might be that some people with PNES might have a different way to experience and manifest distress which is both through physical symptoms and through verbal communication.Results also indicated another difference between people with epilepsy and people with PNES. In people with epilepsy, those that had more traumatic experiences in their lives also had a greater ability to switch their attentional focus. This might reflect the implementation of strategies to cope with traumatic events such as diverting attention to other thoughts or events. In people with PNES, this relationship between traumatic experiences and attentional switching was not observed. This might indicate that the being exposed to traumatic events might make it more difficult for some people with PNES to switch the attentional focus to other thoughts. This might be partly due to having had a greater exposure to traumatic events than the group with epilepsy.
The effects described above are all observed at the level of the whole group. This means that they might not be applicable to each single individual, but they represent a more general trend. Also, these findings constitute preliminary evidence, which means that they will need to be confirmed in future by larger studies. Nonetheless, they are a valuable starting point to understand the mechanisms of epilepsy and PNES better and work towards better recognition and management of these disorders.
PART 2 – CHARACTERISTICS OF THE ELECTRICAL ACTIVITY OF THE BRAIN
In a second study we also analysed the clinical electroencephalogram (EEG) data of 148 people with epilepsy or PNES. The EEG measures the electrical activity of the brain. We looked at recordings that did not contain any seizure activity and we searched for patterns that can help decide if someone has epilepsy or PNES. We used artificial intelligence to understand whether this has the potential to help in the diagnostic process.
Results indicated that it is challenging to identify specific characteristics in the electrical activity of the brain that indicates if someone has epilepsy or PNES outside of the periods of seizures. However, we found some EEG patterns that indicate that people are about to experience epilepsy-related activity. This means that when a specific pattern is detected during the recordings, the EEG technicians could be alerted that brief abnormalities indicating epilepsy are likely to occur in the following minutes or hours. The duration of the EEG appointment could therefore be extended to increase the chances of capturing such abnormalities. This might help speeding up the diagnostic process for people with epilepsy.
Implementation of research findings in clinical practice requires a very high degree of certainty (for example, we need to ensure that these results also apply to different EEG machines and to a very wide range of people). Therefore, these findings need to be replicated by future studies and if they do, they could be implemented in clinical practice as described above.
CONCLUSIONS
In summary, we have detected some cognitive and psychological characteristics that are unique to people with epilepsy and some that are unique to people with PNES. These will help us understand and recognise these conditions better.
Additionally, we have found that it is challenging to detect markers for the diagnosis of epilepsy and PNES in the EEG recordings taken outside the periods of seizures. However, we did identify some markers that might be useful to speed up the diagnosis for a specific subgroup of people who are close to experiencing epilepsy-related abnormalities.REC name
London - Queen Square Research Ethics Committee
REC reference
20/LO/0784
Date of REC Opinion
6 Jul 2020
REC opinion
Further Information Favourable Opinion