From electrical signals to biological processes: unveiling the complexity of electroencephalographic epileptiform spikes across sleep-wake states

Toutant, Darion

From electrical signals to biological processes: unveiling the complexity of electroencephalographic epileptiform spikes across sleep-wake states

dc.contributor.author	Toutant, Darion
dc.contributor.examiningcommittee	Ko, Ji Hyun (Human Anatomy and Cell Science)
dc.contributor.examiningcommittee	Morrison, Jason (Biosystems Engineering)
dc.contributor.supervisor	Ng, Marcus
dc.contributor.supervisor	Moussavi, Zahra
dc.date.accessioned	2024-01-09T16:21:39Z
dc.date.available	2024-01-09T16:21:39Z
dc.date.issued	2023-12-08
dc.date.submitted	2024-01-04T02:34:32Z	en_US
dc.date.submitted	2024-01-09T15:08:51Z	en_US
dc.degree.discipline	Biomedical Engineering	en_US
dc.degree.level	Master of Science (M.Sc.)
dc.description.abstract	This thesis introduces a novel investigation into the morphological characteristics of epileptiform spikes across various sleep-wake states. A gold-standard database of spikes was created, offering insights into their variations across wakefulness, non-rapid-eye-movement (NREM) sleep stages 1-3, and particularly rapid-eye-movement (REM) sleep, and hypothesizing on the dynamics regulating its suppressive ability towards spikes. The study employed lab-developed software to categorize sleep states and validate spikes using data from 7 epilepsy monitoring unit patients. A computational pipeline was developed to assess nine morphological spike features throughout Laplacian, Referential, and Raw montages. Due to non-normal data distribution, statistical analysis was performed using the Kruskal-Wallis test, followed by Dunn's post-hoc testing and Bonferroni correction. Results revealed that the spike features of REM sleep are significantly different from those of other sleep-wake states. In particular, spikes during REM sleep had the shallowest ascending and descending slopes by nearly 50% of the other states, which were nearly symmetrical, blunter peaks with roughly twice the angle of other states and exhibited lower peak amplitudes less than 50% of the voltage of other states. Wakefulness was the most different state concerning duration while being, on average, 15% shorter. Finally, the spike area during REM was roughly twice as small as all other states. This study shows significant spike feature differences throughout sleep-wake states, with REM drastically different in most features. The driving factors for changes in spike morphology throughout the sleep-wake states are unknown. However, this thesis explores the effects of ionic, neurotransmitter, astrocytic and network dynamic processes to help shed light on these changes. Notably, this thesis provides glimpses into the roles of astrocytic involvement, orexinergic systems, and network dynamics as potential contributors to the observed morphological differences within REM. Further investigations are necessary to fully understand these complex electrobiological interactions, which may be responsible for the observed anti-epileptic properties during REM sleep. This study paves the way for future work to expose and leverage the unique anti-epileptic mechanisms of REM sleep, potentially leading to the development of REM-specific therapeutic strategies for epilepsy management.
dc.description.note	February 2024
dc.identifier.uri	http://hdl.handle.net/1993/37961
dc.language.iso	eng
dc.rights	open access	en_US
dc.subject	Epileptiform Discharge
dc.subject	Sleep-Wake States
dc.subject	Epilepsy
dc.subject	REM Sleep
dc.subject	Spike Labelling Graphical User Interface
dc.subject	Electroencephalography
dc.subject	Spike Morphology
dc.title	From electrical signals to biological processes: unveiling the complexity of electroencephalographic epileptiform spikes across sleep-wake states
dc.type	master thesis	en_US
local.subject.manitoba	no