Investigating Cognitive Function in Clinical and Non-clinical Samples using Electroencephalography and Psychometric Assessment: A Comparative Study

Kalatzis, George

Investigating Cognitive Function in Clinical and Non-clinical Samples using Electroencephalography and Psychometric Assessment: A Comparative Study

Kalatzis, George

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Publication Type:: Thesis
Issue Date:: 2021

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Field	Value	Language
dc.contributor.author	Kalatzis, George
dc.date.accessioned	2021-06-02T02:36:59Z
dc.date.available	2021-06-02T02:36:59Z
dc.date.issued	2021
dc.identifier.uri	http://hdl.handle.net/10453/149336
dc.description	University of Technology Sydney. Faculty of Science.	en_US.UTF-8
dc.description.abstract	Diabetes mellitus (DM) (Type 1 (T1DM) and Type 2 (T2DM)) and hypertension (HTN) are associated with subtle cognitive dysfunction; however, few studies have explored the cognitive and electroencephalography (EEG) changes that occur in these conditions. The present cross-sectional study assessed cognitive performance (global and domain-specific) in clinical (T1DM, T2DM, and HTN) and non-clinical samples using established cognitive assessments and EEG, and investigated their associations with blood pressure (systolic (SBP) and diastolic (DBP)) and blood glucose level (BGL). Results were obtained from 94 study participants divided into four groups: non-clinical (n = 49), T1DM (n = 13), T2DM (n = 17), and HTN (n = 15). The experimental protocol was commenced by obtaining pre-study BP measurements and a BGL measurement. Participant lifestyle factors and disease-specific variables (e.g. HbA1c, age of disease onset, etc.) were obtained using the Lifestyle Appraisal Questionnaire (LAQ) and disease-specific questionnaires, respectively. Brain activity was then measured using a 32-channel EEG over two five-minute study phases (baseline (quiet sitting) and active (Stroop Test)). Subsequently, two reliable and validated cognitive screening tools were administered, the Mini-Mental State Examination (MMSE) and the Cognistat. The study was concluded with post-study BP measurements and a BGL measurement. No significant difference was found in global or domain-specific cognitive performance between the groups. In the non-clinical group, post-study BGL was inversely associated with total MMSE score (p < 0.05; r = - 0.32). In the T1DM and T2DM groups, higher BGL was significantly associated (p < 0.05) with theta activity in anterior brain regions, while glycosylated haemoglobin (HbA1C) and disease duration were found to be significantly associated (p < 0.05) with slow-wave oscillations. In the HTN group, higher SBP and DBP was significantly associated (p < 0.05) with slow-wave activities over central and parietal brain areas. These findings provide novel insight into the associations between blood pressure (SBP and DBP) and BGL and EEG activity in non-clinical and clinical groups. The data obtained suggest that the EEG can consistently detect changes in oscillatory brain activity linked to small changes in BP and BGL, identifying the EEG as a potential neurophysiological instrument for early screening for the subtle changes in cognition linked to both DM and HTN. Future use of EEG as a screening tool could avert adverse cognitive outcomes linked to these chronic diseases, such as Alzheimer’s disease (AD) and dementia, and help reduce the substantial socioeconomic and emotional burden associated with them.	en_US.UTF-8
dc.format	Thesis (PhD)
dc.language.iso	en	en_US.UTF-8
dc.relation	https://opus.lib.uts.edu.au/bitstream/10453/149336/2/02whole.pdf
dc.rights	The author owns the copyright in this thesis including all reproduction and reuse rights for the work. The work may not be altered without the permission of the copyright owner. Attribution is essential when quoting or paraphrasing from this thesis.
dc.rights	au.edu.uts.lib/ppc
dc.rights	info:eu-repo/semantics/openAccess
dc.title	Investigating Cognitive Function in Clinical and Non-clinical Samples using Electroencephalography and Psychometric Assessment: A Comparative Study	en_US.UTF-8
dc.type	Thesis
utslib.copyright.status	open_access	*

Abstract:

Diabetes mellitus (DM) (Type 1 (T1DM) and Type 2 (T2DM)) and hypertension (HTN) are associated with subtle cognitive dysfunction; however, few studies have explored the cognitive and electroencephalography (EEG) changes that occur in these conditions. The present cross-sectional study assessed cognitive performance (global and domain-specific) in clinical (T1DM, T2DM, and HTN) and non-clinical samples using established cognitive assessments and EEG, and investigated their associations with blood pressure (systolic (SBP) and diastolic (DBP)) and blood glucose level (BGL). Results were obtained from 94 study participants divided into four groups: non-clinical (n = 49), T1DM (n = 13), T2DM (n = 17), and HTN (n = 15). The experimental protocol was commenced by obtaining pre-study BP measurements and a BGL measurement. Participant lifestyle factors and disease-specific variables (e.g. HbA1c, age of disease onset, etc.) were obtained using the Lifestyle Appraisal Questionnaire (LAQ) and disease-specific questionnaires, respectively. Brain activity was then measured using a 32-channel EEG over two five-minute study phases (baseline (quiet sitting) and active (Stroop Test)). Subsequently, two reliable and validated cognitive screening tools were administered, the Mini-Mental State Examination (MMSE) and the Cognistat. The study was concluded with post-study BP measurements and a BGL measurement. No significant difference was found in global or domain-specific cognitive performance between the groups. In the non-clinical group, post-study BGL was inversely associated with total MMSE score (p < 0.05; r = - 0.32). In the T1DM and T2DM groups, higher BGL was significantly associated (p < 0.05) with theta activity in anterior brain regions, while glycosylated haemoglobin (HbA1C) and disease duration were found to be significantly associated (p < 0.05) with slow-wave oscillations. In the HTN group, higher SBP and DBP was significantly associated (p < 0.05) with slow-wave activities over central and parietal brain areas. These findings provide novel insight into the associations between blood pressure (SBP and DBP) and BGL and EEG activity in non-clinical and clinical groups. The data obtained suggest that the EEG can consistently detect changes in oscillatory brain activity linked to small changes in BP and BGL, identifying the EEG as a potential neurophysiological instrument for early screening for the subtle changes in cognition linked to both DM and HTN. Future use of EEG as a screening tool could avert adverse cognitive outcomes linked to these chronic diseases, such as Alzheimer’s disease (AD) and dementia, and help reduce the substantial socioeconomic and emotional burden associated with them.

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http://hdl.handle.net/10453/149336