Browsing by Author "Alotaibi, Abdulmajeed"

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Applications of DTI and NODDI-MRI in Diabetes Mellitus and Multiple Sclerosis
(Saudi Digital Library, 2023-07-13) Alotaibi, Abdulmajeed; Dineen, Rob
Type 2 diabetes (T2DM) and multiple sclerosis (MS) affect the central nervous system (CNS). Both diseases are major risk factors for brain damage and degeneration, challenging healthcare providers worldwide. Magnetic Resonance Imaging (MRI) can visualise brain structural abnormalities in patients with T2DM and MS, but conventional MRI cannot quantify microstructural changes. As a result, there has been a surge in interest in utilising imaging tools to quantify microstructural changes, such as advanced diffusion MRI models, to understand white matter abnormalities in MS and T2DM. Diffusion tensor imaging (DTI) has been used to quantify microstructural abnormalities in T2DM and MS. Despite the sensitivity of DTI in detecting microstructural changes in white matter, DTI indices are influenced by fibre orientation dispersion, which may lead to the incomplete or erroneous characterisation of the microstructural changes occurring within a voxel. A biophysical diffusion model known as neurite orientation dispersion and density imaging (NODDI) has been proposed to overcome this DTI limitation. My original contribution to knowledge is 1) a current systematic review of DTI studies that detected brain microstructural changes in diabetes; 2) a meta-analysis of NODDI studies in characterising white matter changes in MS; 3) optimising an up-to-date NODDI scanning protocol at the University of Nottingham; 4) using DTI/NODDI metrics derived from the UK Biobank to investigate brain white matter alterations in T2DM; 5) assessing the correlation between the altered DTI/NODDI metrics and metabolic profile in patients with T2DM. I initially optimised the NODDI scanning protocol for this original PhD project. I tested four scanning protocols on a 3T Philips MRI scanner at Sir Peter Mansfield Imaging Centre (SPMIC). The research team agreed that Protocol #3 was the best choice. In parallel, I performed a systematic review to investigate the impact of diabetes on brain microstructure measured by DTI and correlated it with cognitive and metabolic tests. I reviewed 38 DTI studies on both types of diabetes. This review showed that diabetes affects brain microstructure, suggesting its impact on cognitive abilities. I aimed to meta-analyse studies using NODDI metrics to detect the white matter neuroaxonal pathology in MS. The intracellular volume fraction in the white matter lesions and normal-appearing white matter were significantly reduced compared to healthy white matter, suggesting underlying damage or loss of neurites. After the COVID-19 pandemic halted my prospective patient study, I evaluated the microstructural impact of T2DM on brain white matter using DTI and NODDI metrics derived from UK Biobank. I evaluated the relationship between white matter alterations and disease duration/glycated haemoglobin (HbA1c). The study showed that T2DM was associated with subtle but global white matter microstructural changes, as indicated by the alterations of DTI and NODDI parameters. There were weak but statistically significant associations between altered DTI and NODDI parameters in participants with T2DM and glycaemic control/disease duration. T2DM and MS were associated with white matter alterations detected by DTI and NODDI. Although the findings of this thesis demonstrated that DTI still has a potential value as a clinical biomarker in T2DM, NODDI could biophysically characterise white matter neuroaxonal pathology in T2DM and MS, which contributes to DTI parameters.
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Is Fatigue Associated with Oral Health Outcomes Among American Adults?
(King's College London, 2024-08) Alotaibi, Abdulmajeed; Sabbah, Wael
Background: Fatigue is a frequent problem in the American adult population, affecting every aspect of health, from mental to physical wellbeing. Although the negative effects of fatigue on general health are well documented, little research has been identified that investigated its effect on oral health. Among the adverse consequences of fatigue, bad oral habits like neglecting oral hygiene and regular dental check-ups can lead directly to negative outcomes with individual’s teeth, such as tooth loss, tooth decay and periodontal disease. Fatigue is described as the subjective sense of not being able to accomplish a task efficiently owing to decreased effectiveness. Objective: This study examines the correlation between fatigue and oral health among US population. Method: Data were gathered from the 2015-2018 National Health and Nutrition Examination Survey (NHANES), a cross-sectional survey of adults aged 18 and above. The Patient Health Questionnaire-9 (PHQ-9) was used to assess and examine fatigue using a thoroughly validated assessment based on the Prime-MD diagnostic instrument. In NHANES, it is referred to as the Depression Screener Questionnaire (DPQ). The tooth count was established by clinical exams performed by qualified dentists. Logistic regression models were used to determine the relationship between tooth count and fatigue and adjusted for demographic characteristics, socioeconomic status, dental visits, multimorbidity and smoking status. Results: Of the 11,848 participants (mean age: 47.25 years), 52.94% experienced fatigue. The incidence of tooth loss was greater among individuals who reported being 3 fatigued. However, after accounting for demographic characteristics, socioeconomic status, mean poverty income ratio, and multimorbidity, the link between tooth loss and fatigue maintained its statistical significance (Odds Ratio ‘OR’ = 1.21, 95% Confidence Interval ‘CI’: 1.01-1.43). Model 3 found Participants who hadn't seen a dentist in over a year have more chance to experience fatigue (OR = 1.21, 95% CI: 1.04-1.39, p = 0.014). Conclusion: to conclude, having fewer teeth is linked to fatigue among American adults. To manage fatigue and its broader health effects, a multifaceted approach is needed, including regular dental care, reducing socioeconomic disparities, and assessing both physical and mental health. This integrated strategy can improve overall well-being and address the complex link between fatigue and oral health.
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The Effect of Input Enhancement and L1 Glosses on the Acquisition of English Phrasal Verbs
(University of Central Florida, 2024-08-02) Alotaibi, Abdulmajeed; Folse, Keith
This study aimed to investigate the effectiveness of input enhancement (IE) and native language (L1) glossing on second language (L2) learners’ receptive knowledge of English phrasal verbs (PVs) and explore whether learners’ L1 facilitates the effect of input enhancement on learning English PVs. A within-subject design was employed to examine the effect of IE with the aid of L1 glossing on learning PVs. Three short restaurant reviews were tested: one with the target items written in red (IE treatment), one with the target items written in red and glossed in the margin (IE + L1 glossing treatment), and a control text with the target items printed in normal black color without glossing. Sixty-four ESL students practiced the same 15 target words. However, the PVs were divided into three equivalent groups (A, B, C) of 5 PVs each, and participants practiced a given group of PVs under one of the treatment conditions. Afterward, the learners’ receptive knowledge of PVs was measured by a posttest. Results from a repeated measure ANOVA test revealed that students’ scores in both experimental conditions (IE and IE + L1 glossing) were significantly higher than the scores in the control condition, while no statistically significant difference was found between the two experimental conditions. Likewise, there was a statistically significant difference in the posttest scores based on participants’ L1, with Arabic students achieving higher scores than their Spanish-speaking peers. However, this finding should be interpreted with some caution because most Spanish speakers in this study were in the lower-intermediate level while many Arabic students were higher-intermediate learners. Finally, the results revealed that native language did not moderate the effect of the three practice conditions on students’ posttest scores. The current study presents several important implications for L2 instructors, learners, and curriculum developers as well as future researchers.
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