Full metadata record
| DC Field | Value | Language |
|---|---|---|
| dc.contributor | Department of Health Technology and Informatics | en_US |
| dc.contributor.advisor | Ying, Michael (HTI) | en_US |
| dc.contributor.advisor | Pang, Marco (RS) | en_US |
| dc.contributor.advisor | Chen, Fiona (HTI) | en_US |
| dc.creator | Gunda, Simon Takadiyi | - |
| dc.identifier.uri | https://theses.lib.polyu.edu.hk/handle/200/13707 | - |
| dc.language | English | en_US |
| dc.publisher | Hong Kong Polytechnic University | en_US |
| dc.rights | All rights reserved | en_US |
| dc.title | A study to investigate the effects of aerobic exercise training (AET) on the large intracranial and extracranial cerebral arteries and the cognitive and motor functions in post stroke patients | en_US |
| dcterms.abstract | Stroke is a leading cause of morbidity and mortality worldwide, including in Hong Kong, where it ranks as the fourth leading cause of death, accounting for over 6.2% of deaths in 2020. To mitigate the socioeconomic burden due to stroke, robust preventative and treatment management strategies are required. Aerobic exercise training (AET), a non-invasive therapeutic intervention has potential to improve the deconditioned haemodynamic, motor, and cognitive functions associated with stroke. However, limited studies have assessed its effects on cerebrovascular status in post stroke patients. The present study assessed the effects of AET on cerebral arteries' morphological and haemodynamic features, and on cognitive and motor function in chronic post-stroke patients. The study also compared transcranial Doppler ultrasound (TCD) and transcranial color-coded Doppler ultrasound (with (cTCCD) and without (ncTCCD)) angle correction in assessing haemodynamic features of the middle cerebral arteries (MCAs). Furthermore, cerebral arteries structural and hemodynamic features of post-stroke patients and age-matched non-stroke individuals were compared. | en_US |
| dcterms.abstract | Study One compared non-imaging transcranial Doppler ultrasound (TCD) and transcranial color-coded Doppler ultrasound (with (cTCCD) and without (ncTCCD)) angle correction in quantifying middle cerebral arteries (MCAs) haemodynamic parameters. This was a cross-sectional study involving 50 healthy adults aged ≥ 18 years old. The bilateral MCAs were insonated via three trans-temporal windows (TTWs-anterior, middle, and posterior) using TCD, cTCCD, and ncTCCD techniques. The MCA peak systolic velocity (PSV) and mean flow velocity (MFV) were recorded at proximal and distal imaging depths that could be visualised on TCCD with a detectable spectral waveform. A total of 152 measurements were recorded in 41 (82%) subjects with at least one-sided open TTW across the three techniques. The mean PSV measured by TCD, ncTCCD, and cTCCD were 83±18 cm/s, 81±19 cm/s and 93±21 cm/s, respectively, and cTCCD yielded significantly higher PSV than TCD and ncTCCD (Bias =-10cm/s, p<0.001; Bias =-12cm/s, p=<0.001, respectively). In conclusion, the study validated TCCD as a practically applicable imaging technique in assessing MCAs blood flow velocities, whereas TCCD with angle correction (cTCCD) yielded higher and more accurate MCA blood flow velocities than non-imaging TCD and ncTCCD techniques. | en_US |
| dcterms.abstract | Study Two compared the morphological and hemodynamic features of cerebral arteries between post-stroke patients and age-matched controls without a history of stroke. This was a cross-sectional study involving a total of 124 participants (57 post-stroke patients and 67 age-matched non-stroke controls) carried out at the Institutional laboratories. The study explored potential stroke risk biomarkers that could posit as post stroke AET rehabilitation efficacy indicators in the subsequent main RCT study based on novel ultrasound-based techniques, such as 3D arterial analysis, enhanced edge detection algorithms, and arterial stiffness measurements. Mean differences (MD) between post stroke and non-stroke cerebral arteries parameters represented main outcomes. The carotid β-stiffness index (CAS β), elastic modulus (CAS kPa), and pulse wave velocity (CAS PWV) were significantly higher for post stroke patients compared to non-stroke individuals (CAS β: 15.8±26.7 vs 9.3±7.7, p=0.013; CAS kPa: 208.9± 333 kPa vs 123.7± 112kPa, p=0.006, and CAS PWV: 7.8± 3.9m/s vs 6.5± 2.2 m/s, p=0.002), respectively. Conversely, carotid compliance (CAS CC) and distensibility coefficient (CAS DC) for post stroke group were lower compared to non-stroke individuals (0.476±0.27 vs 0.739±0.67, p<0.001; and 0.009 ± 0.006 vs 0.013±0.014, p=0.003). The 3D carotid lumen volume stenosis (%) did not differ between the two groups, indicating that hemodynamic failure due to stenosis is unlikely to be the primary mechanism of stroke occurrence in the study population. Furthermore, post stroke patients exhibited reduced blood flow compared to non-stroke individuals, in both extra and intracranial cerebral arteries (all DCCA parameters, p<0.05; ICA EDV, p=0.022; MCA PSV, p=0.001; MCA EDV, p<0.001 and MCA MFV, p<0.001). | en_US |
| dcterms.abstract | In conclusion, this study highlighted morphological features- CIMT, and all arterial stiffness indices to be significant biomarkers of stroke risk and indicators for monitoring treatment efficacy. Furthermore, population-based reference values for 3D ultrasound carotid lumen volume stenosis (%) and novel carotid arterial stiffness indices are provided for local non-stroke and post-stroke populations. | en_US |
| dcterms.abstract | Study Three assessed the effects of AET on the large intracranial and extracranial cerebral arteries' morphological and haemodynamic features, and on cognitive and motor functions in chronic post-stroke patients. This was a single-blinded randomized controlled trial involving 42 post-stroke patients randomly assigned into either—36 sessions, 3times per week, 30 minutes duration, supervised cycling AET (n=21) or stretching (control) exercises (n=21). Pre and post interventional cerebral arteries' morphological and haemodynamic features were assessed using novel duplex carotid ultrasound (DCUS) applications and transcranial color-coded Doppler (TCCD) ultrasound, whereas Montreal cognitive assessment Hong Kong version (Moca-HK) tool assessed cognition. Mean differences (MD) between pre and post AET values represented study main outcomes. The study demonstrated that 36 sessions of cycling AET targeting high intensity HRR conducted over a 12-week period, elicited significant beneficial changes in cerebral arteries' morphological and functional features— carotid intima-media thickness (CIMT), mean difference (MD)=-0.069, p<0.0001; 3D carotid lumen volume stenosis (%), MD =-2.4, p<0.001; 3D plaque volume, MD =-60mm3, p=0.001; 3D carotid vessel wall volume, MD=-55, 0.031*, and all arterial stiffness indices highlighted in Study 2, p<0.05). Additionally, modest improvements in extracranial cerebral arteries' haemodynamic parameters— (DCCA EDV, MD=1.64, p=0.003; DCCA RI, MD=-0.035, p<0.001, DCCA PI, MD=-0.15, p=0.001); (ICA RI, MD=-0.05, p=-0.001 and ICA PI, MD=-0.2, p<0.001) were observed. Contrarily, no changes in MCA haemodynamic parameters (PSV, EDV, MFV, PI and RI) were observed, suggesting a well functional cerebral thermoregulation mechanism. The study further revealed significant medium effects size improvements on cognitive function (MoCA-Hk, MD=1.38, p=0.006, cohen d=0.63) and motor function (6MWT, mean difference=37m, p=0.002, cohen d=0.72 and TUG time, M. D= -2.84s, p=0.004, cohen d=0.53). Changes in cerebral arteries' morphological and haemodynamic features were observed not to be directly associated with the cognitive functional changes, except for DCCA EDV (Spearman's R=0.330, p=0.033*) suggesting the presence of some indirect mechanisms. | en_US |
| dcterms.abstract | In summary, cycling AET elicited significant beneficial effects on cerebrovascular health, cognitive and motor function in chronic post stroke patients. Noteworthy, was improvement of cerebral arteries' features to values comparable or better than those of age-matched non-stroke individuals. The current study findings have significant clinical implications suggesting cycling AET as game changer in mitigating the deconditioned cerebral arteries vascular status and improving quality of life in post stroke patients. Further studies to explore possible indirect underlying mechanisms and investigate long-term effects of AET in mitigating against future stroke recurrences are recommended. | en_US |
| dcterms.extent | xviii, 245 pages : color illustrations | en_US |
| dcterms.isPartOf | PolyU Electronic Theses | en_US |
| dcterms.issued | 2025 | en_US |
| dcterms.educationalLevel | Ph.D. | en_US |
| dcterms.educationalLevel | All Doctorate | en_US |
| dcterms.LCSH | Cerebrovascular disease -- Patients -- Rehabilitation | en_US |
| dcterms.LCSH | Aerobic exercises | en_US |
| dcterms.LCSH | Cerebral arteries | en_US |
| dcterms.LCSH | Motor ability | en_US |
| dcterms.LCSH | Hong Kong Polytechnic University -- Dissertations | en_US |
| dcterms.accessRights | open access | en_US |
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