The relationship between task complexity and cerebral oxygenation in stroke patients

Fryer, Bradley James (2013-03)

Thesis (MSportSc)--Stellenbosch University, 2013.

Thesis

ENGLISH ABSTRACT: There are a growing number of men and women world-wide who are suffering strokes due to poor lifestyle-related habits. While there is evidence of the differences in cerebral haemodynamics between stroke patients and both elderly and young healthy individuals, limited evidence has examined the effect of rehabilitation on cerebral haemodynamics. Furthermore, most studies have examined changes in cerebral haemodynamics during cognitive and functional tasks in isolation, with no literature published on them simultaneously. The primary aim of this study was to examine whether differences in cerebral haemodynamics exist between stroke patients and healthy elderly individuals while performing a simple and complex cognitive task. Thirty two men and women (age 75 ± 8 years) volunteered to participate in the study and were split into an experimental (n = 14) group consisting of stroke patients and a control (n = 18) group consisting of healthy individuals. Each participant was required to attend one testing session where measurements of oxyhaemoglobin (O2Hb), deoxy-haemoglobin (HHb), tissue oxygenation index (TOI) and total haemoglobin index (THI) were obtained. Measurements were obtained with the participants at rest, while performing the Mini Mental State Exam (MMSE) and the modified Stroop Task as cognitive tests, and the Timed Up-and-Go (TuG) and six minute walk test (6MWT) or Toe Taps (TT) as the functional tests. Furthermore, the outcome scores of the various tests were also recorded. Change in O2Hb levels were lower in the experimental group than in the control group, especially in the left prefrontal cortex (LPFC) while HHb values were higher in the right prefrontal cortex (RPFC) (p > 0.05). There were almost no differences in TOI between the two groups in either the LPFC or RPFC, however, statistically significant differences were seen in THI in the RPFC during the MMSE (p = 0.03), rest period 2 (p = 0.03), the first modified Stroop Task (p = 0.04), as well as the TuG (p = 0.02). Furthermore, significant differences were seen between the two groups with respect to the time taken to complete the TuG, with the experimental group completing it much faster (p = 0.04). The experimental group participants who had received regular rehabilitation performed consistently better across most of the testing phases, with a number of practically significant findings. The results show that definite differences exist between stroke patients and healthy elderly individuals when performing a simple and complex task. The positive effect of low intensity exercise on task performance was clearly seen in both groups, and holds a great deal of practical significance for the development of exercise programmes for healthy individuals, as well as stroke patients. Furthermore, rehabilitation following a stroke has obvious benefits as shown by the positive results of the current study, however, limited research exists to validate these findings, highlighting the need for further research in this area.

AFRIKAANSE OPSOMMING: Daar is ʼn wêreld wye toename in die aantal mans en dames wat beroertes ondervind as gevolg van swak lewenstyl-verwante gewoontes. Alhoewel baie navorsing beskikbaar is oor die verskille in serebrale hemodinamika tussen beroerte pasiënte en bejaardes, asook jong gesonde individue, is daar ʼn beperkte aantal studies oor die effek van rehabilitasie op serebrale hemodinamika. Meeste van hierdie studies het die veranderinge in serebrale hemodinamika tydens kognitiewe of funksionele take in isolasie ondersoek, met geen literatuur waar die effek van albei gesamentlik gemeet word nie. Die hoofdoel van hierdie studie was om die verskille in serebrale hemodinamika tussen beroerte pasiënte en gesonde bejaardes, tydens die uitvoering van ʼn eenvoudige en komplekse kognitiewe taak, te ondersoek. Twee-en-dertig mans en vroue (ouderdom 75 ± 8 jaar) het aan die studie deelgeneem. Die eksperimentele groep (n = 14) het bestaan uit die beroerte pasïente en die kontrole groep (n = 18) was gesonde bejaardes. Elke deelnemer het een toets sessie bygewoon waartydens oksihemoglobien (O2Hb), deoksihemoglobien (HHb), weefsel oksigenasie indeks (TOI) en totale hemoglobien indeks (THI) gemeet is. Metings is tydens rus geneem, asook tydens die kognitiewe toetse, die “Mini Mental State Exam” (MMSE) en die gewysigde Stroop taak gemeet, en die funksionele toetse, naamlik die “Timed Up-and-Go” (TuG) en die ses minute loop toets (6MWT) of “Toe Taps” (TT). Die eksperimentele groep se O2Hb was laer as die kontrole groep, veral in die linker voor frontale korteks (LPFC), en die eksperimentele groep se HHb waardes was hoër in die regter voor frontale korteks (RPFC) (p > 0.05). Daar was geen statisties betekenisvolle verskille in TOI tussen die twee groepe nie, maar wel in die THI in die RPFC tydens die MMSE (p = 0.03), rusperiode twee (p = 0.03), die eerste gewysigde Stroop Taak (p = 0.04) en die TuG toets (p = 0.02). Die kontrole groep was statisties betekenisvol vinniger as die eksperimentele groep in die TuG toets (p = 0.04). Deelnemers in die eksperimentele groep wat gereelde rehabilitasie ontvang het, het konsekwent beter gevaar tydens die toets sessie, en ʼn aantal prakties betekenisvolle verskille is in sekere veranderlikes gevind. Die resultate dui aan dat daar wel ʼn verskil in serebrale hemodinamika bestaan tussen beroerte pasiënte en gesonde bejaardes terwyl hulle eenvoudige en komplekse take verrig. Die positiewe effek van lae intensiteit oefening op prestasie was duidelike sigbaar van beide groepe. Hierdie resultate is prakties betekenisvol as dit kom by die ontwikkeling van oefenprogramme vir gesonde individue asook beroerte pasiënte. Rehabilitasie na ʼn beroerte hou ooglopende voordele in soos aangedui deur die positiewe bevindinge van die huidige studie, hoewel daar beperkte navorsing beskikbaar is om hierdie bevindinge te staaf. Daar is dus ʼn behoefte vir verdere navorsing in hierdie gebied.

Please refer to this item in SUNScholar by using the following persistent URL: http://hdl.handle.net/10019.1/80371
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