To understand how falls occur during walking in older adults, we need to understand how the nervous system maintains stability, and how aging affects walking. Four studies were conducted to better understand the effect of age on gait. Older adults display higher gait variability compared to young adults, possibly because of their slower walking. We compared gait stability at multiple controlled walking speeds. Greater gait variability in healthy elderly existed independent of slower walking. Their diminished strength and flexibility partly explained this difference. To explain slower walking in the elderly, some have suggested that muscle weakness and stiffness may force people to walk slower. Others have suggested that people choose to walk slower to be more stable. We compared dynamic stability of gait at multiple speeds. Healthy older adults also exhibited more stability at slower speeds, yet walked at speeds comparable to young adults despite the lower strength and flexibility. Therefore, weakness and stiffness may not force healthy older adults to walk slower. The goal of the nervous system during walking may be to maintain stability of superior segments. We tested whether superior segments are more stable than inferior segments during walking. Superior segments exhibited less orbital stability during preferred walking speed, in contrast to previous suggestions. This highlighted the importance of trunk control during gait. The effects of aging on the fluctuations in the muscle activity during gait are not well understood. We quantified the stride-to-stride fluctuations of EMG as a measure of muscle activation patterns in state-space. Variability increased with speed except in the gastrocnemius. Orbital stability was less in older adults, suggesting that deviations in the EMG amplitude pattern were not readily corrected. Less local stability was seen in older adults, suggesting that older adults were more sensitive to perturbations. Together, these findings suggest that trunk control is important during gait. Strength and flexibility deficits help explain higher variability and lower stability in older adults. Future work will need to address the effect of strength interventions, neurophysiological decline on gait stability and fall risk.

published_or_final_version / Medical Sciences / Master / Master of Medical Sciences

Thesis (MSportwet)--University of Stellenbosch, 2002. / ENGLISH ABSTRACT: Proprioception is generally defined as the sense of position and movement of the limbs. The sense arises through activity in sensory neurons located in skin, muscles and joint tissues. Joint proprioception provides the neurological feedback needed for the control of muscle actions, and serves as protection against excessive strain on passive joints. The rationale for this study was that if proprioception improves, functional balance will improve. Improvements in functional balance will contribute to improvements in functional skills. An improvement in functional skills can decrease dependence on others, which in turn w\could increase quality of life. The objective of this study was to determine the effectiveness of a proprioceptive training programme, using only low technology apparatus, on the proprioception and functional balance of older adults. Twenty-five older adults (M = 73.1 years) were assigned to either a control (n = 10) or intervention group (n = 15). The Berg Balance Scale was used for assessment of the functional balance of the participants, while the Harrison’s Recovery Test was used to assess proprioception. The intervention group was placed on an eight-week proprioceptive training programme consisting of three, twenty-minute sessions a week. Using paired and unpaired t-tests for the statistical analysis, significant improvements were observed in the intervention group for both proprioception and functional balance (p<0.05). It was concluded that the proprioception and functional balance of older adults could be significantly improved with a proprioceptive programme using only low technology apparatus. / AFRIKAANSE OPSOMMING: Propriosepsie kan gedefinieer word as die liggaam se vermoë om die posisie en die beweging van die afsonderlike liggaamsdele waar te neem. Dit vind plaas deur die registrering van die aktiwiteit van sensoriese neurone wat in die vel, spiere en die sagte weefsel van die gewrigte is. Die neurologiese terugvoer wat noodsaaklik is vir die doeltreffende beheer van spieraksies, is afkomstig van die proprioreseptore in die gewrigte. Dit is as gevolg van hierdie neurologiese terugvoer, dat propriosepsie dien as beskermingsmeganisme teen oormatige stremming op die liggaam se gewrigte. Die beginsel van hierdie studie was dat as propriosepsie verbeter, dit sal lei tot verbeteringe in funksionele balans. Verbetering in funksionele balans sal weer lei tot verbeteringe in funksionele vaardighede. Dit is heel moontlik dat verbetering in funksionele vaardighede ‘n persoon minder afhanklik sal maak van ander. Hoe meer onafhanklik ‘n mens van ander is hoe beter is jou lewenskwaliteit, aangesien jy baie meer dinge kan ervaar en doen. Die doel van hierdie studie was om vas te stel of ‘n propriosepsie inoefenings program, wat slegs van lae tegnologiese apparaat gebruik maak, suksesvol gebruik kan word om die propriosepsie en ook die funksionele balans van ouer volwassenes te verbeter. Vyfen- twintig ouer volwassenes (M = 73.1 jaar) het deelgeneem aan die studie en was òf deel van die kontrole group (n = 10) òf van die oefen groep (n = 15). Funksionele balans is gemeet deur van die “Berg Balance Scale” gebruik te maak, terwyl die “Harrison’s Recovery Test” gebruik is om propriosepsie te meet. Die oefengroup het deelgeneem aan ‘n propriosepsie oefenprogram wat bestaan het uit drie, oefensessies van twintig minute elk vir ag weke. Gepaarde en ongepaarde t-toetse is gebruik gedurende die statistiese analise. Die resultate was statisties betekenisvol vir beide die propriosepsie en die funksionele balans van die oefen groep (p<0.05). Die studie het getoon dat die propriosepsie en funksionele balans van ouer volwassenes statisties betekenisvol verbeter kan word deur middel van ‘n inoefeningsprogram vir die verbetering van propriosepsie waar slegs van lae tegnologiese apparaat gebruik maak word.

The purpose of this thesis was to compare the contributions of attentional resources relevant to postural control between fall-fearful and non-fearful older adults. Levels of postural challenge and instructions of task prioritization were manipulated to obtain this goal. Results indicated that fall-fearful subjects demonstrated a reorganization of attentional resources when challenge to upright standing was imposed. Additionally, only non-fearful subjects demonstrated flexibility in the prioritization of the cognitive task. However both fall-fearful and non-fearful subjects demonstrated flexibility in the prioritization of the postural task. Findings suggested that fall-fearful older adults reorganize the allocation of attentional resources differently than non-fearful counterparts, potentially placing them at greater risk for falling as their awareness of the external environment and threats to balance may be compromised. / xii, 80 leaves : ill. ; 29 cm

The purpose of this thesis was to investigate the influence of postural anxiety on the capacity for Flexible Resource Allocation (FRA) among younger (YA) and older adults (OA). Two experiments were conducted to explore (a) the influence of heightened postural anxiety on the flexible allocation of attention among OA and (b) the influence of concurrent postural challenge and postural anxiety on FRA among YA. Participants performed a postural task concurrently to a cognitive task according to three instructional sets directing task priority. Experiment one revealed that FRA was compromised among OA during circumstances of heightened anxiety. This capacity however, remained available among YA. Therefore, for the second experiment I varied the support surface to explore whether the capacity for FRA could be sustained when posture was challenged beyond static stance. Results indicated that YA altered cognitive task performance according to instructional set without compromising postural stability. These findings suggest that even when posture is challenged during heightened postural anxiety, YA maintain the capacity to automatically allocate attention to a postural task while performing a secondary task. Conversely, it seems that heightened postural anxiety strengthens the attentional bias to posture and subsequently compromises FRA among OA. Overall, results from this thesis suggest that the capacity for FRA is age and situation dependent. / xi, 107 leaves : ill. ; 29 cm

This study presented an overview of the use of Photovoice technique as an information gathering tool that is useful in the study of aging. The processes followed in this study lead to a possible method that could be helpful when assessing needs as they relate to activities of daily living as well as wellness information for individuals. The photos collected in this study along with first person accounts of the pictures enhanced the breadth and depth of information when compared to a traditional survey tool used to study activities of daily living. This study looked at the phenomenon of staying vital in ones home in the later stages of the life span from the perspective of the person living in the situation. / Fisher Institute for Wellness and Gerontology

Over the next decade the ‘Baby Boomer' cohort will increasingly contribute to the proportion of those aged 60 and over in Britain. The issue of how the mobility of older people has changed for different cohort groups has not been considered in a historical context. Ryder (1965) argued that cohort groups could be important in determining behaviour as have other social structural factors, such as socioeconomic status. This thesis merges the disciplines of transport geography and population studies using a novel approach of cohort analysis, which has not been used widely for studying mobility trends. Using National Travel Survey data from 1995-2008, the mobility trends of older people in Britain are explored by creating pseudo cohorts. Pseudo cohorts are artificially created datasets which are constructed from using repeated cross-sectional data (McIntosh, 2005, Uren, 2006). This technique can differentiate ‘age', ‘period' and ‘cohort' effects in mobility trends. Age effects are differences in behaviour between age groups i.e. changes in mobility associated with age itself. Period effects relate to changes in behaviour in all age groups over a period of time. Cohort effects are those associated with behaviour common to particular groups born around the same time (Glenn, 2005, Yang, 2007). The influence of the Scottish concessionary travel policy on the mobility of older people at the aggregate level is also considered using Scottish Household Survey data from 1999-2008. This policy is very blunt and based on assumptions about older age. As cohorts differ, these assumptions may no longer hold and therefore the policy may not be effective. This thesis argues, using a longitudinal demographic perspective, that structural effects shape mobility of cohorts differently over time. The findings reveal although mobility amongst older people is rising in general, there would actually be declining mobility were it not for the Boomer cohort. Amongst younger cohorts mobility is lower. The analysis also shows that women travel further than men, a fundamental break with the past, specific to this generation. This thesis illustrates the importance of cohort membership in explaining mobility change.

This study examined the influence of three predictor variables on perceptions of assisted living: psychological well-being, functional status, and coping strategies. A multiple regression analysis was used to examine the influence of these factors on perceptions of the transition to assisted living.