The purpose of the current thesis was twofold: (1) to examine various factors that might be contributing to age-related learning and memory deficits specifically related to the hippocampus, and (2) to validate our rat model of aging, employing a multilevel analysis. We found age-related deficits on both spatial and non-spatial hippocampus-dependent taks that were accompanied by structural alterations observed in vivo (volune, but not neuronal metabolic function) and post mortem (neuronal density and neurogenesis, but not synaptic or mitochondrial density). Furthermore, our results suggest that the observed hippocampal structural changes, named decreased volume and neurogenesis, predict learning and memory deficits, and both can be accounted for by neurogenic reduction. In addition, the above-mentioned pattern of age-related deficits closely resembles that seen in humans, suggesting the present rat version of aging to be a very useful model for investigating hippocampal aging in humans. / iii, 236 leaves : ill. (some col.) ; 29 cm.

This thesis explores the relationship between the needs people experience in later life and the types of care they receive. The thesis provides evidence on the role of different types of care in supporting the needs of people aged 60+ in England using the English Longitudinal Study of Ageing (ELSA). The research presented adopts a number of new approaches to capturing the multi-dimensional nature of dependency by utilising a range of binary indicators of difficulty performing 10 actions related to upper and lower body mobility, 6 activities of daily living (ADL) and 7 instrumental activities of daily living (IADL). The thesis provides a detailed analysis of the prevalence of these items when considered independently and collectively in combination. A central aim of the research is to develop a more nuanced understanding of dependency to allow for the dimensionality of the needs experienced by older people living in their own homes to be considered. The thesis utilizes a number of different approaches, including simple binary and count-based indicators of need and more complex measures reflecting dependency across different domains of need. These approaches allow a more dynamic picture of dependency in later life to be considered. Using these measures, the research explores the role of different types of care in meeting different types of need. Of these, a unique application of an existing assessment tool is presented, the Indicator of Relative Need (IoRN), which is used as a framework to derive an equivalent measure – the Array of Need (AoN). Given the aim of the study is to investigate the multi-dimensional nature of dependency, various data reduction approaches are used including principal components analysis. Finally, research from similar studies is acknowledged and work from the Survey of Health, Ageing and Retirement in Europe (SHARE) study is reproduced using ELSA. The thesis suggests that when considering the dependency needs experienced by older people living in the community, it is important to be aware that this group includes both less and more dependent older people. As such, developing a better understanding of the dynamic relationship between dependency and the receipt of informal and formal care may require more suitable measurements of dependency.

The focus of the study was two-fold, firstly to determine the effect of age on the capacity of manual materials handling workers and secondly to determine the effect of increasing task mechanisation on the workers’ responses to task demands. The first component of this study, namely Part I, 101 male and 12 female ‘unskilled’ manual workers – of various ages – from a brick manufacturing industry were assessed. Anthropometric, health and strength factors were measured to improve the understanding of the South African manual worker capacity and more specifically, the effect of age on this capacity. Data collection was done between 7.30am and 9.30am in a laboratory-type setting on-site. Anthropometric characteristics (including body mass index, waist to hip ratio, waist circumference and body fat percentage) provided information on the state of obesity and the impact of age in the South African context. Linked to this, the health factors (including blood pressure, resting heart rate and a self-reported questionnaire) provide an extra snapshot of the disease profile in South Africa, and could potentially influence other capacity factors. Isometric strength capacities (of eight different areas, namely: back, leg, bicep, shoulder, pinch, pinch and pull) demonstrated whether South African manual workers show the same decline in strength with aging as seen in industrially advanced countries. The second component of the study, Part II, was performed in situ and measured the workers’ responses to task demands of three brick palletising tasks, one manual (n=21) and two with increasing mechanisation (n=12 each). Spinal kinematics, joint forces and working heart rate were assessed on normal work days during a 30-lift duration and body discomfort measures were taken at the start, middle and end of the work-shift. Spinal kinematics were measured dynamically using a lumbar motion monitor, whereas the spinal forces were estimated using the three dimensional static strength prediction program. The worker capacity results showed that waist to hip ratio, waist circumference and body fat percentage increased significantly with aging, whereas body mass index was not affected by age. All body morphology values were within ‘normal’ ranges. Although diastolic blood pressure increased significantly with age, systolic was not affected significantly by age. Both groups, however, showed an increasing prevalence of hypertension with aging. There were no significant changes in resting heart rate with aging, with a range of 66 bt.min⁻¹ to 74.86 bt.min⁻¹, therefore within normal ranges. Of the strength factors, age only affected shoulder and push strength significantly: Showing a decrease in shoulder strength from 49.89 kgF to 39.91 kgF in the men aged 20-29 to the 50-59 respectively and an increase in push strength from men aged 30-39 and 40-49 to those aged 50-59. Part II results revealed highly frequent lift rates and large degrees of sagittal flexion and lateral bending in all three tasks. These postures adopted for long durations are likely to lead to the development of musculoskeletal disorders. Heart rates of workers from the three tasks were significantly different and heart rates for two tasks were above the recommended 110 bt.min⁻¹. Similarly the body discomfort ratings of the three tasks differed, although a common trend was seen in that lower back pain was the most commonly reported area of discomfort in all tasks. South African manual materials handling males did not show the same responses to aging as men from industrially advanced countries, calling for further research into these differences. Due to the high risks of the three tasks assessed, future research and interventions are required to reduce the risk of injury in the assessed tasks.