Study of the brain using structural magnetic resonance imaging
Randomly selected sub-samples of our midlife (431 participants) and older (478 participants) cohorts have undertaken magnetic resonance imaging (MRI) scans and provided blood samples. The data from this sub-study allows us to examine physical changes to the brain in later life and how they relate to other changes in cognition and mental health. Analysis of the brain has included measurement of the volume of brain structures (eg corpus callosum, hippocampus, amygdala, entorhinal cortex) and assessment of 'white matter hyperintensities' (small areas of dead or damaged brain tissue). The MRI sub-study was undertaken in collaboration with Professor Perminder Sachdev and colleagues from the Neuropsychiatric Institute, University of New South Wales. Our older subgroup have had MRIs at all four completed waves, while the midlife subgroup have had MRIs at waves two, three and four.
Health and memory study
Participants in the oldest age group (117 at Wave 1 and 138 at Wave 2) were selected on the basis of the physical and memory test results obtained in the wave one interview. These participants were invited to take part in a more detailed physical and neurocognitive assessment administered by a medical practitioner. Participants were also asked to have a brain MRI at wave one. This sub-study provides a more fine grained analysis of cognitive capacity and closer examination of relationships between changes in physical health and cognitive performance over time. At Wave 4, neurocognitive tests were added to the main PATH interview for the older cohort. At Wave 4, we also asked our participants to provide the name of a relative or good friend who subsequently provided information on the participant’s health and well-being.
In Wave 3, the midlife and older participants who took part in the 'study of the brain using MRI' at the previous assessment were invited to undergo a cardiovascular examination and to again have a brain MRI. Dr Walter Abhayaratna, a cardiologist at the Canberra Hospital and a researcher at ANU Medical School conducted this sub-study, which aims to evaluate the interrelationships between blood pressure, aortic stiffness, cardiovascular risk factors and conditions, and cognitive function in midlife.
Exercise, energy expenditure and healthy ageing
In Wave 4, our older MRI group were asked to wear an armband to record energy expenditure, physical activity patterns and sleep for one week. Participants were also asked to complete a diet diary during the week, and record types of activities they engaged in each day. The results from this research will allow us to identify associations between physical activity, energy expenditure, chronic disease, and cerebral and cognitive health in older adults. This sub-study has been undertaken in collaboration with the Faculty of Health, University of Canberra.
The eye as a window to the brain
In Wave 4, our older MRI group were also asked to take part in a study in which two colour photographs were taken of the back of both eyes (i.e. the retina) using a specialised retinal camera. One photograph was centred on the macula and one was centred on the optic disc. The aim of this research is to examine the relationship between vasculature in the retina of the eye and changes in the brain that have occurred over the previous 12 years of PATH as measured by MRI. This study also considers the effect of physical health and lifestyle factors on this relationship. This sub-study has been undertaken in collaboration with the Centre for Eye Research Australia.