Imaging the effects of cognitive rehabilitation interventions: developing paradigms for the assessment and rehabilitation of prospective memory

Prospective memory (PM), the ability to remember to carry out future intentions and goals following a delay filled with other unrelated tasks is often compromised following brain injury and other psychological and psychiatric disorders affecting the frontal lobes. It has long been acknowledged that patients with frontal lobe lesions can show relatively intact performance in laboratory settings yet their everyday functioning in multitasking situations requiring PM may be severely impaired (Mesulam 1986). The last 15 years has seen a marked expansion into research and theoretical models of prospective memory and its neural basis with the findings from recent neuroimaging studies suggesting that Brodmann’s area 10 plays an important role in PM (Burgess et al., 2011). The aim of this thesis was to develop paradigms for assessing prospective memory that could be used to measure the behavioural and functional changes in the brain following brief cognitive rehabilitation interventions with the first part of the thesis (Chapters 2-4) investigating the convergent and ecological validity of computerised assessment measures of PM in a group of young and older neurologically healthy individuals, as well as in individuals with acquired brain injury. The second part of the thesis (Chapters 5 and 6) investigated the behavioural and neural changes associated with a brief PM intervention developed from the principles of Goal Management Training (Robertson 1996; Levine et al., 2000; 2012) and Implementation Intentions (Gollwitzer 1993; 1996). Chapter 1 provides a brief overview of the assessment and rehabilitation of PM. Chapter 2 assessed age related changes in performance on the computerised PM tests and a modified version of the Hotel Test (Manly et al., 2002) in a group of young and older neurologically healthy individuals. Both the computerised tasks and the modified Hotel Test (mHT) were found to be sensitive to the effects of ageing. Chapter 3 investigated the effects of a brief break filled with an unrelated task on performance on computerised PM tasks. A brief break was found to have a negative effect on performance with the amount of performance decay correlating with self-reported memory functioning. Chapter 4 assessed the convergent and ecological validity of the computerised PM tasks and their sensitivity to brain injury. The tasks were found to have good convergent validity with the mHT and the CAMPROMPT. The informant- and self-ratings of everyday memory and goal management functioning correlated with task performance in the ABI sample. Chapter 5 investigated whether brief intervention aimed at reducing PM lapses would be successful in improving performance on computerised PM task compared with a control training intervention. Chapter 6 investigated the functional changes in brain activation associated with this brief training. Significant behavioural improvements on the computerised PM tasks were seen following brief training with some evidence of transfer of the effect to a novel task. Significant changes in neural activations within Brodmann’s area 10 were seen following brief training in the trained group compared to the control group. The findings have implications for the assessment and rehabilitation of individuals with PM problems and are discussed in relation to cognitive theories of PM.