Computer based rehabilitation of cognition

Abstract

Research Doctorate - Doctor of Philosophy (PhD)Background: The challenges posed for computerised cognitive training recently are lack of generalization of learned skills as well as maintenance effects. These could be due to not targeting the right cognitive deficit that influences deficits in everyday functioning. This dissertation examined whether training of targeted impaired cognition achieves the intended aims of enhancement, generalization, and sustainability of training effects among people with schizophrenia and healthy aging. Therefore, verbal memory was not targeted in computer based cognitive training in the schizophrenia sample due to the assumption that deficits in verbal memory are underpinned by other cognitive skills. Unlike schizophrenia, broad cognitive skills were targeted in a healthy ageing group. The thesis also aimed to examine whether there is evidence of neuroplasticity following training via electrophysiological measures namely Mismatch Negativity (MMN) and P300 indices. Methodology: Two different experimental designs were used to achieve the aim s of the study. Both studies employed Cogpack software, a computerised cognitive training package. A simple pre- and post-experimental study with a three month follow-up was conducted to determine the efficacy of non-verbal-memory computerised cognitive training (cognitive training that did not include verbal memory) in improving cognition in schizophrenia patients. A randomised waitlist control group was used to evaluate the effect of broad computerised cognitive training in a healthy elderly population. Participants were randomised to an immediate training or a waitlist group and attended baseline assessments. For the immediate group, a 4 week cognitive training period commenced a week after baseline assessments while the waitlist group were assessed for a second time approximately 4 weeks after the initial assessment and then commenced the training program. Both groups were reassessed after completion of Cogpack training and again after three months. Both schizophrenia and healthy ageing people attended three consecutive EEG recordings: baseline, post treatment and 3 month follow-up. Similar to the EEG testing, all participants attended three consecutive neuropsychological testing sessions with the exception being the waitlist group in the ageing study whom attended 4 testing sessions to determine the effects of test practice. Results: Significant improvement on targeted cognitive processes was seen following the training. Generalization to untrained tasks was also evident specifically social cognition evident for groups as well as verbal memory and learning in the schizophrenia study. The training gains were in general maintained at three month follow-up for both groups but there was little evidence of further improvement at follow-up. Practice effects were seen in both executive function and social cognition tasks. Discussion: Participants in both studies tolerated training with Cogpack well. Despite different training exercises being used, these findings provide evidence that Cogpack significantly improved targeted cognition and generalization to other tasks in both schizophrenia and healthy ageing. Effects of training were evident although no effects on electrophysiological measures were found which suggested limited neuroplasticity following the training. There is a need to reduce the mismatch between the individual’s capacities and demands of training tasks to improve core cognitive impairments and promote generalization of learned skills. Further research needs to take account of an individual’s cognitive reserve and develop adaptive computerised cognitive training that can promote neuroplasticity