Autobiographical memory and cognitive theory of mind in non-mild cognitive impairment Parkinson’s patients.

The current study examined autobiographical memory and theory of mind (ToM), both of which are associated with overlapping subsystems in the default mode network, in a group of Parkinson’s disease (PD) patients who were characterised as not representing a stage of mild cognitive impairment, but at risk of future cognitive decline. The Autobiographical Memory Interview (AMI), which separately measures both personal episodic memory and personal semantic memory across the lifespan, was used for the first time in PD; a card sequencing task measured cognitive Theory of Mind (ToM) in these patients. Twenty non-MCI PD participants (18 above a threshold of 29% risk of future cognitive decline and 2 below this threshold) were compared with 15 healthy age and education matched controls (HC). PD participants showed significantly poorer personal episodic memory but unimpaired personal semantic memory, but neither measure was related to the cognitive risk score. Similarly their impaired ToM scores were unrelated to their risk scores. However, the Brief Visuospatial Memory Test showed a greater effect size than any other measures, and performance in the PD group was associated with the risk score, suggesting it may be a useful addition to improving a risk score in this patient group. Future research should examine these measures in larger sample sizes and in PD-MCI and PDD groups, and evaluate their MRI correlates. PD patients who do not meet criteria for PD-MCI nonetheless show a subtle range of cognitive changes, but only a subset may be useful predictors of significant decline in cognition