A matter of precision? Scene imagery in individuals with high-functioning autism spectrum disorder.

The ability to create mental representations of scenes is essential for remembering, predicting, and imagining. In individuals with autism spectrum disorders (ASD) this ability may be impaired. Considering that autistic characteristics such as weak central coherence or reduced communication abilities may disadvantage autistic participants in traditional imagery tasks, this study attempted to use a novel task design to measure the ability of scene imagery. Thirty high-functioning adults with ASD and 27 non-autistic matched control adults were asked to describe imagined fictitious scenes using two types of scene imagery tasks. In a free imagery task, participants were asked to imagine a scene based on a given keyword. In a guided imagery task, participants had to imagine a scene based on a detailed description of the scene. Additionally, narrative abilities were assessed using the Narrative Scoring Scheme. Statistical analyses revealed no group effects in the free and guided imagery of fictional scenes. Participants with ASD performed worse than control participants in the narrative task. Narrative abilities correlated positively with performance in both imagery tasks in the ASD group only. Hence, individuals with ASD seem to show as good imagery abilities as non-autistic individuals. The results are discussed in the light of the differences between imagery and imagination and possible gender differences.

Enhanced spatial navigation skills in sequence-space synesthetes.

Individuals with sequence-space synesthesia (SSS) perceive sequences like months, days and numbers in certain spatial arrangements. Several cognitive benefits have been associated with SSS, such as enhanced mental rotation, more vivid visual imagery and an advantage in spatial processing. The current study aimed to further investigate these cognitive benefits, focusing on spatial navigation skills, to explore if their enhanced sensitivity to spatial relations is reflected in enhanced navigational performance. Synesthetes were distinguished from controls by means of a questionnaire, a consistency test and drawings. A virtual Morris Water Maze (MWM) task with two allocentric and two egocentric navigation conditions was used to assess spatial navigation abilities. For the allocentric tasks, participants had to use object cues to find a hidden platform and for the egocentric tasks, they had to use their own position as a reference. Results showed that synesthetes performed significantly better compared to controls on the allocentric and egocentric tasks that reflected real life situations more accurately. However, this significant result was only found for the time taken to find the platform and not for the length of the path that was taken. In exploratory analyses, no significant relations were found between task performance and the specific features of the manifestation of each individual's synesthesia. Our hypothesis that synesthetes with the ability to mentally rotate their spatial arrangements would perform better on the allocentric task was not confirmed. Results add to the growing body of literature concerning the cognitive benefits of SSS and are consistent with the possibility that enhanced spatial navigation skills emerge from generally enhanced visuospatial abilities in SSS.

Memory training effects in old age as markers of plasticity: a meta-analysis.

In most studies on plasticity using behavioural data, cognitive plasticity has been studied in the context of short-term interventions such as memory training. In order to systematically review the literature on memory training and summarize its effects for old healthy people and people with mild cognitive impairment on multiple functional domains, we conducted a meta-analysis of all published randomized controlled trials (RCT) between 1970 and 2007. Overall, 24 studies examining memory training effects in healthy and in mildly cognitively impaired old adults were identified and included in the analysis. Only memory trainings (e.g. memory skills training, imagery, method of loci) with cognitive outcome measures, duration of intervention with up to one year with at least a baseline and a post-intervention assessment reported, were included. Results demonstrate significant training effects for paired associate learning and immediate and delayed recall in healthy old adults and for immediate recall in mildly cognitively impaired old adults. However, training effects were no larger than those found for active control conditions. Our results suggest that evidence on the effectiveness and specificity of training interventions is scarce. We discuss limitations of existing knowledge about the efficacy of memory training interventions and implications for future research to improve knowledge regarding effective cognitive interventions.