Short-term memory can be defined as the capacity for holding a small amount of information in mind in an active state for a short period of time. Although some instruments have been developed to study spatial short-term memory in real environments, there are no instruments that are specifically designed to assess visuospatial short-term memory in an attractive way to children. In this paper, we present the ARSM (Augmented Reality Spatial Memory) task, the first Augmented Reality task that involves a user's movement to assess spatial short-term memory in healthy children. The experimental procedure of the ARSM task was designed to assess the children's skill to retain visuospatial information. They were individually asked to remember the real place where augmented reality objects were located. The children (N = 76) were divided into two groups: preschool (5–6 year olds) and primary school (7–8 year olds). We found a significant improvement in ARSM task performance in the older group. The correlations between scores for the ARSM task and traditional procedures were significant. These traditional procedures were the Dot Matrix subtest for the assessment of visuospatial short-term memory of the computerized AWMA-2 battery and a parent's questionnaire about a child's everyday spatial memory. Hence, we suggest that the ARSM task has high verisimilitude with spatial short-term memory skills in real life. In addition, we evaluated the ARSM task's usability and perceived satisfaction. The study revealed that the younger children were more satisfied with the ARSM task. This novel instrument could be useful in detecting visuospatial short-term difficulties that affect specific developmental navigational disorders and/or school academic achievement.

The cannabinoid receptor 1 gene (CNR1) has been associated with addictive disorders and schizophrenia in different studies. We have compared the frequencies of the alleles for the 3'-UTR CNR1 microsatellite in a sample of 113 Spanish schizophrenic patients, including 68 with comorbid substance abuse, and 111 healthy controls. We report that the frequency of the allele 4 of this microsatellite is significantly lower in schizophrenia patients when compared with controls (chi(2) = 7.858; df 1; P = 0.005). No differences have been found with respect to substance abuse.Thus, the allele 4 represents, in our sample, a protective factor against schizophrenia (odds ratio 0.468, 95% confidence interval (CI) 0.27-0.79). The population attributable genetic risk for the allele 4 absence is 30% (95% CI = 17-41%) and the attributable risk for the allele 4 absence in those with schizophrenia is 53% (95% CI = 20-73%). Our results suggest that, independent of substance abuse, differences in the cannabinoid system function could be involved in the vulnerability to schizophrenia in Spanish population.

This paper presents the MnemoCity task, which is a 3D application that introduces the user into a totally 3D virtual environment to evaluate spatial short-term memory. A study has been carried out to validate the MnemoCity task for the assessment of spatial short-term memory in children, by comparing the children’s performance in the developed task with current approaches. A total of 160 children participated in the study. The task incorporates two types of interaction: one based on standard interaction and another one based on natural interaction involving physical movement by the user. There were no statistically significant differences in the results of the task using the two types of interaction. Furthermore, statistically significant differences were not found in relation to gender. The correlations between scores were obtained using the MnemoCity task and a traditional procedure for assessing spatial short-term memory. Those results revealed that the type of interaction used did not affect the performance of children in the MnemoCity task.

Age differences during development in visuospatial short-term memory (VSTM) in navigation have not been sufficiently proven. The performance of typically developing children from five age groups (from 5 to 10 years old) and one group of young adults (from 25 to 30 years old) was studied in an Augmented Reality navigational VSTM task that involved remembering the location of objects presented in increasing span lengths. The main results showed that navigational VSTM has not fully developed at the age of 9. The measures of performance significantly improved between ages 8 and 9. The overall performance on our navigational task was not influenced by gender, but there was a slight advantage for males when the difficulty of the task increased regarding the performance accuracy and the errors committed. The Augmented Reality task correlated with traditional spatial tests. Possible cognitive, biological, and methodological explanations for the findings are discussed.

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