Arithmetic learning in advanced age

<div><p>Acquisition of numerical knowledge and understanding of numerical information are crucial for coping with the changing demands of our digital society. In this study, we assessed arithmetic learning in older and younger individuals in a training experiment including brain imaging. In particular, we assessed age-related effects of training intensity, prior arithmetic competence, and neuropsychological variables on the acquisition of new arithmetic knowledge and on the transfer to new, unknown problems. Effects were assessed immediately after training and after 3 months. Behavioural results showed higher training effects for younger individuals than for older individuals and significantly better performance after 90 problem repetitions than after 30 repetitions in both age groups. A correlation analysis indicated that older adults with lower memory and executive functions at baseline could profit more from intensive training. Similarly, training effects in the younger group were higher for those individuals who had lower arithmetic competence and executive functions prior to intervention. In younger adults, successful transfer was associated with higher executive functions. Memory and set-shifting emerged as significant predictors of training effects in the older group. For the younger group, prior arithmetic competence was a significant predictor of training effects, while cognitive flexibility was a predictor of transfer effects. After training, a subgroup of participants underwent an MRI assessment. A voxel-based morphometry analysis showed a significant interaction between training effects and grey matter volume of the right middle temporal gyrus extending to the angular gyrus for the younger group relative to the older group. The reverse contrast (older group vs. younger group) did not yield any significant results. These results suggest that improvements in arithmetic competence are supported by temporo-parietal areas in the right hemisphere in younger participants, while learning in older people might be more widespread. Overall, our study indicates that arithmetic learning depends on the training intensity as well as on person-related factors including individual age, arithmetic competence before training, memory, and executive functions. In conclusion, we suggest that major progress can be also achieved by older participants, but that interventions have to take into account individual variables in order to provide maximal benefit.</p></div

Descriptive statistics of the analysis of transfer effects.

<p>Descriptive statistics of the analysis of transfer effects.</p

Schematisation of the study procedure.

<p>Schematisation of the study procedure.</p

Statistical parametric mapping (<i>t</i>) intensity projection maps rendered onto a stereotactically normalized MRI scan, showing a voxel cluster of the significant interaction of increases of both grey matter volume and training effects in response accuracy for the younger group vs. the older group (statistical significance is thresholded at <i>p</i> < .001, FWE <i>p</i> < .05 corrected at the cluster level).

<p>The number at the bottom right corner of each MRI scan corresponds to the z coordinate in MNI space. The right side of the image corresponds to the right side of the brain.</p

Mean percentage of correct answers (panel a) and mean reaction times in correct trials (panel b) as a function of training session (S1, S2, S3, S4, S5) and group (younger adults, older adults).

<p>Bars indicate the standard error of the mean.</p

Significant results of a Pearson correlation analysis for each age group separately.

<p>Significant results of a Pearson correlation analysis for each age group separately.</p

Brain regions showing a positive correlation between training effects in response accuracy and brain volume for the younger group, and for the contrast younger group vs. older group.

<p>Brain regions showing a positive correlation between training effects in response accuracy and brain volume for the younger group, and for the contrast younger group vs. older group.</p

Association of gait disorders and neurological gait disorders with quality of life.

<p>Abbreviations: GD, Gait disorders.</p><p>The self administered WHO Quality of Life-BREF questionnaire assesses the general quality of life and health as well as the QoL in the four domains physical health, psychological health, social relationships, and environment. Results are reported in mean transformed scores (where 100 points represent maximum of respective item, ± standard deviation); P values refer to differences to the group without GD and are corrected for age and gender.</p

The R2* maps are derived from the substantia nigra of a representative healthy control and several PD patients with increasing disease duration as given on the upper margin of each image.

<p>Images belong to the same subjects included in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0145493#pone.0145493.g005" target="_blank">Fig 5</a>. The white arrows point out increased signals on R2* maps, indicating iron overload. With increasing disease duration the areas of elevated R2* become inhomogeneous.</p

Odds ratios of recurrent falls for the various types of gait disorders and gait speed.

<p>Abbreviations: GD, Gait disorders; OR, odds ratios.</p><p>OR are calculated by logistic regression analysis and corrected for age, gender and MMSE-scores.</p>a<p>Numbers too low in the respective category for the calculation of the ORs.</p>b<p>For continuous variables ORs were calculated for a one standard deviation unit change in variable levels in order to render odds comparable.</p