Significant effect of animal age category (A), d-galactose dose category (B), animal strain (C), and behavioural task (D) on the neurobehavioral score (NBS) measured using standardised mean differences (SMDs).

<p>Horizontal grey bars show the 95% CI of the global estimate of impairment in NBS and vertical error bars show 95% confidence interval (CI). The relative number of animals in each comparison has been presented using bar width.</p

Percentage of included studies for each item in modified version of the CAMARADES' study quality checklist.

<p>Percentage of included studies for each item in modified version of the CAMARADES' study quality checklist.</p

Timber plot of the effect size for each of the included comparisons evaluating impairment in the neurobehavioral score (NBS).

<p>Vertical error bars represent 95% confidence intervals (CI) and horizontal grey bars show the 95% CI of the global estimate of impairment in the NBS. The relative number of animals used in each comparison has been represented by symbol sizes.</p

Significant effect of animal age category (A), d-galactose dose category (B), animal strain (C), and administration duration (D) on the decrease in superoxide dismutase (SOD) level measured using standardised mean differences (SMDs).

<p>Horizontal grey bars show the 95% CI of the global estimate of the decrease in SOD level and vertical error bars show 95% confidence interval (CI). The relative number of animals in each comparison has been presented using bar width.</p

Literature selection summary showing the number of inclusions and exclusions from the initial search.

<p>In phase 1, the relevancy of the publications was assessed based on the title and abstract, however, in the phase 2 it was evaluated based on the main texts.</p