Divergent effects of age on performance in spatial associative learning and real idiothetic memory in humans

This study focuses on age-related differences concerning two kinds of spatial memory assessed by: (1) Paired Associates Learning (PAL) test from the CANTAB Eclipse Battery and (2) Real Idiothetic Memory (RIM) test using real-life settings. Whereas PAL based on visuo-spatial associative learning, the RIM on idiothetic navigation supported by self-motion. Despite a clear age-related drop in PAL reported in existing studies, age-related differences in idiothetic navigation still remain unclear.

In our study 80 healthy volunteers were tested. They were classified according to their age into two groups, i.e. young subjects aged from 20 to 29 years of life and elderly subjects from 64 to 77 years. Each group consisted of 40 participants (20 male and 20 female).

In PAL test a computer program generated six or eight white boxes on the screen which started to open up successively for 3 s in a random order. One of them contained a visual pattern, whereas, the others were empty. Subjects were asked to remember the spatial location of the visual pattern and then touch the box in which it was previously presented. In the RIM test participants were asked to walk on the 3-m diameter arena in darkness in order to find a cue place and then to return to the start point. A white noise was switched on at entering the cue place and switched off at leaving this place.

Elderly subjects indicated poorer performance than their younger counterparts on the PAL. In contrast, for the RIM no clear age effect was evidenced. In both tests no gender effect was observed. A dissociation in age-related changes for these two tests indicates that visuo-spatial associative learning and idiothetic navigation may have different cognitive control which is probably rooted in an interplay of different brain structures.

Date of publication
2 November 2011