Contrasting patterns of memory span decrement in ageing and aphasia.

As compared with young adult controls, elderly subjects matched for verbal ability showed only a minor deficit in mean auditory letter memory span but proportionately more dependence upon the occurrence of letter groupings prevalent in the written language. An aphasic group that also had a relatively limited mean letter span conversely made no detectable use at all of such groupings. These findings suggest that the aged tend if anything towards undue assimilation of information into preformed schemata, while aphasics accommodate to individual messages without evidence of such organization.