Relearning and retention of verbal labels in a case of semantic dementia

Abstract

Background: Previous studies looking at relearning and retention of word labels in people with semantic dementia have shown some improvement in naming immediately after the period of learning but this has not usually been maintained. Studies have also shown rigid learning of names, in the order of presentation and to the picture exemplars only, with no generalisation of learning.

Aims: This study aimed to explore relearning of a small vocabulary set in a person with semantic dementia (CUB) and to examine her ability to generalise this learning. In addition, it aimed to find out how long the learning persisted after therapy was completed given that semantic dementia is a progressive disorder.

Methods & Procedures: A single‐case design was used where CUB was asked to learn 28 words while a further 28 were left as controls. A “look and say” method was used daily for 1 month. As well as examining learning of the therapy and control set, CUB was asked to name 168 other exemplars of the learning set to see whether there had been any transfer of her learning from the therapy set.

Outcomes & Results: CUB not only relearned a set of picture names but retained these without deliberate practice over a 6‐month period. She was also able to generalise this learning to other visually similar exemplars in testing and in daily use. The maintenance of relearning was achieved despite severe deterioration in her semantic memory.

Conclusions: Possible reasons are explored as to why CUB was able to relearn and retain these words and why this may differ from all previously reported cases. Differences in amount of time spent relearning, number of items learned, therapy methods, the severity of semantic memory impairment, the degree of atrophy, and the behavioural profiles of people with semantic dementia do not provide adequate explanations for our individual's differential ability to retain her learning over 6 months. The most plausible explanation is that the person with semantic dementia generalised her learning to her everyday speech and this provided the source of maintenance for the relearned names.

This work was supported by a Royal Society Travel Fellowship awarded to K. Sage. We are grateful to Dr Tomás Ojea from the Hospital Carlos Haya, Málaga for referring CUB to us, and most importantly to CUB and her family for their collaboration throughout.

Keywords:

• Semantic dementia
• Anomia
• Relearning
• Generalisation
• Maintenance.

Notes

This work was supported by a Royal Society Travel Fellowship awarded to K. Sage. We are grateful to Dr Tomás Ojea from the Hospital Carlos Haya, Málaga for referring CUB to us, and most importantly to CUB and her family for their collaboration throughout.