Long-term memory: A review and meta-analysis of studies of declarative and procedural memory in specific language impairment

Abstract

This review examined the status of long-term memory systems in specific language impairment (SLI), in particular declarative memory and aspects of procedural memory. Studies included in the review were identified following a systematic search of the literature and findings combined using meta-analysis. This review showed individuals with SLI are poorer than age matched controls in the learning and retrieval of verbal information from the declarative memory. However, there is evidence to suggest that the problems with declarative learning and memory for verbal information in SLI might be due to difficulties with verbal working memory and language. The learning and retrieval of non-verbal information from declarative memory appears relatively intact. In relation to procedural learning and memory, evidence indicates poor implicit learning of verbal information. Findings pertaining to nonverbal information have been mixed. This review of the literature indicates there are now substantial grounds for suspecting that multiple memory systems may be implicated in the impairment.

Figure 1. Effect sizes of studies examining declarative learning for verbal information in SLI using list learning/retrieval tasks.

Figure 2. Effect sizes of studies examining declarative learning for non-verbal information in SLI using learning/retrieval tasks.

Figure 3. Effect sizes of studies examining retrieval of verbal information from declarative memory in SLI.

Figure 4. Effect sizes of studies examining retrieval of non-verbal information from declarative memory in SLI.

Figure 5. Effect sizes of studies investigating implicit learning and memory of verbal and non-verbal information.