HIV-associated episodic memory impairment: evidence of a possible differential deficit in source memory for complex visual stimuli

Abstract

HIV infection is often associated with frontal systems pathology and related deficits in the strategic encoding and retrieval aspects of episodic memory. However, no prior HIV studies have explicitly examined source memory, which refers to recall of information regarding the context in which a declarative memory was formed. Source memory is heavily reliant on frontal systems and strategic cognitive processes and is singly dissociable from the content of the memory (i.e., item memory), which is more dependent on medial temporal systems and automatic processes. The present study examined item and source memory in 60 individuals with HIV infection and 35 demographically similar seronegative participants. The primary finding of interest was a significant HIV effect on source (but not item) memory for complex visual stimuli. Follow-up correlational analyses showed a significant association between visual source memory errors and impairment on measures of executive functions, working memory, and higher-level list learning encoding strategies. These findings extend the hypothesized profile of strategic encoding and retrieval deficits in HIV to the construct of source memory, which may be differentially affected relative to item memory for complex visual stimuli.

Figure 1

Stimuli examples from the Self Ordered Pointing Task (Panel A) and the item and source memory post-test (Panel B).

Figure 2

Verbal (Panel A) and visual (Panel B) item and source memory errors in the HIV (n = 60) and seronegative comparison (SC; n = 35) groups. Data represent the mean with SEM error bars. SOPT = Self Ordered Pointing Task. * p < .10. ** p < .05.