Theoretically derived CVLT subtypes in HIV-1 infection: Internal and external validation

Abstract

The present study sought to delineate empirically derived memory subtypes using the California Verbal Learning Test (CVLT; Delis et al., 1987) in a sample of adults with HIV-1 infection (N 5 154). Confirmatory factor analysis was used to evaluate eight models of the CVLT structure suggested by Wiegner and Donders (1999). A four-factor model, consisting of Attention Span, Learning Efficiency, Delayed Recall, and Inaccurate Recall appeared to be the best fitting model. Variables with the highest factor loadings from the model were entered in a two-stage cluster analysis. Four reliable CVLT clusters or subtypes were identified: Normal, Atypical, Subsyndromal, and Frontal-striatal. Internal and external validation of subtypes demonstrated that clusters were stable and clinically interpretable. Subtypes were meaningfully related to neuropsychological functioning, and to some extent, depressive symptomatology. Subtypes did not differ significantly with respect to subjective neurocognitive complaints and markers of HIV-1 disease. The present findings highlight the heterogeneity of memory profiles in HIV-1 infection and support a frontal-striatal conceptualization of verbal memory performance. The identification of robust HIV-1 memory subtypes may have important implications for the clinical management of adults infected with HIV-1 infection. (JINS, 2003, 9, 1-16.)

Prospective Memory in HIV-1 Infection

“…In support of this interpretation, the HIV-1 group performed comparably to the HC sample on the recognition task, which indicates that reducing the self-initiated retrieval demands of the task allowed the HIV-1 group to more effectively identify the correct intention and cue. This pattern of ProM retrieval difficulties is consistent with the episodic learning and retrieval profile that has been consistently identified in HIV-1 disease on traditional retrospective recall tasks (e.g., Murji et al, 2003). Specifically, persons with HIV-1 often exhibit dysfunction in the strategic or "executive" aspects of both retrospective and prospective episodic memory tasks, but not in consolidation.…”

“…By way of comparison, retention (i.e., consolidation) and recognition discrimination are less commonly affected in persons with HIV-1 disease (e.g., Delis et al, 1995). Taken together, the memory profile of HIV-1-infection is most consistent with dysfunction in the strategic (i.e., executive) aspects of encoding and retrieval as seen in prototypical "subcortical" disorders, such as Parkinson's and Huntington's diseases (e.g., Massman, Delis, Butters, Levin, & Salmon, 1990;Murji et al, 2003). To date, however, the scope of episodic memory research in HIV-1 disease has been limited to studies of retrospective memory (i.e., memory for past events and experiences).…”

“…Deficient episodic (i.e., retrospective) learning and retrieval are also common in individuals with HIV-1 infection (e.g., Murji et al, 2003). Group studies of HIV-1 disease reveal evidence of limited free recall, diminished use of organizational strategies (e.g., semantic clustering), interference effects, inconsistent recall across learning trials, and high rates of repetition errors (Delis et al, 1995;Murji et al, 2003;Peavy et al, 1994).…”

“…Group studies of HIV-1 disease reveal evidence of limited free recall, diminished use of organizational strategies (e.g., semantic clustering), interference effects, inconsistent recall across learning trials, and high rates of repetition errors (Delis et al, 1995;Murji et al, 2003;Peavy et al, 1994). By way of comparison, retention (i.e., consolidation) and recognition discrimination are less commonly affected in persons with HIV-1 disease (e.g., Delis et al, 1995).…”

HIV-associated prospective memory impairment increases risk of dependence in everyday functioning.

“…Episodic memory impairment is evident in approximately 50% of individuals infected with HIV (e.g., Heaton et al, 1995) and is typically characterized by deficits in higher-level encoding (e.g., Murji, Rourke, Donders, Carter, Shore, & Rourke, 2003) and retrieval (e.g., Delis et al, 1994) strategies. Whilst the literature demonstrates a clear link between HIV-associated episodic memory impairment and IADL declines, such research has been limited to the construct of retrospective memory (RetM); that is, the recollection of past events in response to an explicit prompt (e.g., recalling a physician's specific instructions regarding medication usage upon being asked), which is the putative ability measured by most standard clinical tests of memory (e.g., list learning and recall).…”