Do Patients With HIV-Associated Minor Cognitive/Motor Disorder Exhibit a “Subcortical” Memory Profile? Evidence Using the California Verbal Learning Test

Abstract

A new diagnostic category for HIV seropositive patients–Minor Cognitive/Motor Disorder (MCMD)—was recently proposed by an AIDS task force sponsored by the American Academy of Neurology. Based on past memory research with HIV+ patients who were diagnosed according to the Center for Disease Control (CDC) definition of AIDS, we predicted that HIV+ patients who met the new criteria for MCMD would exhibit a “subcortical” memory profile (i.e., they would display primarily a retrieval deficit). This hypothesis was generally supported, but with some exceptions. The HIV+ patients with MCMD were found to have a mild encoding deficit (suggestive of some cortical involvement) superimposed on a pronounced retrieval deficit (suggestive of more extensive subcortical involvement). These findings are consonant with those from a recent neuropathological study indicating an increase in cortical involvement, in addition to predominately subcortical involvement, in more advance stages of the HIV disease process.

Antiretroviral Adherence and the Nature of HIV-Associated Verbal Memory Impairment

“…Partial support for this hypothesis was found, as both HIV+ groups demonstrated poorer learning and recall on the CVLT than controls; the two HIV+ antiretroviral-adherence groups did not differ with respect to learning and recall performances. This finding is consistent with data showing verbal learning and recall deficits in HIV+ participants, 2–5,27–29 although it is somewhat inconsistent with data suggesting that HIV-associated neurocognitive deficits might lessen with the use of HAART. 12–14 …”

“…On this basis, some might conjecture that differences in the literature regarding the characterization of HIV-related memory impairment may have been due to disparities in treatment regimens between studies. Specifically, many pre-HAART studies demonstrated both retrieval and encoding deficits 27–29 in HIV+ participants, whereas post-HAART studies indicated that HIV+ participants primarily suffered from an encoding deficit. 24–26 However, it is equally possible that the profile of HIV-related memory deficits is somewhat heterogeneous and that those with more pronounced retrieval deficits have greater difficulties with medication adherence.…”

“…23 Moreover, the data on the profile of HIV-related verbal memory impairment are mixed, with some evidence of a primary encoding deficit 24–26 and other evidence of both retrieval and encoding deficits. 27–29 One explanation for this difference is that studies finding retrieval deficits (in addition to encoding deficits) were either conducted before the advent of HAART 27,28 or with samples evidencing relatively low rates of HAART use, 29 whereas those mainly implicating encoding deficits were conducted after HAART use was widespread. 24–26 However, another possibility is that the discrepant findings were due to methodological differences between the studies.…”

“…More recent studies that support the encoding-deficit hypothesis were based on the examination of list-learning characteristics (semantic clustering, 24 serial-position effects 25,26 ) and suggested that HIV-associated verbal memory impairment resulted from strategic processing-deficits at encoding; similar deficits have been found in the investigation of working memory in HIV+ participants. 30 The studies finding retrieval-deficits did so primarily by showing disproportionate memory performance benefits with recognition cueing (i.e., better recognition than recall 27,28 ). This method assumes that greater recognition than recall is suggestive of partial retrieval-deficits.…”

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

“…The CVLT is regarded as a useful tool for characterizing memory profiles associated with different neuropsychological disturbances, including Alzheimer's disease (AD), Huntington's disease (HD), and Korsakoff 's syndrome (e.g., Delis et al, 1991), HIV-1 infection (Becker et al, 1995;Delis et al, 1995;Peavy et al, 1994;White et al, 1997), depression (Massman et al, 1992), and schizophrenia (Paulsen et al, 1995). The scoring system of the CVLT allows quantification of several indices including style of learning (e.g., semantic categorization of related words), consistency of item recall across learning trials, retention of information over short and longer delays, vulnerability to interference, recall errors (e.g., intrusions), and discriminability (ability to detect target words from distracters on recognition testing).…”