title: Recency effects in HIV-associated dementia are characterized by deficient encoding.
abstract: The aim of the present study was to investigate the nature and cognitive mechanisms of serial position learning effects in HIV-associated dementia (HAD). Participants were 16 persons with HAD, 50 non-demented persons with HIV-infection, and 50 demographically comparable HIV-seronegative participants. HAD participants, relative to both comparison groups, exhibited reduced middle region (p<0.01) and elevated recency region (p<0.05) recall on the Hopkins Verbal Learning Test-Revised, but no primacy region effect (p>0.10). On recognition testing, the HAD group was impaired in discriminating targets from distractors (p<0.01) in all three serial position regions; however, they were not impaired on measures of retrieval (p>0.10) within these same regions. In sum, HAD participants relied disproportionately on recency regions of the list, indicating a passive recall style of echoing only the words within their auditory attention span. Interestingly, HAD participants did not evidence significant improvement on measures of recognition, a finding that suggests that the serial position effects are most consistent with a primary encoding deficit.
authors.affiliation: Department of Psychiatry (0847), University of California, San Diego, School of Medicine, La Jolla, CA 92093, USA.
authors.forename: J Cobb
authors.initials: JC
authors.lastname: Scott
authors.forename: Steven Paul
authors.initials: SP
authors.lastname: Woods
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Patterson
authors.forename: Erin E
authors.initials: EE
authors.lastname: Morgan
authors.forename: Robert K
authors.initials: RK
authors.lastname: Heaton
authors.forename: Igor
authors.initials: I
authors.lastname: Grant
authors.forename: Thomas D
authors.initials: TD
authors.lastname: Marcotte
mesh_terms: D015526:AIDS Dementia Complex / Q000503:physiopathology*; D000328:Adult; D003710:Demography; D005260:Female; D015658:HIV Infections / Q000150:complications / Q000503:physiopathology; D006801:Humans; D008297:Male; D011939:Mental Recall / Q000502:physiology*; D008875:Middle Aged; D009483:Neuropsychological Tests / Q000706:statistics & numerical data; D014706:Verbal Learning / Q000502:physiology*