Deficits in cue detection and intention retrieval underlie prospective memory impairment in schizophrenia

Abstract

Emerging evidence indicates that individuals with schizophrenia (SCZ) may exhibit deficits in prospective memory (ProM), a dissociable and ecologically important aspect of episodic memory entailing the formation, maintenance, and execution of future intentions. The present study aimed to elucidate the component processes of ProM impairment in 41 individuals with SCZ relative to 41 demographically similar healthy comparison (HC) participants. Results revealed that the SCZ group performed worse than HCs on overall ProM, with comparable deficits on time-and event-based ProM trials. In the SCZ cohort, better ProM performance was associated with younger age and less severe negative symptoms. Although a significantly greater number of task substitution and loss of time errors were evident in the SCZ group as compared to HCs, the most prevalent error type in SCZ was characterized by a complete failure to respond to the ProM cue. Importantly, the SCZ and HC groups did not differ on a post-test multiple-choice recognition trial, suggesting adequate formation and maintenance (i.e., retention) of the ProM cue-intention pairing when self-directed monitoring and retrieval demands were minimized. Findings indicate that SCZ is associated with impairment in the cue detection and self-initiated retrieval components of executing future intentions, which is consistent with a possible prefrontostriatal loop neuropathogenesis. Further studies are needed to explore the neurobiological mechanisms of SCZ-associated ProM impairment and the impact of such deficits on daily functioning (e.g., medication compliance).

Prospective memory in schizophrenia: The impact of varying retrospective-memory load

“…In line with previous research (e.g., Kumar et al, 2005;Shum et al, 2004;Woods et al, 2007), participants with schizophrenia demonstrated reduced PM performance in comparison to controls. The core finding of the present study is that in both RM load conditions, people with schizophrenia made significantly fewer PM responses than did controls.…”

“…Further, parallel to the increasing Downloaded by [Temple University Libraries] at 20:40 04 January 2015 demands on executive functions in these tasks, group differences increased from the activity-based over the event-based to the time-based task. However, in contrast with Shum et al's (2004) findings, Woods et al (2007) observed an overall PM deficit in schizophrenia with equivalent impairments in time-and event-based PM. Individuals with schizophrenia were impaired in cue detection and self-directed intention retrieval.…”

“…A third objection might be that these results contrast with Woods et al's (2007) finding that when self-initiated retrieval demands were reduced to a minimum (i.e., posttest multiple choice recognition test on cue-intention pairs), individuals with schizophrenia could identify and, hence, remember the correct cue-intention pairs. However, the present study used a slightly different approach to explore cue retention (i.e., free recall).…”

“…In sharp contrast, there are only six studies to date that have assessed prospective-memory (PM) functioning (Elvevag, Maylor, & Gilbert, 2003;Henry, Rendell, Kliegel, & Altgassen, 2007b;Kondel, 2002;Kumar, Nizamie, & Jahan, 2005;Shum, Ungvari, Tang, & Leung, 2004;Woods, Twamley, Dawson, Narvaez, & Jeste, 2007). PM refers to the self-initiated delayed execution of intended actions, such as to remember to go to a doctor's appointment.…”

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

“…Note that, there were insufficient numbers of Place Losing Omissions (n = 0) and Random Errors (n = 2) to permit meaningful analyses. Finally, a 3-choice recognition trial was administered following the completion of all eight ProM tasks (range = 0-8), from which a Retrieval Index was derived by subtracting free recall accuracy (range = 0-8) such that higher scores indicate a greater retrieval deficit (see Woods et al, 2007b).Self-reported ProM was assessed with the Prospective and Retrospective Memory Questionnaire (PRMQ; Smith, Della Sala, Logie, & Maylor, 2000), which is a 16-item questionnaire on which perceived memory difficulties are rated on a 5-point Likert-type scale that ranges from 1 ("never") to 5 ("very often" , 1997). The delayed free recall scores from these three measures were converted to sample-based z-scores (n = 66) and then averaged to create a composite measure of RetM.…”