Age-related declines in context maintenance and semantic short-term memory

This study reports age-related declines in context maintenance (Braver et al., 2001) and semantic short-term memory (STM) and evidence for a relation between the two. A group of younger and older adults completed a context maintenance task (AX-CPT), a semantically oriented STM task (conceptual span), a phonologically oriented STM task (digit span), and a meaning integration task (semantic anomaly judgement). In the AX-CPT task, a target response is required to the probe letter “X” but only when it is preceded by the letter “A” (the context). Either three (short interference) or six distractor letters (long interference) were presented between the cue and the probe. Results indicated an age-related deficit in context maintenance. Age-related declines were also observed for conceptual span and semantic anomaly judgement but not for digit span. Context maintenance was correlated with conceptual span and semantic anomaly judgement but not with digit span. These correlations were largely mediated by age differences, which also explained variance that was unique to (and not shared among) context maintenance, conceptual span, and semantic anomaly judgement.     

A computer model of the temporal course of agrammatic sentence understanding: The effects of variation in severity and sentence complexity

In this article, we present SYNCHRON, a computer model of Kolk and van Grunsven's (1985) hypothesis of agrammatic comprehension deficits. According to this hypothesis, parsing fails in agrammatic aphasies since syntactic representational elements that need to be active simultaneously are often not coactive because of disturbances in timing due to brain damage. SYNCHRON has been especially designed to account for two neglected aspects of agrammatic comprehension: degrees of severity and the sentence-complexity effect. We report an attempt to simulate data from two sentence-picture-matching studies in which a qualitatively similar sentence-complexity effect was found at two different average levels of severity. This pattern was reproduced when the timing disorder was assumed to affect syntactic phrasal categories, but not when it was assumed to affect function-word categories. When phrasal categories were involved, fit was not much affected, whether the damage was assumed to slow down the time for an element to be retrieved, or to decrease the time for an element to remain available.     

No pain,no gain: cross-lagged analyses of posttraumatic growth and anxiety,depression, posttraumatic stress and prolonged grief symptoms after loss

Background and objectives: Major negative life-events including bereavement can precipitate perceived positive life-changes, termed posttraumatic growth (PTG). While traditionally considered an adaptive phenomenon, it has been suggested that PTG represents a maladaptive coping response similar to cognitive avoidance. To clarify the function of PTG, it is crucial to establish concurrent and longitudinal associations of PTG with post-event mental health problems. Yet, longitudinal studies on this topic are scarce. The present study fills this gap in knowledge.

Design: A two-wave longitudinal survey was conducted.

Methods: Four-hundred and twelve bereaved adults (87.6% women) filled out scales assessing PTG and symptoms of depression, anxiety, prolonged grief, and posttraumatic stress at baseline and 6 months later.

Results: The baseline concurrent relationships between all symptom levels and PTG were curvilinear (inverted U-shape). Cross-lagged analyses demonstrated that symptom levels did not predict levels of PTG 6 months later, or vice versa.

Conclusions: Findings suggest PTG after loss has no substantive negative or positive effects on mental health. Development of specific treatments to increase PTG after bereavement therefore appears premature.