Right and left heart failure in severe H1N1 influenza A infection.

Influenza infection can affect cardiac function. The recent pandemic of H1N1 influenza A provided an opportunity to study echocardiographic findings in critically ill infected patients. We hypothesised that critically ill patients with H1N1 infection would have a higher incidence of right and left heart failure than is seen in unselected populations of patients with septic shock and/or acute respiratory distress syndrome (ARDS). We retrospectively studied all patients admitted to four intensive care units at three hospitals in Salt Lake County, UT, USA, with laboratory-confirmed H1N1 infection in whom a clinical echocardiogram was available. 23 out of 48 patients had qualifying echocardiograms. Right ventricular (RV) dilatation (50-80%) and at least moderate systolic impairment (23%) were common, higher than the range described in general populations with ARDS. Left ventricular systolic dysfunction was present in 17% of patients. No single echocardiographic parameter was associated with 28-day mortality or ventilator-free days to 28 days. Critically ill patients with H1N1 infection frequently exhibit right heart dilatation and failure. RV basal dilatation was extremely common. These patients have less left heart failure than expected on the basis of prior descriptions of influenza myopericarditis or of general populations of septic patients.

Measuring automatic retrieval.

A variety of procedures have been used to assess automatic retrieval effects on memory, including implicit memory tests and the process dissociation approach. Theoretical concerns with each are summarized prior to describing a procedure for evaluating automatic retrieval that is based on retrieval speed. Specifically, in a speeded implicit task, participants were encouraged to complete word stems using strictly automatic retrieval by presenting several practice test trials that did not allow responding based on previously studied items and by encouraging speed of responding. This speeded implicit task was compared with a condition in which conscious retrieval of studied information was not possible and a condition in which conscious retrieval was required, providing converging evidence to support the hypothesis that the speeded implicit procedure can yield pure estimates of automatic retrieval. Furthermore, evidence from a standard implicit memory task yielded comparable data that suggests that participants engaged automatic retrieval processes on this task also.

Analyzing estimates of automatic and conscious retrieval in between- and within-subjects designs.

The process dissociation procedure (PDP) was developed as a means of quantifying the contributions of conscious and automatic retrieval to memory performance. Although the required inclusion and exclusion conditions are manipulated within subjects in most experiments, several researchers have expressed concerns that the instructions may be particularly difficult to follow under these conditions. Thus, manipulating instructions between subjects may have some advantages, although some aspects of the statistical analysis of conscious and automatic estimates are not routine in such a design. We describe a procedure for this analysis and present some initial data to illustrate its application to PDP. We also comment on other issues related to the calculation of estimates of automatic and conscious retrieval in between- and within-subjects designs.

Specificity of perceptual processing in rereading spatially transformed materials.

While most studies using the task of reading spatially transformed text do not reveal evidence of specific perceptual transfer, a study by Masson (1986, Experiment 3) provides clear evidence of such effects. Several experiments were designed to identify the basis for this empirical discrepancy. The only substantive evidence of specific perceptual transfer occurred when the words were presented in an unfamiliar typography, although each study suggested a trend toward perceptual specificity effects. The results are discussed in terms of Graf and Ryan's (1990) ideas about the role of distinctive memory representations.

The use of indirect memory tests to assess malingered amnesia: a study of metamemory.

Many techniques have been suggested for identifying criminal suspects who are simulating amnesia for the events surrounding a crime. The present research focuses on indirect memory tests as a potential means of discriminating between those who genuinely suffer from amnesia and those who are simulating. Subjects studied a list of words and subsequently performed either a word completion or a fragment completion task. Under normal indirect test instructions, typical priming effects were observed. When subjects were motivated to simulate amnesia for the list, target completion rates were consistently, and sometimes reliably, below baseline completion rates. This finding is contrary to the performance of genuine amnesics, whose performance on indirect tests typically mirrors that of normal subjects. Indirect tests may prove useful in discriminating genuine and simulating amnesics.

The processing of spatially transformed text.

The present study shows that previous attempts to demonstrate explicit memory for orientation of spatially transformed text were inconclusive. In the present experiments, subjects read spatially transformed sentences and were then given a recognition test that permitted the use of only nonsemantic information. The results revealed clear evidence of incidental retention of nonsemantic information on an immediate test, no improvement in performance under intentional learning conditions, reduced but still better than chance retention following a 48-h delay, and little change in performance with anomalous sentences. These and other results involving the reading of spatially transformed materials are discussed in terms of the interaction of processing requirements at encoding and retrieval.