Peak-end memory bias in laboratory-induced dyspnea: a comparison of patients with medically unexplained symptoms and healthy controls.

OBJECTIVE: Memory for unpleasant experiences is dominated by intensity at the experience's peak and end, with a relative neglect for its duration. Therefore, unpleasant somatic experiences are expected be remembered as less aversive when they end gradually rather than abruptly, even when they last longer (i.e., the "peak-end effect"). We investigated the peak-end effect for dyspnea in healthy participants and in patients with medically unexplained dyspnea (MUD). METHODS: Two aversive dyspnea-inducing tasks were administered to a clinical MUD sample (n = 29) and a matched healthy control group (n = 29) using a rebreathing paradigm (60-second room air, 150-second rebreathing). In a short trial, the breathing system (mouthpiece) was removed immediately after peak dyspnea. In a long trial, breathing was switched to room air after peak dyspnea and continued in the breathing system for 150 seconds (order was counterbalanced across participants). Respiratory parameters were continuously measured, and dyspnea was rated every 10 seconds. Relative unpleasantness of the dyspneic episode was assessed with forced choice questions. RESULTS: More than 70% of the healthy group found the short episode worse than the long one despite equal maximal dyspnea (p = .02). Patients with MUD did not show this peak-end effect (p = .58). The latter had deficient recovery of dyspnea compared with the controls (42.08 [21.86] versus 17.51 [11.18], p < .001), which could not be explained by differences in respiratory physiology. CONCLUSIONS: The peak-end effect in dyspnea has important implications for dyspnea measurement. Its absence in patients with MUD suggests a critical role of distorted perceptual-cognitive processing of aversive somatic sensations in patients with medically unexplained symptoms.

Belgian siblings of children with a chronic illness: Is their quality of life different from their peers?

To assess Belgian siblings' self-reported quality of life (QoL) and the impact of illness on four different paediatric illnesses. Healthy siblings (n = 131) of children with type 1 diabetes, cancer, congenital heart disease (CHD) and cystic fibrosis (CF) completed the Child Health Questionnaire and the Sibling Perception Questionnaire. Results were compared to those of a matched group of siblings of healthy children. Siblings reported a good QoL, similar to controls, with the exception that siblings reported better on the QoL domain pain (p < .01). QoL was not related to time since diagnosis but the impact of illness was higher nearer to the time of diagnosis (r = -.39, p < .001). QoL of siblings of children with CHD or cancer was lower than QoL in the CF or type 1 diabetes group whilst impact of illness was highest for the CHD group. QoL of siblings of a child with a chronic illness is similar to the QoL of peers. Studies investigating siblings' QoL or the impact of illness on siblings should include the day-to-day demands of the illness as well as less obvious illness-related issues like 'hidden stress' and 'sense of control'.