Autonomic prediction of error-related ERP components in perceptual and conceptual tasks in older and younger adults

In studies of cognitive processing, the allocation of attention has been consistently linked to subtle, phasic adjustments in autonomic control. Both autonomic control of heart rate and control of the allocation of attention are known to decline with age. It is not known, however, whether characteristic individual differences in autonomic control and the ability to control attention are closely linked. To test this, a measure of parasympathetic function, vagal tone (VT) was computed from cardiac recordings from older and younger adults taken before and during performance of two attentiondemanding tasks - the Eriksen visual flanker task and the source memory task. Both tasks elicited event-related potentials (ERPs) that accompany errors, i.e., error-related negativities (ERNs) and error positivities (Pe's). The ERN is a negative deflection in the ERP signal, time-locked to responses made on incorrect trials, likely generated in the anterior cingulate. It is followed immediately by the Pe, a broad, positive deflection which may reflect conscious awareness of having committed an error. Age-attenuation ofERN amplitude has previously been found in paradigms with simple stimulus-response mappings, such as the flanker task, but has rarely been examined in more complex, conceptual tasks. Until now, there have been no reports of its being investigated in a source monitoring task. Age-attenuation of the ERN component was observed in both tasks. Results also indicated that the ERNs generated in these two tasks were generally comparable for young adults. For older adults, however, the ERN from the source monitoring task was not only shallower, but incorporated more frontal processing, apparently reflecting task demands. The error positivities elicited by 3 the two tasks were not comparable, however, and age-attenuation of the Pe was seen only in the more perceptual flanker task. For younger adults, it was Pe scalp topography that seemed to reflect task demands, being maximal over central parietal areas in the flanker task, but over very frontal areas in the source monitoring task. With respect to vagal tone, in the flanker task, neither the number of errors nor ERP amplitudes were predicted by baseline or on-task vagal tone measures. However, in the more difficult source memory task, lower VT was marginally associated with greater numbers of source memory errors in the older group. Thus, for older adults, relatively low levels of parasympathetic control over cardiac response coincided with poorer source memory discrimination. In both groups, lower levels of baseline VT were associated with larger amplitude ERNs, and smaller amplitude Pe's. Thus, low VT was associated in a conceptual task with a greater "emergency response" to errors, and at the same time, reduced awareness of having made them. The efficiency of an individual's complex cognitive processing was therefore associated with the flexibility of parasympathetic control of heart rate, in response to a cognitively challenging task.

A phenomenological approach to understanding the psychological response to chronic low back pain

Chronic low back pain (CLBP) is a complex health problem of psychological manifestations not fully understood. Using interpretive phenomenological analysis, 11 semi-structured interviews were conducted to help understand the meaning of the lived experience of CLBP; focusing on the psychological response to pain and the role of depression, catastrophizing, fear-avoidance behavior, anxiety and somatization. Participants characterized CLBP as persistent tolerable low back pain (TLBP) interrupted by periods of intolerable low back pain (ILBP). ILBP contributed to recurring bouts of helplessness, depression, frustration with the medical system and increased fear based on the perceived consequences of anticipated recurrences, all of which were mediated by the uncertainty of such pain. During times of TLBP all participants pursued a permanent pain consciousness as they felt susceptible to experience a recurrence. As CLBP progressed, participants felt they were living with a weakness, became isolated from those without CLBP and integrated pain into their self-concept.

Opioid poisoning and availability of specialized medical care in Ontario, 2002-2006

The prescription of opioid analgesics has risen sharply in North America over the past two decades. This increase has been accompanied by a rise in overdoses. The present study draws on administrative data collected from emergency department contacts to describe the epidemiology of opioid overdose in Ontario b~tween 2002 and 2006 and to examine the role of regional variation in availability of specialist care. The number of poisonings increased from 1250 (10.9 per 100,000) in FY2002 to 1816 (15.2 per 100,000) in FY2005. Local concentration of specialist physicians was significantly associated with the incidence of opioid overdose, inversely at most levels of availability, but positively at very high levels. Regional variation in incidence was also associated with demographics, median family income, and the rate of other drug poisonings. Policy options for limiting opioid-related harms are limited, but improvements in monitoring and clinical management may prove valuable.