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Single Trials (single + trials)

Distribution by Scientific Domains

Psychology	33%
Medical Sciences	33%

Selected Abstracts

A systematic review of the effectiveness of smoking relapse prevention interventions for abstinent smokers

ADDICTION, Issue 8 2010
Shade Agboola
ABSTRACT Aims To carry out a systematic review of the effectiveness of relapse prevention interventions (RPIs) among abstinent smokers who had completed an initial course of treatment or who had abstained unassisted, pooling only outcome data from similar follow-up time points. Methods We used the same search strategy as was used in Cochrane reviews of RPIs to identify randomized trials of behavioural and pharmacological studies of smoking RPIs published up to July 2008. Abstinence from smoking was defined as either continuous abstinence or point prevalence abstinence, measured at three follow-up time points: short term (1,3 months post randomization), medium term (6,9 months) and long term (12,18 months). Abstinence among pregnant/postpartum women was also measured at delivery or the last follow-up prior to delivery. Random effect meta-analysis was used to estimate pooled odds ratios (OR) with 95% confidence intervals (CI). Results Thirty-six studies randomizing abstainers were included. Self-help materials appeared to be effective in preventing relapse at long-term follow up in initially unaided quitters (pooled OR 1.52; 95% CI 1.15 to 2.01, I2 = 0%, NNT = 11, 3 studies). Other behavioural interventions for relapse prevention appeared effective in the short term only. There were positive results for the use of pharmacotherapies for relapse prevention. Bupropion was effective at long-term follow-up (pooled OR 1.49; 95% CI 1.10 to 2.01; I2 = 0%; NNT = 11; 4 studies). Nicotine replacement therapy (NRT) was effective at medium-term (pooled OR 1.56; 95% CI 1.16 to 2.11; I2 = 37%; NNT = 14; 4 trials) and long-term follow-ups (pooled OR 1.33; 95% CI 1.08 to 1.63; I2 = 0%; NNT = 20; 4 trials). Single trials of extended treatment of Varenicline and rimonabant were also found to be effective at short-term and medium-term follow-ups. Conclusions Self-help materials appear to prevent relapse in initially unaided quitters. Use of NRT, bupropion and varenicline appears to be effective in preventing relapse following an initial period of abstinence or an acute treatment episode. There is currently no good evidence that behavioural support prevents relapse after initial unaided abstinence or following an acute treatment period. [source]

Timing and connectivity in the human somatosensory cortex from single trial mass electrical activity

HUMAN BRAIN MAPPING, Issue 4 2002
Andreas A. Ioannides
Abstract Parallel-distributed processing is ubiquitous in the brain but often ignored by experimental designs and methods of analysis, which presuppose sequential and stereotypical brain activations. We introduce here a methodology that can effectively deal with sequential and distributed activity. Regional brain activations elicited by electrical median nerve stimulation are identified in tomographic estimates extracted from single trial magnetoencephalographic signals. Habituation is identified in both primary somatosensory cortex (SI) and secondary somatosensory cortex (SII), often interrupted by resurgence of strong activations. Pattern analysis is used to identify single trials with homogeneous regional brain activations. Common activity patterns with well-defined connectivity are identified within each homogeneous group of single trials across the subjects studied. On the contralateral side one encounters distinct sets of single trials following identical stimuli. We observe in one set of trials sequential activation from SI to SII and insula with onset of SII at 60 msec, whereas in the other set simultaneous early co-activations of the same two areas. Hum. Brain Mapping 15:231,246, 2002. © 2002 Wiley-Liss, Inc. [source]

Validation of Analytical Measurements by Single-trial and Collaborative Study

JOURNAL OF FOOD SCIENCE EDUCATION, Issue 1 2003
C.E. Carpenter
ABSTRACT: Validation of analytical measurements is necessary to report scientifically justifiable results. In this exercise, students validate the accuracy and precision of analytical instruments in single trials and in collaborative study, and validation results are used to report measurements in a scientifically justifiable manner. Tables are provided to guide data collection and to clarify reporting of results. A set of allied questions explores validation theory to develop student understanding, stimulate discussion, and provide feedback to the instructor regarding student comprehension. References are given that reinforce the validation concepts. [source]

Electrocortical and electrodermal responses covary as a function of emotional arousal: A single-trial analysis

PSYCHOPHYSIOLOGY, Issue 4 2008
Andreas Keil
Abstract Electrophysiological studies of human visual perception typically involve averaging across trials distributed over time during an experimental session. Using an oscillatory presentation, in which affective or neutral pictures were presented for 6 s, flickering on and off at a rate of 10 Hz, the present study examined single trials of steady-state visual evoked potentials. Moving window averaging and subsequent Fourier analysis at the stimulation frequency yielded spectral amplitude measures of electrocortical activity. Cronbach's alpha reached values >.79, across electrodes. Single-trial electrocortical activation was significantly related to the size of the skin conductance response recorded during affective picture viewing. These results suggest that individual trials of steady-state potentials may yield reliable indices of electrocortical activity in visual cortex and that amplitude modulation of these indices varies with emotional engagement. [source]

Subgroup Hypotheses: Clinician's Friend or Researcher's Fiction?

ACADEMIC EMERGENCY MEDICINE, Issue 8 2009
Peter C. Wyer MD
Abstract Researchers and clinicians may be tempted to consider apparent differences in effects of interventions in subgroups of study populations for the purposes of individualizing care or directing subsequent focused research efforts. Such "subgroup hypotheses" have a high propensity of being artifacts of chance and are rarely supported when stringent criteria are applied. Subgroup hypotheses emerging from single trials should rarely if ever be considered for application. This article describes published criteria for evaluating the believability of a subgroup hypothesis and presents a conceptual framework for understanding the principles underlying those criteria. Examples of both failed and validated subgroup hypotheses drawn from emergency medicine research are given. [source]

Variable Memory Strategy Use in Children's Adaptive Intratask Learning Behavior: Developmental Changes and Working Memory Influences in Free Recall

CHILD DEVELOPMENT, Issue 4 2007
Martin Lehmann
Variability in strategy use within single trials in free recall was analyzed longitudinally from second to fourth grades (ages 8,10 years). To control for practice effects another sample of fourth graders was included (age 10 years). Video analyses revealed that children employed different strategies when preparing for free recall. A gradual shift from labeling to cumulative rehearsal was present both with increasing age and across different list positions. Whereas cumulative rehearsal was frequent at early list positions, labeling was dominant at later list portions. Working memory capacity predicted the extent of cumulative rehearsal usage, which became more efficient with increasing age. Results are discussed in the context of the adaptive strategy choice model. [source]