Decision-making in amnesia: do advantageous decisions require conscious knowledge of previous behavioural choices?

Previous work has reported that in the Iowa gambling task (IGT) advantageous decisions may be taken before the advantageous strategy is known [Bechara, A., Damasio, H., Tranel, D., ; Damasio, A. R. (1997). Deciding advantageously before knowing the advantageous strategy. Science, 275, 1293-1295]. In order to test whether explicit memory is essential for the acquisition of a behavioural preference for advantageous choices, we measured behavioural performance and skin conductance responses (SCRs) in five patients with dense amnesia following damage to the basal forebrain and orbitofrontal cortex, six amnesic patients with damage to the medial temporal lobe or the diencephalon, and eight control subjects performing the IGT. Across 100 trials healthy participants acquired a preference for advantageous choices and generated large SCRs to high levels of punishment. In addition, their anticipatory SCRs to disadvantageous choices were larger than to advantageous choices. However, this dissociation occurred much later than the behavioural preference for advantageous alternatives. In contrast, though exhibiting discriminatory autonomic SCRs to different levels of punishment, 9 of 11 amnesic patients performed at chance and did not show differential anticipatory SCRs to advantageous and disadvantageous choices. Further, the magnitude of anticipatory SCRs did not correlate with behavioural performance. These results suggest that the acquisition of a behavioural preference--be it for advantageous or disadvantageous choices--depends on the memory of previous reinforcements encountered in the task, a capacity requiring intact explicit memory.

The radiographic assessment of implant patients: decision-making criteria

Indications for the most frequently used imaging modalities in implant dentistry are proposed based on clinical need and biologic risk for the patient. To calculate the biologic risk, the authors carried out dose measurements. They demonstrated that the risk from a periapical radiograph is 20% of that from a panoramic radiograph. A panoramic radiograph and a series of 4 conventional tomographs of a single-tooth gap in the molar region carry 5% and 13% of the risk from computed tomography of the maxilla, respectively. Panoramic radiography is considered the standard radiographic examination for treatment planning of implant patients, because it imparts a low dose while giving the best radiographic survey. Periapical radiographs are used to elucidate details or to complete the findings obtained from the panoramic radiograph. Other radiographic methods, such as conventional film tomography or computed tomography, are applied only in special circumstances, film tomography being preferred for smaller regions of interest and computed tomography being justified for the complete maxilla or mandible when methods for dose reduction are followed. During follow-up, intraoral radiography is considered the standard radiographic examination, particularly for implants in the anterior region of the maxilla or for scientific studies. In patients requiring more than 5 periapical images, panoramic radiography is preferred.

Decision making in patients with acute abdominal pain at a university and at a rural hospital: Does the value of abdominal sonography differ?

Introduction and objectives Abdominal sonography is regarded as a quick and effective diagnostic tool for acute abdominal pain in emergency medicine. However, final diagnosis is usually based on a combination of various clinical examinations and radiography. The role of sonography in the decision making process at a hospital with advanced imaging capabilities versus a hospital with limited imaging capabilities but more experienced clinicians is unclear. The aim of this pilot study was to assess the relative importance of sonography and its influence on the clinical management of acute abdominal pain, at two Swiss hospitals, a university hospital (UH) and a rural hospital (RH). Methods 161 patients were prospectively examined clinically. Blood tests and sonography were performed in all patients. Patients younger than 18 years and patients with trauma were excluded. In both hospitals, the diagnosis before and after ultrasonography was registered in a protocol. Certainty of the diagnosis was expressed on a scale from 0% to 100%. The decision processes used to manage patients before and after they underwent sonography were compared. The diagnosis at discharge was compared to the diagnosis 2 – 6 weeks thereafter. Results Sensitivity, specificity and accuracy of sonography were high: 94%, 88% and 91%, respectively. At the UH, management after sonography changed in only 14% of cases, compared to 27% at the RH. Additional tests were more frequently added at the UH (30%) than at the RH (18%), but had no influence on the decision making process-whether to operate or not. At the UH, the diagnosis was missed in one (1%) patient, but in three (5%) patients at the RH. No significant difference was found between the two hospitals in frequency of management changes due to sonography or in the correctness of the diagnosis. Conclusion Knowing that sonography has high sensitivity, specificity and accuracy in the diagnosis of acute abdominal pain, one would assume it would be an important diagnostic tool, particularly at the RH, where tests/imaging studies are rare. However, our pilot study indicates that sonography provides important diagnostic information in only a minority of patients with acute abdominal pain. Sonography was more important at the rural hospital than at the university hospital. Further costly examinations are generally ordered for verification, but these additional tests change the final treatment plan in very few patients.

Can decision making in general surgery be based on evidence? An empirical study of Cochrane Reviews

BACKGROUND: This empirical study analyzes the current status of Cochrane Reviews (CRs) and their strength of recommendation for evidence-based decision making in the field of general surgery. METHODS: Systematic literature search of the Cochrane Database of Systematic Reviews and the Cochrane Collaboration's homepage to identify available CRs on surgical topics. Quantitative and qualitative characteristics, utilization, and formulated treatment recommendations were evaluated by 2 independent reviewers. Association of review characteristics with treatment recommendation was analyzed using univariate and multivariate logistic regression models. RESULTS: Ninety-three CRs, including 1,403 primary studies and 246,473 patients, were identified. Mean number of included primary studies per CR was 15.1 (standard deviation [SD] 14.5) including 2,650 (SD 3,340) study patients. Two and a half (SD 8.3) nonrandomized trials were included per analyzed CR. Seventy-two (77%) CRs were published or updated in 2005 or later. Explicit treatment recommendations were given in 45 (48%). Presence of a treatment recommendation was associated with the number of included primary studies and the proportion of randomized studies. Utilization of surgical CRs remained low and showed large inter-country differences. The most surgical CRs were accessed in UK, USA, and Australia, followed by several Western and Eastern European countries. CONCLUSION: Only a minority of available CRs address surgical questions and their current usage is low. Instead of unsystematically increasing the number of surgical CRs it would be far more efficient to focus the review process on relevant surgical questions. Prioritization of CRs needs valid methods which should be developed by the scientific surgical community.

[Role of coronary artery bypass grafting in the treatment of coronary artery disease - a well-balanced information of the patients and objective decision making are welcome]

Most recently discussion about the optimal treatment for different subsets of patients suffering from coronary artery disease has re-emerged, mainly because of the uncertainty caused by doctors and patients regarding the phenomenon of unpredictable early and late stent thrombosis. Surgical revascularization using multiple arterial bypass grafts has repeatedly proven its superiority compared to percutaneous intervention techniques, especially in patients suffering from left main stem disease and coronary 3-vessels disease. Several prospective randomized multicenter studies comparing early and mid-term results following PCI and CABG have been really restrictive, with respect to patient enrollment, with less than 5% of all patients treated during the same time period been enrolled. Coronary artery bypass grafting allows the most complete revascularization in one session, because all target coronary vessels larger than 1 mm can be bypassed in their distal segments. Once the patient has been turn-off for surgery, surgeons have to consider the most complete arterial revascularization in order to decrease the long-term necessity for re-revascularization; for instance patency rate of the left internal thoracic artery grafted to the distal part left anterior descending artery may be as high as 90-95% after 10 to 15 years. Early mortality following isolated CABG operation has been as low as 0.6 to 1% in the most recent period (reports from the University Hospital Berne and the University Hospital of Zurich); beside these excellent results, the CABG option seems to be less expensive than PCI with time, since the necessity for additional PCI is rather high following initial PCI, and the price of stent devices is still very high, particularly in Switzerland. Patients, insurance and experts in health care should be better and more honestly informed concerning the risk and costs of PCI and CABG procedures as well as about the much higher rate of subsequent interventions following PCI. Team approach for all patients in whom both options could be offered seems mandatory to avoid unbalanced information of the patients. Looking at the recent developments in transcatheter valve treatments, the revival of cardiological-cardiosurgical conferences seems to a good option to optimize the cooperation between the two medical specialties: cardiology and cardiac surgery.

The end of the corporate life cycle

This paper asks how takeover and failure hazards change as listed firms get older. The hypothesis is that they increase because firms gradually run out of growth opportunities. We find the opposite. Both takeover and failure hazard drop significantly with age. The decline in takeover hazard can be explained with Loderer, Stulz, and Waelchli’s (2013) “buggy whip makers” hypothesis: Because old firms are comparatively well-managed and are affected by limited agency problems, on average, they offer little value added potential to acquirers. Failure hazard drops because to learning. The results are robust to various alternative interpretations and cannot be explained by unobserved heterogeneity. While hazards decline with age, they do not go to zero. This explains why, eventually, all listed firms disappear

The end of the corporate life cycle

This paper asks how takeover and failure hazards change as listed firms get older. The hypothesis is that they increase because firms gradually run out of growth opportunities. We find the opposite. Both takeover and failure hazard drop significantly with age. The decline in takeover hazard can be explained with Loderer, Stulz, and Waelchli’s (2013) “buggy whip makers” hypothesis: Because old firms are comparatively well-managed and are affected by limited agency problems, on average, they offer little value added potential to acquirers. Failure hazard drops because to learning. The results are robust to various alternative interpretations and cannot be explained by unobserved heterogeneity. While hazards decline with age, they do not go to zero. This explains why, eventually, all listed firms disappear