Visual search tasks: measurement of dynamic visual lobe and relationship with display movement velocity.

Visual lobe is a useful tool for predicting visual search performance. Up till now, no study has focused on dynamic visual lobe. This study developed a dynamic visual lobe measurement system (DVLMS) that could effectively map dynamic visual lobe and calculate visual lobe shape indices. The effects of display movement velocity on lobe shape indices were examined under four velocity conditions: 0, 4, 8 and 16 deg/s. In general, with the increase of display movement velocity, visual lobe area and perimeter became smaller, whereas lobe shape roundness, boundary smoothness, symmetry and regularity deteriorated. The elongation index was not affected by velocity. Regression analyses indicated that display movement velocity was important in determining dynamic visual lobe shape indices. Dynamic visual lobe provides another option for better understanding dynamic vision, in addition to dynamic visual acuity. Findings of this study can provide guidelines for analysing and designing dynamic visual tasks. Practitioner Summary: Dynamic visual lobe is important in reflecting the visual ability of searching for a moving target. We developed a dynamic visual lobe measurement system (DVLMS) and examined display movement velocity's effects on lobe shape. Findings revealed that velocity was a key factor affecting dynamic visual lobe shape indices.

Perioperative acute myocardial infarction increases mortality following noncardiac surgery.

OBJECTIVE: To provide insight into diagnosis, treatment, and prevention of perioperative myocardial infarction (PMI). DESIGN: The authors retrospectively analyzed PMI characteristics in patients undergoing noncardiac surgery and identified risk factors for death. SETTING: An affiliated teaching hospital with about 1500 beds. PARTICIPANTS: The authors screened electronic medical records and retrospectively analyzed clinical data from 117,856 patients who underwent noncardiac surgery during the period from August 2003 through June 2011. INTERVENTIONS: Patients were divided into two groups based on survival at 30 days after PMI. MEASUREMENTS AND MAIN RESULTS: PMI was reported in 61 patients, for an overall incidence rate of 5.2 per 10,000. PMI incidence increased significantly with age, with a rate of 0.97 per 10,000 for the 45- to 60-year-old group, and increasing to a rate of 40.4 per 10,000 for the>75-year-old group (p<0.001). The mortality rate of non-PMI patients (n = 117,795) was 0.32%, whereas the mortality rate for the 61 PMI patients was 36.1% (p<0.001). PMI occurred acutely (within 48 to 72 hours of surgery) in the majority of patients (78.7%), and only 18% of these patients complained of chest pain. The majority of patients who suffered PMI had non-ST segment elevation acute myocardial infarction (78.7%). By multiple logistic regression analysis, lack of anticoagulation/antiplatelet therapy and cardiogenic shock were independent risk factors for death in PMI patients (p = 0.001 for both). CONCLUSIONS: PMI incidence increased significantly with advanced age. PMI increased mortality following non-cardiac surgery. The independent risk factors for death in PMI patients following noncardiac surgery were lack of anticoagulation/antiplatelet therapy and cardiogenic shock.