Given a passage with a context and an answer, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.

Context: Behavioral studies of spatial navigation in aging indicate that orientation using an allocentric reference frame (object-centered orientation) is impaired, whereas orientation using egocentric processes (self-centered orientation) is not. It has been proposed that navigational deficits may result from more general alterations of perception and attention or executive functions. The purpose of this study is to assess allocentric and egocentric representation in elderly individuals, and to determine if age-related deficits in spatial navigation are related to an attentional decline.', 'We assessed encoding of the position of geometrical shapes, depending specifically on an allocentric or egocentric reference frame, during ERP recording in young and old subjects.', 'Aging was associated with a performance decline in allocentric, but not egocentric, encoding. Both allocentric and egocentric conditions elicited parietal early components P1 and N1, reflecting top-down modulation, and components P2 and N2, reflecting selective attention and stimulus categorization. We observed age-associated effects on N1 and N2 amplitudes and on N2 latency in both spatial conditions. Moreover, impaired allocentric performance in older subjects was associated with a greater P2 amplitude and delayed P2 latency compared with younger subjects.
Answer: These results suggest that elderly individuals present with deficits when spatial orientation relies on allocentric representation, and are associated with age-related deficits in spatial attention.
Is allocentric but not egocentric orientation impaired during normal aging : an ERP study?

Context: Anemia is an established adverse risk factor in cardiovascular disease. However, the effect of preoperative anemia is not well defined in heart surgery. This study evaluates the effect of preoperative anemia on early clinical outcomes in patients undergoing cardiac surgery.', 'A retrospective, observational, cohort study of prospectively collected data was undertaken on 7,738 consecutive patients undergoing heart surgery between April 2003 and February 2009. Of these, 1,856 patients with preoperative anemia were compared to 5,882 patients without anemia (control group). According to the World Health Organization, anemia was defined as hemoglobin level<13 g/dl for men and <12 g/dl for women. Selection bias not controlled by multivariable methods was assessed with propensity-adjustment method.', 'Overall mortality was 2.1%. Preoperative anemia was associated with tripling in the risk of death (4.6% vs 1.5%, p<0.0001) and postoperative renal dysfunction (18.5% vs 6.5%, p<0.0001). There was also a significant difference between the anemic and non-anemic group in the risk of postoperative stroke (1.9% vs 1.1%, p=0.008), atrial fibrillation (36.7% vs 33%, p=0.003) and length of hospital stay>7 days (54% vs 36.7%, p<0.0001). In propensity-adjusted, multivariable logistic regression, preoperative anemia was an independent predictor of mortality (odds ratio [OR] 1.44, 95% confidence interval [CI] 1.02 to 2.03), postoperative renal dysfunction (OR 1.73, 95% CI 1.43 to 2.1) and length of hospital stay>7 days (OR 1.3, 95% CI 1.15 to 1.47).
Answer: In patients undergoing heart surgery, preoperative anemia is associated with an increased risk of mortality and postoperative morbidity.
Does preoperative anemia increase mortality and postoperative morbidity after cardiac surgery?

Context: Despite recent advancements in post-cardiac arrest resuscitation, the optimal measurement of postarrest outcome remains unclear. We hypothesized that Cerebral Performance Category score can predict the long-term outcome of postarrest survivors who received targeted temperature management during their postarrest hospital care.', 'Retrospective chart review.', 'Two academic medical centers from May 2005 to December 2012.', 'The medical records of 2,417 out-of-hospital and in-hospital patients post cardiac arrest were reviewed to identify 140 of 582 survivors who received targeted temperature management.', 'None.', 'The Cerebral Performance Category scores at hospital discharge were determined by three independent abstractors. The 1-month, 6-month, and 12-month survival of these patients was determined by reviewing hospital records and querying the Social Security Death Index and by follow-up telephone calls. The association of unadjusted long-term survival and adjusted survival with Cerebral Performance Category was calculated. Of the 2,417 patients who were identified to have undergone cardiac arrest, 24.1% (582/2,417) were successfully resuscitated, of whom 24.1% (140/582) received postarrest targeted temperature management. Overall, 42.9% of patients (60/140) were discharged with Cerebral Performance Category 1, 27.1% (38/140) with Cerebral Performance Category 2, 18.6% (26/140) with Cerebral Performance Category 3, and 11.4% (16/140) with Cerebral Performance Category 4. Cerebral Performance Category 1 survivors had the highest long-term survival followed by Cerebral Performance Categories 2 and 3, with Cerebral Performance Category 4 having the lowest long-term survival (p < 0.001, log-rank test). We found that Cerebral Performance Category 3 (hazard ratio = 3.62, p < 0.05) and Cerebral Performance Category 4 (hazard ratio = 12.73, p < 0.001) remained associated with worse survival after adjusting for age, gender, race, shockable rhythm, time to targeted temperature management initiation, total duration of resuscitation, withdrawal of care, and location of arrest.
Answer: Patients with different Cerebral Performance Category scores at discharge have significantly different survival trajectories. Favorable Cerebral Performance Category at hospital discharge predicts better long-term outcomes of survivors of cardiac arrest who received targeted temperature management than those with less favorable Cerebral Performance Category scores.
Does cerebral performance category at hospital discharge predict long-term survival of cardiac arrest survivors receiving targeted temperature management*?