Definition: 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.
Input: Context: It is now well accepted that traumatic white matter injury constitutes a critical determinant of post-traumatic functional impairment. However, the contribution of preexisting white matter rarefaction on outcome following traumatic brain injury (TBI) is unknown. Hence, we sought to determine whether the burden of preexisting leukoaraiosis of presumed ischemic origin is independently associated with outcome after TBI.', 'We retrospectively analyzed consecutive, prospectively enrolled patients of ≥50\xa0years (n\xa0=\xa0136) who were admitted to a single neurological/trauma intensive care unit. Supratentorial white matter hypoattenuation on head CT was graded on a 5-point scale (range 0-4) reflecting increasing severity of leukoaraiosis. Outcome was ascertained according to the modified Rankin Scale (mRS) and Glasgow outcome scale (GOS) at 3 and 12\xa0months, respectively.', 'After adjustment for other factors, leukoaraiosis severity was significantly associated with a poor outcome at 3 and 12\xa0months defined as mRS 3-6 and GOS 1-3, respectively. The independent association between leukoaraiosis and poor outcome remained when the analysis was restricted to patients who survived up to 3\xa0months, had moderate-to-severe TBI [enrollment Glasgow Coma Scale (GCS) ≤12; p\xa0=\xa00.001], or had mild TBI (GCS 13-15; p\xa0=\xa00.002), respectively.
Answer: We provide first evidence that preexisting cerebral small vessel disease independently predicts a poor functional outcome after closed head TBI. This association is independent of other established outcome predictors such as age, comorbid state as well as intensive care unit complications and interventions. This knowledge may help improve prognostic accuracy, clinical management, and resource utilization.

Does severe leukoaraiosis portend a poor outcome after traumatic brain injury?