head injury than their conscious counterparts. Eighty-four patients were able to be followed up adequately, and the results are as follows: 40% became conscious by 6 months, 52% regained consciousness by 1 year, and 58% recovered consciousness within 3 years. Of the remaining 35 (42%) patients, 20 had died and 15 remained in their vegetative state. Analyses of neurologic and demographic features did not indicate any predictive factors for recovery.


Levin et al. (1991a) investigated the relationship between intracranial hypertension and memory deficit 6 months (n = 133) and 1 year (n = 126) after severe closed head injury, using neurobehavioral data from the TCDB. Memory was assessed by administering auditory verbal tests (prose recall from the Wechsler Memory Scale, the Selective Reminding Test, and the Digit Span subtest of the Wechsler Adult Intelligence Scale) and nonverbal visual tests. Those with intracranial hypertension in the first 72 hours after injury displayed some memory impairment at the 6-month assessment; impairment diminished with time and was not significant at the 1-year followup.


Chestnut et al. (1993) prospectively studied the effects of early and late hypotension (defined by systolic blood pressure ≤ 90 mm Hg) on mortality in patients admitted to the TCDB. Of the 1,030 patients admitted, 284 were brain-dead, did not survive resuscitation, or had suffered gunshot wounds, and data on 47 were inadequate (with respect to prehospital course or initial blood pressure or arterial blood-gas results); therefore, 699 patients were eligible for study at the time of hospital arrival. Early shock, defined as hypotension from the time of injury to resuscitation, was experienced by 35% of patients. Mortality was associated with the occurrence of shock: no shock, 27%; shock any time during the early phase, 50%; and presenting with shock, 60%. The association between outcome and hypotension when age, hypoxia, and severe multiple trauma were controlled for was extremely significant (p < 0.0001). Late shock captured the remainder of the patients’ stay after the first intensive-care-unit (ICU) shift (8 hours). Of the 493 eligible patients, 32% experienced late shock. There was a significant difference (p < 0.001) in mortality and morbidity between no shock (17%) and a recording of hypotension after the first ICU shift (66%).


Lu and colleagues (2005) retrospectively studied the decrease in mortality due to severe brain injury from 1984 to 1996. The sample consisted of extracted data from numerous study populations, including 635 patients from the TCDB in 1984–1987 (patients who had penetrating injury, who were deceased on arrival, or who were under 16 years old were excluded). The cohort also included 382 patients from the Medical College of Virginia and 822 from clinical-trial databases. In the total cohort of 1,839 patients, 526 (29%) died. Mortality in the severely brain-injured decreased from 39% in 1984 to 27% in 1996; there was a significant difference (p < 0.0001) in head-injury mortality between 1984–1987 (37%) and 1988–1996 (24%). After adjustment for a variety of factors—including age, admission motor score, and pupillary response—the difference remained significant (p < 0.05).

OTHER COHORT STUDIES

Bryant and Harvey Studies

Bryant and Harvey (1999a) conducted a prospective cohort study to compare rates of acute stress disorder (ASD) and PTSD in MVA survivors who sustained a mild TBI with rates in MVA survivors who did not have a TBI. A major trauma center in New South Wales, Australia,



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