Research Reports - Limited predictive power of hospitalization variables for long-term cognitive prognosis in adult patients with severe traumatic brain injury
J Neuropsychol. 2012 Nov 20.
de Oliveira Thais ME, Cavallazzi G, Formolo DA, de Castro LD, Schmoeller R, Guarnieri R, Schwarzbold ML, Diaz AP, Hohl A, Prediger RD, Mader MJ, Linhares MN, Staniloiu A, Markowitsch HJ, Walz R
OBJECTIVES: Traumatic brain injury (TBI) is a main cause of mortality and
morbidity. Association studies between hospitalization variables and cognitive
impairment after TBI are frequently retrospective, including non-consecutive
patients showing variable degrees of TBI severity, and poor management of missing
(drop out) cases. METHODS: We assessed prospectively the demographic and
hospitalization variables of 234 consecutive patients with severe TBI (admission
Glasgow Coma Scale [GCS] ≤8) and determined their independent association with
cognitive performance in a representative sample (n = 46) of surviving patients
(n = 172) evaluated 3 (±1.8) years after hospitalization. RESULTS: In all, 85% of
patients were male and the mean age was 34 (SD ±13) years. The education level
was 9 (±4.7) years. As expected, education and age showed a moderately to strong
linear relationship with the cognitive performance in 14 of 15 neuropsychological
tests (R coefficient = 0.6-0.8). The cognitive test scores were not independently
associated with gender, admission GCS, associated trauma, and Marshal CT
classification. Admission-elevated blood glucose levels and the presence of
sub-arachnoid haemorrhage were independently associated with lower scores on Rey
Auditory Verbal Learning retention and Logical Memory-I tests, respectively.
CONCLUSIONS: After correction for education and age distribution, the variables
that are commonly associated with mortality or Glasgow Outcome Scale including
admission pupils' examination, Marshal CT Classification, GCS, and serum glucose
showed a limited predictive power for long-term cognitive prognosis.
Identification of clinical, radiological, and laboratory variables as well as new
biomarkers independently associated with cognitive outcome remains an important
challenge for further work involving severe TBI patients.