Serial Mini-Mental Status Examination to Evaluate Cognitive Outcome in Patients with Traumatic Brain Injury

OBJECTIVE This study was aimed at finding out the changes in cognitive dysfunction in patients with traumatic brain injury (TBI) and investigating the factors limiting their cognitive improvement. METHODS Between January 2010 and March 2014, 33 patients with TBI participated in serial mini-mental status examination (MMSE). Their cognitive functions were statistically analyzed to clarify their relationship with different TBI status. Patients who developed hydrocephalus were separately analyzed in regards to their cognitive function depending on the placement of ventriculoperitoneal shunt (VPS). RESULTS Bi-frontal lobe injury (β=-10.441, p<0.001), contre-coup injury (β=-6.592, p=0.007), severe parenchymal injury (β=-7.210, p=0.012), temporal lobe injury (β=-5.524, p=0.027), and dominant hemisphere injury (β=-5.388, p=0.037) significantly lowered the final MMSE scores. The risk of down-grade in the prognosis was higher in severe parenchymal injury [odds ratio (OR)=13.41, 95% confidence interval (CI)=1.31-136.78], temporal lobe injury (OR=12.3, 95% CI=2.07-73.08), dominant hemisphere injury (OR=8.19, 95% CI=1.43-46.78), and bi-frontal lobe injury (OR=7.52, 95% CI=1.31-43.11). In the 11 post-traumatic hydrocephalus patients who underwent VPS, the final MMSE scores (17.7±6.8) substantially increased from the initial MMSE scores (11.2±8.6). CONCLUSION Presence of bi-frontal lobe injury, temporal lobe injury, dominant hemisphere injury, and contre-coup injury and severe parenchymal injury adversely influenced the final MMSE scores. They can be concluded to be poor prognostic factors in terms of cognitive function in TBI patients. Development of hydrocephalus aggravates cognitive impairment with unpredictable time of onset. Thus, close observation and routine image follow-up are mandatory for early detection and surgical intervention for hydrocephalus.