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Patients must be reassessed frequently as their neurological condition often changes rapidly and even precipitously. Assessment every 2 hours is warranted in all patients with moderate head injury (GCS score less than 13 but higher than 8). These patients should also undergo computed tomography (CT) scan of the head and should be admitted to the hospital. If no improvement is noticed within hours after admission for observation, the CT scan should be repeated.

The most useful role of electroencephalography (EEG) in head injuries may be to assist in the diagnosis of nonconvulsive status epilepticus, which may account for a substantial number of coma presentations (up to 8% in one study). Extreme accuracy (99.5%) in prediction of the negative outcome in brain injury is associated with the bilateral absence of somatosensory evoked potentials (6).

Magnetic resonance imaging (MRI) typically is reserved for patients who have mental status abnormalities unexplained by CT scan findings. Magnetic resonance imaging has been demonstrated to be more sensitive than CT scanning, particularly at identifying nonhemorrhagic diffuse axonal injury lesions. In some cases, MRI has shown degeneration of the corpus callosum following severe head injuries with axonal damage. Increased total lesion volume on fluid-attenuated inversion-recovery (FLAIR) MRI images has been demonstrated to correlate with poor clinical outcomes, while diffusion-weighted imaging may disclose abnormal lesions in patients with head injury even when their conventional MRI scans are unremarkable. Remember that white matter hyperintensities in patients with head trauma may recede when initial MRI scans are compared with those obtained in the months following the injury (1,4).

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