Somatosensory evoked potentials in severe traumatic brain injury: a blinded study

Object. Beginning in 1979, the results of somatosensory evoked potential (S SEP) monitoring have been used to predict outcome in patients who have suff ered severe brain trauma. The data indicate that if the cortical components of the SSEPs were bilaterally absent, the outcome was always death or a ve getative state, but previous studies have not been blinded. The aims of thi s study were to correlate the results of SSEP recordings with the outcome i n a prospectively blinded manner and to assess whether monitoring of SSEPs was a useful adjunct to clinical judgment in the prediction of outcome. Methods. The authors studied 105 severely head injured patients (median Gla sgow Coma Scale score of 6) who were admitted to the Waikato Intensive Care Unit. The upper limb SSEPs were classified according to the central conduc tion time (CCT) as normal, of increased latency, or absent. The outcome as assessed using the Glasgow Outcome Scale (GOS) score was evaluated 12 month s after the injury. Conclusions. Of 51 patients with a bilaterally normal CCT, 29 (57%) had a g ood outcome (GOS Score 5). Any delay in CCT was associated with a decreased incidence of good outcome (30%). Unilateral absence of the cortical compon ent of the SSEP was usually associated with a poor outcome (death or severe disability), and bilateral absence was always associated with a poor outco me. The authors conclude that SSEPs correlate well with outcome and that th is is not the result of investigator bias.