There was no difference between dexmedetomidine versus placebo groups in primary end points : change of somatosensory EPs at T1 , latency : 0.01 1.3 ( -0.64 , 0.65 ) vs 0.01 1.3 ( -0.64 , 0.65 ) , P = 0.43 ( -1.24 , 0.45 ) ; amplitude : 0.03 0.14 ( -0.06 , 0.02 ) vs -0.01 0.13 ( -0.07 , 0.05 ) , P = 0.76 ( -0.074 , 0.1 ) ; motor EPs amplitude at T1 : 65.1 194.8 ( -35 , 165 ; n = 18 ) vs 109.2 241.4 ( -24 , 243 ; n = 16 ) , P = 0.57 ( -113.5 , 241.57 ) ; visual EPs at T1 ( right eye ) , amplitude : 2.3 3.6 ( -0.4 , 5.1 ; n = 11 ) vs 0.3 6.0 ( -3.3 , 3.9 ; n = 16 ) , P = 0.38 ( -6.7 , 2.6 ) ; latency N1 : 2.3 3.6 ( -0.4 , 5.1 ) vs 0.3 6.0 ( -3.3 , 3.9 ) , P = 0.38 ( -6.7 , 2.6 ) ; latency P1 : -1.6 13.4 ( -11.9 , 8.7 ) vs -1.4 8.1 ( -6.3 , 3.5 ) , P = 0.97 ( -9.3 , 9.7 ) or secondary end points .