The clinical application of visual evoked potential and auditory evoked potential in patients with attention de-ficit and hyperactive disorder, mental retardation and conduct disorder

Objective To investigate the clinical application of various parameters of visual evoked potential (VEP) and auditory evoked potential (AEP) in patients with attention deficit and hyperactive disorder (ADHD), mental retardation (MR) and conduct disorder (CD). Methods Thirty-seven ADHD patients, 24 MR patients, 22 CD patients and 36 normal subjects were included in this study. The VEP and AEP were recorded from every subject and analyzed. Results A significant difference was found among 4 subject groups, with both latencies (Oz/N_1, P_2) and amplitudes of VEP (Cz/P_2, P_3 and Oz/P_3 ) (P0.05~0.01), and significant difference among 4 subject groups was found with both latencies (Pz/N_2 and Oz/P_3 )and amplitudes (Pz/N_1, P_2 and Oz/N_3) (P0.05~0.01) of AEP. Compared with normal subjects, those in the MR group showed shortened latencies and decreased amplitude of AEP and VEP(normal subjects: N_1 latency of VEP/Oz 107±22 ms, N_2 latency of AEP/Pz 219±28 ms ; MR: N_1 latency of VEP/Oz 129±29 ms, N_2 latency of AEP/Pz 244±27 ms) (P0.01), ADHD group had shortened VEP/P_2 latency (P_2 latency of VEP/Oz: 188± 28 ms in normal group, 167±30 ms in ADHD group, P0.01) delayed AEP/N_2,P_3, decreased VEP amplitude and increased AEP/N_1,P_2 amplitudes(N_1 amplitudes from Oz are 4.5±1.9 μV in normal group, 6.3±3.4 μV in ADHD group; P_2 amplitudes from Pz are 2.3±1.2 μV in normal group, 4.2±2.2 μV in ADHD group, P 0.01) , while EP changes of CD group intermediated that of ADHD and CD. Conclusion The delayed latencies and decreased amplitudes could be seen in MR group, while the shortened latencies and increased amplitudes could be observed in the ADHD group. The characteristics of the evoked potentials from ADHD and MR patients deserve more intensive studies.[JP]