Motion-evoked pattern visual evoked potentials in glaucoma

Purpose: To evaluate motion-evoked brain potentials for glaucoma diagnosis. Patients and Methods: Stripe patterns were presented in Maxwellian view und er different stimulus conditions not combined in a factorial design. Spatia l frequencies of 0.33 and 0.88 cycles/degree, with speeds of 10 and 5.9 deg rees/second and contrasts of 0.04 and 0.93 were used. A 32 degrees whole fi eld and a peripheral 32 degrees-27 degrees annular stimulus were used. Dura tion of motion was 200 milliseconds, and the interstimulus interval was 1,8 00 milliseconds. Recordings were obtained from Oz and P3. Thirty-four healt hy patients, 12 glaucoma suspects, and 26 patients with open-angle glaucoma were tested. Results: Normal response amplitudes decrease with age only under low contra st conditions, whereas response peak times increase under most conditions. Normal responses are much larger at P3 than at Oz, whereas in open-angle gl aucoma, much less difference is seen. In these patients, the response ampli tude at P3 is significantly reduced under all conditions, whereas a delay i n peak time is less pronounced. A small but significant negative correlatio n (r = -0.44, P < 0.05) between response amplitude and mean perimetric defe ct was observed only with the annular stimulation. At a specificity of 90%, a sensitivity of approximately 76.7% for the low contrast and low spatial frequency condition was observed, Conclusions: Motion-evoked responses recorded at P3 are altered in open-ang le glaucoma and thus can be useful as an additional test in glaucoma diagno sis.