Clinical usefulness of transient visual evoked potentials (TVEPs) and steady-state visual evoked potentials (SSVEPs) results in blind dogs

Abstract

Background Visual evoked potentials (VEPs) are used to assess the function of the visual pathway from the retina to the visual cortex. According to the stimulation frequency, VEPs are classified into transient VEPs (TVEPs) and steady-state VEPs (SSVEPs). This study aimed to assess TVEPs and SSVEPs of blind dogs (n = 26) and compared them with those of healthy dogs (control group, n = 13). According to the location of the lesion that caused blindness, the dogs were classified into pre-retinal, retinal, and post-retinal groups. TVEPs and SSVEPs were assessed without anesthesia or sedation. The P2 latency and Negative 1-Positive 2 (N1-P2) amplitude were evaluated in TVEPs, and the signal-to-noise ratio (SNR) and response amplitude (RA) were evaluated in SSVEPs.Results The N1-P2 amplitude (p < 0.001), SNR (p = 0.039), and RA (p < 0.001) were significantly decreased in the post-retinal group compared with those in the control group. The SNR (p < 0.001) and RA (p < 0.001) in the retinal group were significantly lower than those in the control group. The TVEPs and SSVEPs values did not differ significantly between the pre-retinal and control groups. The receiver operating characteristic (ROC) curves showed that the area under the curve value of the RA of SSVEPs (0.928) was higher than that of the N1-P2 amplitude of TVEPs (0.873) in dogs with post-retinal lesions.Conclusions SSVEP parameters can be used to diagnose the cause of blindness and are more suitable for use in veterinary clinical practice than TVEP parameters.