Abstract
The objectives of the study were to evaluate the validity of intraoperative flash visual evoked potentials (VEPs) when electroretinograms (ERGs) were unstable, to compare white versus red light-emitting diodes, and to assess the impact of luminance on ERG variability. Thirty patients were included (Inomed system; pre- and postoperative visual fields). Possible changes in visual fields were assessed with mean defects in perimetry. The receiver operating characteristic (ROC) curves of normalized VEPs and of normalized and corrected VEPs with ERGs were compared. Thirty-two eyes could be analyzed in 20 patients (mainly gliomas and meningiomas): 2 had a severe defect in their visual field, and 6 had a mild defect. The receiver operating characteristic curve indicated (1) normalized and corrected VEPs with ERGs were more reliable than normalized VEPs only (P < 0.03) and (2) an alarm threshold of 80% of normalized and corrected VEPs. No significant difference in variability of ERGs was found with white or red light-emitting diodes with this system. Increased luminance improved stability of ERGs (P < 0.05). Normalization and correction of VEPs with ERGs improved the validity of VEPs and indicated a 20% decrease as alarm criterion. This normalization and correction with peripheral excitation could be generalized to improve the reliability of neuromonitoring.
Overview
- The study aimed to evaluate the validity of intraoperative flash visual evoked potentials (VEPs) when electroretinograms (ERGs) were unstable, to compare white versus red light-emitting diodes, and to assess the impact of luminance on ERG variability. Thirty patients were included (Inomed system; pre- and postoperative visual fields).
- The methodology used for the experiment included assessing possible changes in visual fields with mean defects in perimetry, comparing the receiver operating characteristic (ROC) curves of normalized VEPs and of normalized and corrected VEPs with ERGs, and analyzing the impact of white or red light-emitting diodes on ERG variability. The study used the Inomed system and included 20 patients with mainly gliomas and meningiomas. The study found that normalized and corrected VEPs with ERGs were more reliable than normalized VEPs only (P < 0.03) and that an alarm threshold of 80% of normalized and corrected VEPs was appropriate. No significant difference in variability of ERGs was found with white or red light-emitting diodes with this system. Increased luminance improved stability of ERGs (P < 0.05). Normalization and correction of VEPs with ERGs improved the validity of VEPs and indicated a 20% decrease as alarm criterion. The study's primary objective was to improve the reliability of neuromonitoring.
Comparative Analysis & Findings
- The study compared the outcomes observed under different experimental conditions or interventions detailed in the study. The results showed that normalized and corrected VEPs with ERGs were more reliable than normalized VEPs only (P < 0.03) and that an alarm threshold of 80% of normalized and corrected VEPs was appropriate. No significant difference in variability of ERGs was found with white or red light-emitting diodes with this system. Increased luminance improved stability of ERGs (P < 0.05).
- The key findings of the study were that normalized and corrected VEPs with ERGs were more reliable than normalized VEPs only, and that an alarm threshold of 80% of normalized and corrected VEPs was appropriate. The study also found that increased luminance improved stability of ERGs. These findings suggest that normalization and correction of VEPs with ERGs can improve the reliability of neuromonitoring and provide a more accurate assessment of visual function during surgery.
Implications and Future Directions
- The study's findings have significant implications for the field of research or clinical practice. The study suggests that normalization and correction of VEPs with ERGs can improve the reliability of neuromonitoring and provide a more accurate assessment of visual function during surgery. The study also highlights the importance of using appropriate lighting conditions during surgery to improve the stability of ERGs. Future research could explore the use of different types of light-emitting diodes or other types of lighting to further improve the stability of ERGs and the reliability of neuromonitoring.