Unilateral or asymmetric localization of lambda waves is not a pathologic finding.

@article{Weber2005UnilateralOA,
  title={Unilateral or asymmetric localization of lambda waves is not a pathologic finding.},
  author={P. -C. Weber},
  journal={Journal of child neurology},
  year={2005},
  volume={20 3},
  pages={250-1}
}
This article reports on three children who underwent an electroencephalographic examination. All three showed the feature of asymmetric lambda waves, which is usually interpreted as a pathologic focal phenomenon. The report documents that asymmetric lambda waves and photic driving might be normal variants, not requiring further investigation.