====== Sensory Disruptions: Flashing Lights, Animation, and Sounds ======

Some people with photosensitivity disorders may experience headaches or seizures when viewing [[https://case.edu/accessibility/what-accessibility/guidelines/flashing-content|content that flashes or has rapidly changing colors]]. Avoiding things that flash is one of the most important accessible design considerations because of the severity of the problem for people affected by it. The [[http://trace.umd.edu/peat|Trace Center’s Photosensitive Epilepsy Analysis Tool]] is helpful for testing content that might flash.

For sites that include a dark mode, it’s important to avoid [[https://webcloud.se/blog/2020-04-06-flash-of-unstyled-dark-theme/|flashes of unstyled dark mode screens]] in between page loads on slower connections.

===== Animation =====

People with vestibular disorders, vertigo, and other types of motion sensitivity may have problems with virtually all animation. We should respect browser settings to reduce motion by turning off animation.

  * [[https://alistapart.com/article/designing-safer-web-animation-for-motion-sensitivity/|Designing Safer Web Animation For Motion Sensitivity, Val Head]]
  * [[https://alistapart.com/article/accessibility-for-vestibular/|Accessibility for Vestibular Disorders, Facundo Corradini]]

===== Sounds =====

Sound design is important for people with sensory processing issues. Twitter’s (now defunct) accessibility team did [[https://blog.twitter.com/en_us/topics/product/2022/designing-accessible-sounds-story-behind-our-new-chirps|an extensive research project to make their sound effects less jarring or grating]] for people in this group.