Auditory Disabilities
Videos have two components, images and sound. For students with hearing impairments, you will need to ensure that all audio components are "captured" and presented to students. This is most often in the form of closed captioning. The bonus is that captions are part of universal design and are beneficial to every type of learner.
This video explains the essentials for producing content that is accessible to students with hearing impairments, and it also explains how captions can be beneficial to students without hearing impairments.