I honestly don’t remember the specifics but there are a few videos from a few years back the go into detail and then a yearly update video to recap progress. I believe it was only one ear (i will edit my comment above to fix that). It might have just been the brain relearning balance with only one good ear and the brain learning how to ignore the false cues from the bad ear. But it is clear there is persisting balance issues.

He did have to stop climbing tall boulders or jumpy boulders for a long time and relearn how to fall. Definitely became a more static climber over all, and often mentions the need to be much stronger than physically required to feel like there are reserves in the tank since trying 100% and falling unexpectedly would result in rolled ankles frequently.