I can't produce a reliable summary here: the "article text" provided is just the site's navigation menu and header (band names, "Music/Film/Travel/Art/News/Shop/Mailing List", a "Cover Story | Yard Act" link) — it contains no actual reporting on what Brian Johnson said about his hearing loss. There's no quote, no details, and no context to summarise.

Could you paste the actual body text of the article, or confirm you'd like me to try fetching the URL directly? I don't want to invent details about the cause of his hearing loss that aren't actually in the source.