Make R Markdown output accessible - r

Question

I'd like to output an accessible version of a presentation I'm making with R Markdown ioslides. At this point, I've been struggling to find much documentation on alt-text for dynamically generated images - not pointers to images - there's lots of information available online on that front.
Seems like the easiest thing to do might be to output my document as a word_document instead of a presentation, and ensure that figures have captions, using fig.cap argument in the chunk header.
However, I'd like the captions to be available only as alt-text - so that this document doesn't look strange to folks who aren't using screen reader tech (I'd like to make my alt-text nice and descriptive, but for folks who can see ok, this will seem odd, because the graph will do the talking instead).
I've included a reprex below. How can I still include the fig.cap as alt-text in the output word document, but not have it show up underneath the graph?
Also, if you are aware of any good resources on making RMarkdown docs accessible, I am all ears!!
Thanks for your help.
---
title: 'test doc'
author: "Nova"
date: "April 2020"
output:
word_document:
fig_height: 5
fig_width: 10
height: 500
widescreen: yes
width: 500
---
```{r setup and comments, include=FALSE}
knitr::opts_chunk$set(echo = FALSE,
message = F,
warning = F,
fig.height = 5,
fig.width = 10,
fig.cap = NA)
library(ggplot2)
```
## cars
```{r ggplot, include=T, fig.cap = "this is some alternative text about this figure"}
ggplot(cars)
```

Answer 1

I'd go back to some kind of HTML output, because it's simpler.
If you want ioslides output, you can use fig.cap="Some alt text" in the chunk option to set the alt text for the figure. Unfortunately, this also generates a visible caption, but you can suppress that. For one slide, just insert inline CSS:
<style>
.caption {
display:none;
}
</style>
somewhere on the slide before the figure. To do it for the whole presentation, put that text in a .css file and include it with YAML like
output:
ioslides_presentation:
css: style.css
It's probably also possible to change the template for this output style, but that looks like a lot more work.