From my own research, the two word score measures that Frequency Therapeutics is using in all of the FX-322 trials are significantly better indicators of hearing performance than pure tone audiometry.
Both utilize the the Consonant-Nucleus-Consonant (CNC) lists; These are made up of a randomly selected sample of 50 English words from a bank of about 1000. The words chosen require enough hearing function to distinguish the slight detailed differences in common words. Like: time and dime, home and foam, etc. The bank typically includes both words (time and dime, for example). Furthermore, there's enough data on the CNC lists that researchers know what words are 'harder' and 'easier' to distinguish, so the lists are updated to ensure an even distribution of hard and easy words for any repeated random selection of a 50-word test. Apparently word pairings that get above a certain % of "correct" guesses over time are removed from the revised lists.
The hearing function needed to distinguish CNC - Words-in-Quiet in English, actually requires a sufficient range/sensitivity of hearing across all frequencies in the cochlea. And, because the word list is random, and resampled about every 30 days, is a good indicator of actual improvement from FX-322.
To make matters more challenging, the CNC - Words-in-Noise uses the same list of already challenging words that really put the entire cochlea to test, and add in background audio that intermixes with the words. This requires enough healthy hearing function to not only distinguish the subtle differences between words, but also to filter out a layer of talking overtop of the words.
I'm starting to wonder if these word tests actually are a better indicator of both IHC and OHC function.
I'd also like to point out that the Words-in-Quiet and Words-in-Noise test is probably a better indicator of restoring hearing for people who are experiencing distortion, and other hearing-damage related anomalies. If the restored cochleas are able to detect fine details in words, that sensitivity/clarity gain should help with people who experience distortion listening to music and from other ambient noises (fans, motors, water running, etc). I think this because the word score tests are an indicator that the brain is receiving finer/more sensitive intricate details about sound that is broken down in the cochlea, so as we see language improvements, that should carry over other sound-related events.
Finally, audiogram isn't good because it doesn't show IHC function or any noise-related function.