Re: standards of speech intelligibilty for the hearing impaired?

[Christine Rankovic <rankovic@xxxxxxxxxxxxxxxx>]

Ward:



I have not yet found a clear failure using the audiogram with Fletcher's 
full-blown AI calculation, so my working hypothesis is that "additional 
factors" are not necessary.  I've examined the Fletcher AI's ability to 
predict speech intelligibility scores using data from many different 
published reports, and I'm always looking for more published data which may 
pose a challenge to this hypothesis.  Many (most) published studies provide 
inadequate descriptions of calibration for the purpose of AI calculation.



Regarding your question, I have looked at AI predictions for 
hearing-impaired listeners in steady-state noise, and I found that no 
correction factors were necessary (see Rankovic 1997; 1998 in previous 
email).  I evaluated data from a study of hearing-impaired listeners in 
which CNC word lists were presented in a multitalker babble taken from the 
SPIN test, and I found word score predictions were good (I haven't published 
this finding).  It is notable that the SPIN babble was designed to have no 
substantial temporal holes so it is essentially a steady noise.



Single-talker interference may be an interesting case that I have not yet 
studied .  Also, I have not yet examined the ability of the AI to predict 
speech intelligibility in background noises constructed to have temporal 
holes of controlled depth and duration, although I am aware that some 
researchers have collected this type of data.



Christine Rankovic, PhD

rankovic@xxxxxxxxxxxxxxxx





----- Original Message ----- 
From: "Ward R. Drennan" <drennan@xxxxxxxxxxxxxxxx>
To: "Christine Rankovic" <rankovic@xxxxxxxxxxxxxxxx>
Cc: <AUDITORY@xxxxxxxxxxxxxxx>
Sent: Thursday, February 21, 2008 1:54 PM
Subject: Re: standards of speech intelligibilty for the hearing impaired?


> Sure, the audiogram (ie audibility) is the primary predictor of speech 
> intelligibility, but don't you think the additional factors could improve 
> predictability of practical tasks such as speech intelligibility in noise 
> and babble backgrounds?
>
>
>
> Ward R. Drennan, Ph. D.
> VM Bloedel Hearing Research Center
> Department of Otolaryngology
> University of Washington Box 357923
> Seattle, WA 98195
> Office: (206) 897-1848
> Fax: (206) 616-1828