Subject: Re: [AUDITORY] National Hearing Test From: "Watson, Charles S." <watson@xxxxxxxx> Date: Wed, 30 Oct 2013 16:02:50 +0000 List-Archive:<http://lists.mcgill.ca/scripts/wa.exe?LIST=AUDITORY>Tom, I know it is hard to accept that the telephone test works as well as it doe= s, given the experiences we have all had with a range of signal qualities f= or unselected home telephones. However the data showed that tests taken wi= th over 100 different home phones used by the veterans in our validation st= udy yielded a similar correlation between the telephone SNR for 50% correct= recognition and average pure-tone thresholds to that obtained with the car= efully selected telephones used to administer the test in three VA clinics.= We have also tested a sample of different phones to determine the range o= f distortion and bandwidths, and found them to be acceptable if speech hear= d over them was not noticeably distorted. =20 Most importantly, the range of absolute levels delivered by various phones = would be quite important if the test measured pure-tone thresholds in the q= uiet. The test works because of the insight of Smits and his colleagues th= at SNR thresholds can be quite reliable under a range of reproductive condi= tions for which absolute thresholds would be virtually meaningless. Chuck Watson -----Original Message----- From: Tom Brennan [mailto:g_brennantg@xxxxxxxx=20 Sent: Wednesday, October 30, 2013 6:01 AM To: Watson, Charles S. Cc: AUDITORY@xxxxxxxx Subject: Re: National Hearing Test Actually, my comments about telephone service are based on having lived in = Germany for nearly five years and having a number of friends in Europe. I = do believe their telephone system superior to ours. This is especially tru= e of their cell phone system but is to a lesser degree of their land lines. I wonder if some kind of feedback loop could legally be set up to help know= what kind of phone system a client doing this test i susing. Of course, another issue revolves around the fact that most telephones now = allow the user to control the volume of the receiver thus adding another co= nfo7unding variable to the mix. Tom Tom Brennan KD5VIJ, CCC-A/SLP web page http://titan.sfasu.edu/~g_brennantg/sonicpage.html