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 The Visual Input/Output Locator Algorithm Program (VIOLA) |
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Description:
The VIOLA program is a graphical approach to determining a best-fitting input/output
(I/O) function for choosing and fitting linear or non-linear hearing aids. It is a
32-bit Microsoft Windows application that can run on most systems with Microsoft Windows?
version 95/98. The rationale behind using the VIOLA program is to select a hearing
aid based on consideration of its gain, maximum output, and I/O functioning at two
frequencies. The user must provide loudness perception data from the Contour Test
or, at the least, audiometric thresholds. In the absence of loudness data, threshold
data is used by the program to predict these values. This information is used by the
program to generate a hearing aid prescription. A screen is displayed which includes
an interactive table of hearing aid parameters at the top and adjacent graphs for
two I/O functions at the bottom. The user then specifies values for compression parameters
and observes the goodness of fit between the prescription targets and the performance
of the specified hearing aid. Parameter values may be varied until an acceptable match
is seen between targets and hearing aid performance. For additional information see
Cox, 1995.
VIOLA is a free-standing program which was a module within the IHAFF Suite software.
We no longer support nor distribute the original DOS-based IHAFF software. As of early
2001, the IHAFF Suite software could be downloaded from the web page "frye.com". Access
that Web page, select "Products", and then "Download software".
Changes from the IHAFF version 1.0c of VIOLA
This version of VIOLA requires that all Contour or loudness data and the audiometric
thresholds be entered manually. Most of the changes between this and the earlier version
have to do with the interactive I/O Curves graph screen. The changes have been made
to make the graph more user friendly and more assistive in the fitting process. In
addition to user-entered parameters, a set of five automatically selected fitting
curves containing varying amount of compression is available. There is also a database
function which accommodates the specifications on six different hearing aids of the
dispenser's choice. RMS error information provided on the hearing aid parameter table
assists in selecting the best fitting.
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Purchase:
Obtaining the VIOLA software: 
Format: Version 1.0 of the VIOLA for Windows software is currently available.
Cost: $30 (US)
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References:
Information about the development and research regarding the VIOLA may be found in:
Cox, R.M. (1995). Using Loudness Data for Hearing Aid Selection: the IHAFF Approach.
The Hearing Journal 47(2), pp. 10,39-42.Cox, R.M., Alexander, G.C., Taylor, I.M.,
Gray, G. (1997).
Cox, R.M., Flamme, G.A. (1998). Accuracy of predicted ear canal speech levels using
the VIOLA I/O-based fitting strategy. Ear & Hearing 19(2), pp. 139-148.
Cox, R.M. (1999). What has happened to the IHAFF protocol? The Hearing Journal, 52
(9): 10-18 (1999).
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807 Jefferson Avenue
Memphis, TN 38105
Phone: (901) 678-5800
Fax: (901) 525-1282
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