Audioscan Verifit - Manual (Page 71)

Verifit ® User's Guide Version 3.12  May 2015
Graph, table or 2cc target format
Most on-ear test screens may be viewed in graphic or tabular format.
• In RECD and Directional tests, highlight and <PICK> [Format] to toggle between [Graph] and [Table]
views.
• In Speechmap and Insertion gain, highlight and <PICK> [Format], then highlight and <PICK> [Graph],
[Table] or [2cc targets] from the drop-down list.
• In [2cc targets] format, reserve gain and fitting formula may be changed. Highlight & <PICK> the
appropriate window, then highlight & <PICK> the reserve gain or fitting formula from the drop-down list.
In Speechmap, if DSL or NAL-NL1 has been selected as a target method, then 2cc coupler targets for user gain,
full-on gain and OSPL90 are provided. The full-on gain is just the user gain plus the reserve gain. If no target
method has been selected, only 2cc OSPL90 values are indicated. Target gains are for speech-like signals at a
70 dB input SPL; OSPL90 targets are for 90 dB pure tones.
On-ear targets are converted to 2cc coupler values by using age-appropriate average or measured (if available)
RECD values and the appropriate microphone location effects for the desired style of hearing instrument.
The gain values given assume the hearing instrument is linear for a 70 dB speech input. This assumption is
necessary to allow the microphone location effects to be incorporated.
For BTE and body aids, the 2cc coupler values provided assume a fully-occluding earmold with #13 tubing
extending to the medial tip of the earmold and a "standard" canal length. If a different type of mold is used,
alterations to these values should be made to account for the different acoustic characteristics. For CIC
instruments, the 2cc values take into account that the instrument, when deeply inserted into the ear canal, will
produce a greater SPL in the ear than that measured in the ITE coupler.
SPL or HL scale
In Speechmap and Insertion gain tests you may view results in either dB HL or dB SPL.
Insertion gain tests view the hearing aid as improving the sound-field threshold. In Insertion gain, the HL scale
presents aided results as improved sound-field thresholds while the speech region remains fixed.
Speechmap tests view the hearing aid as increasing the ear canal SPL. Speech gets louder but the threshold
remains fixed. On the HL scale in Speechmap, normal ear canal threshold becomes the 0 dB HL line and all data
is replotted using this reference. A physical interpretation of the data is difficult and the use of HL in Speechmap
is not recommended. All instructions given in this guide assume the SPL Speechmap scale.
To change the scale:
Highlight and <PICK> [Scale] to toggle between a dB SPL and dB HL scale.
Hide or show on-ear curves
To hide or show test curve(s):
1. Highlight, then <PICK> Curve [Hide/Show].
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