Visible Speech Mapping (Vspm440); About Visible Speech Mapping - Interacoustics Affinity 2.0 Additional Information

2.0
Affinity Additional Information

2.9 Visible Speech Mapping (VSPM440)

2.9.1

About Visible Speech Mapping

Visible Speech or Speech Mapping is a term widely used amongst manufacturers of various systems. It
covers a kind of verification-, fitting-, counselling- or sales tool that provides a live demonstration of the
hearing aid features in a clear layout while the client is wearing the instruments. Visible Speech Mapping
addresses the complicated task of explaining clinical and technical issues to people outside audiology.
Interacoustics Visible Speech Mapping is designed to assist you in the important process of fitting and
counselling. The system merges verification and counselling into one screen display visualizing the SPL at
the ear drum with and without hearing aids respectively. As a result you are able to match amplification to
target (e.g. DSL mi/o or NAL-NL1/NAL-NL2) on the aided display and at the same time show the benefit of
using hearing aids by comparing to the unaided condition. The comprehensive layout showing dynamic
range, normal hearing thresholds, and sound examples assists in the process of communicating the
measurement results and helping achieve realistic expectations.
Various speech signals can be used with Visible Speech Mapping. The signal can be generated using a live
microphone input from the client, their companion, the audiologist, or speech samples can be digitally
imported from other sources. For both verification and counselling purposes, calibrated LTASS based
speech signals such as ISTS (International Speech Test Signal) are also available. The idea is to present
unaided and aided speech information to the hearing impaired individual.
Visible Speech Mapping is also available in the paediatric fitting. When it is not feasible to do real-ear
measures, Visible Speech Mapping can be performed using the individual RECD (Real-Ear-to-Coupler
Difference). After measuring the RECD values, the hearing aid is positioned in the test box and verification or
counselling can be performed here using the same principles as for REAR/REIG.
Visible Speech Mapping can be used in all sorts of ways. Clients have very different needs and this section
demonstrates the options offered by the system. The clinician can then tailor the input to meet their individual
requirements.
People with hearing loss are entering a whole new world with a terminology all of its own. By helping them to
absorb and understand what they need to know, Visible Speech Mapping makes counselling and verification
a positive experience.
Note: The Visible Speech Mapping system is based on the LTASS (Long Term Average Speech Spectrum)
and the concept of time-aligned response for a given percentile of the distribution of short-term band sound
pressure level of the speech signal. For each frequency band, the LTASS response is the gain averaged
over the stimulus duration. Speech response is established for a given percentile for each 100 ms sample of
the speech stimulus. These responses are averaged over the duration of the stimulus presentation.
The system produces an estimated REAR and/or a 2cc coupler response for the LTASS and preferred
percentiles of the selected signal. The recommended percentiles are the 30
The system employs three LTASS based signals Male Speech, Female Speech, and ISTS (International
Speech Test Signal). In order to get at precise measure it is highly recommended to use one of these on
which the calculations are based. However, other signals can also be employed if preferred by the individual
clinician. Live Speech is not an option for verification.
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, 65 and 99 percentiles.
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