Nal-Nl1/Nal-Nl2 Options - Interacoustics Affinity 2.0 Additional Information

2.0
Affinity Additional Information
2.6.7.4

NAL-NL1/NAL-NL2 options


User level: If using NAL-NL2 indicate whether you are dealing with a New user or an Experienced
user. Experienced hearing aid users have been shown to prefer more gain than people being fitted
for the first time (Keidser et al., 2008). Thus, the NAL-NL2 decreases gain 4 dB for new hearing aid
users.

Instrument: Select the type of hearing instrument your client is fitted with. This does not directly
affect the target but the information is saved with the session.

Vent size: Select the vent size your client is fitted with. This does not directly affect the target but the
information is saved with the session.

Transducer: Select the transducer used when obtaining the hearing thresholds. The selected
transducer will affect the thresholds and thereby corrections will be applied to the fitting target.
Note: The NAL-NL2 also distinguishes between tonal and non-tonal languages.
(For more information on the NAL-NL2 prescription procedure please refer to Dillon et al. 2010)
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Gain at each frequency depends on importance of each frequency. Low frequencies
are more important in tonal language. Tonal languages (such as Mandarin and
Japanese) convey more information with the pitch of speech than do non-tonal
languages (like English). Consequently, the low frequencies are given more gain for
tonal languages than for non-tonal languages (Dillon et al. 2010). In the REM440
software NAL-NL2 targets will change accordingly when selecting a tonal stimulus in
the stimulus selection (e.g. "Speech female JA"). Therefore, the system has no
separate dropdown menu for this parameter.
Name: Select the NAL-NL1 or NAL-NL2.
Age: Select the age on your client. Research on children's
performance and preference leads us to infer that children
on average prefer a few dB more gain than what NAL-
NL1 prescribes (Ching et al. 2010). For this reason the
NAL-NL2 prescribes 5 dB more gain across frequency for
children under 15 years of age compared to adults.
Furthermore, selecting the correct age is important using
a predicted RECD/REUR since these are highly
dependent on ear canal size which varies across ages.
Gender: Gender can be selected for NAL-NL2 only.
Research has shown that males on average prefer 2 dB
more gain than females with the same degree of hearing
loss (Keidser & Dillon 2006). Consequently, gain is
increased by 1 dB for males, and decreased by 1 dB for
females.
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