About LiSN-S

Listening in Spatialized Noise - Sentences Test (LiSN-S)


Background

Developed by the National Acoustic Laboratories (NAL), and distributed exclusively by Phonak, the LiSN-S is an adaptive, virtual-reality, test that measures speech perception ability in noisy environments. Importantly, it also measures the ability of people to use the spatial cues that normally help differentiate a target talker from distracting speech sounds. An inability to use this information has been found to be a leading cause of difficulty understanding speech in noisy environments, such as the classroom.

Offered as a combined hardware and software package, LiSN-S comprises a proprietary PC software program, performance headphones and a USB-attachable Phonak soundcard. Once installed, the LiSN-S system employs advanced mathematical algorithms to create a virtual three-dimensional acoustic space under the headphones.

The hearing professional can simulate different speech environments, with target and distracter voices competing for the client’s attention. By asking a client to repeat the sentences spoken by the target voice, the audiologist is able to accurately assess the child's ability to identify target speech in challenging situations.

LiSN-S is not only accurate but the test is also quick and easy to administer; in just 20 minutes, audiologists are provided with clear results in easy-to-print document format.


LiSN-S in More Detail

A simple repetition-response protocol is used to assess a listener’s speech reception threshold (SRT) for target sentences presented in competing speech maskers (children’s stories). The targets are made to appear as if they are coming from directly in front of the listener (0° azimuth) whereas the maskers vary according to either their perceived spatial location (0° vs. ±90° azimuth simultaneously), the vocal identity of the speaker/s of the stories (same as, or different to, the speaker of the target sentences), or both. This test configuration results in four listening conditions: same voice at 0º (SV0 or low cue SRT); same voice at ±90º (SV90); different voices at 0º (DV0); and different voices at ±90º (DV90 or high cue SRT).

Performance on the LISN-S is evaluated on the low and high cue SRT, as well as on three “advantage” measures. These advantage measures represent the benefit gained when either talker (pitch), spatial, or both talker and spatial cues are incorporated in the competing speech, compared to the baseline (low cue SRT) condition where minimal cues are present. By using advantage measures the influence of higher-order language, learning and communication skills on test performance is minimized. For example, as these skills affect both the SRT when the distracters are presented at 0°, and the SRT when they are spatially separated at ±90°, these skills will have minimal effect on the difference in dB between the SRTs in these two conditions. Therefore, the differences that inevitably exist between individuals can be controlled for, allowing for clearer evaluation of their abilities to use spatial and voice cues to aid speech understanding.

Performance on each of the various LiSN-S measures is reported as both SRTs and z-scores. A z-score indicates a person’s performance relative to the average for people of the same age. It is expressed in population standard deviation (SD) units, so a z-score of -2 corresponds to a score two standard deviations below average. If the scores are normally distributed, only 2.5% of people will have scores poorer than -2 SD. Similarly, a z-score of -1 corresponds to one standard deviation below average, which only 16% of people would score poorer than.


SRT & Advantage Measures

Normative Data and Test-Retest Reliability

LiSN-S is highly sensitive and scientifically robust; its high test-retest reliability allows the hearing professional to test whether a client’s listening skills have improved after some form of intervention. The LiSN-S is available in Australia, New Zealand and the United Kingdom. Normative data exists for people aged 6 to 60 years. A North American-accented version of the LiSN-S is available in the United States of America and Canada. For more details on normative data, calculation of cut-off scores and test-retest reliability data, see the links below.


Critical Difference Scores

One-sided critical differences are provided in order to determine whether an individual has improved on the LISN-S, following remediation or compensation, taking the mean test-retest differences into account. That is, for an individual SRT or advantage measure score to be significant at the 95 percent confidence interval level, the score must increase by 1.64 times the standard deviation of the test-retest difference plus the mean test-retest difference. For more details on the LiSN-S critical difference scores see the link below.


LiSN-S Spatial Processing Disorder “Pattern Measure"

The Spatial Processing Disorder Pattern Measure provides an indicator of whether a set of LiSN-S results is indicative of the spatial processing disorder (SPD). The pattern measure is more reliable than just observing the spatial advantage score alone, as it uses all four measures in its calculation. For more details on the LiSN-S pattern measure see the link below.


LiSN-S for Hearing-Impaired People

The LiSN-S is also suitable for use with hearing-impaired people. A prescribed gain amplifier has now been incorporated into the LiSN-S software which allows audiologists to assess how well hearing-impaired people will be able to understand speech in background noise, prior to hearing aid fitting.


LiSN-S PGA

Purchasing the LiSN-S

Clinicians wishing to purchase the LiSN-S within Australia can contact Phonak Australia on (02) 8858 1800. Clinicians in North America, the UK or New Zealand can contact Phonak in their own country.


Audio Issues

There have been reports of the PC audio output defaulting to mono. Check the Phonak sound card is set to stereo mode.  You can then use the following simple test to confirm there are no other isses:

  • Play the DV90 condition (the first subtest)
  • Listen to the distractors. You should hear one distractor voice in the left ear and a different distractor voice in the right ear.
  • Temporarily lift the headphone off the left ear.  You should now hear two distractor voices in the right ear.
  • Replace the headphone on the left ear and lift the headphone off the right ear.  You should now hear the same two distractors in the left ear.
  • Replace the headphone and you should be back to hearing one distractor in each ear.
  • Play the target sentence.  It should sound like it is in the centre of the head.
  • Play the DV0 condition. 
  • Listen to the distractors.  You should hear two distractors in the centre of the head. 
  • If you lift either headphone temporarily off either ear, you should hear the same two voices in the other ear. 
  • Play the target sentence.  It should sound like it is in the centre of the head.

If you hear all those as described, it’s very unlikely anything is wrong.  If any of them are not as described, then either:

  1. The sound card is faulty, or
  2. The headphone jack is not fully plugged into the sound card, or
  3. There is something wrong with either the LiSN-S software, the Windows operating system, or the way they interact. 

Additional Documents

Click here for LiSN-S normative data and pattern measures score information.
Click here for LiSN-S test-retest reliability data.
Click here for LiSN-S critical difference scores.
Click here to download brochure on LiSN-S.
Click here to download brochure on LiSN-S normative data for adults.
Click here to download brochure on LiSN-S with prescribed gain amplifier.
Click here for help on interpretation of LiSN-S results.
Click here for LiSN-S instructions for children.
Click here for LiSN-S instructions for adults.

LiSN-S