Super Nasal-Oral Ratiometry System (SNORS)

Super Nasal-Oral Ratiometry System (SNORS)

SNORS detects nasal and oral airflow during speech to provide a non-invasive objective assessment of velopharyngeal dysfunction (VPD) . It uses a lightweight dual chamber mask that is held over the nose and mouth. A soft silicone cuff providing a comfortable air tight seal. Rapid response airflow sensors and microphones are contained in both the nasal and oral chambers of the mask to enable aerodynamic and acoustic analysis.

SNORS mask

  • Lightweight dual chamber mask separates nasal and oral signals
  • Soft silicone cuff moulds to the contours of the face providing a comfortable air tight seal
  • Fast response nasal and oral airflow sensors allow the rapid movements of the velum to be detected
  • Highly directional nasal and oral microphones record speech and enable acoustic analysis
  • Detects voiced and unvoiced sounds
  • Adult and child (4+) sizes available
  • Child mask available in a range of colours


The SNORS mask is easy to dismantle and clean. The soft silicone cuff can be removed and replaced, or sterilized in an autoclave at temperatures up to 134 °C (±3 °C). The flexible nylon casing and sensor housing can be thoroughly cleaned with disposable disinfection wipes.

Autoclavable Siliconce Cuff

SNORS unit

  • Quick release connector for interchangeable adult and child masks
  • Volume control enables optimised audio recording levels
  • Auxiliary channel allows data from other devices to be synchronously recorded
  • Connects to the host computer via USB
  • USB powered - no external power supply required

Compatible software


SNORS 3D uses state-of-the-art computer animation and 3D modelling techniques to illustrate velopharyngeal closure and the amount of nasal-oral airflow during speech.

The animated 3D model consists of the lips, teeth, tongue, lower jaw, hard palate, soft palate and uvula. The transparency of these articulators can be adjusted to reveal hidden structures, and the model can be rotated 360°. Airflow clearly illustrates the difference between nasal, oral, voiced and voiceless sounds.

Nasal airflow Oral airflow
Nasal airflow (soft palate lowered) Oral airflow (soft palate raised)
Voiced airflow Voiceless
Voiced airflow (intermittent flow) Voiceless airflow (continuous flow)
Exhalation Inhalation
Exhalation (blue flow) Inhalation (green flow)

Velopharyngeal closure is represented both numerically and graphically. It is defined as the percentage of the total airflow that is oral:

Velopharyngeal closure equation

The height of the soft palate and uvula represent velopharyngeal closure in the 3D model:

Velopharyngeal closure

Additional features include:

  • Real-time visual feedback of velopharyngeal closure
  • Off-line objective analysis of velopharyngeal closure
  • Auditory playback of speech production
  • Photorealistic and stylised views
  • Windows 10 64-bit and 8 64-bit compatible

icSpeech Professional Edition

When used in combination with icSpeech Professional Edition, the following SNORS parameters are available:

Parameter Description
Nasal airflow Unfiltered nasal airflow signal
Nasal airflow intensity Low pass filtered nasal airflow envelope
Oral airflow Unfiltered oral airflow signal
Oral airflow intensity Low pass filtered oral airflow envelope
Combined airflow Combined nasal and oral airflow
Combined airflow intensity Low pass filtered combined airflow envelope
Aerodynamic nasalance Percentage of the total airflow that is nasal
Aerodynamic ratio Ratio of the difference between nasal and oral airflow to the total airflow
Nasal speech Nasal acoustic signal
Nasal speech intensity Low pass filtered nasal speech envelope
Oral speech Oral acoustic signal
Oral speech intensity Low pass filtered oral speech envelope
Speech Combined nasal and oral acoustic signal
Speech intensity Low pass filtered speech envelope
Pitch Derived from the combined acoustic signal
Acoustic nasalance Percentage of the total acoustic energy that is nasal
Auxiliary Signal derived from user defined auxiliary channel

Aerodynamic nasalance should not be confused with acoustic nasalance. Aerodynamic nasalance relates to the effective velopharyngeal closure, whereas acoustic nasalance relates to perceived nasality. Both parameters are useful and complementary.

There are a number of ways in which these parameters can be displayed. All displays can be synchronously viewed in real-time for biofeedback, recorded for off-line assessment or printed for hard copy.

Bar display

Real-time Bar display

The real-time Bar is a useful biofeedback tool that provides a clear and simple display reflecting the selected SNORS parameter. This allows the speaker to monitor their speech, make corrections, and instantly see the result. Real-time Bar is particularly useful when working with sustained sounds

Waveform displays

The real-time Waveform display allows the speaker to see the dynamics of their speech during the utterance of complete words or phrases.

Waveform Displays

Recording and analysis

Recordings enable precise, repeatable measurements to be performed on the recorded SNORS data. Measurements are made on the waveform display by positioning cursors over areas of interest. The data can also be exported to a comma-separated values (CSV) file for further manipulation.

Multiparameter data export


icSpeech Professional Edition contains six interactive speech therapy games. Each game features adjustable targets, rewards and can be controlled by the SNORS parameters.

Airflow games
SNORS Package

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Package includes:

  • SNORS unit
  • SNORS mask (adult or child)
  • Locking USB cable
  • User manual
  • 12 months guarantee
  • SNORS 3D (optional)
  • icSpeech Professional Edition (optional)
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