A graphical method for calculating the speech intelligibility index and measuring hearing disability from audiograms

Area of Science:

• Audiology
• Speech Science
• Hearing Science

Background:

• The Speech Intelligibility Index (SII) measures the proportion of speech information audible to a listener.
• SII ranges from 0 to 1, indicating the extent of speech information available.
• Understanding SII is crucial for evaluating hearing disability and speech recognition challenges.

Purpose of the Study:

• To describe a graphical method for calculating the Speech Intelligibility Index (SII).
• To adapt the SII calculation for monaural listening conditions at a standard distance and speech effort.
• To incorporate a correction factor for suprathreshold deficits caused by sensorineural hearing loss.

Main Methods:

• A graphical method visualizes speech information using 100 points in an audiogram format.
• Each point contributes 0.01 to the SII, representing available speech information.
• A desensitization factor, dependent on hearing loss, adjusts SII contributions per frequency band.

Main Results:

• The described method provides a straightforward way to determine SII.
• The calculation accounts for the impact of hearing loss on speech audibility.
• The adjusted SII reflects the listener's actual speech recognition capability.

Conclusions:

• The Speech Intelligibility Index (SII) is a valuable tool for quantifying speech information.
• The graphical method offers a practical approach to SII calculation.
• The SII, adjusted for hearing loss, can effectively evaluate hearing disability and its impact on speech intelligibility.