Package: SII
Type: Package
Title: Calculate ANSI/ASA S3.5-1997 (R2024) Speech Intelligibility
        Index
Version: 1.2.4
Date: 2026-08-30
Authors@R: c(person(given = c("Gregory", "R."), family = "Warnes", role = c("aut", "cph")),
             person(given = "Mark", family = "Shaver", role = c("cre", "aut"), email = "mark.shaver@posteo.net"))
Description: 
   Calculates the American National Standards Institute (ANSI) S3.5-1997
   Speech Intelligibility Index (SII) (ANSI 1997,
   (ANSI, 1997)), a standard
   method for computing the intelligibility of speech from acoustical
   measurements of speech, noise, and hearing thresholds. This package
   includes data frames corresponding to Tables 1 - 4 in the ANSI standard as
   well as functions utilizing these tables and user-provided hearing
   threshold and noise level measurements to compute the SII score. The
   methods implemented here extend the standard computations to allow
   calculation of SII when the measured frequencies do not match those
   required by the standard by applying interpolation. Furthermore, the
   package now includes a native, highly optimized C++ implementation of the
   canonical Moore & Glasberg (2004) specific loudness model for impaired
   hearing, which structurally mirrors the bramslow2004 implementation from
   the Auditory Modeling Toolbox (AMT) to calculate loudness in perceptual
   sones. It also includes advanced methods to predict aided SII based on
   hearing aid prescriptive rationales, introducing Open-NL (Open Non-Linear),
   a novel theoretical optimization framework. Open-NL utilizes a Nelder-Mead
   simplex algorithm to maximize the ANSI SII metric, subject to computational
   physiological loudness penalties and simulated hardware Maximum Power
   Output (MPO) constraints, to derive theoretical gain targets. The package
   also provides functions to calculate real-ear insertion gains, estimate
   maximum power output (SSPL90), and prescribe dynamic range compression.
   NOTE: This package is explicitly flagged as a non-clinical academic tool
   designed exclusively for theoretical modeling and simulation. It has not
   undergone clinical validation and is strictly contraindicated for general
   clinical fitting. Unapproved use for direct patient care is prohibited. Any
   application of this tool to human subjects must occur exclusively within
   the strictly controlled context of Institutional Review Board (IRB)
   approved research studies. Development of this package was originally
   funded by the Center for Bioscience Education and Technology (CBET) of the
   Rochester Institute of Technology (RIT).
Depends: R (>= 3.5.0)
Imports: Rcpp
LinkingTo: Rcpp
Suggests: splines, readxl, xtable, testthat
License: GPL-3 | file LICENSE
LazyLoad: yes
NeedsCompilation: yes
Repository: CRAN
Config/roxygen2/version: 8.0.0
Encoding: UTF-8
Packaged: 2026-09-01 00:01:13 UTC; mark
Author: Gregory R. Warnes [aut, cph],
  Mark Shaver [cre, aut]
Maintainer: Mark Shaver <mark.shaver@posteo.net>
Date/Publication: 2026-09-12 14:30:07 UTC
