Psychoacoustics: A comprehensive MATLAB toolbox for auditory testing

Abstract

PSYCHOACOUSTICS is a new MATLAB toolbox which implements three classic adaptive procedures for auditory threshold estimation. The first includes those of the Staircase family (method of limits, simple up-down and transformed up-down); the second is the Parameter Estimation by Sequential Testing (PEST); and the third is the Maximum Likelihood Procedure (MLP). The toolbox comes with more than twenty built-in experiments each provided with the recommended (default) parameters. However, if desired, these parameters can be modified through an intuitive and user friendly graphical interface and stored for future use (no programming skills are required). Finally, PSYCHOACOUSTICS is very flexible as it comes with several signal generators and can be easily extended for any experiment. PSYCHOACOUSTICS is a MATLAB toolbox for auditory threshold estimation. The toolbox improves and extends the Maximum Likelihood Procedure (MLP) toolbox advanced by Grassi and Soranzo (2009). Since its publication, the MLP toolbox has been extensively downloaded and has been used by both academics for teaching and research and by non-academics to test the auditory performance of their patients before and after clinical interventions (for example, Marx, 2013 utilized it to test the acoustic improvements of patients which have received cochlear implant) or to assess age-related auditory abilities (Grassi and Borella, 2013). However, MLP implements just a single adaptive procedure, and so it cannot satisfy the entire acoustic community. Hairston and Maldjian (2009), on the other hand, developed an E-Prime routine to run the Adaptive Staircase procedure. But, again, this routine implements just one adaptive procedure. Another procedure which is largely used by psychoacousticians is the Parameter Estimation by Sequential Testing (PEST). This has been implemented in Palamedes, a free MATLAB toolbox which includes functions to analyse psychophysical experiments. However, the procedure comes with no graphical interface and requires some programming skills. In sum, there are no easy to use toolboxes which implement the three most used adaptive procedures at once. PSYCHOACOUSTICS is a new toolbox that has been developed specifically to fill this gap. It has been developed to work with MATLAB 7.0 or higher; it works with any operative system; it does not require any additional MATLAB toolboxes; and it is equipped with a user friendly and intuitive graphical interface; so, no programming skills are required. The toolbox includes the following methods: i) The Staircase-and its main variants (method of limits Fechner, 1889; Fechner, simple up-down von Békésy, 1947; transformed up-down Levitt, 1971); ii) the PEST (Taylor and Creelman, 1967); iii) the Maximum Likelihood (hereafter referred to as MLP Pentland, 1980; Green, 1990, 1993; Shen and Richards, 2012). In addition, the PSYCHOACOUSTICS toolbox includes many pre-programmed experiments that, with one exception specified below, can be conducted with any of the adaptive procedures included in the toolbox. The experiments included in the toolbox are (i) the most classic psychoacoustic experiments, allowing the user to replicate established experiments or to adapt them to specific needs; (ii) experiments that, so far, have been run with non-adaptive procedures only, allowing the user to conduct the same experiments with adaptive procedures; and (iii) completely new experiments, providing the user with examples of custom usage of the toolbox and to investigate novel psychoacoustics features. The paper is organized in three parts: The first part outlines some of the basics concepts of psychophysics (readers familiar with psychophysical concepts may wish to skip this part); the second part sketches the theory behind the three procedure types implemented in the toolbox; and finally a detailed protocol of the toolbox is outlined together with the description of the collection of psychoacoustic experiments. © 2014 Soranzo and Grassi.