TITLE The development of an Afrikaans test for sentence recognition thresholds in noise AUTHORS

Objective: The development of a valid and reliable Afrikaans test of sentence recognition thresholds in noise. Design: A collection of sentences was developed, rated for naturalness and grammatical complexity, and digitally recorded using a female speaker. Sentences found to have similar psychometric curve slopes, with equivalent intelligibility at three different noise levels, were arranged into 22 phonemically matched lists of ten sentences each. List equivalence was evaluated in normal-hearing listeners in full and reduced bandwidth conditions. Test-retest reliability of the remaining lists was evaluated in a second group of listeners. Study sample: All listeners were native speakers of Afrikaans with normal hearing. For evaluation of list equivalence, ten listeners were used. Twenty other listeners were used to evaluate test-retest reliability. Results: A collection of eighteen phonemically matched lists was produced. Lists were found to be of equivalent difficulty in full and reduced bandwidth conditions, and to have good test-retest reliability in normal-hearing listeners. The average recognition threshold of these lists was -2.73 dB signal-to-noise ratio (standard deviation = 0.64 dB), and within-subject variability was 1.22 dB. Conclusions: The developed test provides a valid and reliable means of measuring sentence recognition thresholds in noise in Afrikaans. INTRODUCTION The most common complaint of patients with sensorineural hearing loss is difficulty in understanding speech in situations with background noise (Smits et al, 2006). Although the basic audiometric test battery includes measures of speech reception or recognition, tests that could measure or predict a patient’s ability to understand speech in noise are not routinely conducted (Killion & Niquette, 2000). However, because many patients have great difficulty in recognizing speech in the presence of Theunissen/Afrikaans sentences-in-noise test 3 noise, the direct assessment of this skill could contribute significantly to effective counselling and selection of amplification options (Killion et al, 2004). Tests of speech recognition using sentence material as stimulus tend to give a more global impression of an individual’s speech perception than single words (Lutman, 1997), and a number of recent studies have therefore focused on the development of a test for speech recognition in noise using sentence materials. A prominent study in this regard was the development of the HINT (Hearing In Noise Test) by Nilsson et al (1994). Many researchers have since developed similar tests in other languages, such as German (Kollmeier & Wesselkamp, 1997), Dutch (Van Wieringen & Wouters, 2008; Versfeld et al, 2000), and French (Luts et al, 2008) or adapted the original HINT in different languages, including Brazilian Portuguese, Brazilian, Canadian French, Cantonese and eight other languages (Soli & Wong, 2008). In South Africa, audiologists face the challenge of delivering services to a cultural and linguistically diverse patient load. There is a shortage of standardised speech audiometry materials and procedures in most of the eleven official languages, which prevents optimal audiological assessment. This shortage of test materials is particularly evident for sentence materials. In view of this dearth of materials for speech audiometry in South Africa, a project was undertaken to develop a test of sentence recognition in noise in one of the official languages. The language selected for the current project was Afrikaans, the third most common home language in the country, spoken by 13.3% of the population (Statistics South Africa, 2001) and the most common home language in the Gauteng province where the research was conducted (Central Statistical Service, 1995). Since there are no standardised or published tests of sentence recognition in noise in Afrikaans, the development of such a test could provide a valuable tool for the assessment of Afrikaans-speaking Theunissen/Afrikaans sentences-in-noise test 4 individuals with peripheral hearing loss and different amplification devices, as well as listeners with auditory processing disorders.