Speech intelligibility measured with shortened versions of Callsign Acquisition Test (CAT).

The Callsign Acquisition Test (CAT) is a new speech intelligibility test developed by the Human Research and Engineering Directorate of the U.S. Army Research Laboratory (ARL-HRED). CAT uses the phonetic alphabet and digit stimuli combined together to form 126 test items. The purpose of this study was to assess the reliability of data collected with shorter versions of CAT. A total of 5 shorter versions of the original list (CAT-120, CAT-60, CAT-40, CAT-30, and CAT-24) were formed and evaluated using 19 participants. Each of the subsets of CAT was presented in pink noise at signal-to-noise ratios (SNRs) of -6dB and -9dB. Results showed that shortened CAT lists have the capability of providing the same predictive power as the full CAT with good test-retest reliability. Under the experimental conditions of this study, any of the shorter versions of the CAT can be utilized in place of the full version to reduce testing times with no effect on predictive power.