Evaluation of the Computer-assisted Speech Perception Assessment Test (CASPA)

Interlist equivalency and short-term practice effects were evaluated for the recorded stimuli of the Computer-Assisted Speech Perception Assessment (CASPA) Test. Twenty lists, each consisting of 10 consonant-vowel-consonant words, were administered to 20 adults with normal hearing. The lists were presented at 50 dB SPL (Leq) in the presence of spectrally matched steady-state noise (55 dB SPL Leq). Phoneme recognition scores for the first list presented were significantly lower than for the second through the twentieth list presented, indicating a small practice effect. Phoneme scores for 4 of the lists (3, 6, 7, and 16) were significantly higher than scores for the remaining 16 lists by approximately 10 percentage points. Eliminating the effects of interlist differences reduced the 95 percent confidence interval of a test score based on a single list from 18.4 to 16.1 percentage points. Although interlist differences have only a small effect on confidence limits, some clinicians may wish to eliminate them by excluding lists 3, 6, 7, and 16 from the test. The practice effect observed here can be eliminated by administering one 10-word practice list before beginning the test.