Aplicación de EAPAVE para sordos

A BRIEF DESCRIPTION of TEST AEPAVE,V.7f. AND

ITS APPLICATION to DEAF PERSONS

AEPAVE is a test designed by ALDEBARAN SOFT. with the purpose of testing the perception of changes of the acoustical features involved in speech and music, namely, pitch, intensity, timbre and duration. Composite forms are also tested, as rhythm and motif. The actual production of rhythms, its human performance can also be tested. Parallel test in visual perception can also be made within EAPAVE; but let us consider only the acoustical section here.

The test utters a series of 30 pairs of stimuli which differ in one or more features on a controllable degree. The subject must decide if the involved feature is raised, lowered or remain stable between the elements of each pair. His responses are statistically evaluated to decide if he perceives the change or not. Normally he will discern easily big jumps, but will find more difficult to assess the direction of the change as the jump became smaller: he will make more and more errors, until his responses are random. A threshold can then be adopted: when the subject answers correctly half of the pairs, after discarding the random correct answers ( a third, since he can choose only between three responses: Up, Down, Hold).

The variation of the features are measured in percentage or in cents, being this logarithmic unit equal to .00006, a 6 per ten thousand, a hundredth of a musical semitone. But the mean threshold varies greatly with each feature: some reference values could be 5 cents for pitch, 75 cents for duration, 200 cents for intensity; timbre cannot be evaluated in a linear scale, since this feature is really a set of then.