4. The system memory of claim 3 , wherein the method further comprises comparing an acoustic feature of the test stimulus to an acoustic feature of the associated user response.
4. The system memory of claim 3 , wherein the method further comprises comparing an acoustic feature of the test stimulus to an acoustic feature of the associated user response. 5. The system memory of claim 4 , wherein the acoustic feature comprises at least one of a cepstral coefficient and a speech feature.