16. The method of claim 14 wherein the fluency measure comprises one or more of the following: a ratio equal to the number of silent periods during the spontaneous speech sample divided by a number of words used in the spontaneous speech sample; a mean of the durations for all silent periods during the spontaneous speech sample; and a standard deviation of the durations of all silent periods during the spontaneous speech sample.
14. The method of claim 13 wherein the one or more speech features comprise one or more of the following for each spontaneous speech sample: a lexical count; a fluency measure; a rate of speech measure; and a speech sample utterance duration.