By Spike Eskin

PHILADELPHIA (CBS) – Michael Vick did not pass his ImPACT test, and will not play Sunday night against the Cowboys, the Eagles announced today.

The test, which must be passed by a player who has suffered a concussion to be able to play again, is described this way:

The test battery consists of a near infinite number of alternate forms by randomly varying the stimulus array for each administration. This feature was built in to the program to minimize the “practice effects” that have limited the usefulness of more traditional neurocognitive tests.

ImPACT takes approximately 20 minutes to complete. The program measures multiple aspects of cognitive functioning in athletes.

Andy Reid told the media on Tuesday that Vick has been improving, but had not yet taken or passed the test. Reid has maintained that when Vick is once again healthy, he will start.

Nick Foles will start for the Eagles Sunday night, his third NFL start.