• The procedure allows to restrain the number of correct responses by chance and detect cheaters.
• The OCT is made up of three series of several blocks identified with colors (red, blue and black).
• The test includes the vials, supports and an answer sheet for the subject.
• The OCT is based on a norm, which has been built using scores of more than 400 healthy subjects.

1. Detection

This first part of the test is used to evaluate the olfactory sensibility. It is based on red and blue series, that is to say 12 blocks of four vials. The subject has to answer the question "Which one of the four vial of a block smell the stronger?". The subject begins with the red series (six blocks) and the first block. He smells the first vial of this block, then the second, the third and the last. He tells which vial (A, B, C or D) of the block smell the stronger. He carries on with the second block of the red series, and so on …

When he has finished with the five blocks of the red series, he follows the same procedure with the five blocks of the blue series.

2. Identification

This second part of the OCT concerns the ability to identify odors. It is based on the 16 blocks of black series.
The subject is asked to find which vial (A, B, C or D) of each block contains an odor and to choose the right descriptor between four proposed. It is a multiple forced choice identification technique. The test allows a second control of odor detection ability and is helpful to asses olfactory sensitivity. Subjects have one minute to give their answer for each block. The test needs 30 minutes to be completed.

This olfactory test is made up of three series of blocks of four vials. Only one vial among the four contains an odor. You have an answer sheet to indicate your answers.

The test comprises two parts.

1. The first part is designed to evaluate your olfactory sensitivity. There is a red and a blue series. You have to answer the question "Which one of the four vial smell the stronger?".

• You'll begin with the red series.
• There is 6 blocks of four vials (numbered 1 to 6).
• Each vial in the same block wear the same number but is identified by a different letters (A to D).
• Open the vials of a block one after the other and smell.
• Then indicate, in the answer sheet, which vial (A, B, C or D) smell the stronger.
• Guess if you are not sure.
• Repeat the same procedure for the 6 blocks of the red series.
• Use the same procedure for the 6 blocks of the blue series.

2. The second part is designed to evaluate your ability to identify odors. You have to answer the two questions "Which one of the four vial contain the odor?" and "What is the odor?".

• There is 16 blocks of four vials (numbered 1 to 16).
• Each vial in the same block wear the same number but is identified by a different letters (A to D).
• Open the vials of a block one after the other and smell.
• Then indicate, in the answer sheet, which vial (A, B, C or D) contain the odor.
• Choose among the four proposed alternatives, the one that you find best identifies the odor.
• One of the alternatives is correct.
• Guess if you are not sure.
• Repeat the same procedure for the 16 blocks.