Final answer:
Testing eye movement involves tracking the tip of a pen to check for proper movements. The statement about using a double H for testing primary up and downgaze is false.
Step-by-step explanation:
Testing eye movement is done by having the patient track the tip of a pen as it is passed through the visual field. The extent of movement is the point of the test, with the examiner checking for proper function of the related nuclei and the medial longitudinal fasciculus (MLF).
In the case of primary up and downgaze, the examiner is not specifically looking for double H movements. Instead, they are observing for proper conjugate movement of the eyes in the vertical plane. Failure of one eye to move properly in conjugation with the other may indicate an abnormality.
So, the statement 'We use a double H to test primary up and downgaze >> A and V patterns' is false.