What action should be taken once jerking is seen during the Onset of Nystagmus Prior to 45 Degrees test?

In the context of the Onset of Nystagmus Prior to 45 Degrees test, if jerking is observed, holding the stimulus steady is the appropriate action. This allows the examiner to accurately assess the degree of nystagmus exhibited by the subject. By stopping the movement of the stimulus, the examiner can observe the oscillations of the eyes more clearly and determine the severity and onset of any nystagmus.

This step is crucial because it helps in evaluating the subject’s level of impairment due to potential alcohol or drug influence. If the stimulus were to be moved or rotated instead, it could lead to additional distractions or confusion, making it difficult to obtain an accurate measurement of the nystagmus. Noting the movement alone does not facilitate a proper assessment of nystagmus, and continuing to move the stimulus would further prevent a clear observation of the condition being diagnosed.