Head Injury

A head injury can result in neurologic changes that totally invalidate any psychophysical testing. Therefore, psychophysical testing in such individuals is of no use in determining state of intoxication.

Head injury decreases cognition making it impossible to give a knowing and voluntary consent.  Decreased cognition and resultant confusion would decrease the ability to respond appropriately to oral instructions and would exacerbate the confusion associated with Miranda Warnings in close proximity to the reading of the informed consent form.  Such confusion eliminates the requisite knowledge to form an informed willful decision.  Therefore, it serves as the basis underlying the “confusion doctrine”.

{Psychophysical tests and Refusal}