A nurse is reviewing the medical record of a client who is experiencing delirium. Which of the following in the health record should the nurse identify as a cause of this disorder?

Choice A Reason: Depth perception is the ability to judge the distance and position of objects in three-dimensional space. Depth perception is assessed by asking the client to touch the tip of a pen or pencil held by the nurse, or by using a stereopsis test.

Choice B Reason: Peripheral vision is the ability to see objects and movements outside the direct line of vision. Peripheral vision is assessed by asking the client to shake the hand of the nurse, who stands at an angle to the client's side, or by using a confrontation test.

Choice C Reason: Color deficit is the inability to distinguish certain colors or shades of colors. Color deficit is assessed by asking the client to identify numbers or shapes on a color plate test, such as the Ishihara test.

Choice D Reason: Double vision is the perception of two images of a single object. Double vision is assessed by asking the client to cover one eye and look at an object, then switch eyes and compare the images, or by using a cover-uncover test.

Choice A Reason: This is incorrect because nystagmus is not a response to stimuli, but a condition that causes involuntary eye movements. Nystagmus can be caused by various factors, such as inner ear disorders, brain lesions, or drug toxicity, but not necessarily by cervical spine injury.

Choice B Reason: This is incorrect because decorticate positioning is a response to stimuli that indicates damage to the cerebral cortex or the corticospinal tract. Decorticate positioning is characterized by flexion of the arms and extension of the legs. It does not indicate cervical spine injury, which affects the spinal cord below the brainstem.

Choice C Reason: This is incorrect because lack of any response to stimuli can indicate various levels of brain damage or coma, but not specifically cervical spine injury. Lack of any response can also be influenced by other factors, such as sedation, hypothermia, or shock.

Choice D Reason: This is correct because decerebrate positioning is a response to stimuli that indicates damage to the brainstem or the upper cervical spine. Decerebrate positioning is characterized by extension and outward rotation of the arms and legs. It indicates a severe and life-threatening injury that can impair vital functions, such as breathing and blood pressure.