The nurse is evaluating the cranial nerves of a person with Parkinson disease who has difficulty swallowing foods. The nurse asks the patient to stick out their tongue and move it rapidly from side to side. The nurse is assessing which cranial nerve?

Choice A reason:Swaying during a Romberg test indicates a positive result, suggesting proprioceptive deficits or sensory ataxia.

Choice B reason:Unequal pupil response to light relates to cranial nerve function, not balance assessed by the Romberg test.

Choice C reason: This is incorrect. Patient taking two attempts to touch their nose while their eyes are closed is a mild impairment of coordination, which may be due to neurologic changes or other factors such as fatigue or medication. This is not a significant finding that requires immediate attention.

Choice D reason: This is incorrect. Patient complaining of mild dizziness is a common symptom of neurologic changes or vestibular dysfunction. It is not a serious finding that requires immediate attention. The nurse should monitor the patient and provide comfort measures.

Choice A reason: There is total absence of dopamine at receptors in brain cells controlling motor movement, causing Parkinson symptoms to appear, is not the correct statement. Parkinson disease is not caused by a complete lack of dopamine, but by a gradual loss of dopamine-producing neurons in the substantia nigra, a part of the brain that regulates movement. The symptoms of Parkinson disease, such as tremor, rigidity, and bradykinesia, appear when about 80% of the dopamine neurons are lost.

Choice B reason: There is an excess of dopamine production and deficiency of acetylcholine production, is not the correct statement. Parkinson disease is not caused by an excess of dopamine, but by a deficiency of dopamine. Dopamine is a neurotransmitter that helps to control movement, balance, and coordination. Acetylcholine is another neurotransmitter that works in opposition to dopamine. When dopamine is low, acetylcholine becomes dominant and causes abnormal muscle movements.

Choice C reason: There is a decreased production of dopamine and excess of acetylcholine, is the correct statement. Parkinson disease is caused by a decreased production of dopamine and excess of acetylcholine. This creates an imbalance in the neurotransmitters that regulate movement, leading to the characteristic symptoms of Parkinson disease, such as tremor, rigidity, and bradykinesia.

Choice D reason: There is a deterioration of the myelin sheath of the basal ganglia and the person has tremors, is not the correct statement. Parkinson disease is not caused by a deterioration of the myelin sheath, but by a degeneration of the dopamine neurons. Myelin is a fatty substance that covers the axons of the nerve cells and helps to transmit electrical impulses. The basal ganglia are a group of structures in the brain that are involved in movement, learning, and emotion. Tremors are one of the symptoms of Parkinson disease, but they are not the only or the most specific one.