USMLE Step 1 NBME Form 31 Exam Prep & Practice Questions 2026/2027

A 68-year-old patient with Parkinson disease is prescribed a dopamine receptor agonist. Which medication is classified as an ergot-derived dopamine agonist? A. Pramipexole B. Ropinirole C. Bromocriptine D. Rotigotine Correct Answer: C. Bromocriptine Rationale: Bromocriptine is an ergot-derived dopamine receptor agonist that can improve Parkinsonian symptoms by directly stimulating dopamine receptors. Pramipexole, ropinirole, and rotigotine are nonergot dopamine agonists. Nonergot agents are generally preferred because ergot derivatives may cause serious complications, including cardiac valvular fibrosis, pulmonary fibrosis, and retroperitoneal fibrosis. Question 2 A 55-year-old patient reports an irresistible urge to move both legs at night. The symptoms worsen during rest and improve temporarily with movement. Which medication is most appropriate? A. Donepezil B. Pramipexole C. Haloperidol D. Dantrolene Correct Answer: B. Pramipexole Rationale: Pramipexole is a nonergot dopamine agonist that may be used for restless legs syndrome and Parkinson disease. Ropinirole is another appropriate dopamine agonist. Donepezil treats Alzheimer disease, haloperidol blocks dopamine receptors and may worsen movement disorders, and dantrolene reduces skeletal muscle calcium release rather than modifying dopaminergic activity. Question 3 A patient with schizophrenia reports hearing voices and believing that government agents are following him. Excess dopamine activity in which pathway is most strongly associated with these symptoms? A. Mesocortical pathway B. Nigrostriatal pathway C. Mesolimbic pathway D. Tuberoinfundibular pathway Correct Answer: C. Mesolimbic pathway Rationale: Excessive dopamine activity in the mesolimbic pathway is associated with positive symptoms of schizophrenia, including hallucinations, delusions, and disorganized behavior. Reduced mesocortical dopamine contributes to negative and cognitive symptoms. The nigrostriatal pathway regulates movement, while the tuberoinfundibular pathway inhibits prolactin secretion from the anterior pituitary. Question 4 A woman taking risperidone develops amenorrhea and galactorrhea. Blockade of dopamine receptors in which pathway most directly caused these adverse effects? A. Mesolimbic B. Mesocortical C. Nigrostriatal D. Tuberoinfundibular Correct Answer: D. Tuberoinfundibular Rationale: Dopamine normally inhibits prolactin secretion through the tuberoinfundibular pathway. D₂-receptor blockade removes this inhibition, producing hyperprolactinemia, galactorrhea, amenorrhea, infertility, sexual dysfunction, and reduced bone density. Nigrostriatal blockade produces extrapyramidal symptoms, while mesolimbic and mesocortical pathways are primarily associated with psychotic and cognitive symptoms. Question 5 A patient experiences recurrent episodes of vertigo lasting several hours, tinnitus, a sensation of ear fullness, and fluctuating hearing loss. Which diagnosis is most likely? A. Vestibular neuritis B. Ménière disease C. Benign positional vertigo D. Acoustic neuroma Correct Answer: B. Ménière disease Rationale: Ménière disease is caused by excessive endolymphatic fluid and produces recurrent vertigo, tinnitus, aural fullness, and fluctuating sensorineural hearing loss. Vestibular neuritis generally causes one prolonged episode without hearing loss. Benign positional vertigo produces brief, position-triggered attacks, while acoustic neuroma causes gradually progressive hearing loss rather than episodic vertigo. Question 6 A patient with spinal cord disease loses vibration, fine touch, and conscious proprioception below the lesion. Which pathway is most likely damaged? A. Lateral spinothalamic tract B. Dorsal column–medial lemniscus pathway C. Anterior corticospinal tract D. Spinocerebellar tract Correct Answer: B. Dorsal column–medial lemniscus pathway Rationale: The dorsal columns transmit fine touch, vibration, pressure discrimination, and conscious proprioception. Their fibers ascend ipsilaterally in the spinal cord before crossing in the medulla. The lateral spinothalamic tract transmits pain and temperature, corticospinal tracts control voluntary movement, and spinocerebellar pathways carry unconscious proprioceptive information to the cerebellum. Question 7 A patient develops spastic paralysis, increased muscle tone, hyperreflexia, and an extensor plantar response after a stroke. Which type of lesion is present? A. Lower motor neuron lesion B. Neuromuscular junction lesion C. Upper motor neuron lesion D. Peripheral sensory nerve lesion Correct Answer: C. Upper motor neuron lesion Rationale: Upper motor neuron lesions produce weakness accompanied by spasticity, hyperreflexia, increased tone, clonus, and a positive Babinski response. Lower motor neuron lesions cause flaccidity, muscle atrophy, fasciculations, and reduced reflexes. Neuromuscular junction diseases generally cause fatigable weakness without sensory loss or an extensor plantar response. Question 8 During examination of the gag reflex, touching the posterior pharyngeal wall normally produces pharyngeal elevation. Which cranial nerves form the afferent and efferent limbs, respectively? A. CN V and CN VII B. CN VII and CN IX C. CN IX and CN X D. CN X and CN XII Correct Answer: C. CN IX and CN X Rationale: The glossopharyngeal nerve, CN IX, carries the sensory or afferent limb of the gag reflex. The vagus nerve, CN X, supplies the motor or efferent response through pharyngeal muscle contraction. CN IX also carries carotid body and sinus afferents and provides motor innervation to the stylopharyngeus muscle. Question 9 A patient develops right-sided partial ptosis, miosis, and decreased facial sweating after a carotid artery injury. Which neurologic syndrome is present? A. Horner syndrome B. Wallenberg syndrome C. Weber syndrome D. Parinaud syndrome Correct Answer: A. Horner syndrome Rationale: Horner syndrome results from interruption of sympathetic innervation to the eye and face. Its classic findings are ipsilateral partial ptosis, miosis, and anhidrosis. Wallenberg syndrome is a lateral medullary stroke, Weber syndrome involves the midbrain and oculomotor nerve, and Parinaud syndrome causes vertical gaze impairment from a dorsal midbrain lesion. Question 10 A patient with traumatic brain injury develops signs of impending cerebral herniation. Which temporary intervention can rapidly lower intracranial pressure? A. Increasing arterial carbon dioxide B. Brief controlled hyperventilation C. Administering hypotonic intravenous fluid D. Placing the patient in the Trendelenburg position Correct Answer: B. Brief controlled hyperventilation Rationale: Hyperventilation lowers PaCO₂, causing cerebral vasoconstriction and temporarily reducing cerebral blood volume and intracranial pressure. It is reserved for acute deterioration or impending herniation because prolonged vasoconstriction may cause cerebral ischemia. Hypercapnia, hypotonic fluids, and head-down positioning increase cerebral blood volume or edema and may worsen intracranial pressure.