Nervous and Senses Disorders Practice Questions
20 free Nervous and Senses Disorders practice questions for the USMLE Step 1. Tap an option to answer — you get instant feedback, the correct answer, and a detailed explanation for every question.
A 68-year-old man suddenly develops right-sided weakness and expressive aphasia. CT shows an infarct in the left frontal lobe. Which artery is most likely occluded?
- A Right middle cerebral artery
- B Left anterior cerebral artery
- C Left middle cerebral artery
- D Basilar artery
Correct answer: Left middle cerebral artery
The left MCA supplies Broca’s area and the motor cortex for the face and arm. Occlusion causes contralateral weakness and expressive aphasia.
A 22-year-old man presents with recurrent seizures preceded by a metallic taste. What is the most likely seizure type?
- A Absence seizure
- B Simple focal seizure
- C Generalized tonic–clonic seizure
- D Myoclonic seizure
Correct answer: Simple focal seizure
Simple focal seizures arise from a localized cortical area and may cause sensory auras such as metallic taste. Consciousness remains intact.
A patient has sudden painless vision loss in one eye. Fundoscopy shows a pale retina with a cherry-red spot. Which condition is most likely?
- A Central retinal artery occlusion
- B Central retinal vein occlusion
- C Retinal detachment
- D Optic neuritis
Correct answer: Central retinal artery occlusion
Central retinal artery occlusion causes sudden vision loss and a characteristic cherry-red macula due to retinal ischemia.
A 4-year-old child has recurrent staring spells lasting 10 seconds, followed by immediate resumption of activity. EEG shows 3 Hz spike-and-wave discharges. Which diagnosis is most likely?
- A Absence seizures
- B Complex focal seizures
- C Atonic seizures
- D Febrile seizures
Correct answer: Absence seizures
Absence seizures involve brief lapses in consciousness and show 3 Hz spike-and-wave patterns on EEG.
A woman experiences vertigo, tinnitus, and fluctuating hearing loss. Which condition is most likely?
- A Acoustic neuroma
- B Ménière disease
- C Presbycusis
- D Otosclerosis
Correct answer: Ménière disease
Ménière disease is characterized by episodic vertigo, tinnitus, and fluctuating sensorineural hearing loss due to endolymphatic fluid buildup.
A man presents with right homonymous hemianopia with macular sparing. Which lesion best explains this finding?
- A Left optic tract lesion
- B Right occipital cortex lesion
- C Left occipital cortex lesion
- D Right optic nerve lesion
Correct answer: Left occipital cortex lesion
Lesions in the left occipital lobe cause right homonymous hemianopia with macular sparing due to dual blood supply to the macula.
A 70-year-old man has a stroke resulting in pure motor hemiparesis. Which brain region is most likely affected?
- A Cerebellar hemisphere
- B Internal capsule
- C Occipital cortex
- D Caudate nucleus
Correct answer: Internal capsule
Lacunar strokes of the internal capsule disrupt corticospinal tract fibers, causing pure motor hemiparesis.
A patient hears ringing in the ears after loud music exposure. Which structure is most likely damaged?
- A Organ of Corti hair cells
- B Auditory ossicle chain
- C Vestibular nerve fibers
- D Tympanic membrane surface
Correct answer: Organ of Corti hair cells
Noise-induced hearing loss damages sensory hair cells in the Organ of Corti. This can produce tinnitus.
A 30-year-old woman presents with episodes of sudden loss of muscle tone triggered by laughter. Which diagnosis is most likely?
- A Epileptic atonic seizure
- B Cataplexy
- C Syncope
- D Basilar migraine
Correct answer: Cataplexy
Cataplexy occurs in narcolepsy and causes sudden loss of muscle tone triggered by emotions such as laughter.
A patient with a stroke loses pain and temperature sensation on the contralateral body and ipsilateral face. Which artery is most likely involved?
- A Anterior cerebral artery
- B Posterior cerebral artery
- C Posterior inferior cerebellar artery
- D Middle cerebral artery
Correct answer: Posterior inferior cerebellar artery
PICA infarction produces Wallenberg syndrome, which includes loss of ipsilateral facial sensation and contralateral body sensation.
A patient develops a lesion of the Meyer's loop. Which visual defect occurs?
- A Bitemporal hemianopia
- B Right inferior quadrantanopia
- C Right superior quadrantanopia
- D Left homonymous hemianopia
Correct answer: Right superior quadrantanopia
Lesions in Meyer's loop (temporal lobe) cause contralateral superior quadrantanopia ('pie in the sky').
A man develops sudden severe vertigo, nystagmus, and nausea after a viral illness. Hearing is normal. Which condition is most likely?
- A Labyrinthitis
- B Vestibular neuritis
- C Acoustic neuroma
- D Ménière disease
Correct answer: Vestibular neuritis
Vestibular neuritis causes acute vertigo without hearing loss. Labyrinthitis includes hearing loss.
A woman with epilepsy is prescribed valproate. Which adverse effect requires monitoring?
- A Hepatotoxicity
- B Thyroid dysfunction
- C Retinopathy
- D Hearing loss
Correct answer: Hepatotoxicity
Valproate can cause hepatotoxicity, especially in children. Liver function tests should be monitored.
A 65-year-old man presents with progressive, painless central vision loss. Fundoscopy shows drusen deposits. What condition is this?
- A Retinitis pigmentosa
- B Wet macular degeneration
- C Dry macular degeneration
- D Diabetic retinopathy
Correct answer: Dry macular degeneration
Dry macular degeneration is characterized by drusen and gradual central vision loss. It is the more common form.
A patient has right facial droop and cannot close the right eye, but forehead movement is intact. Where is the lesion?
- A Right facial nerve (CN VII)
- B Left facial nerve (CN VII)
- C Corticobulbar tract (UMN)
- D Right trigeminal nerve (CN V)
Correct answer: Corticobulbar tract (UMN)
Central (upper motor neuron) lesions spare the forehead because it receives bilateral cortical innervation, so a corticobulbar tract lesion produces contralateral lower-face weakness with forehead sparing.
A patient develops bitemporal hemianopia (loss of both temporal visual fields). Which lesion is most likely?
- A Optic nerve compression
- B Optic chiasm compression
- C Optic tract compression
- D Meyer's loop compression
Correct answer: Optic chiasm compression
Compression of the optic chiasm (often by a pituitary tumor) damages the crossing nasal retinal fibers, producing bitemporal hemianopia.
A 45-year-old woman experiences sudden, electric shock-like facial pain triggered by touch. Which condition is most likely?
- A Cluster headache
- B Migraine with aura
- C Trigeminal neuralgia
- D Partial seizure
Correct answer: Trigeminal neuralgia
Trigeminal neuralgia causes paroxysmal unilateral facial pain triggered by light stimuli. It is due to irritation of CN V.
A man has difficulty hearing high-frequency sounds. Which age-related change explains this?
- A Increased endolymph pressure
- B Basal cochlear hair-cell loss
- C Ossification of the oval window
- D Loss of vestibular hair cells
Correct answer: Basal cochlear hair-cell loss
Presbycusis is age-related hearing loss from degeneration of hair cells at the base of the cochlea, where high-frequency sounds are transduced.
A patient with epilepsy shows a focal seizure that spreads to become generalized. What is this type called?
- A Simple focal seizure
- B Complex focal seizure
- C Secondary generalized seizure
- D Absence seizure
Correct answer: Secondary generalized seizure
Secondary generalized seizures begin as focal and then spread to both hemispheres, leading to tonic–clonic activity.
A patient develops diplopia when looking laterally with the right eye. Which nerve is most likely damaged?
- A Right oculomotor nerve
- B Right trochlear nerve
- C Right abducens nerve
- D Left abducens nerve
Correct answer: Right abducens nerve
The abducens nerve (CN VI) innervates the lateral rectus muscle. Damage prevents lateral eye movement, causing diplopia.