ABPN Neurological Examination and Conditions 2

Question 1

A patient cannot abduct the eye on the affected side and reports horizontal diplopia worse at distance. Which cranial nerve is most likely affected?

Accepted Answer

Abducens (CN VI)

Answer

CN VI innervates the lateral rectus, so its palsy impairs eye abduction and causes horizontal diplopia.

Question 2

A positive Romberg sign indicates a deficit primarily in which system?

Accepted Answer

Proprioceptive/dorsal column pathways

Answer

Romberg is positive when standing balance worsens with eyes closed, indicating loss of proprioceptive input via the dorsal columns.

Question 3

The plantar (Babinski) reflex is considered pathological in an adult when the great toe does what?

Accepted Answer

Extends upward (dorsiflexes)

Answer

An upgoing great toe on plantar stimulation indicates an upper motor neuron lesion.

Question 4

Which finding best distinguishes an upper motor neuron lesion from a lower motor neuron lesion?

Accepted Answer

Hyperreflexia and spasticity

Answer

Upper motor neuron lesions typically cause spasticity and hyperreflexia, whereas lower motor neuron lesions cause flaccidity and hyporeflexia.

Question 5

A patient with resting tremor, bradykinesia, and cogwheel rigidity most likely has dysfunction of which structure?

Accepted Answer

Substantia nigra

Answer

Loss of dopaminergic neurons in the substantia nigra causes the classic parkinsonian triad.

American Board of Psychiatry and Neurology Practice Test