OSCE Neurological Assessment 4

Question 1

A patient with diabetes presents with unilateral ptosis and diplopia but a normally reactive pupil. Which condition is most likely?

Accepted Answer

Diabetic CN III palsy (ischemic)

Answer

Diabetic (ischemic) CN III palsy characteristically spares the pupil because the outer parasympathetic fibers are preserved, unlike compressive lesions such as aneurysms which compress these fibers first.

Question 2

During assessment of gait, a patient walks with wide-based, unsteady steps resembling intoxication with feet apart. This pattern is characteristic of:

Accepted Answer

Cerebellar (ataxic) gait

Answer

Cerebellar ataxia produces a wide-based, lurching gait because the cerebellum coordinates balance and movement; patients widen their stance to maintain stability.

Question 3

A patient can feel light touch but not vibration or joint position sense in the lower extremities bilaterally. The lesion most likely affects:

Accepted Answer

Posterior columns (dorsal columns)

Answer

Vibration and proprioception travel in the posterior (dorsal) columns; selective loss of these modalities with preserved light touch indicates posterior column disease (e.g., B12 deficiency, tabes dorsalis).

Question 4

When testing visual acuity with a Snellen chart, a patient reads the 20/200 line correctly with the right eye but no lower. This means:

Accepted Answer

The patient can read at 20 feet what a normal eye sees at 200 feet

Answer

20/200 means the patient must be at 20 feet to read a letter that a person with normal vision can read at 200 feet, indicating severe visual impairment.

Question 5

Which cranial nerve is tested by asking a patient to shrug their shoulders against resistance?

Accepted Answer

CN XI (accessory)

Answer

CN XI (spinal accessory nerve) innervates the sternocleidomastoid and trapezius muscles; shoulder shrug against resistance specifically tests trapezius function.

OSCE Practice Test

OSCE Practice Test

OSCE Neurological Assessment 4