A 35-year-old woman presents with recurrent, medically unexplained weakness of her right arm that appears during times of emotional stress, with normal neurological examination and normal MRI brain/spine. The MOST important distinguishing clinical sign that supports a functional neurological symptom disorder (conversion disorder) diagnosis is:

• A Absence of any psychological stressor
• B Normal EMG/NCS confirming no organic basis alone
• C Symptom improvement after benzodiazepine administration
• D Hoover's sign (hip extension weakness in the affected leg restored to normal when the examiner tests the contralateral hip flexion — evidencing inconsistency) ✓

Explanation

DSM-5 requires for Functional Neurological Symptom Disorder (FNSD/Conversion Disorder) that the symptom is incompatible with a recognised neurological condition and there is evidence of internal inconsistency on neurological examination. Hoover's sign is a validated positive clinical sign for functional leg weakness: testing voluntary hip extension shows weakness, but when the examiner assesses the contralateral hip flexion (which reflexively activates the weak limb), normal or improved power is noted — demonstrating the inconsistency. Normal investigations alone are insufficient (Rule B requires positive evidence of incompatibility, not merely absence of organic findings).

Reference: Kaplan & Sadock's Synopsis of Psychiatry, 11th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.