Somatoform and Conversion Disorders

A 28-year-old woman presents to the psychiatry outpatient clinic with a 6-month history of progressive weakness and numbness in both legs. She reports that the symptoms began suddenly after a heated argument with her husband, and she has been unable to walk without assistance since then. Physical examination reveals intact motor power (5/5) on manual testing, normal reflexes, and intact sensation to all modalities. However, she demonstrates a characteristic "give-way" weakness and reports that her legs "feel like lead." Imaging of the spine and EMG are both normal. She denies any prior psychiatric illness but admits to significant ongoing marital stress. What is the most likely diagnosis?

A 35-year-old woman from rural Maharashtra presents with a 3-month history of complete blindness in both eyes. She reports that vision loss began after witnessing a serious accident involving her son, who sustained head injuries. Detailed ophthalmological examination, including visual acuity testing, pupillary responses, optic disc examination, and visual field testing by confrontation, are all completely normal. Fundoscopy reveals normal optic discs and retinae bilaterally. Visual evoked potentials (VEP) are normal. The patient reports that she navigates her home without difficulty and does not bump into objects, yet claims she cannot see. She denies any other neurological symptoms. What is the most likely diagnosis?

A 32-year-old woman presents to the neurology outpatient clinic with a 3-month history of progressive weakness and numbness in her left leg. She reports the symptoms began after a heated argument with her husband. On examination, she has marked weakness of hip flexion and knee extension on the left, with intact sensation to light touch and pinprick. Reflexes are brisk and symmetrical. Her gait is antalgic but she walks without assistive device. MRI brain and spine are normal. Electromyography shows no denervation pattern. During the consultation, when distracted by conversation, she briefly walks normally before reverting to her antalgic gait. What is the most likely diagnosis?

A 28-year-old female presents with sudden onset of blindness in her right eye following a confrontation with her mother about her career choice. On examination, her pupils react normally to light and accommodation is intact. Fundoscopy is normal. She reports complete loss of vision but can navigate the room without bumping into objects. Visual evoked potentials are normal. When a rotating drum with alternating black and white stripes is presented, her eyes follow the pattern despite her claim of blindness. What is the most appropriate next step in management?

Which neurological sign is classically associated with conversion disorder and indicates a non-organic (functional) basis for the motor deficit?