A 70-year-old man is brought to the clinic by his family due to a 9-month history of progressive memory loss, difficulty with planning and organizing, and a 'magnetic' gait where his feet appear to stick to the floor. Neurological exam reveals broad-based, shuffling gait and mild cognitive impairment. MRI of the brain shows ventriculomegaly out of proportion to sulcal atrophy. What is the most appropriate next diagnostic and therapeutic step?
✓ Correct Answer: Option C
This presentation is classic for Normal Pressure Hydrocephalus (NPH), characterized by the triad of gait disturbance, dementia, and urinary incontinence. A large-volume lumbar puncture is both diagnostic (if symptoms improve) and potentially therapeutic, guiding shunt placement.