MSFinals-3001

A 28-year-old woman presents to her primary care physician with concerning symptoms that have been occurring on and off for the past few months. She reports experiencing episodes of weakness accompanied by rapid, involuntary movements of her arms. Additionally, she has been experiencing persistent tingling sensations, occasional double vision, electric shocks down her arms and trunk when she flexes her neck, and constipation. Based on these symptoms, what would be the most appropriate initial test to diagnose her condition?