Which ion channels have impaired function as indicated by electrophysiologic findings?
A 33-year-old woman who is right-handed is brought to the physician because of a 3-day history of progressive weakness and numbness of her ARMS and legs. Neurologic examination shows proximal and distal weakness of the upper and lower extremities. There is areflexia. Sensation to vibration and joint position is decreased in the fingers and toes. Nerve conduction studies show a slow conduction velocity in the median, ulnar, peroneal, and tibial nerves.