Extended excitability data. A, B and C, normal controls (n = 14; black filled circles) and RLS patients (n = 14; grey filled circles) for sensory axons (median nerve) (mean ± SD). A, TE for conditioning levels of +20%, –20%, +40%, –40%, –70% and –100% of control threshold. B, I–V relationship for 200 ms conditioning stimuli. C, recovery cycle.