Effects of cigarette smoking on motor functions in patients with multiple sclerosis.

The acute effects of cigarette smoking on motor functions were examined in 21 patients with multiple sclerosis and 11 healthy control subjects. The motor function in the upper extremities was assessed by a simple test battery. Sixteen of 21 patients had a transient deterioration of their motor function immediately after smoking, lasting for 10 minutes. The mean decrease in motor performance score for all 21 patients was 14%. With the same tests performed without smoking only three of 14 patients had a deterioration and the group had a mean 8% improvement. The control group showed a steady improvement over time, both in smoking and in simulation experiments. We conclude that nicotine causes a transient worsening of motor functions in patients with multiple sclerosis, which can be due to its effects on the central nervous system or vegetative-vascular functions.