J Roesche, C Paulus, U Maisch, A Kaspar, E Mauch and HH Kornhuber
Introduction: F-wave size has been shown to reflect changes of motor neuron excitability. The F-wave amplitude changed parallel to the muscle tone after an acute cerebral insult and was reduced by several medicines in long standing poststroke hemiparesis. Physiotherapy plays an important part in the rehabilitation of patients with spasticity. But since qualified physiotherapy is not available every day for patients living at home, therapy with a motorized exercise-cycle is often necessary to treat spasticity in people with multiple sclerosis. The aim of this work is to investigate whether the effects of antispastic treatment with a motorized exercise-cycle can be documented by F-wave-amplitude parameters.
Materials and methods: We examined 35 patients with spastic paraparesis; 31 had multiple sclerosis, one had multiple system atrophy and two patients had familial spastic paraplegia. In the remaining patient a spinal tumor was detected. Their age ranged from 32 to 67 years. Duration of disease ranged from 7 to 39 years. All had increased muscle tone, decreased muscle force and positive Babinski signs. Electrophysiological examination was performed with the `Toennies Multiliner’ immediately before and after a treatment with a motorized exercise cycle. The whole procedure was performed on each leg before and after treatment. Physical therapy was performed using a motorized exercise-cycle for the reduction of spasticity by rhythmical movement of the legs. In this study treatment was performed for 30 min with a speed of 40 rounds per minute.
Results: There was a slight significant decrease of mean amplitudes after treatment with the motorized exercise cycle when only the F-waves were considered. But the decrease was clearly significant when the relation of F waves to the M-responses was taken into account. Both F-wave-M-response ratios were lower after but not before the treatment with the motorized exercise-cycle. In 16 legs none of the four F wave-amplitude parameters taken into consideration decreased. But in only two patients was there no decrease of F-wave-amplitude parameters in both legs.
Discussion: In comparison to the Normal values of the mean F wave/M-response ratio in our patients was clearly increased before and still somewhat subsequent to treatment with a motorized exercise-cycle. In addition, secondary changes in the muscles may occur. This may be the reason for the decrease of F-wave-amplitude/M response ratio after the treatment with a motorized exercise-cycle not being observed in every treated leg. Since F-wave/M-response ratios proved to be more significant to changes of motoneuron excitability than were the raw F-wave-amplitudes, an effect on motoneuron-excitability is sometimes only noticed by comparing F-wave/M-response ratios. The antispastic effect of treatment with a motorized exercise-cycle can be documented by recording F wave-amplitudes.