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Published on: June 15, 2018
F wave measurements detecting changes in motor neuron excitability after ischaemic stroke
1Departement of Neurology, Diósgyor Hospital, Miskolc, Hungary. mikluk33@hotmail.com
Objective:
To study mechanisms that are involved in the hyperexcitability of spinal motor neurons in upper motor neuron lesion, by means of F-wave measurements.
Methods:
F waves from 44 hospitalized stroke patients and 35 healthy controls were recorded from abductor pollicis brevis muscles in the course of two experiments: (1) single stimuli following high-intensity ipsilateral cutaneous conditioning were used to stimulate the median nerve; (2) paired stimuli were given to the median nerve at gradually increasing interstimulus intervals to assess recovery curves. Mean F-wave amplitudes elicited by the conditioning stimuli were compared with mean F-wave amplitudes elicited by the test stimuli on both the hemiparetic and the unaffected side.
Results:
There was no reduction on the hemiparetic side of mean F-wave amplitudes elicited following high-intensity ipsilateral cutaneous stimulation. The recovery of mean F-wave amplitude was completed at longer interstimulus intervals on the hemiparetic side than on the unaffected side and in controls. A correlation was found between this delay of recovery and hemiparetic severity.
Conclusions:
The results of our study support the role of changes in lower motor neuron membrane excitability in the enhancement of F wave amplitudes after stroke.
