Evaluation of the presynaptic inhibition by comparing the amplitudes of H reflexes and F waves. Is it possible?
The H reflexes depend on presynaptic inhibition, but not the F waves. The aim of this study was to explore the possibility for using the comparison of F wave and H reflex amplitudes (F/H ratio) for indirect evaluation of the presynaptic inhibition. An examination of 130 patients with old spastic hemiparesis was performed. The neurophysiological examination included F wave evaluation after stimulation of the tibial nerve, evaluation of soleus H reflex maximal amplitude before (Hmax) and after vibration (Hvibr) applied on the Achilles tendon. The Hvibr/Hmax and F/H amplitude ratios were calculated. Our data revealed that the F/H amplitude ratio is quite different from the Hvibr/Hmax amplitude ratio widely used for evaluation of the presynaptic inhibition. In conclusion comparison of F wave and H reflex amplitudes for indirect evaluation of the presynaptic inhibition is not a valid tool. The differences between H reflexes and F waves do not concern only the presynaptic inhibition.
Milanov
I G
IG
University Neurological Hospital, IV kilometer, III Neurological Clinic, Sofia, Bulgaria.
D000125:Achilles Tendon / Q000503:physiopathology; D000328:Adult; D000368:Aged; D005260:Female; D006181:H-Reflex / Q000502:physiology*; D006429:Hemiplegia / Q000209:etiology / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009046:Motor Neurons / Q000502:physiology; D018482:Muscle, Skeletal / Q000503:physiopathology; D009433:Neural Inhibition / Q000502:physiology*; D009460:Neurologic Examination; D017729:Presynaptic Terminals / Q000502:physiology*; D012026:Reflex, Stretch; D020521:Stroke / Q000150:complications; D013979:Tibial Nerve / Q000503:physiopathology; D014732:Vibration