Comparison of three methods for recording tibial H reflex: a clinical note.
Recording the tibial H reflex from the calf is routine in clinical electromyography. Two widely used methods are Hugon's and Braddom and Johnson's. Both methods produce an H wave with an initial positive deflection. Another method, the "half and half" method, generates an H wave with an initial negative deflection. To compare these methods, H-reflex responses were recorded in the right calf of 20 normal adults with each method using identical amplifier and stimulator settings. Stimulus current was increased by increments of 0.5-1.0 mA until the H reflex and motor (M) wave responses reached maximum amplitudes (Hmax, Mmax). H wave to M wave (H/M) amplitude ratios were calculated. The half-and-half method produced greatest Hmax, Mmax, and H/M ratio. Wave form configuration for the half-and-half method was biphasic with an initial negative deflection; it was triphasic with an initial positive deflection with the other methods. The shapes of M and H waves were similar in two methods but dissimilar in one. Because of the greater amplitude and the initial negative deflection, the H wave may be easier to detect with the half-and-half method and may present a latency that is more easily determined. For these reasons, the half-and-half method is recommended for measuring amplitude and latency in clinical settings.
Nishida
T
T
Department of Neurology, Northwestern University Medical School, Chicago, Illinois, USA.
Levy
C E
CE
Lewit
E J
EJ
Janssen
I
I
D000328:Adult; D000704:Analysis of Variance; D015982:Bias; D004566:Electrodes; D004576:Electromyography / Q000295:instrumentation / Q000379:methods*; D006181:H-Reflex / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D011930:Reaction Time; D015203:Reproducibility of Results; D013977:Tibia