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Do F‐wave measurements detect changes in motor neuron excitability?
Author(s) -
Lin Jenny Z.,
Floeter Mary Kay
Publication year - 2004
Publication title -
muscle and nerve
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.025
H-Index - 145
eISSN - 1097-4598
pISSN - 0148-639X
DOI - 10.1002/mus.20110
Subject(s) - motor neuron , amplitude , f wave , facilitation , stimulation , neuroscience , physics , neuron , medicine , anatomy , psychology , optics , spinal cord , nerve conduction velocity
The use of F waves to assess motor neuron excitability in experimental paradigms has never been validated. Our objective was to determine whether F‐wave area, amplitude, and persistence measurements change in response to manipulations known to alter the excitability of motor neurons. The effects of muscle vibration, contraction of a remote muscle, and high‐intensity stimulation of ipsilateral or contralateral fingers were assessed in 12 healthy volunteers. F‐wave area, amplitude, and persistence all declined with ipsilateral cutaneous stimulation. The other maneuvers facilitated some, but not all, of the F‐wave measurements. Changes in F‐wave area and amplitude were correlated, but neither correlated with changes in persistence. A sample size of 50–75 F waves was needed to approximate amplitude and area results from 100 F waves with an accuracy of ±25%. We conclude that changes in F waves are better at detecting inhibition than facilitation of motor neurons. F waves reflect motor neuron excitability in a general way but do not allow for accurate measures of short‐term changes in excitability. Muscle Nerve 30: 289–294, 2004