Editing F wave (section)

{{Short description|Motor response evoked by electrical stimulation of a nerve}}
{{about|the term as it applies to neuroscience|the type of electronic wavefunction in atomic physics|atomic orbital}}
In [[neuroscience]], an '''F wave''' is one of several motor responses which may follow the [[Muscle contraction|direct motor response (M)]] evoked by electrical stimulation of peripheral motor or mixed (sensory and motor) nerves.<ref name=":0">{{Cite book|title=Neuromuscular function and disease : basic, clinical, and electrodiagnostic aspects|date=2002|publisher=Saunders|others=Brown, William F. (William Frederick), 1939-, Bolton, Charles Francis, 1932-, Aminoff, Michael J. (Michael Jeffrey)|isbn=0-7216-8922-1|edition=1st|location=Philadelphia|oclc=46873002}}</ref> F-waves are the second of two late [[voltage]] changes observed after stimulation is applied to the skin surface above the [[Anatomical terms of location#Proximal and distal|distal]] region of a [[nerve]], in addition to the [[H-reflex]] (Hoffman's Reflex) which is a muscle reaction in response to electrical stimulation of innervating sensory fibers.<ref name=":1">{{Cite book|last1=Smith|first1=M|title=Oxford Textbook of Neurocritical Care|last2=Kofke|first2=WA|last3=Citerio|first3=G|publisher=Oxford University Press|year=2016|pages=175}}</ref><ref name=":2">{{Cite book|last1=Jerath|first1=Nivedita|last2=Kimura|first2=Jun|title=Clinical Neurophysiology: Basis and Technical Aspects |chapter=F wave, A wave, H reflex, and blink reflex |date=2019|series=Handbook of Clinical Neurology|volume=160|pages=225–239|doi=10.1016/B978-0-444-64032-1.00015-1|issn=0072-9752|pmid=31277850|isbn=9780444640321|s2cid=195813560}}</ref> Traversal of F-waves along the entire length of peripheral nerves between the [[spinal cord]] and muscle, allows for assessment of motor nerve conduction between distal stimulation sites in the arm and leg, and related motoneurons (MN's) in the cervical and lumbosacral cord.<ref name=":3">{{Cite journal|last=Fisher|first=Morris A.|date=2007-02-02|title=F-waves--physiology and clinical uses|journal=TheScientificWorldJournal|volume=7|pages=144–160|doi=10.1100/tsw.2007.49|issn=1537-744X|pmc=5901048|pmid=17334607 |doi-access=free }}</ref> F-waves are able to assess both [[Afferent nerve fiber|afferent]] and [[Efferent nerve fiber|efferent]] loops of the alpha motor neuron in its entirety.<ref name=":4">{{Cite book|last=Katirji, Bashar.|title=Electromyography in clinical practice : a case study approach|date=2007|publisher=Mosby Elsevier|isbn=978-0-323-07034-8|edition=2nd|location=Philadelphia|oclc=324995633}}</ref> As such, various properties of F-wave motor nerve conduction are analyzed in [[Nerve conduction study|nerve conduction studies (NCS)]],<ref>{{Cite journal|last1=Mallik|first1=A.|last2=Weir|first2=A. I.|date=2005|title=Nerve conduction studies: essentials and pitfalls in practice|journal=Journal of Neurology, Neurosurgery, and Psychiatry|volume=76|issue=Suppl 2 |pages=ii23–31|doi=10.1136/jnnp.2005.069138|issn=0022-3050|pmc=1765692|pmid=15961865}}</ref> and often used to assess [[Polyneuropathy|polyneuropathies]], resulting from states of neuronal demyelination and loss of peripheral axonal integrity.<ref name=":0" /><ref name=":5">{{Cite journal|last=Fisher|first=Morris A.|date=1992|title=AAEM minimonograph #13: H reflexes and F waves: Physiology and clinical indications|journal=Muscle & Nerve|language=en|volume=15|issue=11|pages=1223–1233|doi=10.1002/mus.880151102|pmid=1488060|s2cid=6174526|issn=1097-4598}}</ref><ref>{{Cite journal|last1=Lachman|first1=T|last2=Shahani|first2=B T|last3=Young|first3=R R|date=1980|title=Late responses as aids to diagnosis in peripheral neuropathy.|journal=Journal of Neurology, Neurosurgery, and Psychiatry|volume=43|issue=2|pages=156–162|issn=0022-3050|pmid=6244369|pmc=490491|doi=10.1136/jnnp.43.2.156}}</ref>

With respect to its nomenclature, the F-wave is so named as it was initially studied in the smaller muscles of the foot.<ref>{{Cite journal|last1=Magladery|first1=J. W.|last2=McDOUGAL|first2=D. B.|date=1950|title=Electrophysiological studies of nerve and reflex activity in normal man. I. Identification of certain reflexes in the electromyogram and the conduction velocity of peripheral nerve fibers|journal=Bulletin of the Johns Hopkins Hospital|volume=86|issue=5|pages=265–290|issn=0097-1383|pmid=15414383}}</ref> The observation of F-waves in the same [[Motor unit|motor units (MU)]] as those present in the direct motor response (M),<ref>{{Cite journal|last1=Wulff|first1=C. H.|last2=Gilliatt|first2=R. W.|date=1979|title=F waves in patients with hand wasting caused by a cervical rib and band|journal=Muscle & Nerve|volume=2|issue=6|pages=452–457|doi=10.1002/mus.880020606|issn=0148-639X|pmid=514311|s2cid=2423723}}</ref> along with the presence of F-waves in deafferented animal and human models,<ref name=":6">{{Cite journal|last1=Fox|first1=J E|last2=Hitchcock|first2=E R|date=1987|title=F wave size as a monitor of motor neuron excitability: the effect of deafferentation.|journal=Journal of Neurology, Neurosurgery, and Psychiatry|volume=50|issue=4|pages=453–459|issn=0022-3050|pmc=1031882|pmid=3585357|doi=10.1136/jnnp.50.4.453}}</ref> indicates that F-waves require direct activation of motor axons to be elicited,<ref>{{Cite book|last=Trontelj|first=JV|title=A study of the F response by single fiber electromyography, in Desmedt JE (ed): New Developments in Electromyography and Clinical Neurophysiology|publisher=Karger|year=1973|location=Basel|pages=318–322}}</ref> and do not involve conduction along afferent sensory nerves. Thus, the F-wave is considered a wave, as opposed to a reflex.