title: Supraorbital nerve conduction study in normal subjects.
abstract: There is currently no examination technique that allows direct measurement of supraorbital nerve conduction velocity and amplitude. Therefore, in this study we describe a novel nerve conduction technique that allows measurement of the supraorbital sensory nerve action potential (SNAP) distal to the supraorbital foramen. Supraorbital SNAPs were recorded bilaterally from 17 healthy volunteers using an antidromic technique. The SNAPs were consistently recordable over the site 6 cm lateral to the midline point that was marked 10 cm above the nasion. Measured parameters included peak latency (mean 2.3 ms, SD 0.3), amplitude (mean 14.6 μV; SD 10.5), and velocity (mean 51.3 m/s, SD 6.8). The mean percentage of interside difference in amplitude was 25.6% (SD 17.3). Cut-off values (97th percentile) were 2.7 ms (peak latency), 3.3 μV (amplitude), 41.9 m/s (conduction velocity), and 54.9% (interside difference in amplitude). Supraorbital SNAPs can be recorded in all normal subjects and used as a quantitative measure of the functioning large fibers in the nerve.
authors.affiliation: Neurology Diagnostic Laboratory, National University Hospital System, Singapore.
authors.forename: Aravindakannan
authors.initials: A
authors.lastname: Therimadasamy
authors.forename: Einar P
authors.initials: EP
authors.lastname: Wilder-Smith
authors.forename: Aymeric Y T
authors.initials: AY
authors.lastname: Lim
authors.forename: Yan Lin
authors.initials: YL
authors.lastname: Yap
authors.forename: Matthew
authors.initials: M
authors.lastname: Yeo
authors.forename: Shenthilkumar
authors.initials: S
authors.lastname: Naidu
authors.forename: Shu Jin
authors.initials: SJ
authors.lastname: Lee
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000328:Adult; D004568:Electrodiagnosis; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000502:physiology; D009431:Neural Conduction / Q000502:physiology*; D009460:Neurologic Examination / Q000379:methods* / Q000592:standards*; D009915:Orbit / Q000294:innervation*; D010525:Peripheral Nerves / Q000502:physiology*; D012016:Reference Values; D011984:Sensory Receptor Cells; D055815:Young Adult