title: Superior oblique myokymia. Quantitative characteristics of the eye movements in three patients.
abstract: Using the magnetic search coil technique, we measured horizontal, vertical, and torsional rotations of both eyes of two patients with idiopathic superior oblique myokymia, and of the affected eye in a third patient. Superior oblique myokymia was strictly monocular and consisted of an initial intorsion and depression of the affected eye and subsequent oscillations with torsional and vertical components. The peak-to-peak torsional and vertical amplitudes of the oscillations were less than 1 degree, but peak velocities frequently exceeded 4 degrees/sec in both planes. Fourier analysis indicated two features: (1) a broad range of frequencies up to about 50 Hz, indicating irregular oscillations; and (2) a superimposed larger-amplitude oscillation in the range from 1.5 to 6 Hz. Taken with electromyographic data from other studies, these results indicate that superior oblique myokymia reflects spontaneous discharge of trochlear motor neurons that have undergone regenerative changes.
authors.affiliation: Department of Neurology, Case Western Reserve University, Cleveland, OH.
authors.forename: R J
authors.initials: RJ
authors.lastname: Leigh
authors.forename: R L
authors.initials: RL
authors.lastname: Tomsak
authors.forename: S H
authors.initials: SH
authors.lastname: Seidman
authors.forename: L F
authors.initials: LF
authors.lastname: Dell'Osso
mesh_terms: D000328:Adult; D000368:Aged; D005207:Fasciculation / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015835:Ocular Motility Disorders / Q000150:complications / Q000503:physiopathology*; D014786:Vision Disorders / Q000209:etiology / Q000503:physiopathology