Epileptic Oscillations
Conjugate ocular oscillations in one extreme gaze position during a seizure
Not really nystagmus because the oscillations are probably initiated by saccades directed away from the seizure focus
Oscillations usually occur in conjunction with head and gaze deviation in a direction opposite to the cerebral hemispheric seizure focus
May be accompanied by tonic-clonic extremity movements on the side of the horizontal gaze deviation
Core clinical features
Fast, moderate-amplitude, horizontal conjugate oscillations in extreme horizontal gaze only on the side opposite to the seizure focus
Oscillations are probably initiated by saccades and followed by a slow drift of the eyes back toward primary gaze position
Head and eyes are deviated in the direction of the saccades
Face and extremities often twitch or contract (“tonic-clonic movements”) on the side of the gaze deviation
Seizure focus usually lies in the cerebral hemisphere on the side opposite to the head and eye deviation and the tonic-clonic extremity movements
Episode usually resolves within minutes but may be sustained (“localization-related status epilepticus”)
When the seizure ends, the eyes may deviate to the opposite side, and the oscillations will stop
When the seizures originate in both cerebral hemispheres, the eyes will deviate downward or upward
Possible accompanying clinical features
If electroencephalography is in progress during the oscillations and head and gaze deviation, epileptic discharges will be captured
Interictal electroencephalogram may also be abnormal
MRI often shows a lesion at the seizure focus
Acute cerebral hemispheric stroke, hemorrhage, inflammation, which cause gaze deviation toward the side of the lesion but no ocular oscillations (See
Acute Cerebral Gaze Deviation
)
Acute pontine stroke, hemorrhage, inflammation, which cause gaze deviation and sometimes nystagmus with its fast phase away from the side of the pontine lesion
Recognize the features of a seizure
Order an electroencephalogram (EEG)
Order brain MRI or CT if the cause is not already known
Treat with anti-convulsants
If the seizures are controlled, the oscillations and other manifestations will cease
