Timothy C. Hain, MD
Please read our disclaimer Return to Index. Page last modified: November 21, 2009
The purpose of this section of the site is to provide an overview of ongoing research pursued by Dr. Hain over the last few decades. It is not intended to "reprise" papers, but rather to integrate together material across time.
Rebound nystagmus (see here for a more clinically oriented page) is a primary position nystagmus which is provoked by prolonged eccentric gaze holding. It appears after the eyes are returned to primary position.
There are two methods of eliciting rebound. The traditional method is to have the patient follow ones finger to one side, hold gaze there for 10 seconds (with constant encouragement by the examiner to keep looking), and then rapid return to central gaze. At that point, the examiner looks for a nystagmus that beats away from the previous direction of gaze holding, lasting for at least 5 beats.
A more modern and sensitive method of eliciting rebound is to use video-freznel goggles. (as shown above). Otherwise the technique is similar. The video-frenzels make it much easier to see small amounts of nystagmus.
An abnormal amount of rebound in the light, as shown below, consists of at least 3 beats of clear nystagmus, with the slow-phases directed towards the previous position of gaze. It must reverse direction according to the direction of previous gaze. When using the video-frenzel goggles, at least 5 beats should be observed.
Rebound Nystagmus -- a right-beating nystagmus occurs after 10 seconds of gaze holding to the left. A left-beating nystagmus appears after 10 seconds of gaze holding to the right.
Supplemental material on the site DVD: Video of rebound nystagmus
Rebound after gaze holding for periods more prolonged than 30 sec, or for eccentricities larger than about 45 deg is of uncertain significance as normal subjects may exhibit rebound under such circumstances (Gordon et al, 1986). Vertical rebound is rare but it can also occur.
Rebound nystagmus in patient with myotonic dystrophy -- type II. (Driss et al, In Press)
Rarely rebound rarely occurs in situations where there is no obvious cerebellar disease. We recently have found patients with myotonic dystrophy who have rebound, possibly due to ocular myotonia. An example of this is shown above. (Driss et al, In press). Persons with myotonia are slow to relax previously contracted muscles. If this occured in the eye muscles, as others have suggested (Versino et al, 2002) it might cause rebound nystagmus.