Fig. 7 Dual jerk nystagmus hypothesized to be comprised of NOT nystagmus superimposed on IN waveforms shown in Figures 5 and 6. The resulting waveforms show sinusoidal modulation of the underlying slow eye movement off target. Depicted are dual jerk right with accelerating slow phases (DJRA), dual jerk right with extended foveation (DJREF), and dual jerk right with linear slow phases (DJRL).