Fig 4.

Quantitative characteristics of periodic alternating nystagmus (PAN) that was manifest in eight ataxia-telangiectasia patients. Each panel represents one patient and each data point represents the slow phase eye velocity of the drift phase of the nystagmus. Data points with the negative sign represent the velocity of the left-ward drifts. The black line in each panel represents the best sinusoidal fit to the slow phase eye velocity. Negative values of eye velocity represent leftward movement (reproduced with permission from Shaikh et al., 2009).