Nystagmus and Saccadic Intrusions

Pendular Nystagmus: a Novel Feature of ANO10-Related Disorders

ANO10-related ataxia is characterized by cerebellar and pyramidal signs, with prominent oculomotor abnormalities, including saccadic abnormalities, strabismus, and ptosis. While nystagmus is frequently observed, the specific subtype of horizontal pendular nystagmus has not been emphasized. This report describes two siblings with early-onset spastic-ataxia with horizontal pendular nystagmus, ultimately diagnosed with SCAR10. This report details the ocular abnormalities spectrum of ANO10-related ataxia by highlighting horizontal pendular nystagmus as a significant clinical feature in early-onset presentations. We also restate the importance of neurological examination, including detailed assessment of ocular movements, for accurate diagnosis and management of hereditary ataxias.

Saccadic intrusions in pediatric non-accidental trauma

Purpose

To report a case of saccadic intrusions in a 9-month-old under the context of non-accidental trauma.

Observations

A 9-month-old female presented with the eye finding of intermittent ocular flutter. Upon imaging for neuroblastoma, she was discovered to have bilateral supratentorial subdural hematomas with internal septations, moderate mass effect on adjacent cerebral parenchyma, pachymeningeal and tentorial enhancement, and cortical vein thrombosis. This constellation of findings was concerning for non-accidental trauma.

Conclusions and importance

Although an extremely rare occurrence, ocular flutter may be a presenting sign in non-accidental trauma, and imaging should absolutely be considered under such circumstances.

Eye and Head Movement Recordings Using Smartphones for Telemedicine Applications: Measurements of Accuracy and Precision

Objective

Smartphones have shown promise in the assessment of neuro-ophthalmologic and vestibular disorders. We have shown that the head impulse test results recorded using our application are comparable with measurements from clinical video-oculography (VOG) goggles. The smartphone uses ARKit's capability to acquire eye and head movement positions without the need of performing a calibration as in most eye-tracking devices. Here, we measure the accuracy and precision of the eye and head position recorded using our application.

Methods

We enrolled healthy volunteers and asked them to direct their eyes, their heads, or both to targets on a wall at known eccentricities while recording their head and eye movements with our smartphone application. We measured the accuracy as the error between the eye or head movement measurement and the location of each target and the precision as the standard deviation of the eye or head position for each of the target positions.

Results

The accuracy of head recordings (15% error) was overall better than the accuracy of eye recordings (23% error). We also found that the accuracy for horizontal eye movements (17% error) was better than for vertical (27% error). Precision was also better for head movement (0.8 degrees) recordings than eye movement recordings (1.3 degrees) and variability tended to increase with eccentricity.

Conclusion

Our results provide basic metrics evaluating the utility of smartphone applications in the quantitative assessment of head and eye movements. While the new method may not replace the more accurate dedicated VOG devices, they provide a more accessible quantitative option. It may be advisable to include a calibration recording together with any planned clinical test to improve the accuracy.

Update on Nystagmus and Other Ocular Oscillations

This review reports on recent advances in understanding nystagmus and other involuntary eye movements. Advances in quantitative evaluations of eye movements using oculography, computational model simulations, genetics, and imaging technologies have markedly improved our understanding of the pathophysiology of involuntary eye movements, as well as their diagnosis and management. Patient-initiated capture of eye movements, especially when paroxysmal, and the online transfer of these data to clinicians would further enhance the ability to diagnose involuntary eye movements.