Faculty Bibliography

Background: Sideline diagnostic tests for concussion are vulnerable to volitional poor performance ("sandbagging") on baseline assessments, motivated by desire to subvert concussion detection and potential removal from play. We investigated eye movements during sandbagging versus best effort on the King-Devick (KD) test, a rapid automatized naming (RAN) task. Methods: Participants performed KD testing during oculography following instructions to sandbag or give best effort. Results: Twenty healthy participants without concussion history were included (mean age 27 ± 8 years). Sandbagging resulted in longer test times (89.6 ± 39.2 s vs 48.2 ± 8.5 s, p < .001), longer inter-saccadic intervals (459.5 ± 125.4 ms vs 311.2 ± 79.1 ms, p < .001) and greater numbers of saccades (171.4 ± 47 vs 138 ± 24.2, p < .001) and reverse saccades (wrong direction for reading) (21.2% vs 11.3%, p < .001). Sandbagging was detectable using a logistic model with KD times as the only predictor, though more robustly detectable using eye movement metrics. Conclusions: KD sandbagging results in eye movement differences that are detectable by eye movement recordings and suggest an invalid test score. Objective eye movement recording during the KD test shows promise for distinguishing between best effort and post-injury performance, as well as for identifying sandbagging red flags.

Sialidosis type 1 is a rare lysosomal storage disorder caused by mutations of the neuraminidase gene. Specific features suggesting this condition include myoclonus, ataxia and macular cherry-red spots. However, phenotypic variability exists. Here, we present detailed clinical and video description of three patients with this rare condition. We also provide an in-depth characterization of eye movement abnormalities, as an additional tool to investigate pathophysiological mechanisms and to facilitate diagnosis. In our patients, despite phenotypic differences, eye movement deficits largely localized to the cerebellum.

BACKGROUND:Eye-hand coordination (EHC) is a sophisticated act that requires interconnected processes governing synchronization of ocular and manual motor systems. Precise, timely and skillful movements such as reaching for and grasping small objects depend on the acquisition of high-quality visual information about the environment and simultaneous eye and hand control. Multiple areas in the brainstem and cerebellum, as well as some frontal and parietal structures, have critical roles in the control of eye movements and their coordination with the head. Although both cortex and cerebellum contribute critical elements to normal eye-hand function, differences in these contributions suggest that there may be separable deficits following injury. METHOD/METHODS:As a preliminary assessment for this perspective, we compared eye and hand-movement control in a patient with cortical stroke relative to a patient with cerebellar stroke. RESULT/RESULTS:We found the onset of eye and hand movements to be temporally decoupled, with significant decoupling variance in the patient with cerebellar stroke. In contrast, the patient with cortical stroke displayed increased hand spatial errors and less significant temporal decoupling variance. Increased decoupling variance in the patient with cerebellar stroke was primarily due to unstable timing of rapid eye movements, saccades. CONCLUSION/CONCLUSIONS:These findings highlight a perspective in which facets of eye-hand dyscoordination are dependent on lesion location and may or may not cooperate to varying degrees. Broadly speaking, the results corroborate the general notion that the cerebellum is instrumental to the process of temporal prediction for eye and hand movements, while the cortex is instrumental to the process of spatial prediction, both of which are critical aspects of functional movement control.

An ability to move freely, when wanted, is an essential activity for healthy living. Visually impaired and completely blinded persons encounter many disadvantages in their day-to-day activities, including performing work-related tasks. They are at risk of mobility losses, illness, debility, social isolation, and premature mortality. A novel wearable device and computing platform called VIS⁴ION is reducing the disadvantage gaps and raising living standards for the visually challenged. It provides personal mobility navigational services that serves as a customizable, human-in-the-loop, sensing-to-feedback platform to deliver functional assistance. The platform is configured as a wearable that provides on-board microcomputers, human-machine interfaces, and sensory augmentation. Mobile edge computing enhances functionality as more services are unleashed with the computational gains. The meta-level goal is to support spatial cognition, personal freedom, and activities, and to promoting health and wellbeing. VIS⁴ION can be conceptualized as the dovetailing of two thrusts: an on-person navigational and computing device and a multimodal functional aid providing microservices through the cloud. The device has on-board wireless capabilities connected through Wi-Fi or 4/5G. The cloud-based microservices reduce hardware and power requirements while allowing existing and new services to be enhanced and added such as loading new map and real-time communication via haptic or audio signals. This technology can be made available and affordable in the economies of transition countries.