Effects of Deep Brain Stimulation on Eye Movements and Vestibular Function

Abstract

Discovery of inter-latching circuits in the basal ganglia and invention of deep brain stimulation (DBS) for their modulation is a breakthrough in basic and clinical neuroscience. The DBS not only changes the quality of life of hundreds of thousands of people with intractable movement disorders, but it also offers a unique opportunity to understand how the basal ganglia interacts with other neural structures. An attractive yet less explored area is the study of DBS on eye movements and vestibular function. From the clinical perspective such studies provide valuable guidance in efficient programming of stimulation profile leading to optimal motor outcome. From the scientific standpoint such studies offer the ability to assess the outcomes of basal ganglia stimulation on eye movement behavior in cognitive as well as in motor domains. Understanding the influence of DBS on ocular motor function also leads to analogies to interpret its effects on complex appendicular and axial motor function. This review focuses on the influence of globus pallidus, subthalamic nucleus, and thalamus DBS on ocular motor and vestibular functions. The anatomy and physiology of basal ganglia, pertinent to the principles of DBS and ocular motility, is discussed. Interpretation of the effects of electrical stimulation of the basal ganglia in Parkinson's disease requires understanding of baseline ocular motor function in the diseased brain. Therefore we have also discussed the baseline ocular motor deficits in these patients and how the DBS changes such functions.

Serum Insulin-Like Growth Factor-1 in Parkinson's Disease; Study of Cerebrospinal Fluid Biomarkers and White Matter Microstructure

“…Therefore, QA has resolved the shortage of FA in the areas of crossing fibers. Notably, we were able to detect the microstructural changes in short association fibers, which are located in the region with high crossing fibers, in patients with PD by using the connectometry approach ( 80 ). Furthermore, several pathological features, such as axonal loss, demyelination, inflammation, or edema can alter FA.…”

Saccadic intrusions in paediatric concussion

“…These patients showed saccadic intrusions during smooth pursuit but not during fixation, contrasting with saccadic intrusions seen in other diseases 2018. In addition, their lack of other oculomotor findings, such as ophthalmoplegias, spontaneous nystagmus, or impaired vestibulo‐ocular reflex, suggest a lack of brainstem involvement 2018.…”

“…These patients showed saccadic intrusions during smooth pursuit but not during fixation, contrasting with saccadic intrusions seen in other diseases. 2 In addition, their lack of other oculomotor findings, such as ophthalmoplegias, spontaneous nystagmus, or impaired vestibulo-ocular reflex, suggest a lack of brainstem involvement. 3 mTBI has commonly been associated with oculomotor changes, such as increased saccadic latencies and impaired convergence, but this is believed to be the first exploration of saccadic intrusions in mTBI.…”

Deep brain stimulation and eye movements

“…This contradicts findings in many studies (Goelz et al, 2017; Wark, 2006; Yugeta et al, 2010), where not only initiation, but also inhibition and fixational stability were improved with STN DBS. Therefore, another model, the oscillation model of BG circuits was proposed (Antoniades, Buttery, et al, 2012; Shaikh et al, 2018; Tokushige et al, 2018; Yugeta et al, 2010): beta band oscillations are increased in PD patients, and because desynchronization of beta band is required to initiate a motor command, motoric thresholds in PD are elevated. STN DBS thus decreases pathologic oscillations and facilitates motor command, but at the same time it also stabilizes SC activity and restores inhibitory saccadic control (Yugeta et al, 2013).…”