Oculomotor Performances Are Associated With Motor and Non-motor Symptoms in Parkinson's Disease

Abstract

Background: Parkinson's disease (PD) patients exhibit deficits in oculomotor behavior, yet the results are inconsistent across studies. In addition, how these results are associated with clinical symptoms is unclear, especially in China.Methods: We designed a case-control study in China including 37 PD patients and 39 controls. Clinical manifestations in PD patients were recorded. Oculomotor performance was measured by a video-based eye tracker system.Results: We found that six oculomotor parameters, including fixation stability, saccadic latency, smooth pursuit gain, saccade frequency, viewing range, and saccade frequency during free-viewing context, were significantly different in PD patients and control group. Combining application of these six parameters could improve diagnostic accuracy to over 90%. Moreover, pursuit gain was significantly associated with PD duration, UPDRS III, in PD patients. Saccade latency was significantly associated with PD duration, Berg balance score, RBD score, and Total LEDD in PD patients.Conclusions: PD patients commonly exhibit oculomotor deficits in multiple behavioral contexts, which are associated with both motor and non-motor symptoms. Oculomotor test may provide a valuable tool for the clinical assessment of PD.

Abnormalities of smooth pursuit in Parkinson’s disease: A systematic review

“…Linder et al (2012) found a correlation between the axial UPDRS score and SPEM gain of their PD patients [12] . Zhang et al, 2016 found a correlation between SPEM gain and disease duration and UPDRS scores [19] .…”

Spontaneous eye movements during eyes-open rest reduce resting-state-network modularity by increasing visual-sensorimotor connectivity

“…Anomalies are more evident for voluntary saccades, in early stages of disease (for review, see Pretegiani & Optican, 2017 ). A behavioral study ( Zhang et al, 2018 ) showed that PD is linked to reduced fixation stability when fixation is required. Conversely, during free viewing of single images, PD patients make fewer saccadic eye movements, and within a more narrow range.…”

“…From a theoretical perspective, identifying neural systems controlling eye movement during rest could allow better partitioning between relatively more ‘active,’ (oculo)motor-related aspect of RS as opposed to other more covert, nonmotor-related aspects of RS. Finally, eye movements themselves could be a possible confounder when studying healthy and clinical populations that differ in oculomotor control, including autism (e.g., Takarae, Minshew, Luna, Krisky, & Sweeney, 2004 ), Parkinson’s disease (e.g., Pretegiani & Optican, 2017 ; Zhang et al, 2018 ), or schizophrenia (e.g., Dowiasch et al, 2016 ; Morita, Miura, Kasai, & Hashimoto, 2020 ).…”

Freezing of saccades in dopa-responsive parkinsonian syndrome

“…Studies of ocular motor difficulties have shown that prolongation of saccade latency is one of the most quantitative ocular motor measurements in idiopathic PD and in atypical parkinsonian syndrome. 15 , 16 , 17 Saccades are fast eye movements used to explore the visual world. 18 Saccades can be divided into reflexive saccade, in response to a target, or volitional saccade, which is self-generated.…”

“…Prolonged reflexive saccade latencies correlate with older age, longer disease duration, and greater severity of disease. 15 , 16 , 17 Although the effect of dopamine replacement on reflexive saccade latencies has been mixed, 19 , 20 , 21 treatment has been shown to improve the latency of volitional saccades. 19 , 20 , 21 , 22 , 23 Subthalamic deep brain stimulation has also been shown to improve saccade latencies.…”