Parkinsonian patients show impaired predictive smooth pursuit

Abstract

To determine if patients with Parkinson's disease (PD) are able to use a visual contextual cue to induce a predictive change in smooth pursuit direction and if this ability depends on the state of the dopaminergic system, we measured predictive smooth pursuit in nine patients with mild to moderate PD during OFF and ON medication. These values were compared with those of nine age-matched and sex-matched healthy controls.Our focus was on the horizontal smooth pursuit when subjects pursued a downward moving target entering a+/-90 deg curve. The target moved on a homogeneous background or on a static "street" that indicated the future trajectory of the target. Our main result is that PD patients were impaired in eliciting predictive smooth pursuit using the context information of the street compared to healthy subjects. The control group elicited predictive pursuit 250 ms before target onset. In contrast, PD patients showed significantly longer latency (100-120 ms) and reduced maximal pursuit velocity. However, without the street guiding pursuit, a delay of about 250 ms was seen in both groups. There was no significant difference in the smooth pursuit performance between OFF and ON medication in the patient group.These results show that early stage PD patients are impaired in the use of static visual information as a cue for predictive pursuit compared to controls and that this deficit does not depend on dopaminergic medication. In the context of predictive eye movement, the involvement of the striatal-frontal pathway and the spatial working memory is discussed.

Subthalamic deep brain stimulation improves smooth pursuit and saccade performance in patients with Parkinson’s disease

“…Noteworthy, the average smooth pursuit latency value found with DBS ON (218 ms) was almost identical to that found in healthy subjects (221 ms) [33], whereas the latency with DBS OFF was 171 ms. A potential explanation for this could be that STN stimulation might suppress a hyperactive start of the smooth pursuit eye movements and thereby allow the visual target to be captured better at movement onset. However, it is interesting that patients with PD show impaired predictive smooth pursuit eye movements in the early stage [50], indicating multi-component dysfunction.…”

Vestibular-Related Frontal Cortical Areas and Their Roles in Smooth-Pursuit Eye Movements: Representation of Neck Velocity, Neck-Vestibular Interactions, and Memory-Based Smooth-Pursuit

“…Conversely, the lack of initial pursuit in patients with Parkinson’s disease suggests that they have difficulty in inducing priming effects during memory-based pursuit (Figures 14A1 vs. 14B1, *) which required the patients to prepare and execute smooth-pursuit to a selected spot using the cue information (see Functional Considerations, cf., Ladda et al, 2008). Basal ganglia outputs project to the FEF and SEF through the thalamus, and Cui et al (2003) described a possible pursuit loop between the caudal FEF and basal ganglia (Figure 15, thick dashed lines, also Lynch and Tian, 2006).…”

Visual Contrast Sensitivity in Early-Stage Parkinson's Disease

“…5,23 Heterogeneity between patient populations in terms of age, symptom severity, and medication likely contributes to the variability in results. In our study, the largest deficits were observed at spatial frequencies of 2 and 4 cyc/ deg, where all subjects performed best (note the similar shape of the contrast sensitivity function in patients and controls; Fig.…”

“…[17][18][19][20] Smooth pursuit and saccades have longer latencies and lower velocity in PD patients versus healthy age-matched controls. [17][18][19][20][21][22][23] Generally, lower pursuit eye velocity gain produces higher retinal image motion (motion blur), impairing perception of moving images. Fixational eye movements are characteristically unstable in PD, with more frequent small saccadic intrusions and tremor than in healthy controls.…”