Cluster analysis reveals distinct patterns of saccade impairment and their relation to cognitive profiles in Parkinson's disease

Abstract

Saccade performance has been reported to be altered in Parkinson's disease (PD), however, with a large variability between studies as both motor and cognitive impairment interfere with oculomotor control. The aim of this study was to identify different patterns in saccade alterations in PD using a data-driven approach and to explore their relationship with cognitive phenotypes. Sixty-one participants with PD and 25 controls performed eye-tracking (horizontal and vertical prosaccades, antisaccades) and neuropsychological testing. Hierarchical cluster analysis was applied to the eye-tracking data to subsequently compare the clusters based on demographical, clinical and cognitive charac teristics. The three identified clusters of saccade alterations differed in cognitive profiles from healthy controls, but not in PD-related motor symptoms or demographics. The rate of directive errors in the antisaccade task was increased in clusters 1 and 2. Further, cluster 1 was defined by a general disinhibition of reflexive saccades and executive dysfunction in the neuropsychological evaluation. In cluster 2, prolonged saccade latencies and hypometria were accompanied by multidomain cognitive impairment. The cluster 3 showed increased antisaccade latency and vertical hypometria despite lack of evidence for cognitive impairment. Our results suggest that there may be at least two opposing patterns of saccade alterations associated with cognitive impairment in PD, which may explain some of the contradictory results of previous studies.

Oculomotor function captured via an electronic tablet informs on cognition and disease severity in Parkinson’s Disease

“…in the past to correlate with several measures of executive function, particularly on tasks that involve psychomotor speed, visual search, attention taskswitching, and inhibition, such as the TMTA and TMTB tests 38,39 , supporting the notion that the anti-saccade task taps into several executive and frontal cognitive processes, including but not limited to cognition inhibition [40][41][42] . These ndings as a whole are also consistent with the ndings of a recent study that used a cluster analysis to identify different patterns in saccade abnormalities in PD and their relationship with cognitive phenotypes 43 . The authors identi ed three clusters, one of which was de ned by a general disinhibition of re exive saccades (i.e.…”

Eye movement function captured via an electronic tablet informs on cognition and disease severity in Parkinson’s disease

“…These saccadic findings as a whole are also consistent with the findings of a recent study that used a cluster analysis to identify different patterns in saccade abnormalities in PD and their relationship with cognitive phenotypes 48 . The authors identified three clusters, one of which was defined by a general disinhibition of reflexive saccades (i.e.…”