Reaching in Stroke with Hemiplegia: The Error between Estimated and Actual Distances in the Visual Field

Abstract

The aim of this study was to examine patients with post-stroke hemiplegia for space estimation disorder during visual reaching for a target. Six patients with post-stroke hemiplegia with no parietal damage were studied, as well as 6 healthy older adults and 6 healthy younger adults as a control group. A target was placed on the table in front of the subject, and then the subject was asked to verbally indicate the farthest reachable point while the target was gradually being moved further away from the subject. The difference was then obtained by measuring the distance from the subject to the indicated point. There was no significant difference in the errors between the estimated and actual values in the healthy older and younger adults. No significant difference was also observed between dominant and non-dominant hands. There were significant differences between the paretic and non-paretic side in the hemiplegic patients, as well as between the paretic side of hemiplegic patients and the dominant hand in the healthy older adults. Compared with healthy subjects, the hemiplegic patients showed a greater difference between the estimated and actual values for both the non-paretic and paretic sides, which indicates an estimation disorder during visual reaching in patients with post-stroke hemiplegia. These results are discussed based on a conversion of the visual coordinates into movement coordinates during visual reaching.