Validity of an Open-access Handedness Recognition Task in Stroke Patients

Overview

This study aims to assess the validity of a hand laterality discrimination task in patients who have suffered a stroke. The protocol involves two assessment sessions consisting of a Single Reaction Time (SRT) task and a Hand Laterality Judgement Task (HLJT). In the HLJT, participants are presented with images of right or left hands at various degrees of rotation and must determine the laterality of each hand. Primary outcomes include reaction time for the SRT, and both accuracy (percentage of correct responses) and decision-making time for the HLJT. Additionally, motor and kinesthetic imagery scales, as well as demographic and cognitive variables, are recorded.

The primary objective of this research is to evaluate the psychometric properties and validity of a hand laterality discrimination task in a post-stroke population. The study design includes two identical measurement points to assess the reliability and accuracy of motor processing. The experimental protocol is divided into two main components: Single Reaction Time (SRT) Task: This task is used to establish a motor processing baseline by measuring the simple reaction time to a stimulus. Hand Laterality Judgement Task (HLJT): A mental rotation task where patients are shown photographs of right and left hands at different angles of rotation. Participants must decide whether the hand shown is a right or a left hand. The variables analyzed are the accuracy rate (percentage of correct responses) and the decision-making time (latency). Upon completion of the HLJT, a structured interview is conducted to identify the mental strategies used during the task. This allows researchers to determine whether patients relied on motor imagery (e.g., mentally moving their own hand) or external visual strategies to achieve the results. To complement these data, the study incorporates validated motor and kinesthetic imagery scales to assess the subjective quality of movement representation. Furthermore, demographic data (such as age and time since stroke) and cognitive variables are collected to control for potential confounding factors that may influence performance on the laterality tasks. To evaluate the changes and the validity of the measurements, an Analysis of Covariance (ANCOVA) will be performed. In this model, the baseline measurement (Session 1) will be included as a covariate to control for initial individual differences in reaction time and accuracy. This approach allows for a more precise estimation of the task's stability and the effect of the variables studied by reducing the error variance associated with the participants' starting scores.