# A CUP HALF FULL: EXPLORING THE KINEMATIC CONSEQUENCES OF VARIATIONS IN THE DRINKING TASK PROTOCOL

## TL;DR

This study shows that small changes in how a drinking task is set up can affect measurements of upper limb movement, suggesting the need for standardized protocols in rehabilitation research.

## Contribution

The study identifies specific protocol variations in the drinking task that significantly affect kinematic metrics, highlighting the need for standardization.

## Key findings

- Seating position affects movement time and trunk displacement.
- Cup starting position influences trunk displacement significantly.
- Target definition impacts movement time.

## Abstract

Kinematic assessment of the drinking task offers objective metrics of upper limb recovery following neurological injury. The rehabilitation research community’s increased interest has led to consensus standardization efforts. These efforts inherently depend on fidelity of the activity protocol underlying drinking task kinematics. This study’s objective is to investigate whether differences in the drinking task protocol, as observed in prior literature, impact common kinematic metrics.

Incomplete block design with repeated-measures.

Six neurotypical participants.

Seating position, cup start position, and target definition for cup return were varied. Mixed effects linear models analysed the impact of protocol variants on validated kinematic metrics used in stroke rehabilitation research.

All considered factors have a significant impact on at least 1 kinematic metric. Seating position impacts movement time (p = 0.035) and trunk displacement (p = 0.017), cup starting position impacts trunk displacement (p = 0.001), and target definition impacts movement time (p = 0.036). Of note, none of the factors significantly altered the number of movement units.

Further refinement and adherence to a standardized protocol for the drinking task activity may reduce between-study effects and promote the successful uptake of upper limb kinematic assessment in the rehabilitation research community.

Movement of the upper limb is commonly impaired after neurological injuries such as stroke. Rehabilitation is a cycle that relies on accurate assessment to guide treatments. Kinematic assessment of the upper limb involves measuring motion of the human body during movement. Kinematics of the drinking task have been recommended for use in the rehabilitation research community. However, performance of a task may depend on how the task is set up. Among prior studies, despite detailed descriptions of the drinking task setup, differences persist and their impact on kinematics is unclear. This pilot study explored how slight variations in the drinking task setup might impact kinematic assessment among 6 adults with typical neurological function. We found that every variation led to significant changes in at least 1 kinematic outcome. This suggests a need for continued refinement of the drinking task protocol to improve repeatability and to support uptake.