The task-specific assistive device (TAD) is a compact and portable assistive device, consisting of an actuated six-bar linkage, designed to facilitate the activity of drinking from a cup without using the hands. In this paper, we examine the effectiveness of the device in supporting patients with conditions of incomplete tetraplegia and hemiplegia by simulating disability in 17 healthy subjects. The average percentage reduction in bending angle of torso with the use of TAD was found to be 40.31% for subjects with simulated incomplete tetraplegia and 37.14% for subjects with simulated hemiplegia. Users also completed the system usability scale (SUS), indicating that the device was easy to use. The user workload, measured using the NASA task load index (NASA-TLX), was found to be minimal and the device was found to be robust through user response to a user experience questionnaire. The results of this work indicate that TAD is a promising solution for facilitating independence in a basic activity of daily living such as drinking from a cup without using the hands.