## 1 Introduction  
Since the early 2000s, various types of robots and robotic devices have entered the field of rehabilitation [1; 2; 3]. Rehabilitation robots such as InMotion or Armeo Power for the upper extremity and Lokomat for the lower extremity, are the main examples of widely used robots for the purpose of treatment in a hospital setting [4; 5; 6; 7; 8]. For use outside the hospital, some of the lower extremity robots such as ReWalk, EKSO, and HAL, are being used by the persons with functional impairments despite their relatively high cost [9; 10]. However, to our knowledge, no specific robot has been commercially and widely utilized to assist in performing activities of daily living (ADL) that require the upper extremities, although some are being used in limited circumstances [11].  
Robots used for only treatment purposes are fixed at a certain location in the hospital, and do not require portability in that setting. Robots to be used in a daily setting should be simple, portable, applicable to real objects rather than virtual reality forms or computer screens, and controllable according to the user's intent. For extraction of the user's intent, some of the most common modalities utilized by developers are force or torque sensors, and surface electromyography [12]. However, persons with severe impairment or near-complete paralysis cannot provide sufficient movement to generate input signals to those sensors. Currently, brain-machine interfaces (BMI) are being focused on as an eventual tool to directly assess user intent. However, non-invasive brain signals such as electroencephalography signals exhibit a low signal-to-noise ratio, which hinders precise control. Furthermore, invasive brain signals such as electrocorticography and signals from intracortical microelectrodes still need further development for use in an everyday setting [13; 14; 15]. Therefore, the purpose of the robot in the development and design stage must be clarified to simplify and adapt the robot structure, including whether it needs to be in a form of an external robotic arm or exoskeleton, so that it may be practically applied in ADL with simple control modalities. To clarify the purpose, the practical demands of the potential users with functional impairment needs to be evaluated to avoid a situation where a perfect robot for both control and function is developed but nobody seeks to use it.  
In this study, the research question was which ADLs are mostly in demand for potential users of the robot in terms of necessity for robotic assistance. We hypothesized that there would exist specific ADLs with more priority to the potential users and that it would differ according to the type of the robot and laterality of the impairment. The type of the assistive robot was classified into two types, an external robotic arm type and an exoskeleton type. The external robotic arm type was defined as a robotic device controlled by one or more motors that is not wearable by a human and fixed on a table or a wheelchair. JACO and iARM are two of the most popular external robotic arms [3]. The exoskeleton type was defined as a robot device controlled by one or more motors, that is wearable on a human body either in the upper or lower extremity and in a portable form, corresponding to anatomical joints of the human body while structural modifications are permitted. The end-effector type robots were excluded because they generally do not provide assistive functions. The aim of this study was to investigate the practical demands of potential users of the assistive robots, specifically for both the external robotic arm and upper limb exoskeleton, and also analyze the differences between them.