## 4 Discussion  
Highly rated ADLs should be taken into consideration when designing a BMI-controlled robot for rehabilitation or ADL assistance, especially if the robot is going to be simple and portable, with selected functions. Several previous studies were conducted on the functional priorities of patients with specific diseases [18; 19; 20]. However, to our knowledge, this is the first study to assess the needs of potential users according to the type of robot and laterality of the impairment. Chronic stroke patients with hemiplegia generally rated bimanual ADL as the most necessary functions for both types of robot. Nearly 80% of stroke patients with hemiplegia become able to perform most one-handed ADLs and several two-handed ADLs according to the degree of hemiparesis. All 24 stroke patients in this study also had hemiplegia and were able to use the unaffected arm properly. Therefore, ADLs that require both upper extremities were rated as the most necessary functions that a robot should provide. Handling foods, dressing, and hairdressing are functions that require both hands to perform. However, the most important and necessary function for the exoskeleton in stroke patients was self-exercise of the upper extremity, which had a higher score than the bimanual functions. The mean duration since stroke onset was about 110 months in our study population. Many of these chronic stroke patients had moderate to severe spasticity in major upper extremity joints. The rate of spasticity after stroke is reported to be approximately 30% to 60% [21]. During a short interview after the survey, the participants stated that they would like to have an upper extremity robot that could help them exercise at home, in addition to the therapies that they receive in rehabilitation centers. It seems that personal robots with exercise functions would help patients continue their exercises at home to enhance functional recovery and decrease spasticity, which would increase patients' ADL performance level. Many studies have also reported that a decrease in spasticity leads to better ADL performance and a lower burden for care [22; 23]. In addition, several studies showed greater functional improvement when robotic rehabilitation therapy was provided for up to 5 hours a day for 12 weeks than when a lesser treatment dose was used, which indicates that continuing exercise with robots throughout the day would result in better outcomes [24; 25; 26]. In the BIG, eating and hairdressing, as well as cleaning, handling foods, dressing, and moving close items, were ADLs that received relatively high scores for the necessity of external robotic arms. For the exoskeletons, dressing, toilet use, transfer, wheelchair control, moving close items, and handling foods showed high demands. A previous study in patients with amyotrophic lateral sclerosis (ALS) also showed that \"using the bathroom\" was among the highest priorities for a BMI in addition to communication and controlling motorized wheelchairs [20]. Self-exercise of the upper extremity also received high scores in both importance and necessity. This result is in agreement with previous studies, which found that patients with spinal cord injuries reported that restoration of walking and arm and hand functions along with bladder and bowel control were all high priorities, and that they would like to use a BMI system to control functional electrical stimulation in order to enhance functional recovery [18; 27]. The patients in this study wanted to control the exoskeleton with a BMI system to perform their upper extremity exercises. Figures 1 and 2 show the importance and necessity of each type of robot in both impairment subgroups. The ADLs in the \(x\)-axis are given in the order of level of dependency, from highly dependent to nearly independent. It is easily noticed that importance and necessity are not in proportion with dependency. The results shown in the figures indicated the ADLs that were considered important, but not actually necessary for everyday lives.