## 4 Discussion
### Behaviors and Characteristics of Personas
#### 4.1.3 Personas with Spinal-Cord Impairments  
The archetypal and atypical personas for spinal-cord impairments are closed-fist persona and opened-palm persona, respectively. Other personas are segregated in terms of sensational dependency or difference in household work experience, whereas the personas of spinal-cord impairments are segregated based on their hand shapes: closed fist and opened palm. Anatomically or physiopathology, it would be sensible to segregate spinal cord impaired personas based on the damaged area on their spinal cord, which causes a different level of neural communications via their spine [44; 45]. Thereby, the level of freedom on the upper limb would have named personas such as tetraplegia with C6 injury or paraplegia with T6 injury or L1 injury. However, such names are too technical for the stakeholders to easily comprehend the specific characteristics of personas. In addition, tetraplegia user with C6 injury is simply in worse condition than the paraplegia with T6 injury with lower sensory level and less freedom of body movement [45], so the difference among personas would be rather minimal, and one persona can inclusively embrace all the issues of the other persona.  
The reason for creating two different personas for a disability type is to represent different frustrations and needs within the disability group. As we observed and interviewed the real users with spinal cord impairments, the difficulties in the use of lower back to bend, to reach an object or operable located below or far, or to obtain visual access with limited sight were common throughout the users. However, hands were used, depending on their hand shapes when operating different types of operable parts like controls, doors, etc. Closed fist users needed wider clearance for their fist to go through, while opened palm users required deeper clearance. Moreover, each persona has the opposite gender with height difference to emphasize the accessibility issues that might occur due to physical differences, such as the difference in height reach and sight.  
Ms. [PERSON], the closed-fist persona, and Mr. [PERSON], the opened-palm persona, are the archetypal and atypical personas for the spinal cord users, respectively. The closed-fist type of disabled user is addressed in the ADA checklist [8], while the opened-palm typeof user is not; the opened-palm user is often not considered. Thus, we defined [PERSON], the closed-fist persona, as the archetypal persona for spinal cord impaired users.  
As shown in Figure A5, Ms. [PERSON] is short in height, and sitting in a wheelchair makes her shorter and therefore less able to perceive items or appliance compartments located above her eye level, without extending her neck. Her hands are stiffened in the shape of a fist, requiring wider clearance for her whole fist to go through when she tries to operate an appliance in particular. Also, her fist does not allow her to precisely control a button or touch type interface, resulting in unintentional activation. She prefers to have an appliance that allows her to utilize both of her hands since it is not easy to grasp or hook her fist through a handle, especially by one hand.  
Mr. [PERSON] from Figure A6 is comparably taller than [PERSON], making it harder for him to perceive or reach items located on a floor. A longer arm may allow him to reach further and higher, but his thicker body requires larger clearance than [PERSON]. Moreover, his hands stiffened in the shape of an opened palm, requiring longer and deeper clearance to operate an appliance. Moreover, his fingers are more vulnerable to being jammed.