Presentation
DH16 - Usability and User Experience of Environmental Control Units: Temporal Stress and Control Modalities’ Effects on Performance Measures and Cognitive and Affective States
SessionPoster Session 2
DescriptionAssistive technology (AT) provides products and services to improve an individual’s life. These products can improve one’s functioning in multiple capacities such as communication, mobility, vision, cognition, and more (WHO, 2024). The populations that AT serves can have different conditions caused by aging, disease/injury, or natural impairments, leading to extensive research to produce customized and individuated products (Berger, 2023). This study focuses on patients with limited mobility due to spinal cord injuries/disorders (SCI/D). These patients not only suffer from a lack of mobility but can likely have lasting negative effects such as pain, stress, and increased dependence on others. As of 2016, spinal cord injuries in the U.S. have affected as many as 282,000 patients with 42,000 of them being veterans living with chronic SCI/D (Fyffe et al., 2019). The Veterans Health Administration (VHA) has reported that 26,000 patients with traumatic spinal cord injury do have eligibility for VHA-sponsored treatment, however, the costs post-surgery can average $606,349(Merritt et al., 2019). Therefore, these veterans with SCI/D not only have the burden of mobility limitations but are at risk of financial bankruptcy. To counteract these adverse effects of SCI/D, environmental control units (ECUs) have been developed to allow these patients to regain levels of function, feelings of independence, and reduce potentially egregious medical expenses.
ECUs are a type of AT that serve patients with SCI/D to accomplish tasks that encompass functionality and entertainment which their physical limitations would otherwise prevent. These devices reenable SCI/D patients to interact with their environment through means such as communication (i.e., phone calls/intercoms), operating electronic controls (i.e., room lights, alarms), and entertainment needs (i.e., television, internet). Past research on ECUs has shown SCI/D patients to have improved feelings of independence and “feeling enabled” while being accepted overall by this specific population (Judge et al., 2011; Veronck et al., 2017). Although there is high acceptance of this device, there remain significant design issues that detrimentally affect its usability and user experience.
In human-computer interaction (HCI), a user can manipulate an interface to form an input command. The ECU’s design to promote such direct and indirect manipulation was the focus in this study. Direct manipulation in HCI, refers to a physical touch with a body part and continuous movement to direct command on a digital interface (Wu et al., 2023). However, some SCI/D veterans may not have the physical capabilities to interact with the ECU in this way. Therefore, another type of HCI manipulation is more inclusive for those individuals with greater mobility issues; indirect manipulation is when the user gives commands to a system but is controlled without direct, physical touch. This type can be mouse and click, voice command, etc. (Wu et al., 2023). In HCI, voice-driven technology increases accessibility for those with mobility impairments and speech recognition systems can recognize, but not understand what is being said (Harada et al, 2009; Farid & Murtagh, 2003). This flaw in voice command systems can be an extra obstacle for a voice control modality versus a touch screen. The ISO 9241 standard of ergonomics of human-system interaction states that usability must enable users to achieve goals such as effectiveness, efficiency, and satisfaction (ISO, 2018). Different evaluations can be used to measure usability: learning performance, time of a task, speed of performance, error rate, and subjective satisfaction. When designing an interface, it is best practice to utilize this testing to maximize usability so system users can achieve the stated goals.
SCI/D patients can benefit from using ECUs; however, there is a gap in the literature for usability testing on these devices, and due to this limited research, patients will not maximize these benefits because the designers will not have the full understanding of how to engage them with this assistive product. ECUs can provide entertainment and a sense of independence, but there are safety critical tasks that are time-sensitive to be remedied that SCI/D populations need to operate faster such as emergency calls, nurse assistance, or even adjusting bed positioning to prevent issues such as pressure ulcers (Fries, 2005). This study aims to empirically examine the effects of control modality types and different temporal stressors on performance, perceived workload and perceived usability when interacting with an ECU. The results from this testing can produce results that can generate generalizable information about the interface design principles that can improve usability for the ECU’s design to increase benefits for SCI/D patients.
The present study was a usability test conducted on an environmental control unit. Two different input modalities were tested to evaluate this device: direct (touchscreen) vs. indirect (voice control). A time pressure stressor was added to see if this influenced performance and perceptions of user experience: high (30 seconds) vs. low (60 seconds). This 2x2 between-subjects design had four experimental groups: Touchscreen-High Time Pressure, Voice Control-High Time Pressure, Touchscreen-Low Time Pressure, and Voice Control-Low Time Pressure. This study evaluated how the type of control modality and time pressure affected usability (e.g., task completion times, lostness) and user experience (e.g., perceived workload, perceived usability) of an ECU through the performance of daily tasks, for which spinal cord injury patients would commonly use the device. Such tasks include: adding a contact name, making a phone call, add an email address, start a game of solitaire, and seeking out and initiating play of a specific training video. These were all a-priori daily tasks that anyone can perform and not specific to the target population or the ECU. Therefore, the use of these tasks can be completed by patients of varying spinal cord injuries but are still capable of evaluating the usability of said device. All participants were required to be at least 18 years of age and reported normal or corrected-to-normal vision. The participants were also asked if they had prior experience with computers, touchscreens, and environmental control units. The completed dataset consisted of 44 participants (25 female, 19 male, mean age = 36.61 years, SD = 19.85, range: 18- 83 years) and all were able-bodied and neurotypical which is not reflective of the target population. After completing these tasks, the participants’ task completion times and lostness were calculated and recorded from their session. Then, each participant self-reported their perceived workload with the NASA Task Load Index (NASA-TLX) and their perceived usability via the System Usability Scale (SUS). The results from this study showed significant differences in usability and user experience. However, these results also displayed issues including a high failure rate of task completion, high levels of average weighted global workload to complete easy tasks, and meeting minimal acceptance to unacceptable levels of perceived usability.
This experimental design created a foundation for more usability testing to be conducted on ECUs with the other types of modalities and other types of stressors placed on users as they complete tasks. Further investigation into the environments where this device would be used, and testing target users (SCI/D patients) would yield better representative and generalized data to determine long-term benefits for improving its usability.
ECUs are a type of AT that serve patients with SCI/D to accomplish tasks that encompass functionality and entertainment which their physical limitations would otherwise prevent. These devices reenable SCI/D patients to interact with their environment through means such as communication (i.e., phone calls/intercoms), operating electronic controls (i.e., room lights, alarms), and entertainment needs (i.e., television, internet). Past research on ECUs has shown SCI/D patients to have improved feelings of independence and “feeling enabled” while being accepted overall by this specific population (Judge et al., 2011; Veronck et al., 2017). Although there is high acceptance of this device, there remain significant design issues that detrimentally affect its usability and user experience.
In human-computer interaction (HCI), a user can manipulate an interface to form an input command. The ECU’s design to promote such direct and indirect manipulation was the focus in this study. Direct manipulation in HCI, refers to a physical touch with a body part and continuous movement to direct command on a digital interface (Wu et al., 2023). However, some SCI/D veterans may not have the physical capabilities to interact with the ECU in this way. Therefore, another type of HCI manipulation is more inclusive for those individuals with greater mobility issues; indirect manipulation is when the user gives commands to a system but is controlled without direct, physical touch. This type can be mouse and click, voice command, etc. (Wu et al., 2023). In HCI, voice-driven technology increases accessibility for those with mobility impairments and speech recognition systems can recognize, but not understand what is being said (Harada et al, 2009; Farid & Murtagh, 2003). This flaw in voice command systems can be an extra obstacle for a voice control modality versus a touch screen. The ISO 9241 standard of ergonomics of human-system interaction states that usability must enable users to achieve goals such as effectiveness, efficiency, and satisfaction (ISO, 2018). Different evaluations can be used to measure usability: learning performance, time of a task, speed of performance, error rate, and subjective satisfaction. When designing an interface, it is best practice to utilize this testing to maximize usability so system users can achieve the stated goals.
SCI/D patients can benefit from using ECUs; however, there is a gap in the literature for usability testing on these devices, and due to this limited research, patients will not maximize these benefits because the designers will not have the full understanding of how to engage them with this assistive product. ECUs can provide entertainment and a sense of independence, but there are safety critical tasks that are time-sensitive to be remedied that SCI/D populations need to operate faster such as emergency calls, nurse assistance, or even adjusting bed positioning to prevent issues such as pressure ulcers (Fries, 2005). This study aims to empirically examine the effects of control modality types and different temporal stressors on performance, perceived workload and perceived usability when interacting with an ECU. The results from this testing can produce results that can generate generalizable information about the interface design principles that can improve usability for the ECU’s design to increase benefits for SCI/D patients.
The present study was a usability test conducted on an environmental control unit. Two different input modalities were tested to evaluate this device: direct (touchscreen) vs. indirect (voice control). A time pressure stressor was added to see if this influenced performance and perceptions of user experience: high (30 seconds) vs. low (60 seconds). This 2x2 between-subjects design had four experimental groups: Touchscreen-High Time Pressure, Voice Control-High Time Pressure, Touchscreen-Low Time Pressure, and Voice Control-Low Time Pressure. This study evaluated how the type of control modality and time pressure affected usability (e.g., task completion times, lostness) and user experience (e.g., perceived workload, perceived usability) of an ECU through the performance of daily tasks, for which spinal cord injury patients would commonly use the device. Such tasks include: adding a contact name, making a phone call, add an email address, start a game of solitaire, and seeking out and initiating play of a specific training video. These were all a-priori daily tasks that anyone can perform and not specific to the target population or the ECU. Therefore, the use of these tasks can be completed by patients of varying spinal cord injuries but are still capable of evaluating the usability of said device. All participants were required to be at least 18 years of age and reported normal or corrected-to-normal vision. The participants were also asked if they had prior experience with computers, touchscreens, and environmental control units. The completed dataset consisted of 44 participants (25 female, 19 male, mean age = 36.61 years, SD = 19.85, range: 18- 83 years) and all were able-bodied and neurotypical which is not reflective of the target population. After completing these tasks, the participants’ task completion times and lostness were calculated and recorded from their session. Then, each participant self-reported their perceived workload with the NASA Task Load Index (NASA-TLX) and their perceived usability via the System Usability Scale (SUS). The results from this study showed significant differences in usability and user experience. However, these results also displayed issues including a high failure rate of task completion, high levels of average weighted global workload to complete easy tasks, and meeting minimal acceptance to unacceptable levels of perceived usability.
This experimental design created a foundation for more usability testing to be conducted on ECUs with the other types of modalities and other types of stressors placed on users as they complete tasks. Further investigation into the environments where this device would be used, and testing target users (SCI/D patients) would yield better representative and generalized data to determine long-term benefits for improving its usability.
Event Type
Poster Presentation
TimeTuesday, April 14:45pm - 6:15pm EDT
LocationFrontenac Foyer