# Usability and Acceptance Analysis of Wearable BCI Devices
## 2 Usability and Acceptability of Brain-Computer Interface Devices  
Usability, interoperability, accessibility, portability, and a lack of standards (devices, performance, clinical, and end-user metrics) are some of the primary issues that have been found in the deployment of these devices to end users [19]. For example, current commercial EEG headsets and bands are either cost-prohibitive if they return good data, or they are affordable but lack interoperability--the seamless communication and collaboration between various systems or devices--or do not return enough data to be used in different fields, such as BCI or studies of cognitive overload--the status when the brain is overloaded with information, efficiency, and decision-making are reduced--and mental fatigue [15; 20]. EEG tends to have low spatial resolution and a high frequency of disruptions, including motion artifacts and eye movements, despite its superior temporal resolution [21]. Early in the development phase, the decision to adopt such on-chip real-time signal approaches should be made because many of the widely used signal de-noising techniques are not appropriate for real-time or mobile applications [22]. Furthermore, the user experience is greatly impacted by the device's design, usability, and dependability. Adapting to various head shapes and sizes, hair types, user preferences [19], and the movements the user is required to do [6] is a problem when developing an EEG headset. Although a one-size-fits-all configuration is preferable, the adaptability of the system must be considered early in the design process and tested thoroughly. It is well known that high contact pressure can cause pain or discomfort; in fact, according to [PERSON] et al. [23], examining pressure sensitivity--which is defined as the pressure discomfort threshold of various areas--may result in new specifications and/or design guidelines. Therefore, the contact pressure characteristics of a product on the skin that may affect the user's comfort experience must be taken into consideration as one of the relevant variables in the design process of gadgets that are worn, touched, and with which users have physical interaction [23]. The results of a 3D Pressure Discomfort Threshold (PDT) mapping study of the head, face, and neck conducted on 28 users are presented by [PERSON] et al. [23]. In contrast to other research, this work presented a PDT map that had a high density of landmarks and a novel technique that merged 3D landmark positions with pressure pain threshold data. According to the findings, the areas with the lowest pressure tolerance are the nose, front of the neck, mouth, jaw, cheeks, and cheekbones; the areas with the medium pressure tolerance are the forehead, temples, and back of the neck; and the areas with the highest-pressure tolerance are the scalp and rear of the head. However, these regions represent the main areas of interest for BCI devices, and for this reason, these must involve in-depth studies to ensure comfort and usability. [PERSON] [24] outlines a three-level model for proper product design. This model includes the visceral level, which is the most fundamental and immediate level and deals with our initial responses to the product's visual or sensory features (such as its quality and appearance). The reflexive level, which encompasses conscious cognition, comes after the behavioral level, which is related to the product's usability features. In a broader sense, the reflexive level describes how well the product aligns with the user's image and addresses social expectations in addition to mental and emotional factors [24]. These elements have an impact on how consumers evaluate a device's acceptance. A number of studies have looked at models of device acceptance that are based on the Expectation Confirmation Theory (ECT), the Unified Theory of Acceptance and Use of Technology (UTAUT), and the Technology Acceptance Model (TAM).