## 2 Background  
Individuals who have dysarthria interact with voice technologies differently than those who do not have speech disorders. The primary issue in this interaction is the performance of these systems, which tends to deteriorate for people who have dysarthria, worsening as the severity of the condition increases. Prior studies have indicated that these commercial devices require further improvements to better accommodate users who have dysarthria [13; 19; 29; 30]. One primary challenge lies in their accuracy, particularly in understanding commands issued with dysarthric speech. Variability in volume and pitch adds another layer of complexity [19; 31]. For example, fluctuations in volume and pitch within a single word or sentence can confuse these systems, making it difficult to accurately capture the intended command [32]. Moreover, these devices may time out before the user finishes speaking [19; 31]. Another issue arises owing to the unique characteristics of dysarthric speech, which often includes breaths between syllables. Current devices struggle to handle this as a form of input [30].  
As an alternative to verbal interactions, another technique that aligns with the capabilities of users who have dysarthria has been suggested. This alternative involves using nonverbal voice cues for interaction [15; 27]. In interviews conducted with 19 participants who had dysarthria [15], it was found that this method of interaction was well accepted by the individuals. This acceptance reflected their willingness and interest in using any potential mode of interaction that may streamline their experience. A pilot study testing nonverbal voice cues focused on system design and the memorability aspects of usability. The findings indicated that the participants could effectively recall the nonverbal cues after a period and such cues could be a viable alternative to traditional verbal commands.  
Although SVAs are controlled mainly through voice, it has been suggested that they could also be controlled through other modalities to overcome the challenges faced by people who have dysarthria [12]. This study evaluates interactions with SVAs using eye gaze interaction, because people who have dysarthria usually do not suffer from issues with eye movement or visual impairment, so using eye gaze technology is an appropriate practical option [33]. Eye gaze technology works by tracking eye movement to determine the eye gaze position, enabling users to perform a variety of actions. For example, such a device could allow a user to turn on a light by looking at a \"light\" button. This could occur through detecting dwell time or blinking, depending on the eye tracking device setting.  
To date, there is a relatively small body of literature concerned with the usability of eye gaze systems when used by people who have speech impairments in general and dysarthria specifically [34; 35; 36]. [PERSON] [37] investigated some aspects of usability by exploring user satisfaction and how eye gaze can affect the quality of life for people who have disabilities. The study found that users were satisfied with the use of eye gaze and it had a positive impact on their daily life. Work by [PERSON] [38] also evaluated the use of eye gaze devices. In addition to obtaining user feedback about the use of the device,it evaluated the issues that may arise and the adjustments that were required to allow for efficient use. [PERSON] and [PERSON] [34] used surveys to assess the usability of eye gaze technology for people who have physical and communication impairments. The findings showed that most of the participants were satisfied with using eye gaze to control computers and it was efficient to use.