# Considering the Consequences of Cybersickness in
## 4 Discussion
### Demographic of Cybersickness  
The age of subjects may lead to different levels of virtual reality sickness. It has been found that the elderly may experience eye tiredness much more than adults or the young [46]. However, in our research, the comparison of the experiments for age groups showed that the old were not obviously oversensitive when applying virtual rehabilitation. Compared to older people, younger people and adults might be more available for interaction in virtual environments, if there are no big difficulties when using the devices and completing the tests [47]. The scores of the SSQ were also determined by other factors, such as skills, and not just age. When facing difficult missions, such as bicycling or gesture-based movement, older people might be unable to finish the process. More importantly, the SSQ scores for age might be misleading because of the limited number of cases. This conclusion should be proven by more studies from multiple directions in the future. In virtual rehabilitation scenarios, symptoms are more important and worthy of attention in virtual environment cybersickness. Firstly, for brain injuries, it has been shown that using immersive virtual rehabilitation as a treatment option may help individuals with brain injuries train their attention [48; 49], which may affect the subject's ability to learn new motor skills [50]. Studies on the effects of virtual reality on vital \"theta waves\" in the hippocampus have been beneficial. For instance, virtual reality improved brain activity associated with memory and learning [51] in the treatment of conditions, including Alzheimer's disease, stroke, traumatic brain injury, and Parkinson's disease. Virtual reality rehabilitation, therefore, offers possible novel treatments for brain injuries, but the cybersickness evaluation scores are so high that product developers should pay more attention to reducing the side effects [52]. Virtual reality provides a secure setting to enhance rehabilitation, particularly with the declining availability of labor and resources in our aging population. Secondly, for exam users who have cognitive impairment [53], VR-based treatments have been used as health promotion tools to enhance mobility, prevent falls, and train cognitive skills in people who have dementia and those who are at risk of acquiring dementia. According to studies, virtual rehabilitation technology can be used to improve an individual's abilities, such as memory and concentration, and to diagnose attention deficit hyperactivity disorder (ADHD) through hand or body involvement. The development of attention skills may delay cognitive aging [54]. A study at the University of Montreal examined the effects of video games on the grey matter in the area of the brain that supports memory formation, and the results demonstrated the value of exercise games in rehabilitation. All symptoms associated with cognitive impairment pointed to the need for tailored interventions and designed approaches to mitigate the negative effects of cybersickness [55; 56]. Finally, a study revealed that virtual rehabilitation improved the effectiveness of VR exercise and particularly aided patients with physical inactivity in improving their physical fitness, muscular strength, and balance [57]. However, there were still flaws in the VR rehabilitation of physical inactivity. For instance, in the case of conducting a mission with a set time frame, the poor efficacy of training increased the amount of cybersickness. VR therapy is beneficial for both youth and the elderly who have gait impairment, vestibular issue, multiple sclerosis, spinal cord injury, neck discomfort, or chronic pain. However, when playing the same exercise game or other rehabilitation assignment simultaneously, a serious disease may cause discomfort and worsen physical or mental conditions [58]. There are individual differences in the severity of cybersickness symptoms based on personal medical conditions.