In this study, we unitized HAMD-17 and HAMA to assess depression and anxiety of two groups of PSD patients before and after rehabilitation. The most important clinically relevant finding was that VR could effectively alleviate depression and anxiety in PSD patients. Apart from that, as known, BDNF has been implicated in PSD pathology and treatment.[30] Substantial evidence indicates a decisive aspect of BDNF promoter methylation in patients with depression [31, 32]and anxiety [33]. BDNF analysis results presented the most conclusive evidence yet that VR is inextricably linked to the excellent prognosis of PSD.
Furthermore, as an objective measure of brain function, functional near-infrared imaging also reveals that VR has a beneficial impact on PSD. The increased oxyhemoglobin concentration in the brain indicates that neurons in this region are more active, and the decreased concentration of deoxyhemoglobin can indirectly explain this fact. Given that the prefrontal region is closely related to depression symptoms[34], VR can help PSD patients relax more than psychological counseling alone and has a better curative effect on PSD.
Another source of strong evidence is that as inflammatory factors, such as interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) decreased considerably, the decline rate was accelerated and declined more under VR intervention. Prior research has indicated that IL-6 and TNF-α elevate inflammatory immune response, resulting in neurotransmitter secretion disorder and neural plasticity reduction, holding an important role in PSD occurrence.[35] The ratio of TNF-α and IL-6 in PSD subjects enlarged considerably.[36] Accordingly, the decline of these two indicators also demonstrates that VR exhibits a miraculous effect on PSD. These results further support the assumption that VR can treat PSD.
The most important clinically relevant finding was FGF21 advancement. Until now, little attention has been paid to the relationship between FGF21 and PSD. Much literature has proved that FGF21 can alleviate depression symptoms; FGF21 is considered a common regulator of mood response. It upregulated pro-inflammatory cytokines by NF-κB suppression, inhibited microglial expression in the hippocampus, and mobilized the inflammatory response in primary microglia to markedly improved depression-like behavior deficits in LPS induced depressive-like behaviors in the mouse.[37] Another research indicates that FGF21 was recently found to exhibit a robust neuroprotective role and act as a mediator of the effects of mood stabilizers.[38] Since FGF21 advancement can ameliorate patients' depressive states, we assume that FGF21 is a potential key marker in PSD. The difference in FGF21 levels indicated that the diversity of FGF21 in the control group was limited, and the change of FGF21 in the experimental group was extraordinarily significant. In addition, the comparison of FGF21 levels between the two groups at the end of the experiment revealed that the experimental group had significantly higher levels than the control group. Increased FGF21 levels in the experimental group corroborate previous findings that FGF21 has a beneficial impact on depression. Furthermore, the correlation analysis reveals that HAMD-17 score is intimately related to FGF21. We further suggest that FGF21 also exhibits a progressive impact on PSD. VR likely increases FGF21, which could act as a mechanism of PSD mitigation. However, ameliorating depression impact of VR on PSD patients is gradual. There are several possible explanations for this result; a possible explanation is that FGF21 alleviates depression through metabolism. Because FGF21 can modulate emotion by mitochondrial metabolism, we devise some motion in VR compared with psychological counseling. Another possible explanation is that VR stimulates FGF21 to downregulate inflammatory factors, thus alleviating depression in PSD patients. Nonetheless, this study did not go further to delve into the mechanism of VR on PSD; thus, we cannot provide the exact mechanism. It is also conceivable through other mechanisms, which require further exploration.
Virtual reality has recently been a hot topic in post-stroke rehabilitation. VR studies have largely focused on physical rehabilitation, and few scholars investigated post-stroke psychological rehabilitation. Numerous studies demonstrate that psychological therapies could recover the disposition of PSD patients; however, numerous patients are resistant to therapy due to the disorder's tedious pattern and sluggish response. In addition, the staff time and expertise are costly for most families. [39] VR psychological rehabilitation program features rich scenes, immersive music, and pictures and can move with screen movement; its low cost and engaging nature encourage patients to collaborate effectively.
Although this study's findings will undoubtedly be scrutinized extensively, there are some immediately dependable conclusions for this experiment that VR is progressive on PSD. The most astonishing advantage of VR is that it causes individuals to act as though they are in a real-world, allowing people to confront problems more peacefully in VR than in real life and experiment with new therapeutic methods to solve obstacles. For PSD, it could be possible to eradicate the need for any therapist input, thus significantly reducing the time required by skilled therapists. As a result, VR could assist in increasing the access to the most impressive psychological prescriptions. It may become a forward-looking option for psychological operation. We introduce the first RCT double-blind experiment to contemplate virtual reality in PSD. FGF21 is also a dominant factor in depression, but there is no research on PSD. We are also the first to probe FGF21 impact on PSD. According to current literature, this study is the first double-blind RCT study in PSD patients’ homes or community. It is advantageous to establish circumstances under which neither group is aware of the other group's intervention. We assigned two groups of people to scale assessment and rehabilitation in a double-blind experiment.
This study also presented the prospects of virtual reality rehabilitation in post-stroke. The most auspicious perception leads to creating a local district model for each patient according to the highest possible ecological validity. Studies have demonstrated that rehabilitating PSD patients at home or in the community is better than in hospitals.[40] The prospect of neurology lies in the implementation of new technologies with traditional techniques. It seems to be a limitless VR utility in neurology, especially personalized medical rehabilitation programs. This kind of personalization should result in a much more tempting perspective, such as faster social health for PSD patients. Further research is needed to advance and discover the mechanism of VR in PSD.
The most important limitation is the insufficient subjects and significant lack of follow-up based on an uncontrolled factor associated with COVID-19 incidence. Further research is required to establish a multicenter clinical study of PSD. An additional disadvantage is that the study did not collect cerebrospinal fluid (CSF) of patients, but the peripheral blood was collected. The level of evidence was not as high as that of CSF. CSF should be collected for further research if conditions permit. Another limitation of this study is that no previous research has been conducted on how VR improves FGF21, and the mechanism of FGF21 in PSD has not been explored, which is the next hot focus of research. One weakness in this study that could affect the results is that only ischemic stroke was adopted. Due to the small sample size, there was no study on hemorrhagic stroke and no subgroup analysis of patients with different stroke locations; this is also the subject of further investigation.