Table 6.

Guidelines for possible hardware factors relating to non-visual feedback influencing cybersickness.

ID_factor Evidence level	Non-visual feedback (hardware)	Description	Guidelines
CYB_32 VI	Type of haptic feedback	Haptic feedback allows adding acceleration cues, therefore, movement information (Porcino et al., 2020b). Adding haptic stimuli doesn't always positively affect cybersickness (Plouzeau et al., 2017; Gonçalves et al., 2020). But it also appears that it can reduce cybersickness (Liu et al., 2019)	Adding haptic feedback (e. g., vibrations) related to movement could alleviate cybersickness (Plouzeau et al., 2017; Gonçalves et al., 2020)
CYB_33 VII	Ambient temperature	HMDs themselves produce heat and can lead to thermal discomfort (Wang Z. et al., 2019). It can impact eyes tear films (Turnbull et al., 2019). Ambient temperature doesn't always impact cybersickness symptoms (Saeidi et al., 2021). Devices to stimuli thermoception exist (Han P. H. et al., 2017; Günther et al., 2020; Lee et al., 2020; Liu et al., 2021b). Airflow seems to reduce cybersickness (D'Amour et al., 2017; Harrington et al., 2019) but not always (Paroz and Potter, 2018)	No clear guidelines can be drawn from the literature on the most suitable temperature for VR use. Thermoception depends on what part of the body is at stake (Kim et al., 2017; Viana and Voets, 2020) and relative temperative adaptation duration depending on inside and outside delta. Devices stimulating users' thermoception could generalize. Ideal ambient temperature for VR use is not clear. 37°C is the average human internal temperature. Stimuli that increase to fever temperature could participate in cybersickness symptoms. We can hypothesize that wearing an HMD can get uncomfortable, mainly because the device also produces heat while functioning
CYB_34 VII	Olfactory feedback	Smell doesn't always impact cybersickness, whether positively or negatively (Narciso et al., 2019). But it can reduce symptoms (Ranasinghe et al., 2020)	Olfactory stimuli could help drive visual attention, impacting movement perception (Tsai et al., 2021) Researches still need to address how olfactive stimuli can influence or not cybersickness
CYB_35 VII	Audio feedback	Audio-visual mismatches could participate in cybersickness, although no clear proof exists (Siddig et al., 2019; Widyanti and Hafizhah, 2021). Therefore, audio feedback needs to be coherent as it could influence cybersickness. However, few contributions address this issue	Create matching audio-visual cues in virtual environments to allow spatial congruency and coherent movement perception (Stanney et al., 2020b)