Test-Retest Instability of Temporal Summation and Conditioned Pain Modulation Measures in Older Adults.

OBJECTIVE: The temporal stability (test-retest reliability) of temporal summation of pain (TS) and conditioned pain modulation (CPM) has yet to be established in healthy older adults. The purpose of this study was to compare the temporal stability of TS and CPM in healthy older and younger adults and to investigate factors that might influence TS and CPM stability. METHODS: In a test-retest study, 40 healthy older adults and 30 healthy younger adults completed two sessions of quantitative sensory testing within a two-week period that included TS of heat pain, TS of mechanical pain, and CPM with pressure pain thresholds and suprathreshold heat pain as test stimuli and a cold water immersion as a conditioning stimulus. Participants also completed self-report measures of situational catastrophizing, anxiety, clinical pain, and physical activity. Absolute and relative stability were examined for each variable. Bivariate correlations examined the associations of age, clinical, behavioral, and psychological variables with the intra-individual stability of TS and CPM. RESULTS: The results revealed moderate to excellent stability for the TS measures and poor to moderate stability for CPM. The results also revealed significant age differences for two of the TS measures and CPM, with younger adults having greater stability compared with older adults. Additionally, the magnitude and stability of psychological factors were correlated with stability of TS. CONCLUSIONS: These findings suggest that TS and CPM may be more reliable in younger compared with older adults. Furthermore, psychological states may be an important factor influencing the stability of TS in healthy adults.

Exploring actual and perceived levels of physical activity intensity during virtual reality active games.

Background: Research suggests that engaging in active virtual reality (VR) video games can elicit light to moderate levels of physical activity (PA), making it a novel and fun mode of exercise. Further research is needed to understand the influence of VR on perceptions of exertion and enjoyment during PA. Objective: The objectives of this study are (1) to compare actual and perceived exertion within and between active VR games with varying levels of difficulty and (2) to determine how playing active VR games influences PA enjoyment during gameplay. Methods: A total of 18 participants completed four separate study sessions, during which they engaged in either a 15-min bout of traditional exercise (stationary cycling) or played one VR game. Heart rate (HR) and ratings of perceived exertion (RPE) using the Borg CR10 scale were assessed during VR gameplay and cycling. Enjoyment was measured after gameplay. VR games included playing Holopoint at level 2 and level 3 and Hot Squat. Repeated measures ANOVAs were used to examine (1) changes in HR and RPE across time within games and (2) differences in actual and perceived levels of intensity and enjoyment between games. Bivariate correlations examined the relationship between the degree of change in actual intensity and the degree of change in perceived intensity during each VR game and cycling. Results: The analyses revealed that RPE and HR significantly increased from baseline during each condition and generally increased across the 15-min of gameplay. Hot Squat and cycling elicited a significantly higher percentage of heart rate reserve (%HRR) than Holopoint at levels 2 and 3. Holopoint level 3 elicited a higher %HRR than Holopoint level 2. The participants reported greater average and max RPE during Hot Squat and cycling compared with Holopoint at levels 2 and 3. The correlations revealed a significant positive correlation between the degree of change in HR and RPE for cycling, but no significant correlations were observed for any of the VR conditions. The physical activity during Holopoint at both levels was rated as more enjoyable than Hot Squat and cycling. Conclusion: Our data support the notion that VR has the potential to alter individuals' perceptions of exertion during PA and, in particular, may reduce their awareness of increases in actual exertion.

The acute hypoalgesic effects of active head-mounted display virtual reality games.

The purpose of this study was to determine: (1) whether physically active virtual reality (VR) games exert an acute hypoaglesic effect on the thigh and bicep compared to a non-active VR game and an exercise only condition matched for exercise intensity in healthy individuals, and (2) whether movement variables during gameplay are associated with the hypoalgesic effect of the games. Twenty young adults completed five separate study sessions, with each session devoted to playing one head-mounted display VR game or stationary cycling for 15 minutes. The games included Holopoint at level 2 and level 3, Hot Squat, and Relax Walk. Pressure pain thresholds at the thigh and bicep were measured pre and post VR gameplay and cycling. Participants wore a heart rate monitor and accelerometers on the wrist and thigh during play to measure the intensity and quantity of movement. Repeated measures ANOVAs revealed that pressure pain thresholds on the bicep increased from pre to posttest for each condition. The results also revealed that pressure pain thresholds on the thigh increased only for the conditions eliciting the greatest cardiovascular response, which included Holopoint at level 3, Hot Squat, and cycling. Bivariate correlations indicated that moderate to vigorous physical activity of the thigh was associated with pain reduction at the thigh during Holopoint. These results revealed that active VR games and exercise exerted a more widespread hypoalgesic effect compared to the non-active VR game, which was likely driven in part by the intensity and quantity of movement during gameplay.