RESUMEN
Background: The aim of the current pilot study was to evaluate the usability, acceptability, and tolerability of virtual reality (VR)-based cognitive stimulation exercises (CSEs) in healthy young versus old populations before health care integration. A secondary aim was to assess the accuracy of VR games as a proxy for cognitive stimulation, specifically for attention. VR-based CSEs promise to improve attention and brain function through varied learning systems. Methods: This is a Phase 1 feasibility clinical trial at a single center. It involves 30 healthy volunteers randomly selected using the American Society of Anesthesiologists (ASA) physical status classification system. Participants fall into ASA 1 (age >18-35 years, n = 15) or ASA 2 (age >60 years, n = 15) categories. All participants tested the ReCognitionVR-based CSEs. Feasibility criterion: Participants in each group were monitored for completion of 20 minutes of VR-based CSEs. Acceptability criterion: Proportion of participants with system usability scale (SUS) >35 or SUS score of 87.5. Safety (tolerability) monitoring: Sessions were monitored for neurological, cardiovascular, or pulmonary adverse events (AEs). Safety criterion: No more than 10% of sessions stopped due to neurological, cardiovascular, or pulmonary AEs. Results: The primary outcome (feasibility) of ReCognitionVR-based CSEs was 100%. For the secondary outcome (acceptability), there was no group difference in SUS scores (ASA 1 = 88.17 ± 12.83 vs. ASA 2 = 88.39 ± 10.22, P = 0.81). For the tertiary outcome (safety), mild transient uneasiness was reported by two (13.4%) ASA 1 participants (resolved in 2 minutes), and one (6.67%) ASA 1 participant experienced a temporary >20% increase in blood pressure from baseline. No ASA 2 participants had AEs. Conclusion: The feasibility, acceptability, and safety of ReCognitionVR-based CSEs in healthy elderly volunteers are acceptable, indicating that the evaluation of the ReCognitionVR-based CSEs in hospitalized patients is reasonable.
RESUMEN
The process of manipulating information within working memory is central to many cognitive functions, but also declines rapidly in old age. Improving this process could markedly enhance the health-span in older adults. The current pre-registered, randomized and placebo-controlled study tested the potential of online repetitive transcranial magnetic stimulation (rTMS) applied at 5 Hz over the left lateral parietal cortex to enhance working memory manipulation in healthy elderly adults. rTMS was applied, while participants performed a delayed-response alphabetization task with two individually titrated levels of difficulty. Coil placement and stimulation amplitude were calculated from fMRI activation maps combined with electric field modeling on an individual-subject basis in order to standardize dosing at the targeted cortical location. Contrary to the a priori hypothesis, active rTMS significantly decreased accuracy relative to sham, and only in the hardest difficulty level. When compared to the results from our previous study, in which rTMS was applied over the left prefrontal cortex, we found equivalent effect sizes but opposite directionality suggesting a site-specific effect of rTMS. These results demonstrate engagement of cortical working memory processing using a novel TMS targeting approach, while also providing prescriptions for future studies seeking to enhance memory through rTMS.
RESUMEN
Online repetitive transcranial magnetic stimulation (rTMS), applied while subjects are performing a task, is widely used to disrupt brain regions underlying cognition. However, online rTMS has also induced "paradoxical enhancement". Given the rapid proliferation of this approach, it is crucial to develop a better understanding of how online stimulation influences cognition, and the optimal parameters to achieve desired effects. To accomplish this goal, a quantitative meta-analysis was performed with random-effects models fitted to reaction time (RT) and accuracy data. The final dataset included 126 studies published between 1998 and 2016, with 244 total effects for reaction times, and 202 for accuracy. Meta-analytically, rTMS at 10â¯Hz and 20â¯Hz disrupted accuracy for attention, executive, language, memory, motor, and perception domains, while no effects were found with 1â¯Hz or 5â¯Hz. Stimulation applied at and 10 and 20â¯Hz slowed down RTs in attention and perception tasks. No performance enhancement was found. Meta-regression analysis showed that fMRI-guided targeting and short inter-trial intervals are associated with increased disruptive effects with rTMS.
