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GPS accuracy is poor in indoor environments and around buildings. Thus, reading and following signs still remains the most common mechanism for providing and receiving wayfnding information in such spaces. This puts individuals who are blind or visually impaired (BVI) at a great disadvantage. This work designs, implements, and evaluates a wayfnding system and smartphone application called CityGuide that can be used by BVI individuals to navigate their surroundings beyond what is possible with just a GPS-based system. CityGuide enables an individual to query and get turn-by-turn shortest route directions from an indoor location to an outdoor location. CityGuide leverages recently developed indoor wayfnding solutions in conjunction with GPS signals to provide a seamless indoor-outdoor navigation and wayfnding system that guides a BVI individual to their desired destination through the shortest route. Evaluations of CityGuide with BVI human subjects navigating between an indoor starting point to an outdoor destination within an unfamiliar university campus scenario showed it to be effective in reducing end-to-end navigation times and distances of almost all participants.

Background Recent studies reported a long-lasting effect of COVID-19 infection that extends beyond the active disease and disrupts various body systems besides the respiratory system. The current study aims to investigate the post-acute effect of SARS-CoV-2 infection on cardiovascular autonomic activity, reactivity and sensitivity in patients who had the infection at least 3 months before. Methods This was a comparative cross-sectional observational study. Fifty-nine subjects were allocated into two groups, controls (n=31), who had no history of positive COVID-19 infection, and the post-COVID patients (n=28) who were recruited 3 to 8 months after testing positive for SARS-CoV-2 by reverse transcription polymerase chain reaction (RT-PCR). Baseline cardiovascular autonomic activity was evaluated through recording of baseline heart rate variability (HRV), autonomic reactivity was determined through standard cardiovascular autonomic reflex tests (CART), and cardiac autonomic sensitivity was assessed through cardiac baroreceptor sensitivity (cBRS). Results Higher incidence of orthostatic hypotension was observed in post-COVID patients compared to controls (39.3% and 3.2%, respectively, p <0.001). Additionally, significantly reduced handgrip test, and heart rate response to head-up tilt was illustrated in the post-COVID group (p <0.001). About 85.7% of post-COVID participants had at least one abnormal cardiovascular reflex test (CART) compared to the control group (p <0.001). Although HRV parameters (TP, LF, HF, SDRR, RMSSD, pRR50), and the cBRS were numerically lower in the post-COVID-19 group, this did not reach the level of significance. Conclusion The results of the present study are suggestive of altered cardiovascular reactivity in post-acute COVID patients and demand further investigation and longer term follow up.