Speckle pattern forms when a rough object is illuminated with coherent light (laser) and the backscattered radiation is imaged on a screen. The pattern changes over time due to movement in the object. Such time-integrate speckle pattern can be statistically analyzed to reveal the flow profile. For higher velocity the speckle contrast gets reduced. This theory can be utilized for tissue perfusion in capillaries of human skin tissue and cerebral blood flow mapping in rodents. Early, the technique was suffered from low resolution and computational intricacies for real-time monitoring purpose. However, modern engineering has made it feasible for real-time monitoring in microcirculation imaging with improved resolution. This review illustrates several modifications over classical technique done by many researchers. Recent advances in speckle contrast methods gain major interest, leading towards practical implementation of this technique. The review also brings out the scopes of laser speckle-based analysis in various medical applications.
This article presents technical developments in and clinical applications of functional electrical stimulation (FES) in the recovery of gait and motor function in poststroke rehabilitation. We review stroke incidence, stimulator design, brain-computer interface-based FES systems, and clinical applications of FES. Developments in different types of foot drop stimulators are reviewed, including hard-wired and microprocessor-based surface stimulator systems. The replacement of the foot switch by using artificial and "natural" sensors as the primary control in foot drop stimulators is reviewed. In addition, this review evaluates the clinical effects of FES applications in gait, motor control, and functional ability compared to conventional therapy alone during poststroke rehabilitation. The literature suggests the combination of FES and a conventional rehabilitation program has a positive therapeutic effect on the recovery of gait, motor function, energy expenditure, and functional ability in stroke patients. On the basis of our review, we recommend using FES therapy along with a conventional rehabilitation program in the poststroke rehabilitation process. In summary, this article describes the need for rigorous technological development, clinical studies, and collaboration between clinicians and engineers for FES systems. Future research would facilitate the design of costeffective FES systems as well as analysis of FES applications in stroke patients to optimize the rehabilitation process.
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