Haptic perception by metabolic, toxic and/or immunologic factors. Examples of medical conditions that can cause neuropathies are diabetes mellitus, chronic kidney disease, thyroid dysfunction (hyper- and hypothyroidism) as well as hepatitis, liver cirrhosis and alcohol dependency. Loss of the sense of touch is a catastrophic deficit that can impair walking and other skilled actions such as holding objects or using tools. Immersive environments can recreate the feeling of haptic interaction. Exoskeletal gloves such as the Exo-Skin Soft Haptic exoskeletal interface, developed at Drexel University, can be programmed to take a patient through a program of physical therapy exercises to retrain muscles and
Haptic technology by a fingertip, as a programmable function of the finger's motion. The TPaD Tablet Project uses an ultrasonic technology to modulate the slipperiness of a glass touchscreen, as if a user's finger is floating on a cushion of air. In February 2013, Apple Inc. was awarded the patent for a more accurate haptic feedback system that is suitable for multitouch surfaces. Apple's U.S. Patent for a "Method and apparatus for localization of haptic feedback" describes a system where at least two actuators are positioned beneath a multitouch input device to provide vibratory feedback when a user makes contact with the