Hyphenate the following passage where appropriate.
Pointing on a two dimensional display is a fundamental operation in not only general purpose but also hand held computing devices. Future user interfaces are likely to replace traditional devices such as mouse and trackpad with so called natural user interface devices such as finger worn motion sensing rings and camera based gesture tracking systems such as the Microsoft Kinect. For users who suffer from motion impairment, alternative pointing devices must be devised that make use of other parts of the body, including eye trackers, head trackers, brainwave, muscle tension sensors, and even tongue trackers. Unfortunately, it has been a challenge to build a low cost, low power, user friendly, low complexity, drop resistant, responsive pointing device for such users. More recently, however, the emergence of miniature inertial measurement units (IMU) in the form of microelectromechanical systems (MEMS) and mixed signal components make it possible to create the next generation pointing device.