Visual acuity (clearness of vision) usually is measured by an eye doctor using an eye chart. It measures the smallest letters that can be reliably identified by the patient at a specified distance. The traditional test requires the patient to look and report which letters they see.

Functional near infrared spectroscopy (fNIRS) is an emerging optical neuroimaging technology that indirectly measures neuronal activity in the cortex via neurovascular coupling. It quantifies hemoglobin concentration ([Hb]) and thus measures the same hemodynamic...

Improved devices have been proposed for collecting sweat for biochemical analysis — especially for determination of the concentration of Ca2+ ions in sweat as a measure of loss of Ca from bones. Unlike commercially available sweat-collection patches used previously in monitoring...

Each year, health care costs for managing chronically ill patients increase as the life expectancy of Americans continues to grow. To handle this situation, many hospitals, doctors’ practices, and home-care providers are turning to disease management, a system of coordinated health care interventions and communications,...

A constant-force resistive exercise unit (CFREU) has been invented for use in both normal gravitational and microgravitational environments. In comparison with a typical conventional exercise machine, this CFREU weighs less and is less bulky: Whereas weight plates and associated bulky supporting structures...