We investigate the relation between grip force and grip stiffness for the human hand with and without voluntary cocontraction. Apart from gaining biomechanical insight, this issue is particularly relevant for variable-stiffness robotic systems, which can independently control the two parameters, but for which no clear methods exist to design or efficiently exploit them. Subjects were asked in o...

BACKGROUND AND PURPOSE Motor symptoms of Parkinson's disease (PD) are typically assessed using clinical scales such as the Unified Parkinson's Disease Rating Scale, but clinical scales are insensitive to subtle changes early in the disease process. The goal of this project was to use current sensing technology to develop a quantitative assessment tool to document fine motor deficits in PD based...

BACKGROUND AND PURPOSE Recent evidence indicates that intensive massed practice may be necessary to modify neural organization and effect recovery of motor skills in patients following stroke. Virtual reality (VR) technology has the capability of creating an interactive, motivating environment in which practice intensity and feedback can be manipulated to create individualized treatments to ret...

objectives: nowadays, snap-fits are used in the automotive industry as a proper alternative for mechanical joints, cabling joints, and car interior lining joints. due to the special form of these joints, which are assembled manually, the contact area between snap-fits and the worker's fingertips can be too small. this can cause skin pain on the worker's fingertips. therefore, an ergonomic study...

This paper presents a strategy meant to allow anthropomorphic robot hands to grasp objects of unknown shape in imitation of the human grasping reflex. A 10-month-old baby may bend his/her thumb and four fingers in an attempt to grasp an object when it comes in contact with the palm. After grasping it, if the object is attempted to be removed from the baby’s hand, the baby holds the object more ...

Abstract Vision-based haptic sensors have emerged as a promising approach to robotic touch due affordable high-resolution cameras and successful computer vision techniques; however, their physical design the information they provide do not yet meet requirements of real applications. We present robust, soft, low-cost, vision-based, thumb-sized three-dimensional sensor named Insight, which contin...

This article was accepted fur publication September 26, 1991. Behavioral research has indicated that thumbsucking often covaries with hair pulling and that the elimination of thumb-sucking can result in the elimination of the hair pulling with which it was associated (e.g., Frlman & Hove, 1987; Knell & Moore, 1988). Treatments for persistent thumb-sucking, however, have shown minimal or transie...

In previous investigations of the control of grasp stability, humans manipulated test objects with flat grasp surfaces. The surfaces of most objects that we handle in everyday activities, however, are curved. In the present study, we examined the influence of surface curvature on the fingertip forces used when humans lifted and held objects of various weights. Subjects grasped the test object b...

We examined the extent to which subjects with Parkinson's disease (PD) modulate normal fingertip forces during five-digit grasping based on the object's center of mass (CM). We also tested the effect of trial-to-trial predictability of CM location on the distribution of all fingertip forces relative to thumb force. Ten right-handed subjects with PD (OFF and ON medication) and 10 healthy age-mat...

BACKGROUND Pen needles (PNs) are essential for insulin injections using pen devices. PN characteristics affect patients' injection experience. OBJECTIVE The goal of this study was to evaluate the impact of a new extra-thin wall (XTW) PN versus usual PNs on overall patient preference, ease of injection, perceived time to complete the full dose, thumb button force to deliver the injection, and ...