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Biomedical subjects

M T Fatehi

Publications and source records attributed to M T Fatehi.

4 recordsLinked to original sources
PubMed1989

Monopolar needle stimulation: safety considerations.

Stimulation of nerves for conduction studies can be performed with a monopolar needle used routinely for electromyographic studies. Although invasive, this technique allows precise localization of stimulation and access to deeply situated nerve trunks, thus providing otherwise unobtainable information regarding peripheral nerve function. The electric current at the needle tip was measured during supramaximal stimulation of the median and peroneal nerves at distal and proximal sites. After measuring the area of uninsulated needle tip, the local current density was calculated. The maximum current during the stimulation of 0.05msec duration was 0.80mA and the resulting current density was 4.1mA/mm2. It is calculated that this current could cause a local maximum temperature rise of 2.5C in the tissue within 0.5mm of the needle tip. This current flow would not be expected to cause either direct electric or heat damage to the tissue.

Electrodiagnosis↗
PubMed1988

Ground reaction forces, center of pressure, and duration of stance with and without an ankle-foot orthosis.

We analyzed the effects of an ankle-foot orthosis (AFO) on the ground reaction forces, the position of the center of pressure, and the timing of stance phase events during walking in 18 healthy volunteers between the ages of 19 and 38 years. The magnitude and direction of the ground reaction forces and the locus of the center of pressure were recorded every one-sixtieth of a second during free-speed ambulation. The horizontal force components of the ground reaction force were plotted vectorially, and the vertical force component was displayed by its magnitude expressed in percentage body weight. All this information was superimposed on the subject's footprint and statistically analyzed, comparing right to left, narrow to wide, and ipsilateral to contralateral use of an AFO. The results showed a significant reduction in the mean duration of the stance phase of 4.83% (p less than 0.05) with the AFO. This reduction was due primarily to the significant reduction during midstance of 7% (p less than 0.025), which was more pronounced with the use of the wide AFO. Using an AFO also resulted in a mean increase of 20% (p less than 0.05) in the vertical force magnitude at the end of push-off. With the use of an AFO, there was a shift of the point of impact at heel strike to a more posterior location and a shift of the trajectory of the center of pressure to a more lateral position throughout the stance phase. These changes should be kept in mind when prescribing an ankle-foot orthosis.

Adult↗
PubMed1987

Integrated communication/environmental controller system for the physically disabled.

A wireless integrated communication/environmental controller system (ICECS) is described, which offers total communication as well as environmental control for the disabled person. The system is flexible and simple enough to be used from the wheelchair by patients with spinal cord injuries. The system has three parts: the mobile unit, the base unit, and a set of remote-control receiver modules. The mobile unit and the base unit are linked together by radio, while the base unit and the remote receiver modules communicate over a power line carrier. The telephone mode allows telephone calls to be placed and received. Different electrical devices are controlled by the environmental control mode. The intercom mode permits two-way communication with an attendant or the nursing station. The modes can be switched simply by pressing a button on the mobile unit. Sixteen soft-touch switches arranged in a 4 X 4 matrix allow operation by hand or mouthstick.

Communication Devices for People with Disabilities↗