The Autogenic Clinical/Lab System (ACLS) is a personal-computer-based instrumentation system for physiological training. This system can be used to implement a program of multiparameter physiological conditioning known as autogenic-feedback training exercise (AFTE).

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A Human Subject Receives Feedback by viewing display screens during AFTE.

Ground-based research to study the physiological effects of microgravity is dependent upon the acquisition and processing of physiological data. In the past, the real-time processing of these data has been difficult to achieve because of a need for dedicated instrumentation to calculate and display such derived variables as cardiac output, vascular resistance, thoracic fluid changes, and vagus-nerve activity. The dedicated instrumentation tends to be physically large (nonportable) and expensive (because of engineering input needed to design and build specific functions), and it is difficult to modify algorithms. However, by changing from a design approach based on dedicated instrumentation to one based on digital processing of physiological and other data in a Pentium/100 or similar computer, it has been possible to construct a physically smaller system (the ACLS) that costs less and can be modified more easily through changes in software.

In both the U.S. and Russian space programs, a great deal of effort is being spent studying the effects of long-term exposure to reduced gravitational fields. The objective is to develop effective countermeasures that will minimize the deleterious effects of microgravity on the human body. The approach used by NASA/Ames researchers involves the use of AFTE to eliminate or reduce space motion sickness and the dizziness that can occur when flight crews return to the gravitational effects of a terrestrial existence.

AFTE in its current form is a six-hour training program based on a highly efficient and effective training method of enabling people to control voluntarily several of their own physiological responses to a variety of environmental stressors. The AFTE approach has been successful in combating intractable airsickness in pilots, and for improving pilot performance during search and rescue missions. In clinical studies with patients, substantial relief from symptoms of nausea, syncope, and severe abdominal pain has been observed.

AFTE, as implemented by use of the ACLS, involves the real-time acquisition and display of 16 input variables, 20 digitally displayed output variables (see figure), and printed averages, plus the generation of coupled audible tones, voice commands, and respiratory pacing signals. The software for the ACLS was written for the Windows 98 operating system, using Microsoft Visual BASIC. This software combination was chosen because of the ease with which one can develop visual displays and user interfaces.

Analog data are collected by use of a commercial DI-200 data-acquisition board and WinDaq/200 data-acquisition software. Four video display adapters have been installed to enable the use of four video monitors on a single computer. The four monitors are configured to display various subsets of the available data, as follows: Each of monitors 1 and 2 makes as many as 16 channels of analog data available to the researcher and the subject; monitor 3 presents to the researcher digital meters of all calculated variables; and in effectuating part of the training process monitor 4 shows selected digital meters to the subject.

Audible tones, coupled to any two of 20 derived parameters, can be selected by the researcher and presented to the subject. The tones are generated on the internal sound card of the personal computer by use of software developed in the C computing language and implemented under Visual BASIC.

This work was done by Patricia Cowings, Bruce Taylor, and William Toscano of Ames Research Center. For further information, access the Technical Support Package (TSP) free on-line at www.nasatech.com/tsp  under the Electronics & Computers category.

This invention has been patented by NASA (U.S. Patent No. 5,694,939). Inquiries concerning nonexclusive or exclusive license for its commercial development should be addressed to

the Patent Counsel
Ames Research Center
(650) 604-5104.

Refer to ARC-14048-2.


NASA Tech Briefs Magazine

This article first appeared in the February, 2001 issue of NASA Tech Briefs Magazine.

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