HRV analysis is based on measuring variability in heart rate; specifically, variability in intervals between R waves - “RR intervals”. These RR intervals are then analyzed by spectral (as in Nerve-Express) or some other form of mathematical analysis (e.g., chaos, wavelet theories). Such mathematical analysis generates multiple parameters; typically 20-30. The problem of SNS-PSNS quantification, which has remained for many years the principal dilemma of HRV analysis, is specifically in reducing all possible variations of these multiple parameters to a quantitative relationship between only two parameters: SNS and PSNS.

Nerve-Express is the first and only system to solve the problem of SNS-PSNS quantification. This technological breakthrough is achieved by using proprietary algorithms and a new approach based on one of the leading theories of Artificial Intelligence - Marvin Minsky's Frame Theory. Nerve-Express objectively and reliably evaluates the state of ANS in "real-time" (up to 24 hours) as well as during Orthostatic test and Valsalva maneuver combined with Deep Breathing. Due to its highly sophisticated HRV analysis, Nerve-Express is the only system that enables quantification of 74 ANS states with a corresponding qualitative description for each one.

The algorithms used by Nerve-Express have been developed and tested for over twenty years in studies involving more than twenty thousand patients .

Nerve-Express implements a battery of three tests as the most comprehensive and informative combination of tests for ANS purposes:

1. Orthostatic test as the initial method for ANS provocation;
2. Valsalva maneuver combined with Deep Breathing as the optimal method for revealing the hidden abilities of the Autonomic function and distinguishing between chronic and temporary abnormalities;
3. Real-time Nerve-Monitor test as the ultimate method for ANS assessment in long-term therapy, continuous monitoring (especially, under anesthesia/intensive care), research and experimentation.