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We conclude that GES is more effective in improving long-term GI symptoms and costs, and decreasing use of healthcare resources than intensive medical therapy, in this sample of patients with the symptoms of GP followed for 3 years. Certain patients with GP form a high-risk group in terms of costs, quality of life, morbidity and mortality.

Gastric electrical stimulation (GES) is effective to improve symptoms of nausea and vomiting in most patients, but very little is known about the effect of varying stimulation parameters. We analysed stimulation parameters in a pilot study of 22 patients (12 idiopathic, four diabetic and four postsurgical) with drug-refractory gastroparesis who did not respond optimally to initial settings. Patients underwent high-frequency/low energy GES using identical initial stimulation parameters: 5 mA of current, 330 micros pulse width, 14 Hz for 0.1 s on and 5.0 s off. Due to lack on optimal response, 22 patients underwent alteration of an algorithm using stimulation parameters. At follow-up (mean of 4.3 years) a dose-response relationship for charge, power and energy were compared with baseline for the whole group and for each diagnostic subgroup by anova data are reported as mean +/- SE. Based on the mean of individual dose-response curves, differences in data are charge, current per pulse and energy per pulse were noted for the whole group at follow up vs baseline. The subgroup of patients with postsurgical gastroparesis required the most energy using the algorithm. In conclusion, an algorithmic approach to identify optimal stimulation parameters in GES for individual patients is associated with symptom improvement. Also, certain subgroups appear to have different energy parameters. Based on this preliminary data, the use of an algorithm for some patients with GES is feasible and may have potential for clinical application. A randomized-controlled trial of different stimulation parameters for GES seems warranted.

A microelectrode technique has been developed to enable the study of stress-generated potentials (SGP) in bone to a spatial resolution of 5 micrometers. The technique has been used to measure the electrical potentials as a function of bone micromorphology in four-point bending. Electric fields ranging from 30 to 10(3) times greater than is measured by conventional macroscopic methods have been discovered at the Haversian canals for human and bovine cortical bone. The amplitude and direction of the electric field in the osteons depend specifically upon the amplitude and the sign (i.e., compression or tension) of the stress. The implications of this finding with regard to the origin of SGP and their possible physiological significance are considered.

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