Finite Element study of skin and fat delineation in an obese subject for transcranial Direct Current Stimulation
- Resource Type
- Conference
- Authors
- Truong, Dennis Q.; Magerowski, Greta; Pascual-Leone, Alvaro; Alonso-Alonso, Miguel; Bikson, Marom
- Source
- 2012 Annual International Conference of the IEEE Engineering in Medicine and Biology Society Engineering in Medicine and Biology Society (EMBC), 2012 Annual International Conference of the IEEE. :6587-6590 Aug, 2012
- Subject
- Bioengineering
Communication, Networking and Broadcast Technologies
Components, Circuits, Devices and Systems
Computing and Processing
Signal Processing and Analysis
Skin
Conductivity
Solid modeling
Brain models
Electrodes
Electric fields
- Language
- ISSN
- 1557-170X
1094-687X
1558-4615
Because of pilot data suggesting the efficacy of transcranial Direct Current Stimulation (tDCS) in treating a range of neuropsychiatric disorders as well as in controlling cravings, there is interest to apply to obese subjects. The abnormal thickness of fat that exist in obese subjects may influence current delivery from scalp electrodes to the brain. MRI-derived Finite Element (FE) models of a morbidly obese subject were created with and without fat delineated. The inclusion of fat to the FE model reduced the effective volume of the relatively conductive skin. This led to greater current penetration to the cortical surface. Electric field was substantially greater (60%) in magnitude and a difference in the spatial profile was noted in the model with fat. Additional models testing the effect of varying fat conductivity revealed an inflection in current penetration as fat conductivity is varied. It was postulated that this may be due to a shunting effect both when the shell of fat surrounding the skull is too resistive for penetration and when the fat is so conductive as to lead current around rather than through the head. Precise FE tDCS model of obese patients requires the precise inclusion of fat.