Towards an optimized tetrapolar electrical impedance lithium detection probe for bipolar disorder: A simulation study

Bipolar disorder is characterized as a manic-depressive syndrome with severe risks to the individual. Bipolar patients' therapy involves administration of lithium which has proven to be effective for mood stabilization. The therapeutic concentration window for lithium in blood plasma is typically between 0.6-1.5 mM and is of vital importance that concentrations do not exceed the 1.5mM as it can be toxic. Accurate monitoring of the concentration changes of Lithium in blood, down to levels of approximately 0.2mM is vital since toxicity levels are in close proximity to therapeutic levels. This paper aims to study the sensitivity of tetrapolar electrical impedance measurements when used to monitor changes in the conductivity of a solution/sample as in the case of changes in Lithium concentration in blood.