Method and system for determining settings for deep brain stimulation

1. A method for determining a relation between stimulation settings for a brain stimulation probe and a corresponding V-field, the brain stimulation probe comprising multiple stimulation electrodes, the V-field being a potential distribution in brain tissue surrounding the stimulation electrodes, the method comprising:

sequentially applying a test current to n stimulation electrodes, n being a number between 2 and the number of stimulation electrodes of the brain stimulation probe;

for each test current at one of the n stimulation electrodes, measuring a resulting excitation voltage at m stimulation electrodes, m being a number between 2 and the number of stimulation electrodes of the brain stimulation probe;

from the stimulation settings and the measured excitation voltages, deriving an (m*n) coupling matrix having m lines and n columns, an entry Z q, p in the coupling matrix reflecting an amount of electrical impedance between two of the stimulation electrodes and positioned on line q and column p of the coupling matrix, where q is an integer number between 1 and m, and p is an integer number between 1 and n, Z q, p being related to a voltage obtained on an electrode q when a current is applied on electrode p, and where the electrode q and the electrode p are selected from the n stimulation electrodes; and

using the coupling matrix for determining the relation between the stimulation settings and the corresponding V-field.

2. The method for determining the relation between stimulation settings for the brain stimulation probe and the corresponding V-field as claimed in claim 1 , the method further comprising:

receiving a predetermined set of stimulation settings; and

using the relation between the stimulation settings and the corresponding V-field for determining the V-field corresponding to the predetermined set of stimulation settings.

3. The method for determining the relation between stimulation settings for the brain stimulation probe and the corresponding V-field as claimed in claim 1 , the method further comprising:

receiving a description of a target V-field; and

using the relation between the stimulation settings and the corresponding V-field for determining a set of required stimulation settings for obtaining the target V-field.

4. A computer program product for determining the relation between stimulation settings for the brain stimulation probe and the corresponding V-field, which program is operative to cause a processor to perform the method as claimed in claim 1 .

5. A control system for determining a relation between stimulation settings for a brain stimulation probe and a corresponding V-field, the brain stimulation probe comprising multiple stimulation electrodes, the V-field being a potential distribution in brain tissue surrounding the stimulation electrodes, the control system comprising:

means for applying test currents to the stimulation electrodes;

means for measuring an excitation voltage resulting from the applied test currents; and

a processor being arranged for

instructing the means for applying test currents to sequentially apply a test current to n stimulation electrodes, n being a number between 2 and the number of stimulation electrodes of the brain stimulation probe;

instructing the means for measuring the excitation voltage to measure at m stimulation electrodes an excitation voltage caused by each test current, m being a number between 2 and the number of stimulation electrodes of the brain stimulation probe;

from the stimulation settings and the measured excitation voltages, deriving an (m*n) coupling matrix having m lines and n columns, an entry Z q, p in the coupling matrix reflecting an amount of electrical impedance between two of the stimulation electrodes and positioned on line q and column p of the coupling matrix, where q is an integer number between 1 and m, and p is an integer number between 1 and n, Z q, p being related to a voltage obtained on an electrode q when a current is applied on electrode p, and where the electrode q and the electrode p are selected from the n stimulation electrodes; and

using the coupling matrix for determining the relation between the stimulation settings and the corresponding V-field.

6. A method for determining a relation between stimulation settings for a brain stimulation probe and a corresponding V-field, the brain stimulation probe comprising multiple stimulation electrodes, the V-field being a potential distribution in brain tissue surrounding the stimulation electrodes, the method comprising:

sequentially applying a test current to n stimulation electrodes, n being a number between 2 and the number of stimulation electrodes of the brain stimulation probe;

for each test current at one of the n stimulation electrodes, measuring a resulting excitation voltage at m stimulation electrodes, m being a number between 2 and the number of stimulation electrodes of the brain stimulation probe;

from the stimulation settings and the measured excitation voltages, deriving an (m*n) coupling matrix having m lines and n columns, an entry Z q, p in the coupling matrix reflecting an amount of electrical impedance between two of the stimulation electrodes and positioned on line q and column p of the coupling matrix, where q is an integer number between 1 and m, and p is an integer number between 1 and n, Z q, p being related to a voltage obtained on an electrode q when a current is applied on electrode p, and where the electrode q and the electrode p are selected from the n stimulation electrodes;

using the coupling matrix for determining the relation between the stimulation settings and the corresponding V-field;

forcing a non-zero test voltage on a particular electrode of the stimulation electrodes while forcing zero voltage on all other electrodes;

measuring the resulting currents in the electrodes necessary to create said forced voltages;

determining an admittance matrix, the elements of the admittance matrix reflecting the measured resulting currents; and

generating the coupling matrix by mathematical inversion of the admittance matrix.

7. The method for determining the relation between stimulation settings for the brain stimulation probe and the corresponding V-field as claimed in claim 6 , the method further comprising:

receiving a predetermined set of stimulation settings; and

using the relation between the stimulation settings and the corresponding V-field for determining the V-field corresponding to the predetermined set of stimulation settings.

8. The method for determining the relation between stimulation settings for the brain stimulation probe and the corresponding V-field as claimed in claim 6 , the method further comprising:

receiving a description of a target V-field; and

using the relation between the stimulation settings and the corresponding V-field for determining a set of required stimulation settings for obtaining the target V-field.

9. A computer program product for determining the relation between stimulation settings for the brain stimulation probe and the corresponding V-field, which program is operative to cause a processor to perform the method as claimed in claim 6 .

10. A control system for determining a relation between stimulation settings for a brain stimulation probe and a corresponding V-field, the brain stimulation probe comprising multiple stimulation electrodes, the V-field being a potential distribution in brain tissue surrounding the stimulation electrodes, the control system comprising:

means for applying test currents to the stimulation electrodes;

means for measuring an excitation voltage resulting from the applied test currents; and

a processor being arranged for

instructing the means for applying test currents to sequentially apply a test current to n stimulation electrodes, n being a number between 2 and the number of stimulation electrodes of the brain stimulation probe;

instructing the means for measuring the excitation voltage to measure at m stimulation electrodes an excitation voltage caused by each test current, m being a number between 2 and the number of stimulation electrodes of the brain stimulation probe;

from the stimulation settings and the measured excitation voltages, deriving an (m*n) coupling matrix having m lines and n columns, an entry Z q, p in the coupling matrix reflecting an amount of electrical impedance between two of the stimulation electrodes and positioned on line q and column p of the coupling matrix, where q is an integer number between 1 and m, and p is an integer number between 1 and n, Z q, p being related to a voltage obtained on an electrode q when a current is applied on electrode p, and where the electrode q and the electrode p are selected from the n stimulation electrodes;

using the coupling matrix for determining the relation between the stimulation settings and the corresponding V-field;

instructing the means for applying test currents to force a non-zero test voltage on a particular electrode of the multiple stimulation electrodes while forcing zero voltage on all other electrodes;

instructing the means for measuring the excitation voltage to measure the resulting currents in the electrodes necessary to create said forced voltages;

determining an admittance matrix, the elements of the admittance matrix reflecting the measured resulting currents; and

generating the coupling matrix by mathematical inversion of the admittance matrix.