Measuring device for measuring the bioelectrical activity of the central nervous system

• US 4,275,743 A
• Filed: 07/11/1979
• Issued: 06/30/1981
• Est. Priority Date: 07/17/1978
• Status: Expired due to Term

• Current Assignee: Siemens AG
• Original Assignee: Siemens AG
• Inventors: Hjort, Bo
• Primary Examiner(s): Cohen, Lee S.
• Application Number:
  US06/057,127
• Time in Patent Office: 720 Days
• Field of Search: 128/639-644, 128/710-712, 128/731-734
• US Class Current: 600/544
• CPC Class Codes: A61B 5/291 for electroencephalography [EEG]
• CPC Class Codes: A61B 5/31 for electroencephalography [EEG]
• CPC Class Codes: G06G 7/60 for living beings, e.g. their nervous systems ; for problems in the medical field

Abstract

In an exemplary embodiment, a plurality of electrodes to be applied to the patient are employed and potential differences between the electrodes and a reference potential derived from the electrode potentials are formed. Weighting resistors are interposed which weight the potential differences, and the weighted values are combined in such a manner that the potential components proceeding from a specific point under the electrode system and especially from a point below the scalp are comprehended according to their magnitude while signal components proceeding from other points are suppressed.

Claims

1. Measuring apparatus for measuring bioelectrical activity of the central nervous system, said apparatus comprising a multiplicity of electrodes (0, 1 through 6) arranged in an area array for providing an extensive covering pattern for an exterior application surface of a patient, said area array having a midpoint at one of the electrodes (1) for alignment with respect to an interior point beneath the patient exterior application surface whose potential is to be measured, the electrodes (0, 2 through 6) being arranged at a multiplicity of different distances from the midpoint of the area array such that the electrodes of the area array exhibit a multiplicity of different distances from such interior point during a measurement operation, and means (1'"'"'-6'"'"', 16) coupled with the respective electrodes (0, 1 through 6) and responsive to the potentials of the respective electrodes during a measurement operation to transmit weighted potentials in accordance with the potentials of the respective electrodes but with a relative weighting thereof in accordance with a multiplicity of respective different weighting factors corresponding to the spreading out of a hypothetical potential emanating from such interior point via respective paths penetrating the tissue layers between such interior point and the respective electrodes at the patient exterior application surface, and sum the weighted potentials for the respective electrodes such that a sum signal is produced essentially exclusively representing the magnitude of the potential at the interior point.

2. A measuring device according to claim 1, characterized in that said means comprises a summation circuit (16), and resistances (1'"'"' through 6'"'"') whose resistance values correspond to the weighting factors, the resistances being connected between the electrodes (1 through 6) and the summation circuit (16) for the purpose of weighting.

3. A measuring device according to claim 1, characterized in that a mount (18, 23) has the electrodes (0, 1 through 6) secured in a predetermined geometrical arrangement, said mount (18, 23) having means accommodating its application to the head of a patient.

4. A measuring device according to claim 3, characterized in that the electrodes (0, 1 through 6) are spring-seated in the mount (18, 23) so as to be approximately perpendicular to the application surface.