INCRIMP

The measurement of the electrical activity of the brain, the so-called electroencephalography (EEG), is a standard method for the diagnosis and monitoring of disorders of the central nervous system. Examples are epilepsy, sleep disorders and consciousness disorders caused by brain lesions. The clinical use of brain-computer interfaces for rehabilitation in motor dysfunctions is also based on the registration of electroencephalograms (also abbreviated to EEG). The exact diagnosis of epilepsy requires continuous EEG measurement over several hours to weeks. The recording can be stationary or telemetric with partial freedom of movement within a ward. As part of pre-surgical epilepsy diagnostics for patients with drug-resistant epilepsies, invasive discharges with implanted electrodes are also performed in order to obtain additional information on the spatial and temporal development of the epileptic discharges. During the invasive discharge, which lasts on average 7 to 14 days, the patients are in an intensive monitoring unit. During this time, there is an increased risk of complications (infections, bleeding) due to the insertion of the electrodes and the existing diversion of cable connections through the skull and skin to the outside. Long-term EEG recordings are desirable from a medical point of view, but are often not feasible with the current state of electrode and recording technology.
More recent therapeutic approaches are aimed at suppressing the spread of epileptic activity by targeted microstimulation of cerebral structures. This requires the permanent implantation of a system to derive and stimulate brain activity. Since neurological disorders can also be the result of biochemical balance disorders, the possibility of measuring "brain chemistry" is desirable. This requires suitable, chemically inert electrodes and implants with corresponding functionality for long-term use.

In order to solve the various tasks, a system that can be completely implanted in the skull is being developed. The system is based on universal electrodes that can be used for various applications. The microsystem developments include suitable carbon-based microelectrodes (Carbon Nano Tubes) integrated into flexible large-area polymer substrates, as well as innovative microelectronic approaches for data acquisition and telemetry, and solutions for assembly and connection technology. As an example for other applications, a system for intracranial EEG derivations and a suitable implantation method will be developed.