Novel hardware components and control principles were developed to form the basis for the MoreGrasp system. These include a new wireless electroencephalogram (EEG)-recording system for use with gel-less electrodes. In detail, a 32-channel and a 16-channel EEG system using water-based electrodes were developed. A prototype of a dry-sensor based system was developed in the final phase of the project. New functional electrical stimulation (FES)-based multi-pad (3x5) electrode arrays together with a high-voltage stimulation channel multiplexer were developed and integrated into a forearm sleeve to form a personalizable grasp NP. This electrode array is used for systematic screening as part of the MoreGrasp evaluation toolkit and as part of the final sensorized grasp NP. With the NP based on this new type of multi-pad electrodes it is possible to overcome the problem of varying grasp patterns during forearm rotation and to generate position-independent grasp patterns in particular of thumb movements. A miniaturized extendable wireless sensor platform was developed, including a chain of IMUs and integrated into the forearm sleeve
In terms of BCI, a paradigm shift was performed to achieve the highest level of intuitive control possible with EEG-based systems. Instead of detecting motor imagery induced brain patterns, the paradigm uses movement-related cortical potentials (MRCPs), generated by attempts of the movements later generated by the NP. With it, control is natural because the single attempts of different grasp patterns causing different MRCPs are classified. The detected movement intent is then used for executing the according grasp pattern by the NP. A high-end laptop is the core data acquisition, processing and control unit (CU), and a tablet computer serves as a single communication and status interface to end users and operators. The CU and the FES/multiplexer are packed away in a rucksack in behind the wheelchair, so the tablet is the only "visible" device. Additionally, a smartwatch feeds back the current status of the system, type of grasp, grasp strength etc. . The novel BCI-controlled grasp NP hardware is supported by various software developments, including drivers and protocols for operation of different sensors, and output devices controlled wirelessly. A general software framework has been introduced for implementation of shared control principles. The complete MoreGrasp system includes the BCI system, the NP, a shoulder position sensor and inertial measurement unit (IMU) chain (for measurement of forearm rotation angle) based on novel miniaturized wireless sensors, a smartwatch, and instrumented objects, in selected environments, that allow for pre-selecting the appropriate grasp pattern without input by the end user.
All hard- and software components have been extensively tested and improved in an iterative user-centered design process based on the feedback of able-bodied subjects and individuals with SCI.
A clinical algorithm for the use of the FES components and the workflow for FES training were defined to support clinicians in the setup of the NP. Procedures for performing and documenting of the BCI/FES training have been developed and integrated into the MoreGrasp Training Toolkit.
As part of the project website, a registration platform was implemented so that individuals with SCI can communicate their interest to become a potential end user of the MoreGrasp system and to start the screening process. Additionally, a web-based too (Matchmaking Platform) was implemented as part of the MoreGrasp evaluation toolkit to support clinical decision makers to identify potential end users and initiate further steps..
Finally, a multi-center proof-of-concept study is currently ongoing where all the MoreGrasp components have been successfully introduced to end users with high SCI at their homes, which finally aims at proving the feasibility of the MoreGrasp approach and ultimately the improvement of quality in life.
Results were disseminated in scientific journals, conferences and in hands-on-demonstrations in workshops. MoreGrasp and its concept were presented to occupational therapists, rehabilitation experts and SCI physicians. Also, the general public was informed about the project through press releases, public talks and open house events.
The EEG devices are already in the product list of BBT, while the development of the multi-pad electrodes and multiplexer are currently influencing developments of UKL-HD and MEDEL. TUG, UKL-HD and KNOW are further planning to release an app with the electronic forms for a tablet-based documentation of clinical scores. Other results are made available through open access licences.
