Modular Mobile Biosignal Acquisition for Real-World fNIRS (and EEG) Research

Artinis-NIRx proposes a modular, staged solution centred on our core expertise: wearable fNIRS. To the best of our knowledge, the requested all-in-one platform is not currently available commercially, but key components can form the basis of a jointly developed system. Our primary recommendation is a high-quality, cost-efficient fNIRS + IMU solution, with EEG as an extension.

1. Proposed System Architecture

The primary configuration is the lightweight, dual-sensor PortaLite MKII fNIRS system with integrated IMU, operated through a dedicated smartphone app. It provides high-quality bilateral prefrontal fNIRS in a compact form factor and offers an excellent balance of measurement quality, mobility, usability and cost. The existing app provides system control and session management. The high-frequency optical fNIRS signal can also provide PPG-like pulsatile waveforms, enabling heart-rate estimation, while Tissue Saturation Index is derived directly from the optical measurements. Where dedicated raw PPG is required, an external sensor must be integrated. For dedicated audio and speech recordings, a seprate smartphone app could be used.

For EEG, our preferred approach is to integrate a best-in-class solution from a specialised partner whose technology best matches the project’s scientific, technical and budgetary requirements. This combines leading expertise in each modality and avoids compromises associated with a single-vendor solution. We are committed to developing seamless synchronisation, unified control, a documented API and consolidated data handling so users experience one integrated platform despite its modular architecture.

As a secondary option, PortaLite MKII can be combined with the TMSi APEX EEG system distributed by Artinis-NIRx and unobtrusive electrodes such as cEEGrids to create a fully wearable, research-grade EEG-fNIRS platform. This option has not yet been fully integrated or validated and would require further work on synchronised acquisition, unified software, smartphone operation and consolidated export.

We currently estimate full APEX-PortaLite integration at 15-24 months, which may be outside the scope of the project. Integration with another suitable mobile EEG platform may be achievable sooner; smartphone-based operation will need to be assessed during system design.

The architecture is inherently modular, allowing fNIRS, EEG and future sensors to operate independently or together.

Additional modalities such as eye tracking, temperature, pressure and dedicated physiological sensors may be incorporated as requirements evolve.

2. Robustness in Everyday Use

PortaLite MKII is designed for mobile research and combines low weight, secure mounting, integrated motion sensing and continuous signal-quality monitoring. These features support reliable recordings and artefact identification during naturalistic use. Validation would progress from laboratory tests to movement tasks and real-world pilots. Multimodal configurations would also be tested for synchronisation, interference and connection recovery.

3. Usability & User Experience

PortaLite MKII is compact, unobtrusive and suitable for self-application within less than 5 minutes. Correct placement can be supported through marked positions, illustrated instructions, in-app guidance, signal-quality checks and, if required, a dedicated headband. The recording interface shows clearly recording status, battery level, connection and signal quality.

For combined EEG-fNIRS use, comfort and setup time will depend mainly on the EEG electrode concept. cEEGrids may simplify placement and reduce visual obstruction, but must be validated for the target population. Contact materials are easy to clean and replace; a standardised transport and charging solution should be developed to support field use.

4. Scalability & Production

The concept builds on the established PortaLite MKII and, where applicable, TMSi APEX. Standard hardware can be supplied within about three weeks for initial validation. A limited validation batch should precede design freeze and volume production.

Scale-up can begin in parallel by securing key components and supplier capacity. As most parts are commercially available, manufacturing risk is reduced. After validation and design freeze, production is expected to ramp up within 6-9 months, with partial deliveries possible earlier. Software integration and customisation would proceed in parallel, focusing on synchronised multimodal acquisition.

5. Power & Operation

Each wearable component uses its own rechargeable battery, while the smartphone provides the central interface and audio functions. Coordinated battery monitoring, low-power warnings, local buffering, automatic reconnection and data-integrity checks would support stable long-duration use.

Annexes

Annexes 1 and 2 provide indicative, non-binding pricing and technical specifications. Product brochures and illustrations for PortaLite MKII, TMSi APEX and cEEGrids are included.