Application — Cortical surface
UMC Utrecht fully implanted ECoG BCI in locked-in ALS, 2016
Device
No device entry covers this hardware yet. The spec card below lists what the source says.
Lab or organization
UMC Utrecht fully implanted ECoG BCI in locked-in ALS, 2016
A fully implanted communication system for a woman who was 58 at consent, locked in by late-stage ALS diagnosed in 2008, ventilated through a tracheostomy and communicating by eye tracker. The paper reports the period from implantation on October 27, 2015 to July 2016. First authors Mariska Vansteensel, Elmar Pels and Erik Aarnoutse contributed equally; Nick F. Ramsey is the last author. ClinicalTrials.gov NCT02224469.
Participants and hardware
- One participant.
- Four subdural electrode strips (Resume II, Medtronic), four 4 mm electrodes per strip with 1 cm spacing, placed through burr holes under fMRI and neuronavigation guidance. Two strips were over the hand region of left motor cortex and two over left prefrontal cortex as a backup.
- Two strips were connected to an amplifier and transmitter (Activa PC+S, Medtronic) under the left clavicle. The paper says this device is CE certified for Parkinson’s disease, essential tremor and epilepsy, and that Medtronic provided the implant components, antenna and receiver free of charge to UMC Utrecht.
- Control: attempted right-hand movement produced a “brain click” used to select letters in commercial spelling software on a tablet.
Results as stated
| Measure | Value |
|---|---|
| Target task | Correct 91 +/- 6% of 83 runs (day 15 to 262) |
| Click task | Correct 87 +/- 7% of 37 runs (day 157 to 238) |
| Typing | Independent control 28 weeks after electrode placement, equivalent to two letters per minute |
| Home use | Unassisted from day 197; used on 32 days between day 197 and 266, 86 minutes per day on average |
Limits
One patient, with slow typing. The paper notes the system still needed help positioning the antenna, and that it supplemented and at times replaced the eye tracker (for example where lighting made eye tracking impossible).
Primary sources
- Vansteensel MJ et al., Fully Implanted Brain-Computer Interface in a Locked-In Patient with ALS, New England Journal of Medicine (2016), DOI 10.1056/NEJMoa1608085.