Unique Cortical Physiology Associated With Ipsilateral Hand Movements and Neuroprosthetic Implications

Abstract

Background and Purpose-Brain computer interfaces (BCIs) offer little direct benefit to patients with hemispheric stroke because current platforms rely on signals derived from the contralateral motor cortex (the same region injured by the stroke). For BCIs to assist hemiparetic patients, the implant must use unaffected cortex ipsilateral to the affected limb. This requires the identification of distinct electrophysiological features from the motor cortex associated with ipsilateral hand movements. Methods-In this study we studied 6 patients undergoing temporary placement of intracranial electrode arrays. Electrocorticographic (ECoG) signals were recorded while the subjects engaged in specific ipsilateral or contralateral hand motor tasks. Spectral changes were identified with regards to frequency, location, and timing. Results-Ipsilateral hand movements were associated with electrophysiological changes that occur in lower frequency spectra, at distinct anatomic locations, and earlier than changes associated with contralateral hand movements. In a subset of 3 patients, features specific to ipsilateral and contralateral hand movements were used to control a cursor on a screen in real time. In ipsilateral derived control this was optimal with lower frequency spectra. Conclusions-There are distinctive cortical electrophysiological features associated with ipsilateral movements which can be used for device control. These findings have implications for patients with hemispheric stroke because they offer a potential methodology for which a single hemisphere can be used to enhance the function of a stroke induced hemiparesis. (Stroke. 2008;39:3351-3359.)

Decoding Motor Signals From the Pediatric Cortex: Implications for Brain-Computer Interfaces in Children

“…In particular, if a certain part of the brain is not functioning to achieve a functional motor output, as in the case of spastic hemiplegia, in which 1 hemisphere is affected; the use of an alternate cortical location of motor intention may be required. Thus the demonstration of ipsilateral motor movements as a generator of effective control signals by 4 of our pediatric subjects, as has been reported, 14 is particularly exciting.…”

“…14,15 The average (with 95% confidence interval [CI]) mean and maximum accuracy during the overt control experiments were calculated for both groups and compared.…”

Proceedings of the Third International Workshop on Advances in Electrocorticography

“…This is of particular importance for BMI applications targeting paresis caused by motor cortex damage, e.g., in stroke. Using a single-trial classification approach, we extended results from previous studies indicating that arm movement kinematics can be reconstructed from ipsilateral cortex [85, 87, 88]. We investigated the relationship between contra- and ipsilateral activity and found that, in some areas, ipsi- and contralateral movement representations are similar enough that classifiers trained on contralateral activations transfer to ipsilateral activations, and vice versa.…”

EEG Waves for Robotics and Prosthesis Grasping and Motorization

“…In order to achieve that, we shall rely on a developed brain wave signal detection devices (like the massive signals head cap) for brain waves detection rehabilitation that synthesizes recent developments in neurophysiology, electronics, and physical therapy into a BCI hand orthosis. Such brain waves signals were present in cortex anterior to ipsilateral primary motor cortex, with wave patterns operating below 40Hz [12], [13]. Such patterns are accessible via EEG.…”