@article{flint_li_wang_vaidya_barry_ghassemi_tomic_brkic_ripley_liu_et al._2022, title={Noninvasively recorded high-gamma signals improve synchrony of force feedback in a novel neurorehabilitation brain-machine interface for brain injury}, volume={19}, ISSN={["1741-2552"]}, DOI={10.1088/1741-2552/ac7004}, abstractNote={Objective.Brain injury is the leading cause of long-term disability worldwide, often resulting in impaired hand function. Brain-machine interfaces (BMIs) offer a potential way to improve hand function. BMIs often target replacing lost function, but may also be employed in neurorehabilitation (nrBMI) by facilitating neural plasticity and functional recovery. Here, we report a novel nrBMI capable of acquiring high-γ(70-115 Hz) information through a unique post-traumatic brain injury (TBI) hemicraniectomy window model, and delivering sensory feedback that is synchronized with, and proportional to, intended grasp force.Approach. We developed the nrBMI to use electroencephalogram recorded over a hemicraniectomy (hEEG) in individuals with TBI. The nrBMI empowered users to exert continuous, proportional control of applied force, and provided continuous force feedback. We report the results of an initial testing group of three human participants with TBI, along with a control group of three skull- and motor-intact volunteers.Main results. All participants controlled the nrBMI successfully, with high initial success rates (2 of 6 participants) or performance that improved over time (4 of 6 participants). We observed high-γmodulation with force intent in hEEG but not skull-intact EEG. Most significantly, we found that high-γcontrol significantly improved the timing synchronization between neural modulation onset and nrBMI output/haptic feedback (compared to low-frequency nrBMI control).Significance. These proof-of-concept results show that high-γnrBMIs can be used by individuals with impaired ability to control force (without immediately resorting to invasive signals like electrocorticography). Of note, the nrBMI includes a parameter to change the fraction of control shared between decoded intent and volitional force, to adjust for recovery progress. The improved synchrony between neural modulations and force control for high-γsignals is potentially important for maximizing the ability of nrBMIs to induce plasticity in neural circuits. Inducing plasticity is critical to functional recovery after brain injury.}, number={3}, journal={JOURNAL OF NEURAL ENGINEERING}, author={Flint, Robert D. and Li, Yongcheng and Wang, Po T. and Vaidya, Mukta and Barry, Alex and Ghassemi, Mohammad and Tomic, Goran and Brkic, Nenad and Ripley, David and Liu, Charles and et al.}, year={2022}, month={Jun} }
 @article{thielbar_spencer_tsoupikova_ghassemi_kamper_2020, title={Utilizing multi-user virtual reality to bring clinical therapy into stroke survivors' homes}, volume={33}, ISSN={["1545-004X"]}, DOI={10.1016/j.jht.2020.01.006}, abstractNote={Introduction Lifespans after the occurrence of a stroke have been lengthening, but most stroke survivors will experience chronic impairment. Directed, repetitive practice may reduce deficits, but clinical access is often limited by a variety of factors, such as transportation. Purpose of the Study To introduce a multiuser virtual reality platform that can be used to promote therapist-client interactions when the client is at home. Methods The Virtual Environment for Rehabilitative Gaming Exercises encourages exploration of the hand workspace by enabling multiple participants, located remotely and colocated virtually, to interact with the same virtual objects in the shared virtual space. Each user controls an avatar by corresponding movement of his or her own body segments. System performance with stroke survivors was evaluated during longitudinal studies in a laboratory environment and in participants' homes. Active arm movement was tracked throughout therapy sessions for both studies. Results Stroke survivors achieved considerable arm movement while using the system. Mean voluntary hand displacement, after accounting for trunk displacement, was greater than 350 m per therapy session for the Virtual Environment for Rehabilitative Gaming Exercises system. Compliance for home-based therapy was quite high, with 94% of all scheduled sessions completed. Having multiple players led to longer sessions and more arm movement than when the stroke survivors were trained alone. Conclusions Multiuser virtual reality offers a relatively inexpensive means of extending clinical therapy into home and enabling family and friends to support rehabilitation efforts, even when physically remote from each other.}, number={2}, journal={JOURNAL OF HAND THERAPY}, author={Thielbar, Kelly and Spencer, Nicole and Tsoupikova, Daria and Ghassemi, Mohammad and Kamper, Derek}, year={2020}, pages={246–253} }
 @article{ghassemi_triandafilou_barry_stoykov_roth_mussa-ivaldi_kamper_ranganathan_2019, title={Development of an EMG-Controlled Serious Game for Rehabilitation}, volume={27}, ISSN={["1558-0210"]}, DOI={10.1109/TNSRE.2019.2894102}, abstractNote={A majority of the seven million stroke survivors in the U.S. have hand impairments, adversely affecting performance of a variety of activities of daily living, because of the fundamental role of the hand in performing functional tasks. Disability in stroke survivors is largely attributable to damaged neuronal pathways, which result in inappropriate activation of muscles, a condition prevalent in distal upper extremity muscles following stroke. While conventional rehabilitation methods focus on the amplification of existing muscle activation, the effectiveness of therapy targeting the reorganization of pathological activation patterns is often unexplored. To encourage modulation of activation level and exploration of the activation workspace, we developed a novel platform for playing a serious game through electromyographic control. This system was evaluated by a group of neurologically intact subjects over multiple sessions held on different days. Subjects were assigned to one of two groups, training either with their non-dominant hand only (unilateral) or with both hands (bilateral). Both groups of subjects displayed improved performance in controlling the cursor with their non-dominant hand, with retention from one session to the next. The system holds promise for rehabilitation of control of muscle activation patterns.}, number={2}, journal={IEEE TRANSACTIONS ON NEURAL SYSTEMS AND REHABILITATION ENGINEERING}, author={Ghassemi, Mohammad and Triandafilou, Kristen and Barry, Alex and Stoykov, Mary Ellen and Roth, Elliot and Mussa-Ivaldi, Ferdinando A. and Kamper, Derek G. and Ranganathan, Rajiv}, year={2019}, month={Feb}, pages={283–292} }
 @article{vaidya_flint_wang_barry_li_ghassemi_tomic_yao_carmona_mugler_et al._2019, title={Hemicraniectomy in Traumatic Brain Injury: A Noninvasive Platform to Investigate High Gamma Activity for Brain Machine Interfaces}, volume={27}, ISSN={["1558-0210"]}, DOI={10.1109/TNSRE.2019.2912298}, abstractNote={Brain-machine interfaces (BMIs) translate brain signals into control signals for an external device, such as a computer cursor or robotic limb. These signals can be obtained either noninvasively or invasively. Invasive recordings, using electrocorticography (ECoG) or intracortical microelectrodes, provide higher bandwidth and more informative signals. Rehabilitative BMIs, which aim to drive plasticity in the brain to enhance recovery after brain injury, have almost exclusively used non-invasive recordings, such electroencephalography (EEG) or magnetoencephalography (MEG), which have limited bandwidth and information content. Invasive recordings provide more information and spatiotemporal resolution, but do incur risk, and thus are not usually investigated in people with stroke or traumatic brain injury (TBI). Here, in this paper, we describe a new BMI paradigm to investigate the use of higher frequency signals in brain-injured subjects without incurring significant risk. We recorded EEG in TBI subjects who required hemicraniectomies (removal of a part of the skull). EEG over the hemicraniectomy (hEEG) contained substantial information in the high gamma frequency range (65-115 Hz). Using this information, we decoded continuous finger flexion force with moderate to high accuracy (variance accounted for 0.06 to 0.52), which at best approaches that using epidural signals. These results indicate that people with hemicraniectomies can provide a useful resource for developing BMI therapies for the treatment of brain injury.}, number={7}, journal={IEEE TRANSACTIONS ON NEURAL SYSTEMS AND REHABILITATION ENGINEERING}, author={Vaidya, Mukta and Flint, Robert D. and Wang, Po T. and Barry, Alex and Li, Yongcheng and Ghassemi, Mohammad and Tomic, Goran and Yao, Jun and Carmona, Carolina and Mugler, Emily M. and et al.}, year={2019}, month={Jul}, pages={1467–1472} }