Lansberg, M. G. | bioRxiv Science

bioRxiv2025

Neuroanatomical Basis of Coma in Acute Ischemic Stroke

BackgroundAcute ischemic stroke (AIS) can lead to profound disturbances in consciousness, including coma, which is associated with poor prognosis and increased mortality. Clarifying the lesion patterns that precipitate loss of consciousness can refine pathophysiological models and guide prognosis. ObjectivesIn this study, we aim to identify the brain regions most commonly affected in comatose AIS and determine whether specific combinations of lesions are necessary and sufficient to produce coma. MethodsWe retrospectively analyzed 476 AIS patients (52 comatose) using diffusion-weighted imaging. Infarcts were automatically segmented, manually verified, and normalized to MNI space. Support vector regression lesion-symptom mapping (SVR-LSM) quantified voxel-wise associations with coma, controlling for lesion volume. To assess the necessity and sufficiency of lesion combinations, we employed permutation-based nested logistic regression models comparing all subsets of four anatomical predictors: brainstem, thalamus, cerebellum, and the rest of brain lesions. ResultsSVR-LSM revealed that coma was strongly associated with lesions involving the brainstem, thalamus, and cerebellum, whereas non-comatose patients exhibited predominantly cortical infarcts. Nested model comparisons showed that concurrent lesions to both the brainstem and thalamus were necessary and sufficient for coma. Additional involvement of the cerebellum or cerebral cortex did not improve predictive performance. ConclusionsComa after AIS results from a dual-node subcortical lesion pattern involving both the brainstem and thalamus. Cerebellar and cortical lesions, even when extensive, did not induce coma in the absence of the dual-brainstem and thalamic lesions. These observations emphasize the predominant role of lesion location over lesion volume in the pathogenesis of coma. They also support mechanistic models that position the brainstem and thalamic hubs as central to the neural circuitry underlying arousal. Furthermore, these findings delineate a specific anatomical substrate that may serve as a strategic target for circuit-based neuroprotective and neuromodulatory therapies.

neuroscience↗

bioRxiv2020

Perspectives on the design and performance of upper-limb wearable stimulation devices for stroke survivors with hemiplegia and spasticity

BackgroundVibrotactile stimulation may improve limb function after stroke; however, current studies are limited by the stationary and clinic-based apparatus used to apply this stimulation. A wearable device could provide vibrotactile stimulation in a mobile form factor, enabling further study of this technique. ObjectiveThe aim of this work is twofold: (1) Design and validate a wearable device for stroke survivors that provides vibrotactile stimulation to the upper limb, and (2) Understand features that influence stroke survivors interaction with an upper-limb wearable device. MethodsA vibrotactile glove was designed to apply stimulation to the stroke-affected hand. This device, the vibrotactile stimulation (VTS) Glove, features small electronics, provides hours of stimulation, and has the appearance of a fingerless fitness glove. We performed two studies. In Study 1, sixteen stroke survivors were given the glove and asked to wear it for three hours daily for eight weeks. Usage time, indicating adherence, was calculated by onboard sensors. The device was evaluated using a log of damages and feedback from participants. Self-reported behaviors during glove use were also collected. In Study 2, eight stroke survivors evaluated new device prototypes in a three-round iterative design study. Interviews were used to collect participant feedback as they donned and doffed the prototypes. Task completion time and correctness were measured. Thematic content analysis was used to define actionable design revisions between each round of evaluation and identify key perspectives on design principles. ResultsThe VTS Glove is lightweight, wireless, and durable. Based on Study 1, adherence appears feasible. Each participant recorded over 140 hours wearing the VTS Glove. Participants reported wearing the glove during activities such as church, social events, dining out, and using the computer. However, 69% of participants struggled to extend or insert their fingers to don the device. Our analysis in Study 2 identified six other relevant perspectives from survivors regarding the wearable devices: hand supination is difficult, grip varies without awareness, devices may lead to sweat, separate finger attachments require dexterity, social comfort is perceived as unimportant, and the affected hand is infrequently used. New device designs with revised features (VTS Phalanx, VTS Armband, and VTS Palm) could be donned in an average time of 48 seconds (vs. 5.05 minutes to don the VTS Glove).

bioengineering↗