Faculty Bibliography

Advanced wearable devices are increasingly incorporating high-resolution multi-camera systems. As state-of-the-art neural networks for processing the resulting image data are computationally demanding, there has been a growing interest in leveraging fifth generation (5G) wireless connectivity and mobile edge computing for offloading this processing closer to end-users. To assess this possibility, this paper presents a detailed simulation and evaluation of 5G wireless offloading for object detection in the case of a powerful, new smart wearable called VIS4ION, for the Blind-and-Visually Impaired (BVI). The current VIS4ION system is an instrumented book-bag with high-resolution cameras, vision processing, and haptic and audio feedback. The paper considers uploading the camera data to a mobile edge server to perform real-time object detection and transmitting the detection results back to the wearable. To determine the video requirements, the paper evaluates the impact of video bit rate and resolution on object detection accuracy and range. A new street scene dataset with labeled objects relevant to BVI navigation is leveraged for analysis. The vision evaluation is combined with a full-stack wireless network simulation to determine the distribution of throughputs and delays with real navigation paths and ray-tracing from new high-resolution 3D models in an urban environment. For comparison, the wireless simulation considers both a standard 4G-Long Term Evolution (LTE) sub-6-GHz carrier and high-rate 5G millimeter-wave (mmWave) carrier. The work thus provides a thorough and detailed assessment of edge computing for object detection with mmWave and sub-6-GHz connectivity in an application with both high bandwidth and low latency requirements.

Background: Remotely-supervised transcranial direct current stimulation (RS-tDCS) is a telerehabilitation protocol that provides access to tDCS treatment to participants with aphasia in their homes using real-time monitoring via videoconference and overcomes barriers associated with in-person tDCS treatment of neurological disease. Aims: Two feasibility studies for participants with aphasia are presented herein that investigate (1) RS-tDCS procedural implementation, acceptability, and demand, and (2) acceptability of ten repeated consecutive RS-tDCS sessions. Methods & Procedures: Thirteen participants with aphasia were enrolled in Study 1: (1) seven participants with stroke-induced latent aphasia, (2) four participants with stroke-induced clinically diagnosed aphasia, and (3) two participants with logopenic variant primary progressive aphasia (lvPPA). Four supervisors (1 certified speech-language pathologist [SLP], 3 graduate SLPs-in-training) were trained to supervise RS-tDCS and also provided survey responses. All participants participated in RS-tDCS training and a virtual simulation of home delivery. Two participants with stroke-induced aphasia (1 latent aphasia, 1 clinically diagnosed aphasia) were enrolled in 10 consecutive sessions of RS-tDCS alongside computerized treatment in their home for Study 2. Outcomes & Results: This work provides preliminary evidence for the feasibility of RS-tDCS for people with stable and progressive aphasia of varying severity and typology and includes both participant and clinician perspectives. Importantly, no major barriers to use of RS-tDCS were revealed for people with aphasia, though eHelpers were required for two participants. Conclusions: This work confirms that remotely supervised at-home tDCS studies can be used to enable much-needed efficacy trials, with sufficient sample size, power, and dosing considerations, that will determine the clinical efficacy of tDCS as a treatment adjuvant to aphasia treatment.

PURPOSE/OBJECTIVE:Compare the detection rate of seizures on scalp EEG with simultaneous intracranial stereo EEG (SEEG) recordings. METHODS:Twenty-seven drug-resistant epilepsy patients undergoing SEEG with simultaneous scalp EEG as part of their surgical work-up were included. A total of 172 seizures were captured. RESULTS:Of the 172 seizures detected on SEEG, 100 demonstrated scalp ictal patterns. Focal aware and subclinical seizures were less likely to be seen on scalp, with 33% of each observed when compared with focal impaired aware (97%) and focal to bilateral tonic-clonic seizures (100%) (P < 0.001). Of the 72 seizures without ictal scalp correlate, 32 demonstrated an abnormality during the SEEG seizure that was identical to an interictal abnormality. Seizures from patients with MRI lesions were statistically less likely to be seen on scalp than seizures from nonlesional patients (P = 0.0162). Stereo EEG seizures not seen on scalp were shorter in duration (49 seconds) compared with SEEG seizures seen on scalp (108.6 seconds) (P < 0.001). CONCLUSIONS:Scalp EEG is not a sensitive tool for the detection of focal aware and subclinical seizures but is highly sensitive for the detection of focal impaired aware and focal to bilateral tonic-clonic seizures. Longer duration of seizure and seizures from patients without MRI lesions were more likely to be apparent on scalp. Abnormalities seen interictally may at times represent an underlying seizure. The cognitive, affective, and behavioral long-term effects of ongoing difficult-to-detect seizures are not known.