An online three-class Transcranial Doppler ultrasound brain computer interface.

Brain computer interfaces (BCI) can provide communication opportunities for individuals with severe motor disabilities. Transcranial Doppler ultrasound (TCD) measures cerebral blood flow velocities and can be used to develop a BCI. A previously implemented TCD BCI system used verbal and spatial tasks as control signals; however, the spatial task involved a visual cue that awkwardly diverted the user's attention away from the communication interface. Therefore, vision-independent right-lateralized tasks were investigated. Using a bilateral TCD BCI, ten participants controlled online, an on-screen keyboard using a left-lateralized task (verbal fluency), a right-lateralized task (fist motor imagery or 3D-shape tracing), and unconstrained rest. 3D-shape tracing was generally more discernible from other tasks than was fist motor imagery. Verbal fluency, 3D-shape tracing and unconstrained rest were distinguished from each other using a linear discriminant classifier, achieving a mean agreement of κ=0.43±0.17. These rates are comparable to the best offline three-class TCD BCI accuracies reported thus far. The online communication system achieved a mean information transfer rate (ITR) of 1.08±0.69bits/min with values reaching up to 2.46bits/min, thereby exceeding the ITR of previous online TCD BCIs. These findings demonstrate the potential of a three-class online TCD BCI that does not require visual task cues.

Management of patients with implantable cardioverter-defibrillators and pacemakers who require radiation therapy.

BACKGROUND: Radiation therapy (RT) may pose acute and long-term risks for patients with cardiac implantable electronic devices (CIEDs), including pacemakers (PMs) and implantable cardioverter-defibrillators (ICDs). However, the frequency of these problems has not been accurately defined. OBJECTIVE: The purpose of this study was to determine the prevalence of CIEDs among patients requiring RT and report the common CIED-related problems when patients are managed according to a standard clinical care path. METHODS: In a single tertiary-care center, we prospectively screened all patients requiring RT and identified patients with ICDs or PMs. We collected clinical data about their cancer, RT treatment plan, and CIED. Radiation dose to the device was estimated in all patients, and any device malfunction during RT was documented. RESULTS: Of the 34,706 consecutive patients receiving RT, 261 patients (0.8%, mean age 77.9 ± 9.4 years) had an implantable cardiac device: 54 (20.7%) ICDs and 207 (79.3%) PMs. The site of RT was head and neck (27.4%), chest (30.0%), and abdomen/pelvis (32.6%). Using our care path, 63.2% of patients required continuous cardiac monitoring, 14.6% required device reprogramming, 18.8% required magnet application during RT, and 3.4% required device repositioning to the contralateral side before RT. Four patients (1.5%) had inappropriate device function during RT: 3 experienced hemodynamically tolerated ventricular pacing at the maximum sensor rate, and 1 experienced a device power-on-reset. No patient died or suffered permanent device failure. CONCLUSION: Nearly 1% of patients receiving RT in this series has a PM or ICD. However, with a systematic policy of risk assessment and patient management, significant device-related complications are rare.