Binary Semantic Classification Using Cortical Activation with Pavlovian-Conditioned Vestibular Responses in Healthy and Locked-In Individuals

To develop a more reliable brain–computer interface (BCI) for patients in the completely locked-in state (CLIS), here we propose a Pavlovian conditioning paradigm using galvanic vestibular stimulation (GVS), which can induce a strong sensation of equilibrium distortion in individuals. We hypothesized that associating two different sensations caused by two-directional GVS with the thoughts of “yes” and “no” by individuals would enable us to emphasize the differences in brain activity associated with the thoughts of yes and no and hence help us better distinguish the two from electroencephalography (EEG). We tested this hypothesis with 11 healthy and 1 CLIS participant. Our results showed that, first, conditioning of GVS with the thoughts of yes and no is possible. And second, the classification of whether an individual is thinking “yes” or “no” is significantly improved after the conditioning, even in the absence of subsequent GVS stimulations. We observed average classification accuracy of 73.0% over 11 healthy individuals and 85.3% with the CLIS patient. These results suggest the establishment of GVS-based Pavlovian conditioning and its usability as a noninvasive BCI.

EEG power spectral density in locked-in and completely locked-in state patients: a longitudinal study

Persons with their eye closed and without any means of communication is said to be in a completely locked-in state (CLIS) while when they could still open their eyes actively or passively and have some means of communication are said to be in locked-in state (LIS). Two patients in CLIS without any means of communication, and one patient in the transition from LIS to CLIS with means of communication, who have Amyotrophic Lateral Sclerosis were followed at a regular interval for more than 1 year. During each visit, resting-state EEG was recorded before the brain-computer interface (BCI) based communication sessions. The resting-state EEG of the patients was analyzed to elucidate the evolution of their EEG spectrum over time with the disease's progression to provide future BCI-research with the relevant information to classify changes in EEG evolution. Comparison of power spectral density (PSD) of these patients revealed a significant difference in the PSD's of patients in CLIS without any means of communication and the patient in the transition from LIS to CLIS with means of communication. The EEG of patients without any means of communication is devoid of alpha, beta, and higher frequencies than the patient in transition who still had means of communication. The results show that the change in the EEG frequency spectrum may serve as an indicator of the communication ability of such patients.

A dataset of EEG and EOG from an auditory EOG-based communication system for patients in locked-in state

The dataset presented here contains recordings of electroencephalogram (EEG) and electrooculogram (EOG) from four advanced locked-in state (LIS) patients suffering from ALS (amyotrophic lateral sclerosis). These patients could no longer use commercial eye-trackers, but they could still move their eyes and used the remnant oculomotor activity to select letters to form words and sentences using a novel auditory communication system. Data were recorded from four patients during a variable range of visits (from 2 to 10), each visit comprised of 3.22 ± 1.21 days and consisted of 5.57 ± 2.61 sessions recorded per day. The patients performed a succession of different sessions, namely, Training, Feedback, Copy spelling, and Free spelling. The dataset provides an insight into the progression of ALS and presents a valuable opportunity to design and improve assistive and alternative communication technologies and brain-computer interfaces. It might also help redefine the course of progression in ALS, thereby improving clinical judgement and treatment.

Inhomogeneous superconductivity and quasilinear magnetoresistance at amorphous LaTiO3/SrTiO3 interfaces

We have studied the transport properties of LaTiO3/SrTiO3 (LTO/STO) heterostructures. In spite of 2D growth observed in reflection high energy electron diffraction, transmission electron microscopy images revealed that the samples tend to amorphize. Still, we observe that the structures are conducting, and some of them exhibit high conductance and/or superconductivity. We established that conductivity arises mainly on the STO side of the interface, and shows all the signs of the two-dimensional electron gas usually observed at interfaces between STO and LTO or LaAlO3, including the presence of two electron bands and tunability with a gate voltage. Analysis of magnetoresistance (MR) and superconductivity indicates the presence of spatial fluctuations of the electronic properties in our samples. That can explain the observed quasilinear out-of-plane MR, as well as various features of the in-plane MR and the observed superconductivity.

Sleep in the completely locked-in state (CLIS) in amyotrophic lateral sclerosis

Persons in the completely locked-in state (CLIS) suffering from amyotrophic lateral sclerosis (ALS) are deprived of many zeitgebers of the circadian rhythm: While cognitively intact, they are completely paralyzed, eyes mostly closed, with artificial ventilation and artificial nutrition, and social communication extremely restricted or absent. Polysomnographic recordings in eight patients in CLIS, however, revealed the presence of regular episodes of deep sleep during night time in all patients. It was also possible to distinguish an alpha-like state and a wake-like state. Classification of rapid eye movement (REM) sleep is difficult because of absent eye movements and absent muscular activity. Four out of eight patients did not show any sleep spindles. Those who have spindles also show K-complexes and thus regular phases of sleep stage 2. Thus, despite some irregularities, we found a surprisingly healthy sleep pattern in these patients.

Electroencephalography of completely locked-in state patients with amyotrophic lateral sclerosis

Patients in completely locked-in state (CLIS) due to amyotrophic lateral sclerosis (ALS) lose the control of each and every muscle of their body rendering them motionless and without any means of communication. Though some studies have attempted to develop brain-computer interface (BCI)-based communication methods with CLIS patients, little information is available of the neuroelectric brain activity of CLIS patients. However, because of the difficulties with and often loss of communication, the neuroelectric signature may provide some indications of the state of consciousness in these patients. We recorded electroencephalography (EEG) signals from 10 CLIS patients during resting state and compared their power spectral densities with those of healthy participants in fronto-central, central, and centro-parietal channels. The results showed significant power reduction in the high alpha, beta, and gamma bands in CLIS patients, indicating the dominance of slower EEG frequencies in their oscillatory activity. This is the first study showing group-level EEG change of CLIS patients, though the reason for the observed EEG change cannot be concluded without any reliable communication methods with this population.

Semantic and BCI-performance in completely paralyzed patients: Possibility of language attrition in completely locked in syndrome

Patients with completely locked-in syndrome (CLIS) are incapable of any voluntary muscle movement and do not have any means of communication. Recently functional near infrared spectroscopy (fNIRS) based brain computer interface (BCI) has been successfully used to enable communication with these patients. The developed fNIRS-BCI system relies on the intactness of language comprehension in these patients in all dimensions of language. Interwoven language and motor cortex in brain, and lack of muscular activity in long run, can cause language attrition due to complete immobility in CLIS patients. In this study we have investigated effects of semantic content of sentences presented to a CLIS patient on the performance of the BCI system during a YES/NO paradigm. Comparison of communication success rate in BCI classification between different semantic categories indicate that semantic content of sentences presented to a CLIS patient can affect the BCI performance. Affected concepts are mostly associated with executive words. These findings can be beneficial towards development of more reliable communication device for patients in CLIS. In addition, these results may assist in elucidating the cognitive changes in completely paralyzed patients with the passage of time since the onset of total immovability.

Kicking off a Retropharyngeal Abscess

Aim Retropharyngeal abscesses (RPA) are deep neck space infections that can pose an immediate life-threatening emergency, such as airway obstruction. [1] Methods We describe an atypical presentation of RPA in a three year old girl who attended with a history of post-traumatic Neck pain. Results MB presented to the Emergency department with neck pain and reduced range of motion following a kick to the neck by a sibling. Examination was unremarkable. Cervical spine x-ray showed psuedosubluxation of C2/C3 with a concern regarding facet joint injury. Ultimately, MRI revealed a RPA, which was incised and drained, and the patient treated with antibiotics. MB did not have any classic symptoms and signs of RPA. The history was misleading the treating physicians, and hence a delay in diagnosis. Conclusion This case highlights an unusual presentation of a retropharyngeal abscess and reminds us that trauma can often be a red herring in a patient’s presentation.

Ovarian steroid cell tumor, not otherwise specified

Ovarian steroid cell tumours are rare virilizing tumours. They are three types of tumours of ovary which are characterized by steroid cell proliferation : Leydig cell tumour, steroid cell tumour, Not Otherwise Specified (NOS) and stromal luteoma. Here we present a case of 36 year old female, who presented with history of weight loss since last two and half months. There is history of amenorrhoea and hirsuitism. Her CA was 125: 11.4 IU/ml (0-35 U/mL). Blood Testosterone levels was elevated with value of 150 ng/ml (5.71-77 ng/ml). Serum Inhibin A, Inhibin B, FSH, LH and prolactin were within normal limits. The steroid cell tumour, NOS are mostly benign but few of them behave in malignant fashion. Hayes and Scully gave few histopathological features which favour malignant behavior. These tumours should be differentiated from leydig cell tumour by lack of cytoplasmic Reinkes' crystals as well as from other neoplasms like primary clear cell carcinoma, metastatic clear cell renal cell carcinoma and adrenocortical tumour.

Introduction of an Oral Fluid Challenge Protocol in the Management of Children with Acute Gastroenteritis: A Regional Hospital Experience

Oral rehydration therapy (ORT) remains the ideal first line therapy for acute gastroenteritis (AGE). Our aim was to assess the impact of introducing an Oral Fluid Challenge (OFC) protocol on outcomes such as intravenous fluid use and documentation in our institution. A single centre study with data collected retrospectively pre-implementation (April 2015) of the OFC protocol and post implementation (April 2016). Consecutive sampling of the first 55 patients presenting with GE like symptoms and underwent OFC were recruited. One hundred and ten patients were included in this study with 55 patients per cycle. The rates of IVF use decreased from 22% (12) in cycle one to 18% (10) in cycle two. There was an improvement in documentation by 26% (14) for level of dehydration and 52% (31) for OFC volume from cycle one to two. Overall, the addition of the OFC protocol to the management of patients with uncomplicated AGE would help streamline and improve care.

Disappearance of the hyperdense MCA sign after stroke thrombolysis: implications for prognosis and early patient selection for clot retrieval

Disappearance of the hyperdense middle cerebral artery sign (HMCAS) following intravenous thrombolysis for ischaemic stroke is associated with improved outcome. Debate exists over which radiological thrombus characteristics can predict disappearance of the HMCAS after thrombolysis such as vessel attenuation or extent of thrombus length. Methods Ischaemic stroke patients treated with intravenous thrombolysis from our hospital were entered into a European registry. Patient demographics, stroke severity pre- and 24 hours post-thrombolysis were recorded. Patients with HMCAS were identified from the registry using records from 2010-2013. Images from the pre and post-thrombolysis computed tomography scan were measured. Thrombus characteristics (length and attenuation), extent of ischaemic change and clinical outcome (stroke severity and 3 month survival) were compared between patients with and without HMCAS disappearance. Logistic regression analysis was performed to identify predictors of HMCAS disappearance. Results HMCAS was present in 88/315 (28%) of thrombolysed ischaemic stroke patients. 36/88 (41%) of patients had thrombus disappearance 24 hours after thrombolysis. HMCAS disappearance was associated with reduced stroke severity, less radiological ischaemic change, and higher 3 month survival (87% vs 56%). Median thrombus length was shorter in the HMCAS disappearance group (11 vs 17 mm, p = 0.0004), but no significant difference in vessel attenuation was observed (48 vs 51 Hounsfield Units, p = 0.25). HMCAS disappearance occurred in 73% of cases where HMCAS length was > 10 mm, 38% when length was 10-20 mm, and 21% if < 20 mm. Thrombus length was the only independent predictor of HMCAS disappearance (odds ratio 0.90 per mm; 95% CI 0.84-0.96, p = 0.01). Conclusion Disappearance of HMCAS is associated with better clinical and radiological outcomes. A shorter thrombus is more likely to disappear postthrombolysis. The data highlight the limitation of intravenous thrombolysis in patients with longer hyperattenuated vessels, and the potential role for clot retrieval in such patients.