Evaluation of regional ventilation by electric impedance tomography during percutaneous dilatational tracheostomy in neurocritical care: a pilot study.

BACKGROUND: Percutaneous dilatational tracheostomy (PDT) has become a widely performed technique in neurocritical care, which is however known to be accompanied by some risks to the patient. The aim of this pilot study was to assess the derecruitment effects of PDT with the electric impedance tomography (EIT) during the PDT procedure in neurocritical care. METHODS: The prospective observational pilot study investigated 11 adult, intubated, mechanically ventilated patients with acute brain disease. We recorded EIT data to determine regional ventilation delay standard deviation (RVD SD), compliance win (CW) and loss (CL), end-expiratory lung impedance (EELI), with the EIT belt placed at the level of Th 4 before, during and after the PDT, performed in the standard PDT position ensuring hyperextension of the neck. RESULTS: From 11 patients, we finally analyzed EIT data in 6 patients - EIT data of 5 patients have been excluded due to the insufficient EIT recordings. The mean RVD SD post-PDT decreased to 7.00 ± 1.29% from 7.33 ± 1.89%. The mean post-PDT CW was 27.33 ± 15.81 and PDT CL 6.33 ± 6.55. Only in one patient, where the trachea was open for 170 s, was a massive dorsal collapse (∆EELI - 25%) detected. In other patients, the trachea was open from 15 to 50 s. CONCLUSIONS: This pilot study demonstrated the feasibility of EIT to detect early lung derecruitment occurring due to the PDT procedure. The ability to detect regional changes in ventilation could be helpful in predicting further progression of ventilation impairment and subsequent hypoxemia, to consider optimal ventilation regimes or time-schedule and type of recruitment maneuvres required after the PDT.

Cognitive Enhancement and Brain-Computer Interfaces: Potential Boundaries and Risks.

Electroencephalography (EEG) systems and brain-computer interfaces (BCIs) are terms frequently involved in the field of neurological research. Under a technological point of view, BCI is considered to be a significant achievement within the frame of learning disabilities rehabilitation. Nevertheless, the specifications for efficient use for cognitive enhancement and its potential boundaries are under concern. Author's main objective is to discuss BCI concrete components and potential advances as well as depict potential limitations while using technological devices within the frame of the learning procedure. Within this context, requirements, advantages, possible addiction risks, and boundaries regarding the specifications for brain-computer interfaces and technology in order to serve long-term research and developmental learning goals are discussed.

Comparison of optic disc evaluation methods in neurology emergency patients.

BACKGROUND: The optic disc examination is critical for the diagnostics of several acute neurological disorders. However, dilation of the pupil is not recommended for neurological patients, which complicates ophthalmoscopy. AIMS OF THE STUDY: Present pilot study compared a portable fundus camera to an ophthalmoscope in fundus examinations of neurological emergency patients. To our knowledge, this is the first comparative study of the subject. The fundus photographs were later reviewed with an ophthalmologist. METHODS: The study included 60 adults, volunteer neurological emergency patients with either headache, cerebrovascular disorder, or acute confusional state (delirium). Patients' non-mydriatic fundus examination was conducted with an ophthalmoscope and a Smartscope Pro fundus camera. RESULTS: Fundus photography succeeded in 56 (93%), partially succeeded in 2 (3%), and failed in 2 (3%) cases compared with ophthalmoscopy that succeeded in 35 (58%), partially succeeded in 14 (23%), and failed in 11 (18%) cases (P < .0005). The researcher and the ophthalmologist agreed in the findings in 54 out of 58 cases (93%). In six cases (7%), the researcher had failed to detect a non-critical ophthalmic finding. CONCLUSIONS: The neurological fundus examination by fundus camera seems to be superior to regular ophthalmoscopy in defining the critical optic disc findings in emergency patients.

Improving the Accuracy and Training Speed of Motor Imagery Brain-Computer Interfaces Using Wavelet-Based Combined Feature Vectors and Gaussian Mixture Model-Supervectors.

In this paper, we propose a set of wavelet-based combined feature vectors and a Gaussian mixture model (GMM)-supervector to enhance training speed and classification accuracy in motor imagery brain-computer interfaces. The proposed method is configured as follows: first, wavelet transforms are applied to extract the feature vectors for identification of motor imagery electroencephalography (EEG) and principal component analyses are used to reduce the dimensionality of the feature vectors and linearly combine them. Subsequently, the GMM universal background model is trained by the expectation-maximization (EM) algorithm to purify the training data and reduce its size. Finally, a purified and reduced GMM-supervector is used to train the support vector machine classifier. The performance of the proposed method was evaluated for three different motor imagery datasets in terms of accuracy, kappa, mutual information, and computation time, and compared with the state-of-the-art algorithms. The results from the study indicate that the proposed method achieves high accuracy with a small amount of training data compared with the state-of-the-art algorithms in motor imagery EEG classification.

Deep tendon reflex: The background story of a simple technique.

Wilhelm Erb and Carl Otto Westphal from Prussia first described the knee jerk in the same issue of the journal Archiv für Psychiatrie und Nervenkrankheiten in January 1875. This article retraces the history of development of 'deep tendon reflex' as an integral clinical sign during every neurological examination. The history of the evolving shapes of the reflex hammer, the iconic trademark and the ultimate signature of a neuroscientist, is also presented.

Medical Devices; Neurological Devices; Classification of Cranial Motion Measurement Device. Final order.

The Food and Drug Administration (FDA or Agency) is classifying the cranial motion measurement device into class II (special controls). The special controls that will apply to the device are identified in this order and will be part of the codified language for the cranial motion measurement device's classification. The Agency is classifying the device into class II (special controls) in order to provide a reasonable assurance of safety and effectiveness of the device.

Medical Devices; Neurological Devices, Classification of the Vibratory Counter-Stimulation Device. Final order.

The Food and Drug Administration (FDA) is classifying the vibratory counter-stimulation device into class II (special controls). The special controls that will apply to the device are identified in this order and will be part of the codified language for the vibratory counter-stimulation device's classification. The Agency is classifying the device into class II (special controls) in order to provide a reasonable assurance of safety and effectiveness of the device.

The use of the 25 Sprotte needle markedly reduces post-dural puncture headache in routine neurological practice.

OBJECTIVES: The objectives of this article are to test the feasibility of lumbar puncture (LP) using 25-gauge (G) needles in daily neurological practice and to compare the risk of post-dural puncture headache (PDPH) with four types of needles. METHODS: In a prospective rater-blind study, pros and cons of four different LP needles, the 20G Quincke (20Q), 22G Sprotte (22S), 25G Whitacre (25W) and 25G Sprotte (25S), were evaluated in 394 LPs performed by seven neurologists. The neurologist performing the LP recorded the type and size of needle, intensity of pain, safety, time of the procedure and failure or success. Between five and 15 days later another neurologist, blind to the type of needle used, completed an ad-hoc questionnaire for PDPH. RESULTS: PDPH developed in 35.9% patients when using a 20Q needle, and in 12.9%, 6.8% and 1.6%, respectively, when using a 22S, 25W or 25S needle. The difference in incidence of PDPH following LP performed with the 20Q needle and the 25S or 22S was statistically significant (p < 0.001 and p = 0.008, respectively) and it approached significance when comparing the 25S and 25W (p = 0.06). As 25W and 25S needles need CSF aspiration, LP requires more time and skill. Pain caused by LP was similar with the four needles. CONCLUSION: The use of the 25S needle in diagnostic LP reduces the frequency and severity of PDPH.

Medical Devices; Neurological Devices; Classification of the Thermal System for Insomnia. Final order.

The Food and Drug Administration (FDA) is classifying the thermal system for insomnia into class II (special controls). The special controls that will apply to the device are identified in this order and will be part of the codified language for the thermal system for insomnia's classification. The Agency is classifying the device into class II (special controls) in order to provide a reasonable assurance of safety and effectiveness of the device.

Medical Devices; Neurological Devices; Classification of the Computerized Cognitive Assessment Aid for Concussion. Final order.

The Food and Drug Administration (FDA) is classifying the Computerized Cognitive Assessment Aid for Concussion into class II (special controls). The special controls that will apply to the device are identified in this order and will be part of the codified language for the computerized cognitive assessment aid for concussion's classification. The Agency is classifying the device into class II (special controls) in order to provide a reasonable assurance of safety and effectiveness of the device.

How to minimize the risk for headache? A lumbar puncture practice questionnaire study.

Background - To lower the risk for post lumbar puncture (LP) headache the American Academy of Neurology (AAN) recommended using small bore atraumatic needles together with stylet reinsertion in a report from 2005. It is unclear whether these recommendations are followed or not. Objectives - To investigate the diagnostic LP preferences with respect to the AAN guidelines among neurologists by use of a short online questionnaire, and to review previously published literature on the subject. Results - A total of 284 respondents who performed diagnostic LPs completed the questionnaire. Almost half (41%) answered that they always use atraumatic needles. The most common reason (73%) for not using atraumatic needles was that these were not available. Less than half of the respondents who performed LPs had knowledge about the AAN guidelines for diagnostic LPs, and 48-76% agreed with the different recommendations therein. Five previously (1998-2015) published studies investigating LP practice among neurologists were identified. The reported frequency of atraumatic needle use (always/routinely) varied between 2 and 16%. Discussion - Atraumatic needle use was more common in this study compared with previous publications. There is still skepticism regarding some of the AAN recommendations, and needle availability appears to be the most important factor preventing atraumatic needle use. To increase the use of atraumatic needles we may perform additional studies investigating their potential benefits, and arrange training sessions for neurologists to increase their awareness and level of comfort with the atraumatic LP technique.

Medical Devices; Neurological Devices; Classification of the Computerized Cognitive Assessment Aid. Final order.

The Food and Drug Administration (FDA) is classifying the computerized cognitive assessment aid into class II (special controls). The special controls that will apply to the device are identified in this order, and will be part of the codified language for the computerized cognitive assessment aid's classification. The Agency is classifying the device into class II (special controls) in order to provide a reasonable assurance of safety and effectiveness of the device.

Twenty years of functional near-infrared spectroscopy: introduction for the special issue.

Papers from four different groups were published in 1993 demonstrating the ability of functional near infrared spectroscopy (fNIRS) to non-invasively measure hemoglobin concentration responses to brain function in humans. This special issue commemorates the first 20years of fNIRS research. The 9 reviews and 49 contributed papers provide a comprehensive survey of the exciting advances driving the field forward and of the myriad of applications that will benefit from fNIRS.

NIRS in clinical neurology - a 'promising' tool?

Near-infrared spectroscopy (NIRS) has become a relevant research tool in neuroscience. In special populations such as infants and for special tasks such as walking, NIRS has asserted itself as a low resolution functional imaging technique which profits from its ease of application, portability and the option to co-register other neurophysiological and behavioral data in a 'near natural' environment. For clinical use in neurology this translates into the option to provide a bed-side oximeter for the brain, broadly available at comparatively low costs. However, while some potential for routine brain monitoring during cardiac and vascular surgery and in neonatology has been established, NIRS is largely unknown to clinical neurologists. The article discusses some of the reasons for this lack of use in clinical neurology. Research using NIRS in three major neurologic diseases (cerebrovascular disease, epilepsy and headache) is reviewed. Additionally the potential to exploit the established position of NIRS as a functional imaging tool with regard to clinical questions such as preoperative functional assessment and neurorehabilitation is discussed.

Manually controlled instrumented spasticity assessments: a systematic review of psychometric properties.

AIM: The first aim of this study was to systematically review and critically assess manually controlled instrumented spasticity assessment methods that combine multidimensional signals. The second aim was to extract a set of quantified parameters that are psychometrically sound to assess spasticity in a clinical setting. METHOD: Electronic databases were searched to identify studies that assessed spasticity by simultaneously collecting electrophysiological and biomechanical signals during manually controlled passive muscle stretches. Two independent reviewers critically assessed the methodological quality of the psychometric properties of the included studies using the COSMIN guidelines. RESULTS: Fifteen studies with instrumented spasticity assessments met all inclusion criteria. Parameters that integrated electrophysiological signals with joint movement characteristics were best able to quantify spasticity. There were conflicting results regarding biomechanical-based parameters that quantify the resistance to passive stretch. Few methods have been assessed for all psychometric properties. In particular, further information on absolute reliability and responsiveness for more muscles is needed. INTERPRETATION: Further research is required to determine the correct parameters for quantifying spasticity based on integration of signals, which especially focuses on distinguishing the neural from non-neural contributions to increased joint torque. These parameters should undergo more rigorous exploration to establish their psychometric properties for use in a clinical environment.

Informatics for neurocritical care: challenges and opportunities.

Neurocritical care relies on the continuous, real-time measurement of numerous physiologic parameters. While our capability to obtain such measurements from patients has grown markedly with multimodal monitoring in many neurologic or neurosurgical intensive care units (ICUs), our ability to transform the raw data into actionable information is limited. One reason is that the proprietary nature of medical devices and software often prevents neuro-ICUs from capturing and centrally storing high-density data. Also, ICU alarm systems are often unreliable because the data that are captured are riddled with artifacts. Informatics is the process of acquiring, processing, and interpreting these complex arrays of data. The development of next-generation informatics tools allows for detection of complex physiologic events and brings about the possibility of decision support tools to improve neurocritical care. Although many different approaches to informatics are discussed and considered, here we focus on the Bayesian probabilistic paradigm. It quantifies the uncertainty inherent in neurocritical care instead of ignoring it, and formalizes the natural clinical thought process of updating prior beliefs using incoming patient data. We review this and other opportunities, as well as challenges, for the development and refinement of informatics tools in neurocritical care.

Medical devices; neurological devices; classification of the neuropsychiatric interpretive electroencephalograph assessment aid. Final order.

The Food and Drug Administration (FDA) is classifying the neuropsychiatric interpretive electroencephalograph (EEG) assessment aid into class II (special controls). The Agency is classifying the device into class II (special controls) in order to provide a reasonable assurance of safety and effectiveness of the device.

Absence of consensus in diagnostic criteria for familial neurodegenerative diseases.

BACKGROUND: A small proportion of cases seen in neurodegenerative conditions such as amyotrophic lateral sclerosis (ALS), Parkinson's disease and Alzheimer disease are familial. These familial cases are usually clinically indistinguishable from sporadic cases. Identifying familial cases is important both in terms of clinical guidance for family members and for gene discovery. METHOD: Surveys assessing the definition of familial amyotrophic lateral sclerosis (FALS) were completed by clinicians with an interest in ALS. RESULTS: 95 surveys were completed by respondents from 15 countries. A third of total respondents stated that they thought that neurologists were using the same definition for FALS (33.3%, 30). No consensus was achieved among clinicians when provided with five different definitions for FALS. However, the preferred definition was 'a patient with ALS with either a first or second degree relative also with ALS' (37.8%, 31). CONCLUSION: There is no consensus on a standard definition for FALS among clinicians. It is likely that similar inconsistencies apply to other conditions, such as Parkinson's disease and Alzheimer disease, in which both familial and sporadic diseases occur. Inconsistent classification could hinder gene discovery.

Can we use diffusion MRI as a bio-marker of neurodegenerative processes?

Magnetic resonance imaging (MRI) is an imaging technique with a rapidly expanding application range. This methodology, which relies on quantum physics and substance magnetic properties, is now being routinely used in the clinics and medical research. With the advent of measuring functional brain activity with MRI (functional MRI), this methodology has reached a larger section of the neuroscience community (e.g. psychologists, neurobiologists). In the past, the use of MRI as a biomarker or as an assay to probe tissue pathophysiological condition was limited. However, with the new applications of MRI: molecular imaging, contrast-enhanced imaging and diffusion imaging, MRI is turning into a powerful tool for in vivo characterization of tissue pathophysiology. This review focuses on the diffusion MRI. Although it only measures the averaged Brownian translational motion of water molecules, using different analysis schemes, one can extract a wide range of quantitative indices that represent tissue morphology and compartmentalization. Statistical and visualization routines help to relate these indices to biologically relevant measures such as cell density, water content and size distribution. The aim of this review is to shed light on the potential of this methodology to be used in biological research. To that end, this review is intended for the non-MRI specialists who wish to pursue biological research with this methodology. We will overview the current applications of diffusion MRI and its relation to cellular biology of brain tissue.