Development of a Magnetoresistive-Based Wearable Eye-Tracking System for Oculomotor Assessment in Neurological and Otoneurological Research—Preliminary In Vivo Tests

Over the past 20 years, several eye-tracking technologies have been developed. This article aims to present a new type of eye tracker capable of producing detailed information on eye and head movements using an array of magnetoresistive detectors fixed on the patient’s head and a small magnet inserted into a contact lens, adapted to the curvature of the cornea of the subject. The software used for data analysis can combine or compare eye and head movements and can represent them as 2D or 3D images. Preliminary data involve an initial patient who was asked to perform several tasks to establish the accuracy, reliability, and tolerance of the magnetic eye tracker and software. The tasks included assessment of saccadic eye movements and pursuit, “drawing” alphabetic shapes or letters, and reading. Finally, a Head Impulse Test (HIT) was performed to estimate the VOR gain, comparing the standard deviation established via vHIT with that established via this magnetic eye tracker (mHIT). This prototypical device is minimally invasive, lightweight, relatively cheap, and tolerable, with a high degree of reliability and precision. All these characteristics could lead to the future use of the magnetic eye tracker in neurological and otoneurological fields

Risk of falls, vestibular multimodal processing, and multisensory integration decline in the elderly-Predictive role of the functional head impulse test

Age-related degeneration of the vestibular system, also known as presbyastasis, leads to unstable gait and higher risk of falls. These conditions affect lifestyle and may have non-negligible social repercussions due to fear-related states of anxiety and depression. In order to develop a model for predicting risk of falls, we assessed vestibulo-ocular function by video and functional Head Impulse Tests (vHIT and fHIT) and their possible correlations with Tinetti Balance Test score. Thirty-one patients over 65 years of age admitted with trauma due to falls were recruited. Vestibular evaluation (complete otoneurological assessment, vHIT, fHIT), cognitive tests (Mini Mental State Examination), anxiety and depression evaluation and Tinetti Balance Test were performed. The possibility of a correlation between the head impulse tests (vHIT, fHIT) and the Tinetti Balance Test was investigated by logistic regression analysis (Nagelkerke r(2) and Wald test). A linear correlation was found between the Tinetti Balance Test score and fHIT, whereas no correlation was found for vHIT. Functional HIT is an effective test for predicting the risk of falls in elderly patients

A Wearable Wireless Magnetic Eye-Tracker, in-vitro and in-vivo tests

A wireless, wearable magnetic eye tracker is described and characterized. The proposed instrumentation enables simultaneous evaluation of eye and head angular displacements. Such a system can be used to determine the absolute gaze direction as well as to analyze spontaneous eye re-orientation in response to stimuli consisting in head rotations. The latter feature has implications to analyze the vestibulo-ocular reflex and constitutes an interesting opportunity to develop medical (oto-neurological) diagnostics. Details of data analysis are reported together with some results obtained in-vivo or with simple mechanical simulators that enable measurements under controlled conditions

The foreground transfer function for HI intensity mapping signal reconstruction: MeerKLASS and precision cosmology applications

Blind cleaning methods are currently the preferred strategy for handling foreground contamination in single-dish HI intensity mapping surveys. Despite the increasing sophistication of blind techniques, some signal loss will be inevitable across all scales. Constructing a corrective transfer function using mock signal injection into the contaminated data has been a practice relied on for HI intensity mapping experiments. However, assessing whether this approach is viable for future intensity mapping surveys where precision cosmology is the aim, remains unexplored. In this work, using simulations, we validate for the first time the use of a foreground transfer function to reconstruct power spectra of foreground-cleaned low-redshift intensity maps and look to expose any limitations. We reveal that even when aggressive foreground cleaning is required, which causes ${>}\,50\%$ negative bias on the largest scales, the power spectrum can be reconstructed using a transfer function to within sub-percent accuracy. We specifically outline the recipe for constructing an unbiased transfer function, highlighting the pitfalls if one deviates from this recipe, and also correctly identify how a transfer function should be applied in an auto-correlation power spectrum. We validate a method that utilises the transfer function variance for error estimation in foreground-cleaned power spectra. Finally, we demonstrate how incorrect fiducial parameter assumptions (up to ${\pm}100\%$ bias) in the generation of mocks, used in the construction of the transfer function, do not significantly bias signal reconstruction or parameter inference (inducing ${<}\,5\%$ bias in recovered values).Comment: 25 pages, 20 figures. See Figure 4 for the main demonstration of the transfer function's performance for reconstructing signal loss from foreground cleaning. Submitted to MNRAS for publicatio

X-ray irradiated cultures of mouse cortical neural stem/progenitor cells recover cell viability and proliferation with dose-dependent kinetics

Exposure of the developing or adult brain to ionizing radiation (IR) can cause cognitive impairment and/ or brain cancer, by targeting neural stem/progenitor cells (NSPCs). IR effects on NSPCs include transient cell cycle arrest, permanent cell cycle exit/differentiation, or cell death, depending on the experimental conditions. In vivo studies suggest that brain age influences NSPC response to IR, but whether this is due to intrinsic NSPC changes or to niche environment modifications remains unclear. Here, we describe the dose-dependent, time-dependent effects of X-ray IR in NSPC cultures derived from the mouse foetal cerebral cortex. We show that, although cortical NSPCs are resistant to low/moderate IR doses, high level IR exposure causes cell death, accumulation of DNA double-strand breaks, activation of p53- related molecular pathways and cell cycle alterations. Irradiated NSPC cultures transiently upregulate differentiation markers, but recover control levels of proliferation, viability and gene expression in the second week post-irradiation. These results are consistent with previously described in vivo effects of IR in the developing mouse cortex, and distinct from those observed in adult NSPC niches or in vitro adult NSPC cultures, suggesting that intrinsic differences in NSPCs of different origins might determine, at least in part, their response to IR

Cost-effectiveness analysis of personalised versus standard dosimetry for selective internal radiation therapy with TheraSphere in patients with hepatocellular carcinoma

Aims: To perform a cost-effectiveness analysis (CEA) comparing personalised dosimetry with standard dosimetry in the context of selective internal radiation therapy (SIRT) with TheraSphere for the management of adult patients with locally advanced hepatocellular carcinoma (HCC) from the Italian Healthcare Service perspective. Materials and methods: A partition survival model was developed to project costs and the quality-adjusted life years (QALYs) over a lifetime horizon. Clinical inputs were retrieved from a published randomised controlled trial. Health resource utilisation inputs were extracted from the questionnaires administered to clinicians in three oncology centres in Italy, respectively. Cost parameters were based on Italian official tariffs. Results: Over a lifetime horizon, the model estimated the average QALYs of 1.292 and 0.578, respectively, for patients undergoing personalised and standard dosimetry approaches. The estimated mean costs per patient were €23,487 and €19,877, respectively. The incremental cost-utility ratio (ICUR) of personalised versus standard dosimetry approaches was €5,056/QALY. Conclusions: Personalised dosimetry may be considered a cost-effective option compared to standard dosimetry for patients undergoing SIRT for HCC in Italy. These findings provide evidence for clinicians and payers on the value of personalised dosimetry as a treatment option for patients with HCC