The device was tested and validated using our enhanced EEG-NIRS tissue mimicking fluid phantom for sensitivity mapping. Typical somatotopic electrical evoked potential experiments were performed to verify clinical applicability.

Near infrared spectroscopy (NIRS) is regarded as a potential medical diagnostic technique for investigation of hemodynamic changes. However, uncertainties pertaining to the origin of NIRS signals have hampered its clinical interpretation. The uncertainities in NIRS measurements especially in case of living tissues are due to lack of rigorous combined theoretical-experimental studies resulting in clear understanding of the origin of NIRS signals. For their reliable interpretation it is important to understand the relationship between spatial changes in optical properties and corresponding changes in the NIRS signal. We investigated spatial sensitivity of near infrared optical measurements using an experimental approach. It uses a liquid optical phantom as tissue equivalent, which is explored under robot-control by a small, approximately point like perturbation of desired optical properties, and a NIRS instrument for trans-illumination/reflection measurements. The experimentally obtained sensitivity has been analyzed and compared with numerical simulations. In preliminary experiments we investigated the influence of various optical properties of the medium and of source/detector distances on the spatial sensitivity distribution. The acquired sensitivity maps can be used to define characteristic parameters. As an example, we used a 25% threshold to define a penetration depth measure which provides values in good accordance with published ones. To the best of our knowledge this is the first experimental study of NIRS spatial sensitivity. The presented method will allow in depth experimental investigation of the influence of various conditions pertaining to medium such as optical properties of tissue (scattering and absorption) and of the source/detector configuration. 1977-1981 (1996). Zakynthinos, and I. Vogiatzis, "Near-infrared spectroscopy and indocyanine green derived blood flow index for non-invasive measurement of muscle perfusion during exercise," J. Appl. Physiol. 108(4), 962-967 (2010). 19. M. Xia, V. Kodibagkar, H. Liu, and R. P. Mason, "Tumour oxygen dynamics measured simultaneously by nearinfrared spectroscopy and 19f magnetic resonance imaging in rats," Phys. Med. Biol. 51, 45-60 (2006). 20. S. Nioka and B. Chance, "Nir spectroscopic detection of breast cancer," Technol. Cancer Res. Treat. 4, 497-512 (2005). 21. M. Firbank, M. Oda, and D. T. Delpy, "An improved design for a stable and reproducible phantom material for use in near-infrared spectroscopy and imaging," Phys. Med. Biol. 40, 955-961 (1995). 22. M. Firbank, E. Okada, and D. T. Delpy, "Investigation of the effect of discrete absorbers upon the measurement of blood volume with near-infrared spectroscopy," Phys.

This paper presents the design and simulation of a handheld device for people with hand tremor, such as Parkinson's and essential tremor patients. This device can be used as a pen for smartphones or as a spoon. The designed system includes two links, which are connected to two servomotors, which are mounted in orthogonal directions. To attenuate the effect of hand tremor on the tip of device, PID and computed torque methods are used to actively control the system. These controllers are used to control the rotation of the motors for moving the links in opposite directions of the hand tremor. Performance of the device with mentioned controllers is studied for different applications and finally, the results of both controllers are discussed and compared. Based on the presented results in this study, the designed device is able to suppress the hand tremor up to 75% during eating and 65% during following a spiral pattern. Graphical abstract Design of a noninvasive and smart hand tremor attenuation system: a simulation study.

The ability to extract rhythmic structure is important for the development of language, music and social communication. Although previous studies show infants’ brains entrain to the periodicities of auditory rhythms and even different metrical interpretations (e.g., groups of two vs. three beats) of ambiguous rhythms, whether the premature brain tracks beat and meter frequencies had not been explored previously. We used high-resolution electroencephalography, while premature infants (n = 19, five male, mean age 32 ± 2.59 wGA) heard two auditory rhythms in the incubators. We observed selective enhancement of the neural response at both beat and meter-related frequencies. Further, neural oscillations at the beat and duple (groups of 2) meter were phase aligned with the envelope of the auditory rhythmic stimuli. Comparing the relative power at beat and meter frequencies across stimuli and frequency revealed evidence for selective enhancement of duple meter. This suggests that even at this early stage of development, neural mechanisms for processing auditory rhythms beyond simple sensory coding are present. Our results add to a few recent neuroimaging studies demonstrating discriminative auditory abilities of premature neural networks. Specifically, our results demonstrate the early capacities of the immature neural circuits and networks to code both simple beat and beat grouping (i.e., hierarchical meter) regularities of auditory sequences. Considering the importance of rhythm processing for acquiring language and music, our findings indicate that even before birth, the premature brain is already learning this important aspect of the auditory world in a sophisticated and abstract way.Significant Statement:Processing auditory rhythm is of great neurodevelopmental importance. In an electroencephalography experiment in premature newborns, we found converging evidence that when presented with auditory rhythms the premature brain encodes multiple periodicities corresponding to beat and beat grouping (meter) frequencies, and even selectively enhances the neural response to meter compared to beat, as in human adults. We also found that the phase of low frequency neural oscillations align to the envelope of the auditory rhythms, and that this phenomenon becomes less precise at lower frequencies. These findings demonstrate the initial capacities of the developing brain to code auditory rhythm, and the importance of special care to the auditory environment of this vulnerable population during a highly dynamic period of neural development.

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