Concussed patients with chronic symptoms commonly report dizziness during exposure to environments with complex visual stimuli (e.g. supermarket aisles, busy crossroads). Such visual induced dizziness is well-known in patients with vestibular deficits, in whom it indicates an overreliance on visual cues in sensory integration. Considering that optokinetic after-nystagmus (OKAN) reflects the response of the central network integrating visual and vestibular self-motion signals (velocity storage network), we investigated OKAN in 71 patients [17 (23.9%) females, 30.36 ± 9.05 years old] who suffered from persistent symptoms after a concussion and presented clinical signs suggesting visual dependence. Data were retrospectively compared with 21 healthy individuals [13 (61.9%) females, 26.29 ± 10.00 years old]. The median values of the slow cumulative eye position and of the time constant of OKAN were significantly higher in patients than in healthy individuals (slow cumulative eye position: 124.15 ± 55.61° in patients and 77.87 ± 45.63° in healthy individuals-p = 0.012; time constant: 25.17 ± 10.27 s in patients and 13.95 ± 4.92 s in healthy individuals-p = 0.003). The receiving operating curve (ROC) estimated on the time constant had an overall area under the curve of 0.73. Analysis of the ROC suggests that a test measuring the OKAN time constant could obtain a sensitivity of 0.73 and specificity of 0.72 in determining the origin of the visual-related disturbances in those patients (threshold 16.6 s). In a subset of 43 patients who also performed the Sensory Organization Test (SOT), the proposed OKAN test was twice as sensitive as the SOT. This study suggests that concussed patients with persisting visual symptoms may have an underlying impairment of the velocity storage mechanism and that measuring the OKAN time constant can objectify such impairment.
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http://dx.doi.org/10.1007/s00415-020-10359-8 | DOI Listing |
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Department of Orthopedic Surgery, 5th Azar hospital, Golestan University of Medical Sciences, Gorgan, Iran.
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Ecol Evol
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Instituto Milenio de Oceanografía (IMO) Universidad de Concepción Concepción Chile.
Mechanisms driving the spatial and temporal patterns of species distribution in the Earth's largest habitat, the deep ocean, remain largely enigmatic. The late Miocene to the Pliocene (~23-2.58 Ma) is a period that was marked by significant geological, climatic, and oceanographic changes.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2025
Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.
Reaction and interaction dynamics of azobenzene-tethered DNA (photoresponsive DNA) with T7 RNA polymerase (T7RNAP) were studied after photoisomerization of azobenzene from the - to -forms using the transient grating (TG) and time-resolved fluorescence polarization techniques. Two types of photoresponsive DNA were examined: AzoPBD, tethered at the protein binding site, and AzoTATA, tethered at the unwinding site. A diffusion change was observed after photoexcitation of -AzoPBD within 1 ms, and this change is explained in terms of a structural change from a bent to an extended conformation upon the -to- photoisomerization.
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Mol Brain
January 2025
Research Centre for Idling Brain Science, University of Toyama, Toyama, 930-0194, Japan.
Cognitive processes such as action planning and decision-making require the integration of multiple sensory modalities in response to temporal cues, yet the underlying mechanism is not fully understood. Sleep has a crucial role for memory consolidation and promoting cognitive flexibility. Our aim is to identify the role of sleep in integrating different modalities to enhance cognitive flexibility and temporal task execution while identifying the specific brain regions that mediate this process.
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