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Birch AA, El-Bouri WK, Marchbanks RJ, Moore LA, Campbell-Bell CM, Kipps CM, Bulters DO. Pulsatile tympanic membrane displacement is associated with cognitive score in healthy subjects. CEREBRAL CIRCULATION - COGNITION AND BEHAVIOR 2022; 3:100132. [PMID: 36324393 PMCID: PMC9616339 DOI: 10.1016/j.cccb.2022.100132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 02/17/2022] [Accepted: 02/27/2022] [Indexed: 06/16/2023]
Abstract
To test the hypothesis that pulsing of intracranial pressure has an association with cognition, we measured cognitive score and pulsing of the tympanic membrane in 290 healthy subjects. This hypothesis was formed on the assumptions that large intracranial pressure pulses impair cognitive performance and tympanic membrane pulses reflect intracranial pressure pulses. 290 healthy subjects, aged 20-80 years, completed the Montreal Cognitive Assessment Test. Spontaneous tympanic membrane displacement during a heart cycle was measured from both ears in the sitting and supine position. We applied multiple linear regression, correcting for age, heart rate, and height, to test for an association between cognitive score and spontaneous tympanic membrane displacement. Significance was set at P < 0.0125 (Bonferroni correction.) A significant association was seen in the left supine position (p = 0.0076.) The association was not significant in the right ear supine (p = 0.28) or in either ear while sitting. Sub-domains of the cognitive assessment revealed that executive function, language and memory have been primarily responsible for this association. In conclusion, we have found that spontaneous pulses of the tympanic membrane are associated with cognitive performance and believe this reflects an association between cognitive performance and intracranial pressure pulses.
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Affiliation(s)
- Anthony A. Birch
- Neurological Physics Group, Department of Medical Physics, University Hospital Southampton NHS Foundation Trust, Southampton, SO16 6YD, UK
- University of Southampton, Faculty of Medicine, Southampton, SO17 1BJ, UK
| | - Wahbi K. El-Bouri
- Neurological Physics Group, Department of Medical Physics, University Hospital Southampton NHS Foundation Trust, Southampton, SO16 6YD, UK
- University of Southampton, Faculty of Engineering and Physical Sciences, Southampton, SO17 1BJ, UK
- Liverpool Centre for Cardiovascular Sciences, Department of Cardiovascular and Metabolic Medicine, University of Liverpool, Liverpool, UK
| | - Robert J. Marchbanks
- Neurological Physics Group, Department of Medical Physics, University Hospital Southampton NHS Foundation Trust, Southampton, SO16 6YD, UK
- University of Southampton, Faculty of Medicine, Southampton, SO17 1BJ, UK
| | - Laura A. Moore
- Neurological Physics Group, Department of Medical Physics, University Hospital Southampton NHS Foundation Trust, Southampton, SO16 6YD, UK
| | - Cherith M. Campbell-Bell
- Neurological Physics Group, Department of Medical Physics, University Hospital Southampton NHS Foundation Trust, Southampton, SO16 6YD, UK
| | - Christopher M. Kipps
- University of Southampton, Faculty of Medicine, Southampton, SO17 1BJ, UK
- Department of Neurology, University Hospital Southampton NHS Foundation Trust, Southampton, SO16 6YD, UK
| | - Diederik O. Bulters
- University of Southampton, Faculty of Medicine, Southampton, SO17 1BJ, UK
- Department of Neurosurgery, University Hospital Southampton NHS Foundation Trust, Southampton, SO16 6YD, UK
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Self-Similar Functional Circuit Models of Arteries and Deterministic Fractal Operators: Theoretical Revelation for Biomimetic Materials. Int J Mol Sci 2021; 22:ijms222312897. [PMID: 34884701 PMCID: PMC8657472 DOI: 10.3390/ijms222312897] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 11/15/2021] [Accepted: 11/24/2021] [Indexed: 12/15/2022] Open
Abstract
In this paper, the self-similar functional circuit models of arteries are proposed for bioinspired hemodynamic materials design. Based on the mechanical-electrical analogous method, the circuit model can be utilized to mimic the blood flow of arteries. The theoretical mechanism to quantitatively simulate realistic blood flow is developed by establishing a fractal circuit network with an infinite number of electrical components. We have found that the fractal admittance operator obtained from the minimum repeating unit of the fractal circuit can simply and directly determine the blood-flow regulation mechanism. Furthermore, according to the operator algebra, the fractal admittance operator on the aorta can be represented by Gaussian-type convolution kernel function. Similarly, the arteriolar operator can be described by Bessel-type function. Moreover, by the self-similar assembly pattern of the proposed model, biomimetic materials which contain self-similar circuits can be designed to mimic physiological or pathological states of blood flow. Studies show that the self-similar functional circuit model can efficiently describe the blood flow and provide an available and convenient structural theoretical revelation for the preparation of in vitro hemodynamic bionic materials.
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