Brain death. Brain death is a recent invention.
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Apnea↗
Biomedical subjects
David W Evans
Publications and source records attributed to David W Evans.
Spectral content of the intraocular pressure pulse wave: glaucoma patients versus normal subjects.
BACKGROUND: Many studies have found that the intraocular pressure (IOP) is lower in glaucomatous populations than in normal groups. An alternative method of analysis, commonly used in the investigation of arterial blood pressure, is to reduce the pulse waveform to its component Fourier parts. The purpose of this study, therefore, was to determine whether such a technique is applicable to the IOP pulse and to investigate whether it was superior at differentiating diseased from healthy eyes. METHODS: Using a pneumatonometer, continuous 10-s IOP recordings were taken from 10 glaucoma patients and 10 normal subjects. The IOP recordings were then analysed using the fast Fourier transform (FFT) to determine their spectral components. In addition, standard IOP parameters (pulse amplitude, pulse volume, and pulsatile ocular blood flow) were measured to allow comparison with the waveform analysis technique. RESULTS: Analysis by FFT successfully determined the IOP pulse's higher spectral components up to the fourth harmonic. In addition, although standard measurements of the IOP pulse (such as pulse amplitude) were insignificant, the second ( P=0.034), third ( P=0.015) and fourth ( P=0.013) harmonics of the waveform successfully differentiated between the glaucoma and normal groups. CONCLUSION: Spectral analysis of the IOP pulse appears to be a promising technique in the investigation of ocular vascular disease.
Blood Pressure↗
Magical beliefs and rituals in young children.
Thirty-one children were administered a structured interview that assessed their beliefs about magic, tricks and wishes. Children were also presented with demonstrations of magic tricks/illusions, and asked to offer explanations as to how they worked. Parents completed the Childhood Routines Inventory (CRI), a 19-item parent report measure that assesses children's rituals, habits and sensory-perceptual experiences that we have termed "compulsive-like" behavior. Results indicated that children's rituals and compulsions were positively related to their magical beliefs, and inversely related to their uses of concrete, physical explanations to describe various phenomena. In particular, children's beliefs about the effects of wishing were most consistently correlated with their compulsive-like rituals and routines. The findings extended the work on magical beliefs and obsessive-compulsive phenomena to the normative manifestation of compulsive behaviors found in typical development.
Child↗
Mechanisms and effects of spinal high-velocity, low-amplitude thrust manipulation: previous theories.
OBJECTIVES: When the clinical efficacy of spinal manipulative treatment for spinal pain has been assessed, high-velocity low-amplitude thrust (HVLAT) manipulation and mobilization have been regarded as clinical interventions giving identical and equivalent biologic effects. The objective of this review is to critically discuss previous theories and research of spinal HVLAT manipulation, highlighting reported neurophysiologic effects that seem to be uniquely associated with cavitation of synovial fluid. DATA SOURCE: The biomedical literature was searched for research and reviews on spinal manipulation. MEDLINE and EMBASE databases were used to help find relevant articles. STUDY SELECTION: All articles relevant to the objectives were selected. DATA EXTRACTION: All available data were used. DATA SYNTHESIS: The main hypotheses for lesions that respond to HVLAT manipulation were critically discussed: (1) release of entrapped synovial folds or plica, (2) relaxation of hypertonic muscle by sudden stretching, (3) disruption of articular or periarticular adhesions, and (4) unbuckling of motion segments that have undergone disproportionate displacements. RESULTS: There appear to be 2 separate modes of action from zygapophyseal HVLAT manipulation. Intra-articular "mechanical" effects of zygapophyseal HVLAT manipulation seem to be absolutely separate from and irrelevant to the occurrence of reported "neurophysiologic" effects. Cavitation should not be an absolute requirement for the mechanical effects to occur but may be a reliable indicator for successful joint gapping. CONCLUSIONS: It is hoped that identification of these unique neurophysiologic effects will provide enough theoretical reason for HVLAT manipulation and mobilization to be assessed independently as individual clinical interventions.
Cervical Vertebrae↗
American Medical Records Association.
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Confidentiality↗