Article

Oscillations in Cerebral Haemodynamics in Patients with Falciparum Malaria

Department of Medical Physics and Bioengineering, University College London, Malet Place Engineering Building, Gower Street, London, WC1E 6BT, UK.
Advances in Experimental Medicine and Biology (Impact Factor: 2.01). 01/2013; 765:101-7. DOI: 10.1007/978-1-4614-4989-8_15
Source: PubMed

ABSTRACT Spontaneous oscillations in cerebral haemodynamics studied with near-infrared spectroscopy (NIRS), become impaired in several pathological conditions. We assessed the spectral characteristics of these oscillations in 20 patients with falciparum malaria admitted to Ispat General Hospital, Rourkela, India. Monitoring included continuous frontal lobe NIRS recordings within 24 h of admission (Day 0), together with single measurements of a number of clinical and chemical markers recorded on admission. Seven patients returned for follow-up measurements on recovery (FU). A 2,048 sampling-point segment of oxygenated haemoglobin concentration ([ΔHbO(2)]) data was subjected to Fourier analysis per patient, and power spectral density was derived over the very low frequency (VLF: 0.02-0.04 Hz), low frequency (LF: 0.04-0.15 Hz) and high frequency (HF: 0.15-0.4 Hz) bands. At Day 0, VLF spectral power was 21.1 ± 16.4, LF power 7.2 ± 4.6 and HF power 2.6 ± 5.0, with VLF power being statistically significantly higher than LF and HF (P < 0.005). VLF power tended to decrease in the severely ill patients and correlated negatively with heart rate (r = 0.57, P < 0.01), while LF power correlated positively with aural body temperature (r = 0.49, P < 0.05). In all but one of the patients who returned for FU measurements, VLF power increased after recovery. This may be related to autonomic dysfunction in severe malaria, a topic of little research to date. The present study demonstrated that application of NIRS in a resource-poor setting is feasible and has potential as a research tool.

Download full-text

Full-text

Available from: Rajyabardhan Pattnaik, Jul 20, 2014
1 Follower
 · 
106 Views
 · 
18 Downloads
  • Source
    • "Statistical analysis was performed on oscillations of HbO 2 , because spontaneous oscillations are most prominent in HbO 2 (Obrig et al., 2000; Schroeter et al., 2004; Li et al., 2010; Kolyva et al., 2013). In order to make valid comparisons of SDs and PSDs of different vasomotion components between different sleep stages, the SDs and PSDs of cerebral and muscular HbO 2 and SpO 2 were normalized to their mean values of the whole-night measurements (Schroeter et al., 2004, 2005; Kolyva et al., 2013 "
    [Show abstract] [Hide abstract]
    ABSTRACT: Vasomotion is important in the study of vascular disorders, including stroke. Spontaneous low and very low hemodynamic oscillations (3–150 mHz) measured with near-infrared spectroscopy (NIRS) reflect the endothelial (3–20 mHz), neurogenic (20–40 mHz) and myogenic (40–150 mHz) components of vasomotion. We investigated sleep-specific patterns of vasomotion by characterizing hemodynamic oscillations with NIRS in healthy subjects, and tested the feasibility of NIRS as a bedside tool for monitoring vasomotion during whole-night sleep. To characterize local cerebral vasomotion, we compared cerebral NIRS measurements with muscular NIRS measurements and peripheral arterial oxygen saturation (SpO2) during different sleep stages in 14 healthy volunteers. Spectral powers of hemodynamic oscillations in the frequency range of endothelial vasomotion were systemically predominant in every sleep stage, and the powers of endothelial and neurogenic vasomotion decreased in deep sleep as compared with light sleep and rapid eye movement (REM) sleep in brain, muscle, and SpO2. The decrease in the powers of myogenic vasomotion in deep sleep only occurred in brain, and not in muscle. These results point to a predominant role of endothelial function in regulating vasomotion during sleep. The decline in cerebral endothelial and neurogenic vasomotion during progression to deeper non-REM sleep suggests that deep sleep may play a protective role for vascular function. NIRS can be used to monitor endothelial control of vasomotion during nocturnal sleep, thus providing a promising non-invasive bedside tool with which to study the sleep-relevant pathological mechanisms in vascular diseases and stroke.
    European Journal of Neuroscience 08/2014; 40(9). DOI:10.1111/ejn.12702 · 3.67 Impact Factor
  • Source
    • "In-vivo monitoring of brain physiology is an important target area for application of diffuse optical techniques in the clinic. Specifically, the deep tissue penetration of near-infrared light, coupled with its sensitivity to hemodynamic signatures has led to novel studies in critical care monitoring [1–5] and to exploration of the normal functional responses of specific brain networks [6–10]. The vast majority of this work employs the technique of diffuse optical spectroscopy (DOS), or near-infrared spectroscopy (NIRS); DOS probes local oxy- and deoxy-hemoglobin tissue concentrations and variations thereof. "
    [Show abstract] [Hide abstract]
    ABSTRACT: A pilot study explores relative contributions of extra-cerebral (scalp/skull) versus brain (cerebral) tissues to the blood flow index determined by diffuse correlation spectroscopy (DCS). Microvascular DCS flow measurements were made on the head during baseline and breath-holding/hyperventilation tasks, both with and without pressure. Baseline (resting) data enabled estimation of extra-cerebral flow signals and their pressure dependencies. A simple two-component model was used to derive baseline and activated cerebral blood flow (CBF) signals, and the DCS flow indices were also cross-correlated with concurrent Transcranial Doppler Ultrasound (TCD) blood velocity measurements. The study suggests new pressure-dependent experimental paradigms for elucidation of blood flow contributions from extra-cerebral and cerebral tissues.
    Biomedical Optics Express 07/2013; 4(7):978-994. DOI:10.1364/BOE.4.000978 · 3.50 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: An almost sinusoidal, large amplitude ~0.1 Hz oscillation in cortical hemodynamics has been repeatedly observed in species ranging from mice to humans. However, the occurrence of 'slow sinusoidal hemodynamic oscillations' (SSHOs) in human functional magnetic resonance imaging (fMRI) studies is rarely noted or considered. As a result, little investigation into the cause of SSHOs has been undertaken, and their potential to confound fMRI analysis, as well as their possible value as a functional biomarker has been largely overlooked. Here, we report direct observation of large-amplitude, sinusoidal ~0.1 Hz hemodynamic oscillations in the cortex of an awake human undergoing surgical resection of a brain tumor. Intraoperative multispectral optical intrinsic signal imaging (MS-OISI) revealed that SSHOs were spatially localized to distinct regions of the cortex, exhibited wave-like propagation, and involved oscillations in the diameter of specific pial arterioles, confirming that the effect was not the result of systemic blood pressure oscillations. fMRI data collected from the same subject 4 days prior to surgery demonstrates that ~0.1 Hz oscillations in the BOLD signal can be detected around the same region. Intraoperative optical imaging data from a patient undergoing epilepsy surgery, in whom sinusoidal oscillations were not observed, is shown for comparison. This direct observation of the '0.1 Hz wave' in the awake human brain, using both intraoperative imaging and pre-operative fMRI, confirms that SSHOs occur in the human brain, and can be detected by fMRI. We discuss the possible physiological basis of this oscillation and its potential link to brain pathologies, highlighting its relevance to resting-state fMRI and its potential as a novel target for functional diagnosis and delineation of neurological disease.
    NeuroImage 10/2013; 87. DOI:10.1016/j.neuroimage.2013.10.044 · 6.36 Impact Factor
Show more