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Title: Psychosomatic symptoms during South East Asian haze crisis are related to changes in cerebral hemodynamics
Authors: Tan B.Y.
Leong A.Z.
Leow A.S.
Ngiam N.J.
Ng B.S.
Sharma M.
Yeo L.L. 
Seow P.A.
Hong C.S.
Chee Y.H.
Chen J.
Du Z.
Wong L.Y.
Batra A.
Sarkar N.
Teoh H.-L. 
Ho R.C. 
Sharma V.K. 
Keywords: vasoactive agent
age distribution
air conditioning
brain blood flow
brain blood vessel
cerebral hemodynamics
controlled study
disease association
environmental exposure
environmental parameters
health hazard
major clinical study
middle cerebral artery
nervous system parameters
pollutant standards index
psychosomatic disorder
pulsatility index
resistivity index
Southeast Asia
transcranial Doppler ultrasonography
Issue Date: 2019
Publisher: Public Library of Science
Citation: Tan B.Y., Leong A.Z., Leow A.S., Ngiam N.J., Ng B.S., Sharma M., Yeo L.L., Seow P.A., Hong C.S., Chee Y.H., Chen J., Du Z., Wong L.Y., Batra A., Sarkar N., Teoh H.-L., Ho R.C., Sharma V.K. (2019). Psychosomatic symptoms during South East Asian haze crisis are related to changes in cerebral hemodynamics. PLoS ONE 14 (1) : e0208724. ScholarBank@NUS Repository.
Abstract: Objectives Forest fires in South Asia lead to widespread haze, where many healthy individuals develop psychosomatic symptoms. We investigated the effects of haze exposure on cerebral hemodynamics and new symptoms. We hypothesised that vasoactive substances present in the haze, would lead to vasodilation of cerebral vasculature, thereby altering cerebral hemodynamics, which in turn may account for new psychosomatic symptoms. Methods Seventy-four healthy volunteers were recruited, and serial transcranial Doppler (TCD) ultrasonography was performed to record blood flow parameters of bilateral middle cerebral arteries (MCA). The first TCD was performed in an air-conditioned environment. It was repeated outdoors after the participants spent 30-minutes in the haze environment. The prevailing level of pollutant standards index (PSI) was recorded. Appropriate statistical analyses were performed to compare cerebral hemodynamics at baseline and after haze exposure in all participants. Subgroup analyses were then employed to compare the findings between symptomatic and asymptomatic participants. Results Study participants’ median age was 30 years (IQR 26–34), and new psychosomatic symptoms were reported by 35 (47.3%). There was a modest but significant decrease in pulsatility index (PI) and resistivity index (RI) in the left MCA after haze exposure (PI: p = 0.026; RI: p = 0.021). When compared to baseline parameters, haze exposure resulted in significantly lower mean PI (p = 0.001) and RI (p = 0.001) in symptomatic patients, but this difference was not present in asymptomatic patients (PI: p = 0.919; RI: p = 0.970). Conclusion Haze causes significant alterations in cerebral hemodynamics in susceptible individuals, probably responsible for various psychosomatic symptoms. The prognostic implications and health effects of haze require evaluation in a larger study. © 2019 Tan et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Source Title: PLoS ONE
ISSN: 19326203
DOI: 10.1371/journal.pone.0208724
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