Document Detail


Monitoring cerebral hemodynamics with transcranial Doppler ultrasound during cognitive and exercise testing in adults following unilateral stroke.
MedLine Citation:
PMID:  23366386     Owner:  NLM     Status:  In-Data-Review    
Abstract/OtherAbstract:
An observational study was performed as a preliminary investigation into the use of transcranial Doppler ultrasound (TCD) for recording cerebral hemodynamic changes during multiple tasks. TCD is a method of measuring cerebral blood flow (CBF) using ultrasound transducers in contact with the surface of the head. Using the maximum flow envelope of the Doppler spectrum returning from the middle cerebral artery (MCA), standard clinical flow indices can be calculated and displayed in real time providing information concerning perturbations in CBF and their potential cause. These indices as well as flow velocity measurements have been recognized as useful in measuring changes in responses to various stimulus that can be used to indicate cardiovascular health. For this study, the pulsatility index (PI) and resistivity index (RI) were chosen since they indicate composite changes indicative of vasoconstriction and vasodilatation which are normal hemodynamic responses under appropriate conditions. A total of eleven participants were recruited to take part in this study. Nine of these individuals had no known disability (Controls); two had experienced unilateral cerebrovascular accidents (Strokes) in the ipsilateral MCA distribution. Maximum velocity envelopes of the spectral Doppler data were recorded using a fixation device designed to stabilize two ultrasound probes (2 MHz) to sample the bilateral MCAs CBF. These measures were performed separately while the subject performed four activities: 1) rest, 2) cognitive challenge, 3) cardiovascular exercise, and 4) simultaneous exercise and cognitive challenge. Cardiovascular parameters were calculated from the data by extracting maximum (Vs) and minimum flow velocities (Vd), PI, RI, and time signatures for each cardiac cycle. The data for all participants shows significant changes in cardiovascular parameters between states of rest and exercise, as well as slight trends across time. Although the data are preliminary, they show the capability of using Doppler spectral examination of the bilateral MCAs in individuals with physical limitation performing cardiovascular exercise. The novelty of examining a population using dynamic exercise who before could not perform such exercise offers the opportunity to study the impact of exercise on global cerebral recovery in unilateral stroke with significant physical impairment.
Authors:
Brian P Watt; Judith M Burnfield; Edward J Truemper; Thad W Buster; Gregory R Bashford
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference     Volume:  2012     ISSN:  1557-170X     ISO Abbreviation:  Conf Proc IEEE Eng Med Biol Soc     Publication Date:  2012 Aug 
Date Detail:
Created Date:  2013-01-31     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101243413     Medline TA:  Conf Proc IEEE Eng Med Biol Soc     Country:  United States    
Other Details:
Languages:  eng     Pagination:  2310-3     Citation Subset:  IM    
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