Cognitive Neurodynamics

, Volume 9, Issue 6, pp 615–626 | Cite as

A cerebral blood flow evaluation during cognitive tasks following a cervical spinal cord injury: a case study using transcranial Doppler recordings

  • Héloïse Bleton
  • Ervin Sejdić
Research Article


A spinal cord injury (SCI) is one of the most common neurological disorders. In this paper, we examined the consequences of upper SCI in a male participant on the cerebral blood flow velocity. In particular, transcranial Doppler was used to study these effects through middle cerebral arteries (MCA) during resting-state periods and during cognitive challenges (non-verbal word-generation tasks and geometric-rotation tasks). Signal characteristics were analyzed from raw signals and envelope signals (maximum velocity) in the time domain, the frequency domain and the time–frequency domain. The frequency features highlighted an increase of the peak frequency in L-MCA and R-MCA raw signals, which revealed stronger cerebral blood flow during geometric/verbal processes respectively. This underlined a slight dominance of the right hemisphere during word-generation periods and a slight dominance of the left hemisphere during geometric processes. This finding was confirmed by cross-correlation in the time domain and by the entropy rate in information-theoretic domain. A comparison of our results to other neurological disorders (Alzheimer’s disease, Parkinson’s disease, autism, epilepsy, traumatic brain injury) showed that the SCI had similar effects such as general decreased cerebral blood flow and similar regular hemispheric dominance in a few cases.


Transcranial Doppler Spinal cord injury Cognitive tasks Cerebral blood flow velocity Signal processing 


  1. Aaslid A, Markwalder T, Nornes H (1982) Noninvasive transcranial Doppler ultrasound recording of flow velocity in basal cerebral arteries. J Neurosurg 57(6):769–774PubMedCrossRefGoogle Scholar
  2. Abásolo D, Hornero R, Gómez C, García M, López M (2006) Analysis of EEG background activity in Alzeimer’s disease patients with Lempel–Ziv complexity and central tendency measure. Med Eng Phys 28(4):315–322PubMedCrossRefGoogle Scholar
  3. Aboy M, Hornero R, Abásolo D, Álvarez D (2006) Interpretation of the Lempel–Ziv complexity measure in the context of biomedical signal analysis. IEEE Trans Biomed Eng 53(11):2282–2288PubMedCrossRefGoogle Scholar
  4. Adcock J, Wise R, Oxbury J, Matthews P (2003) Quantitative fMRI assessment of the differences in lateralization of language-related brain activation in patients with temporal lobe epilepsy. NeuroImage 18(2):423–438PubMedCrossRefGoogle Scholar
  5. Ahmed S, Shahjahan M, Murase K (2011) A Lempel–Ziv complexity-based neural network pruning algorithm. Int J Neural Syst 21(5):427–441PubMedCrossRefGoogle Scholar
  6. Alexandrov A, Sloan M, Wong L, Douville C, Razumovsky A, Koroshetz W, Kaps M, Tegeler C (2007) Practice standards for transcranial Doppler ultrasound: part I—test performance. J Neuroimaging 17(1):11–18PubMedCrossRefGoogle Scholar
  7. Allen J, Coan J, Nazarian M (2004) Issues and assumptions on the road from raw signals to metrics of frontal EEG assymetry in emotion. Biol Psychol 67(1–2):183–218PubMedCrossRefGoogle Scholar
  8. Bernd Ringelstein E, Droste D, Babikian V, Evans D, Grosset D, Kaps M, Markus H, Russell D, Siebler M (1998) Consensus on microembolus detection by TCD. Stroke 29(3):725–729CrossRefGoogle Scholar
  9. Bishop C, Powell S, Rutt D, Browse N (1986) Transcranial Doppler measurement of middle cerebral artery blood flow velocity: a validation study. Stroke 17(5):913–915PubMedCrossRefGoogle Scholar
  10. Bode H (1992) Intracranial blood flow velocities during seizures and generalized epileptic discharges. Eur J Pediatr 151(9):706–709PubMedCrossRefGoogle Scholar
  11. Brass L, Pavlakis S, DeVivo D (1988) Transcranial Doppler measurements of the middle cerebral artery. Effect of hematocrit. Stroke 19(12):1466–1469PubMedCrossRefGoogle Scholar
  12. Bridge P, Sawilowsky S (1999) Increasing physicians’ awareness of the impact of statistics on research outcomes: comparative power of the t test and Wilcoxon rank-sum test in small samples applied research. J Clin Epidemiol 52(3):229–235PubMedCrossRefGoogle Scholar
  13. Bulla-Hellwig M, Vollmer J, Götzen A, Skreczek W, Hartje W (1996) Hemispheric asymmetry of arterial blood flow velocity changes during verbal and visuospatial tasks. Neuropsychologia 34(10):987–991PubMedCrossRefGoogle Scholar
  14. Burroni L, Orsi A, Monti L, Hayek Y, Rocchi R, Vattimo A (2008) Regional cerebral blood flow in childhood autism: a SPET study with SPM evaluation. Nucl Med Commun 29(2):150–156PubMedCrossRefGoogle Scholar
  15. Catz A, Bluvshtein V, Korczyn A, Pinhas I, Gelernter I, Nissel T, Vered Y, Bornstein N, Akselrod S (2007) Modified cold pressor test by cold application to the foot after spinal cord injury: suggestion of hemodynamics control by the spinal cord. Am J Phys Med Rehabil 86(11):875–882PubMedCrossRefGoogle Scholar
  16. Cirak B, Ziegfeld S, Misra Knight V, Chang D, Avellino A, Paidas C (2004) Spinal injuries in children. J Pediatr Surg 39(4):607–612PubMedCrossRefGoogle Scholar
  17. Claassen J, Diaz-Arrastia R, Martin-Cook K, Levine B, Zhang R (2009) Altered cerebral hemodynamics in early Alzheimer disease: a pilot study using transcranial Doppler. J Alzheimer’s Dis 17(3):621–629Google Scholar
  18. Compton J, Redmond S, Symon L (1987) Cerebral blood velocity in subarachnoid haemorrhage: a transcranial Doppler study. J Neurol Neurosurg Psychiatry 50(11):1499–1503PubMedCentralPubMedCrossRefGoogle Scholar
  19. Costa M, Stegagno L, Schandry R, Ricci Bitti P (1998) Contingent negative variation and cognitive performance in hypotension. Psychophysiology 35(6):737–744PubMedCrossRefGoogle Scholar
  20. Cupini L, Matteis M, Troisi E, Sabbadini M, Bernardi G, Caltagirone C, Silvestrini M (1996) Bilateral simultaneous transcranial Doppler monitoring of flow velocity changes during visuospatial and verbal working memory tasks. Brain 119(4):1249–1253PubMedCrossRefGoogle Scholar
  21. Curt A, Bruehlmeier M, Leenders K, Roelcke U, Dietz V (2004) Differential effect of spinal cord injury and functional impairment on human brain activation. J Neurotrauma 19(1):43–51CrossRefGoogle Scholar
  22. Davidoff G, Roth E, Thomas P, Doljanac R, Dijkers M, Berent S, Morris J, Yarkony G (1990) Depression and neuropsychological test performance in acute spinal cord injury patients: lack of correlation. Arch Clin Neuropsychol 5(1):77–88PubMedCrossRefGoogle Scholar
  23. Dawson G (1982) Cerebral lateralization in individuals diagnosed as autistic in early childhood. Brain Lang 15(2):353–368PubMedCrossRefGoogle Scholar
  24. DeCarlo L (1997) On the meaning and use of kurtosis. Psychol Methods 2(3):292–307CrossRefGoogle Scholar
  25. Deppe M, Knecht S, Henningsen H, Ringelstein E (1997) Average: a Windows® program for automated analysis of event related cerebral blood flow. J Neurosci Methods 75(2):147–154PubMedCrossRefGoogle Scholar
  26. Deppe M, Ringelstein E, Knecht S (2004) The investigation of functional brain lateralization by transcranial Doppler sonography. Neuroimage 21(3):1124–1146PubMedCrossRefGoogle Scholar
  27. DePuy V, Berger V, Zhou Y (2005) Wilcoxon–Mann–Whitney test. Encyclopedia of statistics in behavioral science. Wiley, LondonGoogle Scholar
  28. Derejko M, Slawek J, Wieczorek D, Brockhuis B, Dubaniewicz M, Lass P (2006) Regional cerebral blood flow in Parkinson’s disease as an indicator of cognitive impairment. Nucl Med Commun 27(12):945–951PubMedCrossRefGoogle Scholar
  29. Diehl B, Diehl R, Stodieck S, Bernd Ringelstein E (1997) Spontaneous oscillations in cerebral blood flow velocities in middle cerebral arteries in control subjects and patients with epilepsy. Stroke 28(12):2457–2459PubMedCrossRefGoogle Scholar
  30. Dowler R, O’Brien S, Haaland K, Harrington D, Feel F, Fiedler K (1995) Neuropsychological functioning following a spinal cord injury. Appl Neuropsychol 2(3/4):124–126PubMedCrossRefGoogle Scholar
  31. Droste D, Harders A, Rastogi E (1989a) A transcranial Doppler study of blood flow velocity in the middle cerebral arteries performed at rest and during mental activities. Stroke 20(8):1005–1011PubMedCrossRefGoogle Scholar
  32. Droste D, Harders A, Rastogi E (1989b) Two Transcranial Doppler studies on blood flow velocity in both middle cerebral arteries during rest and the performance of cognitive tasks. Neuropsychologia 27(10):1221–1230PubMedCrossRefGoogle Scholar
  33. Duschek S, Schandry R (2004) Cognitive performance and cerebral blood flow in essential hypotension. Psychophysiology 41(6):905–913PubMedCrossRefGoogle Scholar
  34. Duschek S, Weisz N, Schandry R (2003) Reduced cognitive performance and prolonged reaction time accompany moderate hypotension. Clin Auton Res 13(6):427–432PubMedGoogle Scholar
  35. Escalante-Mead P, Minshew N, Sweeney J (2003) Abnormal brain lateralization in high-functioning autism. J Autism Dev Disord 33(5):539–543PubMedCrossRefGoogle Scholar
  36. Everts R, Harvey A, Lillywhite L, Wrennall J, Abbott D, Gonzalez L, Kean M, Jackson G, Anderson V (2010) Language lateralization correlates with verbal memory performance in children with focal epilepsy. Epilepsia 51(4):627–638PubMedCrossRefGoogle Scholar
  37. Fisher R, Van Emde Boas W, Blume W, Elger C, Genton P, Lee P, Engel J (2005) Epileptic seizures and epilepsy: definitions proposed by the International League Against Epilepsy (ILAE) and the International Bureau for Epilepsy (IBE). Epilepsia 46(4):470–472PubMedCrossRefGoogle Scholar
  38. Fox P, Raichle M (1986) Focal physiological uncoupling of cerebral blood flow and oxidative metabolism during somatosensory stimulation in human subjects. Proc Natl Acad Sci USA 83(4):1140–1144PubMedCentralPubMedCrossRefGoogle Scholar
  39. Gao J, Hu J, wen Tung W (2011) Complexity measures of brain wave dynamics. Cogn Neurodyn 5(2):171–182PubMedCentralPubMedCrossRefGoogle Scholar
  40. George M, Costa D, Kouris K, Ring H, Ell P (1992) Cerebral blood flow abnormalities in adults with infantile autism. J Nerv Ment Dis 180(7):413–417PubMedCrossRefGoogle Scholar
  41. Ghajar J (2000) Traumatic brain injury. Lancet 356(9233):923–929PubMedCrossRefGoogle Scholar
  42. Giller C, Bowman G, Dyer H, Mootz L, Krippner W (1993) Cerebral arterial diameters during changes in blood pressure and carbon dioxide during craniotomy. Neurosurgery 32(5):737–742PubMedCrossRefGoogle Scholar
  43. Gonzalez F, Chang J, Banovac K, Messina D, Martinez-Arizala A, Kelley R (1991) Autoregulation of cerebral blood flow in patients with orthostatic hypotension after spinal cord injury. Paraplegia 29:1–7PubMedCrossRefGoogle Scholar
  44. Han C-X, Wang J, Yi G-S, Che Y-Q (2013) Investigation of EEG abnormalities in the early stage of Parkinson’s disease. Cogn Neurodyn 7(4):351–359PubMedCentralPubMedCrossRefGoogle Scholar
  45. Hartje W, Ringelstein E, Kistinger B, Fabianek D, Willmes K (1994) Transcranial Doppler ultrasonic assessment of middle cerebral artery blood flow velocity changes during verbal and visuospatial cognitive tasks. Neuropsychologia 32(12):1443–1452PubMedCrossRefGoogle Scholar
  46. Hayman G, Govindarajulu Z, Leone F, Kim P, Jennrich R (1970) Selected tables in mathematical statistics. American Mathematical Society, ProvidenceGoogle Scholar
  47. Hilton M (1997) Wavelet and wavelet packet compression of electrocardiograms. IEEE Trans Biomed Eng 44(5):394–402PubMedCrossRefGoogle Scholar
  48. Hirtz D, Thurman D, Gwinn-Hardy K, Mohamed M, Chaudhuri A, Zalutsky R (2007) How common are the “common” neurologic disorders? Neurology 68(5):326–337PubMedCrossRefGoogle Scholar
  49. Hosking J (1990) L-moments: analysis and estimation of distributions using linear combinations of order statistics. J R Stat Soc Ser B (Methodol) 52(1):105–124Google Scholar
  50. Houtman S, Serrador J, Colier W, Strijbos D, Shoemaker K, Hopman M (2001) Changes in cerebral oxygenation and blood flow during LBNP in spinal cord-injured individuals. J Appl Physiol 91(5):2199–2204PubMedGoogle Scholar
  51. Hu J, Gao J, Principe J (2006) Analysis of biomedical signals by the Lempel–Ziv complexity: the effect of finite data size. IEEE Trans Biomed Eng 53(12):2606–2609PubMedCrossRefGoogle Scholar
  52. Joo E, Tae W, Hong S (2008) Cerebral blood flow abnormality in patients with idiopathic generalized epilepsy. J Neurol 255(4):520–525PubMedCrossRefGoogle Scholar
  53. Kelley R, Chang J, Scheinman N, Levin B, Duncan R, Lee S (1992) Transcranial Doppler assessment of cerebral flow velocity during cognitive tasks. Stroke 23(1):9–14PubMedCrossRefGoogle Scholar
  54. Knake S, Haag A, Hamer H, Dittmer C, Bien S, Oertel W, Rosenow F (2003) Language lateralization in patients with temporal lobe epilepsy: a comparison of functional transcranial Doppler sonography and the Wada test. NeuroImage 19(3):1228–1232PubMedCrossRefGoogle Scholar
  55. Knecht S, Deppe M, Ebner A, Henningsen H, Huber T, Jokeit H, Ringelstein E (1998) Noninvasive determination of language lateralization by functional transcranial Doppler sonography. Stroke 29(1):82–86PubMedCrossRefGoogle Scholar
  56. Krassioukov A (2009) Autonomic function following cervical spinal injury. Respir Physiol Neurobiol 169(2):157–164PubMedCrossRefGoogle Scholar
  57. Krejza J, Mariak Z, Walecki J, Szydlik P, Lewko J, Ustymowicz A (1999) Transcranial color Doppler sonography of basal cerebral arteries in 182 healthy subjects: age and sex variability and normal reference values for blood flow parameters. J Cereb Blood Flow Metab 172(1):213–218Google Scholar
  58. Larsen F, Olsen K, Hansen B, Paulson O, Knudsen G (1994) Transcranial Doppler is valid for determination of the lower limit of cerebral blood flow autoregulation. Stroke 25(10):1985–1988PubMedCrossRefGoogle Scholar
  59. Lee J, Sejdić E, Steele C, Chau T (2010) Effects of liquid stimuli on dual-axis swallowing accelerometer signals in a healthy population. Biomed Eng Online 9(1):7PubMedCentralPubMedCrossRefGoogle Scholar
  60. Lempel A, Ziv J (1976) On the complexity of finite sequences. IEEE Trans Inf Theory 22(1):75–81CrossRefGoogle Scholar
  61. Li M, Huang H, Boninger M, Sejdić E (2014) An analysis of cerebral blood flow from middle cerebral arteries during cognitive tasks via functional transcranial Doppler recordings. Neurosci Res 84:19–26PubMedCrossRefGoogle Scholar
  62. Lindegaard K, Lundar T, Wiberg J, Sjøberg D, Aaslid R, Nornes H (1987) Variations in middle cerebral artery blood flow investigated with noninvasive transcranial blood velocity measurements. Stroke 18(6):1025–1030PubMedCrossRefGoogle Scholar
  63. Markwalder T, Grolimund P, Seiler R, Roth F, Aaslid R (1984) Dependency of blood flow velocity in the middle cerebral artery on end-tidal carbon dioxide partial-pressure. a transcranial ultrasound Doppler study. J Cereb Blood Flow Metab 4(3):368–372PubMedCrossRefGoogle Scholar
  64. Marmarou A, Anderson R, Ward J, Choi S, Young H, Eisenberg H, Foulkes M, Marshall L, Jane J (1991) Impact of ICP instability and hypotension on outcome in patients with severe head trauma. J Neurosurg 75(1s):S59–S66Google Scholar
  65. Morris J, Roth E, Davidoff G (1986) Mild closed head injury and cognitive deficits in spinal-cord-injured patients: incidence and impact. J Head Trauma Rehabil 1(2):31–42CrossRefGoogle Scholar
  66. Morris M, Scherr P, Hebert L, Bennett D, Wilson R, Glynn R, Evans D (2002) Association between blood pressure and cognitive function in a biracial community population of older persons. Neuroepidemiology 21(3):123–130PubMedCrossRefGoogle Scholar
  67. Nanda R, Wyper D, Harper A, Johnson R (1974) Cerebral blood flow in paraplegia. Paraplegia 12:212–218PubMedCrossRefGoogle Scholar
  68. Nishida H, Takahashi M, Lauwereyns J (2014) Within-session dynamics of theta–gamma coupling and high-frequency oscillations during spatial alternation in rat hippocampal area CA1. Cogn Neurodyn 7(5):363–372CrossRefGoogle Scholar
  69. Oja H (1990) Descriptive statitics for multivariate distributions. Stat Probab Lett 1(6):327–332CrossRefGoogle Scholar
  70. Papoulis A (1991) Probability, random variables, and stochastic processes. WCB/McGraw-Hill, New YorkGoogle Scholar
  71. Phillips A, Ainslie P, Krassioukov A, Warburton D (2013) Regulation of cerebral blood flow after spinal cord injury. J Neurotrauma 30:1551–1563PubMedCrossRefGoogle Scholar
  72. Pincus S, Gladstone I, Ehrenkranz R (1991) A regularity statistic fore medical data analysis. J Clin Monit 7(4):335–345PubMedCrossRefGoogle Scholar
  73. Porta A, Baselli G, Liberati D, Montano N, Cogliati C, Gnecchi-Ruscone T, Malliani A, Cerutti S (1998) Measuring regularity by means of a corrected conditional entropy in sympathetic outflow. Biol Cybern 78(1):71–78PubMedCrossRefGoogle Scholar
  74. Porta A, Guzzetti S, Montano N, Pagani M, Somers V, Malliani A, Baselli G, Cerutti S (2000) Information domain analysis of cardiovascular variability signals: evaluation of regularity, synchronisation and co-ordination. Med Biol Eng Comput 38(2):180–188PubMedCrossRefGoogle Scholar
  75. Porta A, Guzzetti S, Montano N, Furlan R, Pagani M, Somers V (2011) Entropy, entropy rate, and pattern classification as tools to typify complexity in short heart period variability series. IEEE Trans Inf Theory 48(11):1282–1291Google Scholar
  76. Rasmussen T, Milner B (1977) The role of early left-brain injury in determining lateralization of cerebral speech functions. Ann NY Acad Sci 299:355–369PubMedCrossRefGoogle Scholar
  77. Reid J, Spencer M (1972) Ultrasonic Doppler technique for imaging blood vessels. Science 176(4040):1235–1236PubMedCrossRefGoogle Scholar
  78. Rombouts S, Goekoop R, Stam C, Barkhof F, Scheltens P (2005) Delayed rather than decreased BOLD response as a marker for early Alzheimer’s disease. NeuroImage 26(4):1078–1085PubMedCrossRefGoogle Scholar
  79. Rosso O, Blanco S, Yordanova J, Kolev V, Figliola A, Schrmann M, Basar E (2001) Wavelet entropy: a new tool for analysis of short duration brain electrical signals. J Neurosci Methods 105(1):65–75PubMedCrossRefGoogle Scholar
  80. Sadowsky C, Volshteyn O, Schultz L, McDonald J (2002) Spinal-cord injury. Disabil Rehabil 24(13):680–687PubMedCrossRefGoogle Scholar
  81. Schmidt P, Krings T, Willmes K, Roessler F, Reul J, Thron A (1999) Determination of cognitive hemispheric lateralization by “functional” Transcranial Doppler cross-validated by functional MRI. Stroke 30(5):939–945PubMedCrossRefGoogle Scholar
  82. Schneider P, Rossman M, Bernstein E, Torem S, Ringelstein E, Otis S (1988) Effect of internal carotid artery occlusion on intracranial hemodynamics. Transcranial Doppler evaluation and clinical correlation. Stroke 19(5):589–593PubMedCrossRefGoogle Scholar
  83. Scott J, Warburton D, Williams D, Whelan S, Krassioukov A (2011) Challenges, concerns and common problems: physiological consequences of spinal cord injury and microgravity. Spinal Cord 49(1):4–16PubMedCrossRefGoogle Scholar
  84. Scott Burgin W, Malkoff M, Felberg R, Demchuk A, Christou I, Grotta J, Alexandrov A (2000) Transcranial Doppler ultrasound criteria for recanalization after thrombolysis for middle cerebral artery stroke. Stroke 31(5):1128–1132CrossRefGoogle Scholar
  85. Sejdić E, Djurović I, Jiang J (2009) Time-frequency feature representation using energy concentration: an overview of recent advances. Digit Signal Proc 19(1):153–183CrossRefGoogle Scholar
  86. Sejdić E, Kalika D, Czarnek N (2013) An analysis of resting-state functional transcranial Doppler recordings from middle cerebral arteries. PLoS One 8(2):e55405-1–e55405-9CrossRefGoogle Scholar
  87. Shih W, Ashford J, Coupal J, Ryo Y, Stipp V, Magoun S, Gross K (1999) Consecutive brain SPECT surface three-dimensional displays show progression of cerebral cortical abnormalities in Alzheimer’s disease. Clin Nucl Med 24(10):773PubMedCrossRefGoogle Scholar
  88. Silvestrini M, Pasqualetti P, Baruffaldi R, Bartolini M, Handouk Y, Matteis M, Moffa F, Provinciali L, Vernieri F (2006) Cerebrovascular reactivity ad cognitive decline in patients with Alzheimer disease. Stroke 37(4):1010–1015PubMedCrossRefGoogle Scholar
  89. Soustiel J, Glenn T, Shik V, Boscardin J, Mahamid E, Zaaroor M (2005) Monitoring of cerebral blood flow and metabolism in traumatic brain injury. J Neurotrauma 22(9):955–965PubMedCrossRefGoogle Scholar
  90. Standring S (2008) Gray’s Anatomy: the anatomical basis of clinical practice. Churchill Livingstone, LondonGoogle Scholar
  91. Szirmai I, Amrein I, Pálvölgyi L, Debreczeni R, Kamondi A (2010) Evaluation of cerebrovascular spasm with transcranial Doppler ultrasound. J Neurosurg 112(2):37–41Google Scholar
  92. Tachibana H, Kawabata K, Tomino Y, Sugita M, Fukuchi M (1993) Brain perfusion imaging in Parkinson’s disease and Alzheimer’s disease demonstrated by three-dimensional surface display with \(^{123}\)I-Iodoamphetamine. Dement Geriatr Cogn Disord 4(6):334–341CrossRefGoogle Scholar
  93. Tiao G, Box G (1981) Modeling multiple time series with applications. J Am Stat Assoc 76(376):802–816Google Scholar
  94. Tzeng Y, Lucas S, Atkinson G, Willie C, Ainslie P (2010) Fundamental relationships between arterial baroflex sensitivity and dynamic cerebral autoregulation in humans. J Appl Physiol 108(5):1162–1168PubMedCrossRefGoogle Scholar
  95. Vergara L, Gosalbéz J, Fuente J, Miralles R, Bosch I (2004) Measurement of cement porosity by centroid frequency profiles of ultrasonic grain noise. Biomed Eng Online 84(12):2315–2324Google Scholar
  96. Vingerhoets G, Stroobant N (1999) Lateralization of cerebral blood flow velocity changes during cognitive task: a simultaneous bilateral transcranial Doppler study. Stroke 30(10):2152–2158PubMedCrossRefGoogle Scholar
  97. Wecht J, Rosado-Rivera D, Jegede A, Cirnigliaro C, Jensen M, Kirshblum S, Bauman W (2012) Systemic and cerebral hemodynamics during cognitive testing. Clin Auton Res 22(1):25–33PubMedCrossRefGoogle Scholar
  98. White H, Venkatesh B (2006) Applications of transcranial Doppler in the ICU: a review. Intensive Care Med 32(7):981–994PubMedCrossRefGoogle Scholar
  99. Whitehouse A, Bishop D (2008) Cerebral dominance for language function in adults with specific language impairment or autism. Brain 131(12):3193–3200PubMedCentralPubMedCrossRefGoogle Scholar
  100. Wong K, Li H, Chan Y, Ahuja A, Lam W, Wong A, Kay R (2000) Use of transcranial Doppler ultrasound to predict outcome in patients with intracranial large-artery occlusive disease. Stroke 31(11):2641–2647PubMedCrossRefGoogle Scholar
  101. Zanette E, Fieschi C, Bozzao L, Roberti C, Toni D, Argentino C, Lenzi G (1989) Comparison of cerebral angiography and transcranial Doppler sonography in acute stroke. Stroke 20(7):899–903PubMedCrossRefGoogle Scholar
  102. Zoubir A, Boashash B (1998) The bootstrap and its application in signal processing. IEEE Signal Process Mag 15(1):56–76CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media Dordrecht 2015

Authors and Affiliations

  1. 1.Department of Electrical and Computer EngineeringUniversity of PittsburghPittsburghUSA

Personalised recommendations