O46	The potential and limitations of functional TCD in the investigation of brain lateralization S. Knecht, Dept. of Neurology, University of Münster Functional Transcranial Doppler Sonography (fTCD) measures cerebral perfusion changes related to neuronal activation in a way comparable to functional magnetic resonance tomography (fMRI). FTCD contends itself with comparison of averaged, event-related blood flow velocity changes within the territories of two cerebral arteries, for example the left versus the right middle cerebral artery. It can thus serve to evaluate the functional lateralization of higher cognitive functions like hemispheric language dominance. Because of its high reliability it can be employed to substitute the invasive amobarbital procedure in order to determine language lateralization in individual patients before neurosurgical procedures. Because of its easy applicability, robustness and mobility it can also be employed for examining large numbers of subjects (including children) in order to obtain representative data on the variability of lateralization of higher cognitive functions or scan for atypical pattern of lateralization. Unlike other techniques, FTCD provides continuous information on cerebral blood flow and can detect shifts and trends related to autonomous parameters. FTCD is limited by its spatial resolution defined by the vascular territories. Caveats for fTCD, like other functional imaging techniques, are that the validity of results depends on adequate control of the task parameters, particularly cooperation and reference condition, and that caution must be exerted when inferring from patterns of activation to patterns of deficits following brain damage.
O47	USE OF FUNCTIONAL TRANSCRANIAL DOPPLER FOR THE EARLY PREDICTION OF RECOVERY AFTER STROKE M.Silvestrini, R.Baruffaldi Department of Neurology University of Ancona, Italy Background: Flow velocity changes detected with fTCD reflect blood volume changes induced by cerebral activity. In subjects with focal brain lesion, fTCD investigation could allow to determine patterns of rehorganization of cerebral function. Methods: During bilateral monitoring of MCAs mean flow velocity, 50 patients with an ischemic lesion in the left or right hemisphere were submitted to a protocol of cognitive and motor stimulations, including verbal, visuo-spatial and passive movements tasks. Patients were examined within two weeks from stroke occurrence. Results: During each specific task, the possibility to activate the lesioned area, as demonstrated by a significant increase in flow velocity in the corresponding MCA, was only present in patients who showed a good functional recovery in the following two months. Conclusions: f TCD offers the potential for a non-invasive, reliable and cost-effective detection of cerebral functional activity changes in the presence of an ischemic injury. These data seem to be interesting for the possibility to support early prognostic indications.
O48	EMOTIONAL PROCESSING IN PARKINSON DISEASE: A STUDY using functional transcranial doppler sonography E. Troisi, MD^1, A. Peppe, PhD^1, M. Pierantozzi, PhD^2, M. Matteis, PhD^1, F. Vernieri, MD^2,4, P. Stanzione MD^2, M. Silvestrini, MD^3, C. Caltagirone, MD^1,2 ^1Fondazione IRCCS S. Lucia , Rome; ^2Neurological Clinic, Tor Vergata University of Rome; ^3 Neurological Clinic, University of Ancona; ^4 AFaR: Neurology Division - Fatebenefratelli Hospital, Isola Tiberina, Rome Background: This study evaluated the use of transcranial Doppler ultrasonography for detecting selective changes in cerebral blood flow velocity during emotional processes. The aim was to investigate the possibility of obtaining functional information on the neuropsychology of emotions in patients with Parkinson disease (PD). Methods: Blood flow velocity changes were investigated in both Middle Cerebral Arteries (MCA) during a rest condition and when viewing non emotional (tasks 1 and 3) and emotional (task 2) slide sequences. The study included 12 PD patients and 12 healthy subjects. All patients were in treatment with Levodopa or dopamine agonist. Investigation of PD patients was performed during an on-phase. Results: The three tasks produced significantly different effects on the right and left side in the PD patients compared to the control group. During the two non emotion-related tasks the increase of MFV compared to the basal values was similar in the two middle cerebral arteries in both groups [( PD Patients: Task 1: left MCA = 3.95 % +/- 2.2; Right MCA= 4.33% +/- 2.3; Task 3: left MCA = 3.04% +/- 1.9; Right MCA= 2.71% +/- 2.2) (control group: Task 1: left MCA = 4.57% +/- 1.4; Right MCA= 4.46% +/- 1.7; Task 3: left MCA = 2.32% +/- 0.9; Right MCA= 2.52% +/- 1.2)]; the negative emotional task was accompanied by a significantly higher increase in the right (10.53 % +/- 3.2) than in the left middle cerebral artery (4.52% +/- 1.51) only in the control group. In fact, the PD patients showed a bilateral and symmetrical increase of MFV (Left MCA = 4.28% +/- 2.3 and right MCA 5.77% +/-3.8). To determine whether there was a dysfunction in cerebrovascular reactivity and a deficit in the ability to activate both hemispheres in response to non emotion-related stimuli in the PD patients, the protocol study included a cerebrovascular reactivity test to apnea, a motor task (thumb-to-finger opposition), a cognitive task (word fluency and visual discrimination of objects), performed by both patients and controls. The pattern of MFV changes during these tasks was not statistically different in the two experimental groups. In order to evaluate the possible influence of drug treatment on cerebrovascular reactivity, seven patients were also evaluated during an off-phase, after a 48-hour wash-out period. Changes in MFV during every task were similar to that observed during the on-phase. Conclusions: These results show the possibility of obtaining specific functional information from bilateral transcranial Doppler and suggest the selective and specific deficit of PD patients in emotional processing.
O49	Changes of cerebral blood flow velocity during gestures with or without meaning. A functional Transcranial doppler study. M. Matteis^1, C. Caltagirone^1,2, E. Troisi^1, F. Federico^1,3, M. Silvestrini^4, L. Petrosini^3. ^1IRCCS S. Lucia, Roma ; ^2Clinica Neurologica, Università di Roma "Tor Vergata"; ^3Dipartimento di Psicologia, Università di Roma "la Sapienza"; ^4Clinica Neurologica,Università di Ancona Background: The aim of the study was to investigate with functional Transcranial doppler the possibility to reveal different activation patterns during the performance of meaningful and meaningless actions in healthy subjects. Methods: Mean flow velocity changes were recorded in middle cerebral arteries (MCAs) of fifteen normal subjects during a rest phase and during performing meaningful and meaningless actions. The meaningful task was the action of pouring the sugar into the cup with a tea-spoon. The meaningless action was the imitation of a movement of arm similar to that is necessary for pouring the sugar in a cup but without no goal. Results: During performing the meaningful action mean flow velocity (MFV) in MCAs increased significantly more then during performing meaningless similar action (p<0.001). While during the meaningless action MFV increased more significantly in contralateral than in ipsilateral MCA to the arm performing the task ( right arm: left MCA = 7.14 %; right MCA = 3.96 %; left arm: left MCA = 3.85 %; right MCA = 6.87 %), the meaningful action determined bilateral increase of MFV only when the task was performed with the left arm. In fact, when the meaningful task was performed with right arm, the increase of MFV was significantly higher in the contralateral MCA (right arm: left MCA = 11.28 %; right MCA = 7.1 %; left arm: left MCA = 13.71 %; right MCA = 12.21 %). Conclusions: The activation of the ipsilateral hemisphere during the execution of meaning movements with the left arm, can be explained with the important role of the left hemisphere in the gesture organisation. The results of our study suggest that Transcranial doppler could provide useful complementary information for comprehension changes in cerebral activity during motor tasks with different action contents (meaningful vs. meaningless).
O50	CAROTID DISTENSIBILITY AS A MARKER OF SUBCLINICAL ATHEROSCLEROSIS: THE NORTHERN MANHATTAN COHORT STUDY T. Rundek, R. Ramas, J. Pittman, M.S. Elkind, B. Boden-Albala, R.L.Sacco Neurological Institute, Columbia University, New York, NY Objective: To determine the association between carotid distensibility (CD) and vascular risk factors in a population-based sample of stroke-free subjects. Background: Impaired vascular function is an early event in experimental studies of atherogenesis. Decreased carotid distensibility may be an important early marker of subclinical atherosclerosis and a novel risk factor for coronary heart disease and stroke. CD is currently being investigating in several large epidemiological studies in the US and Europe. Methods: Carotid distensibility was assessed as part of the Northern Manhattan Cohort Study using high-resolution B-mode ultrasound according to the standard carotid distensibility protocol. The systolic and diastolic diameters (mm) of the right common carotid artery from 5 B/D-mode registrations were measured and averaged. CD was expressed as inverse of STIFFNESS ( ln [SBP / DBP] / STRAIN; where STRAIN was %change of intraluminal diameter during dilatation in systolic and contraction in diastolic phase relative to the diastolic diameter). Results: Carotid distensibility was analyzed in 313 subjects (mean age 68± 9 y; 62% women; 52% Caribbean-Hispanic, 24% African-American, 20% Caucasian). STRAIN was 7.5± 4.5% (range 1.2-27%), STIFFNESS 9.30± 7.14 (range 2.01-51.64), and CD 0.15± 0.09 (range 0.02-0.50). Hypertension was present in 52% of subjects, hypercholesterolemia in 44%, and diabetes in 13%; 19% were current smokers. In the final multivariate regression model (after inclussion of variables significantly associated with CD in univariate models), increased STIFFNESS was associated with older age (b =0.018, p<0.05), and white race-ethnicity (b =2.553, p<0.05), but not with vascular risk factors. Conclusion: Carotid distensibility may be a marker of subclinical atherosclerosis independent of other vascular risk factors. Reversal of arterial wall dysfunction may prevent plaque formation, and reduce the risk of stroke or coronary heart disease. Carotid distensibility may be a useful method in assessing vascular risk and serve as a surrogate end-point for vascular events in interventional trials.
O51	NEUROVASCULAR COUPLING IN HEALTHY ADULTS UNDER DIFFERENT POSTURAL CONDITIONS AS EVALUATED BY FUNCTIONAL TCD E. Azevedo^1, B. Rosengarten^3, R. Santos^1, J. Freitas^2, M. Kaps^3 Neurosonology^1 and Autonomic Units^2, Hospital S. João, University of Porto, Portugal and Neurology Department^3, University of Giessen, Germany Background: Neurovascular coupling adapts cerebral blood flow to cortical activity. Cerebral autoregulation adapts cerebral blood flow to arterial blood pressure. Using a control system approach for data analysis we aimed to investigate the influence of different postural conditions and thus orthostatic stress on the neurovascular coupling. Methods: We enrolled 15 healthy adult volunteers without cardiovascular risk factors or on drug medication. The individuals performed a visual stimulation task with a reading test while they were sitting, supine and upright in a tilt table. Simultaneously they were monitored with Finapres for systemic blood pressure and heart rate, and with transcranial Doppler for blood flow velocity in the left PCA P2 segment and right MCA. We used a recently introduced control system approach to study the evoked flow curve. The parameters studied were flow velocity with eyes closed, stable flow velocity under stimulation, oscillatory feature of the assumed control system model, dumping of the system and rate time. ANOVA test was used for comparing the values of the variables in the different postural settings, inferring statistical significance at a p<0,05 level. Results: Although there was a significant variation with the different orthostatic conditions in the values of systolic (p=0,027) and diastolic (p=0,001) systemic blood pressure and heart rate (p=0,0001), there was no significant change in the cerebral blood velocities. Furthermore, no statistical significant difference occurred in the evoked flow curve for the studied parameters under the three postural settings. Conclusions: Functional cerebral flow regulation seems to be unaffected by postural variation, which is indicative for a wide compensatory range of static autoregulation to maintain adequate cerebral blood flow even in conditions when the neurovascular coupling mechanism is active. As long as cerebral autoregulation is assumed to be intact functional neurovascular coupling tests are independent from the postural condition.
O52	Missing Correlation of Intracranial Blood Flow Velocities and Carotid Volume Flow after Subarachnoid Hemorrhage Eicke BM, Valerius CH, Kerz Th* Dept. of Neurology, *Dept. of Neurosurgery, University of Mainz, Germany Background: Transcranial Doppler has been applied to detect cerebral vasospasm following subarachnoid hemorrhage. Recently, it has been shown by comparitive SPECT and TCD studies that increased flow velocities may indicate both, hypoperfusion due to vasospasm but also hyperperfusion due to an impaired autoregulation. Methods: To differentiate between a hypo and hyperperfusion state noninvasively we studied 14 patients (mean age 58, range 38-76 yrs.) with nontraumatic subarachnoid hemorrhage. These patients were studied within 3 days post hemorrhage (baseline) and 5-7 days after the acute event. We correlated the intracranial flow velocities in the middle and anterior cerebral artery (TCD) with the extracranial volume flow rate in the common carotid artery as obtained by gray scale duplex scanning. Results: We found no correlation between changes of intracranial flow velocities and changes of extracranial volume flow rate (r^2=0.0017). Two patients developed flow velocities with mean flow velocities exceeding 120 cm/s in all four vessels insonated. Volume flow rate decreased in one of these patients by 18%, in the other it increased by 24%. Conclusion: The TCD based diagnosis of cerebral vasospam in patients with subarachnoid hemorrhage is not valid without further hemodynamic evaluation of the individual patient. An alternative method to SPECT is the assessment of the extracranial volume flow rate (duplex scanning of the carotid arteries) to differentiate between a hypo and hyperperfusion state. This approach is non-invasive, reliable, does not require radioactive substances and can be performed as a bedside investigation on the ICU.