bluuebunny/crossref_metadata_2025 huggingface dataset:
Neurological and Functional Outcome in Patients With Supratentorial Hemorrhages
Authors: Lampl Yair , Gilad Ronit , Eshel Yehiel , Sarova-Pinhas Ida
Published: June 2011

Background and Purpose
A prospective study was performed to evaluate neurological and functional outcome after spontaneous supratentorial bleeding. The aim of the study was to determine whether clinical or neuroradiological parameters could predict the outcome of these patients during the first hours of hospitalization.

Methods
Two hundred seventy-nine patients—52 with thalamic, 87 with putaminal, and 140 with lobar hemorrhages—were followed prospectively and examined on admission and at 2 weeks, 3 months, and 6 months after onset. The patients underwent clinical (according to the Glasgow Coma Scale) and neuroradiological examinations on admission and were scored clinically and functionally (according to Stroke Severity score and Barthel Index) on the follow-up periods. Risk factors and the correlation between findings on admission and the latest clinical and functional results were calculated with the χ
2
test, Pearson correlation test, and Student’s
t
test. Multivariate analysis was calculated with the stepwise regression test.

Results
In all of the bleeding locations, lethal outcome was significantly correlated with size of the hematoma (
P
<.001) and Glasgow Coma Scale score on admission (
P
<.001). Intraventricular blood expansion was found to have a better prognosis in thalamic bleeding (
P
<.007) and a worse prognosis in lobar hemorrhage (
P
<.01). The functional outcome after 6 months was directly correlated with the size of the bleeding area in lobar and putaminal hemorrhages. No correlation was found in thalamic bleeding. A worse functional outcome was found in putaminocapsular bleeding (
P
=.004) and in patients with ischemic heart disease. A limited better recovery prognosis was found in patients with lobar hematoma in the temporal lobe (
P
=.052).

Conclusions
The probability of lethal outcome can be calculated on admission in all patients with supratentorial bleeding and in correlation with the location and size of the bleeding area and level of consciousness. Intraventricular expansion of blood is a better prognostic factor in thalamic bleeding and a worse one in lobar hematoma. Functional outcome is correlated with size of the bleeding area and level of consciousness on admission in putaminal and lobar hemorrhages but has no correlation to thalamic hemorrhage.
Amphetamine Paired With Physical Therapy Accelerates Motor Recovery After Stroke
Authors: Walker-Batson Delaina , Smith Patricia , Curtis Sandra , Unwin Hal , Greenlee Ralph
Published: June 2011

Background and Purpose
In animal models of brain injury, administration of numerous pharmaceuticals is reported to facilitate functional recovery. However, only drugs that increase the release of norepinephrine have been shown to promote recovery when administered late (days to weeks) after injury. To determine whether these findings were applicable to humans, we administered the norepinephrine stimulant dextroamphetamine, paired with physical therapy, to hemiplegic stroke patients.

Methods
Ten hemiplegic patients who suffered an acute ischemic infarction were entered between days 16 and 30 after onset and randomly assigned to receive either 10 mg of dextroamphetamine or a placebo orally every fourth day for 10 sessions paired with physical therapy. The Fugl-Meyer Motor Scale was used at baseline, within each session, and for 12 months after onset as the dependent measure. Confounding medications such as α-adrenergic antagonists or agonists were excluded in all subjects.

Results
Although there were no differences between the groups at baseline (
P
=.599), there was a significant (
P
=.047) difference between the groups when the drug had been discontinued for 1 week and at the 12-month follow-up visit (
P
=.047).

Conclusions
Administration of dextroamphetamine paired with physical therapy increased the rate and extent of motor recovery in a small group of hemiplegic stroke patients. These data support and extend previous findings of the facilitatory aspects of certain types of drugs on recovery from brain injury. The use of neuromodulation may allow the nervous system to adapt previously unused or alternative pathways to relevant external input.
Can Cerebrovascular Reactivity Be Measured With Near-Infrared Spectroscopy?
Authors: Smielewski Peter , Kirkpatrick Peter , Minhas Paven , Pickard John D. , Czosnyka Marek
Published: June 2011

Background and Purpose
We used near-infrared spectroscopy (NIRS) to monitor the cerebral oxygenation changes during CO
2
reactivity tests.

Methods
Fifty healthy volunteers were examined (age range, 19 to 68 years). The monitored parameters were as follows: transcranial Doppler (TCD) time-averaged middle cerebral artery flow velocity end-tidal CO
2
(Et
co
2
); change in concentration of cerebral oxyhemoglobin (Hb
o
2
), deoxyhemoglobin (Hb), and total hemoglobin; mean arterial blood pressure; peripheral arterial oxygen saturation (Sa
o
2
); and extracranial tissue perfusion with the use of cutaneous laser-Doppler flowmetry. The examination protocol included both hypercapnia and hypocapnia. The cerebrovascular reactivity indexes were calculated as follows: TCD, relative change in flow velocity per 1 kPa increase in Et
co
2
; NIRS, absolute change in Hb
o
2
, Hb, and total hemoglobin concentration (micromoles per liter) per 1 kPa increase in Et
co
2
.

Results
Mean middle cerebral artery flow velocity was found to be 58 cm/s at a mean baseline Et
co
2
of 4.7 kPa. Mean cerebrovascular reactivities were as follows: TCD, 24%/kPa (SEM, 1.1); Hb
o
2
, 2.06 μmol/L per kilopascal (SEM, 0.08); Hb, −0.63 μmol/L per kilopascal (SEM, 0.09); and total hemoglobin concentration, 1.44 μmol/L per kilopascal (SEM, 0.1). Statistical analysis revealed significant correlation between reactivities calculated with the use of NIRS and TCD (
P
<.001). Although some fluctuations were observed in Sa
o
2
and laser-Doppler flux, they were not correlated with either Et
co
2
or NIRS.

Conclusions
NIRS signal changes in Hb
o
2
, Hb, and total hemoglobin concentration are very sensitive to alterations in Et
co
2
, which are largely independent of extracranial tissue perfusion. NIRS may be developed as an alternative method for testing cerebrovascular reactivity and may be of particular clinical importance when the ultrasound window is poor.
Application of Transcranial Doppler Sonography to Evaluate Cerebral Hemodynamics in Carotid Artery Disease
Authors: Hartl Wolfgang H. , Fürst Heinrich
Published: June 2011

Background and Purpose
Transcranial Doppler sonography in combination with manipulation of cerebral resistance vessels is widely used to screen patients with suspected intracranial hemodynamic disturbances. Maximal flow velocity (V
max
), mean flow velocity (V
mean
), cerebral pulsatility index (CP
i
), and cerebral resistance index (CR
i
) have all been used to describe cerebral hemodynamics. The present study examined CO
2
reactivity of the above hemodynamic variables with respect to its variability between different age groups and its capability to discriminate between normal and abnormal findings.

Methods
Absolute and relative CO
2
reactivity of V
max
, V
mean
, CR
i
, and CP
i
were determined in both hemispheres in 30 young and 37 elderly control subjects and in 245 consecutive patients with strictly unilateral symptomatic (n=101) or asymptomatic (n=144) carotid artery disease (>80% stenosis or occlusion).

Results
Hemispheric reactivities of V
mean
, CR
i
, and CP
i
were significantly age dependent. Hemispheric V
max
reactivity and interhemispheric differences of individual reactivities (except absolute CP
i
reactivity) did not vary with age and could therefore be used to define normal values. Patient classification according to these values revealed different frequencies of subjects with pathological findings (3% for hemispheric V
max
reactivity, 5% to 7% for interhemispheric differences of V
max
or V
mean
reactivity, 39% and 45% for interhemispheric differences of relative CR
i
and CP
i
reactivity, respectively).

Conclusions
Hemispheric reactivities are less suitable to evaluate cerebral hemodynamics than interhemispheric differences, since most of the latter do not vary with age. However, interhemispheric differences vary with respect to their discriminatory power. Power is low for interhemispheric differences of V
max
and V
mean
reactivity, since the corresponding frequencies of abnormal findings do not differ from the 5% frequency expected in the reference population (reference range defined as mean±2 SD). With respect to the discriminatory power, interhemispheric differences of relative CR
i
and CP
i
reactivity may be superior to other parameters.
Activity of Smooth Muscle Phosphatases 1 and 2A in Rabbit Basilar Artery in Vasospasm
Authors: Fukami Masahiro , Tani Eiichi , Takai Akira , Yamaura Ikuya , Minami Nobutaka
Published: June 2011

Background and Purpose
Subarachnoid hemorrhage frequently leads to a long-term cerebral artery narrowing called vasospasm. Recently, the involvement of myosin light chain kinase has been found in experimental vasospasm in our laboratory. We therefore measured the activity of serine/threonine protein phosphatases 1 and 2A in the rabbit basilar artery in vasospasm and in vasocontraction to study their role, particularly in regard to vasospasm compared with vasocontraction.

Methods
Vasospasm was produced in the rabbit basilar artery by a two-hemorrhage method. Vasocontraction was induced by local application of KCl or serotonin to the rabbit basilar artery after a transclival exposure. The control animals were treated with saline instead of fresh blood. Serine/threonine protein phosphatase activity in the basilar artery was assayed with the use of [
32
P]phosphorylase-a as a substrate; protein phosphatase 1 activity was evaluated as protein phosphatase activity in the presence of 1 nmol/L okadaic acid, whereas protein phosphatase 2A activity was assessed as protein phosphatase activity inhibited by 1 nmol/L okadaic acid.

Results
Values of mean activity of protein phosphatase 1 in myofibrillar extract were 3.58±0.26 nmol/min per milligram in the control group, 3.22±0.12 nmol/min per milligram in the spastic group on day 2, and 3.01±0.16 nmol/min per milligram in the spastic group on day 4 (a significant decrease in protein phosphatase 1 activity in the spastic group on days 2 and 4). In contrast, these values did not show any significant changes in the KCl and serotonin groups. Values of mean activity of protein phosphatase 2A in cytosolic extract were 0.90±0.07 nmol/min per milligram in the control group, 0.75±0.10 nmol/min per milligram in the spastic group on day 2, and 0.62±0.17 nmol/min per milligram in the spastic group on day 4 (a significant reduction in protein phosphatase 2A in the spastic group on days 2 and 4). There was no evidence of significant changes of protein phosphatase 2A in cytosolic extract in the KCl and serotonin groups.

Conclusions
Protein phosphatase 1 in myofibrillar extract is reported to catalyze the dephosphorylation of myosin light chain and calponin, whereas protein phosphatase 2A in cytosolic extract catalyzes the dephosphorylation of calponin and caldesmon. In addition, the phosphorylation of calponin and caldesmon results in the loss of their ability to inhibit smooth muscle contraction. Therefore, the significant decrease in activity of protein phosphatases 1 and 2A in vasospasm may result in uninterrupted vascular smooth muscle contraction by the preservation of phosphorylation of not only myosin light chain but also calponin and caldesmon.
Contrast-Enhanced Transcranial Imaging
Authors: Otis Shirley , Rush Michael , Boyajian Robert
Published: June 2011

Background and Purpose
Pulsed color Doppler imaging of cerebrovascular structures permits rapid visual identification of the intracranial vessels. In some patients, however, the clinical utility of transcranial ultrasound examinations is limited by poor tissue penetration and inadequate imaging of vessels. This phase-two clinical trial evaluates whether administration of an echocontrast agent in such ultrasound-refractory patients enhances image acquisition enough to yield meaningful diagnostic impressions.

Methods
This is a phase-two clinical trial of safety and efficacy of the “galactose/palmitic acid–based microbubble preparation” Levovist injection (Berlex Laboratories). Thirty subjects with clinical indications for cerebrovascular imaging but refractory to transcranial Doppler studies were enrolled in a nonrandomized, single-center study. Echocontrast agent was administered intravenously in a tiered-dose protocol. Safety was determined by clinical and laboratory monitoring for 18 to 24 hours. Efficacy of contrast enhancement was determined by comparisons between each patient’s precontrast (control) and postcontrast images.

Results
No significant patient discomfort, side effects, or adverse reactions occurred that were due to the intravenous administration of the echocontrast agent. Optimal image enhancement was obtained using the 300-mg/mL concentration (3 g bolus) of contrast. Visualization of both individual arterial segments and/or the entire circle of Willis was demonstrated. Clinical confidence of diagnostic impressions was achieved in 77% (23/30) of subjects.

Conclusions
The transpulmonary ultrasound contrast agent (Levovist injection) was easily administered and found to be safe in the 30 patients studied and increased the diagnostic utility of transcranial ultrasound in 77% of the patients studied.
Detection of Cerebral Microemboli by Means of Transcranial Doppler Monitoring Before and After Carotid Endarterectomy
Authors: van Zuilen Erik V. , Moll Frans L. , Vermeulen Freddie E.E. , Mauser Henk W. , van Gijn Jan , Ackerstaff Rob G.A.
Published: June 2011

Background and Purpose
The main purpose of carotid endarterectomy (CEA) for neurologically symptomatic high-grade extracranial carotid artery stenosis is to remove the suspected source of cerebral microemboli. Transcranial Doppler (TCD) ultrasonography has the potential for detecting solid microemboli in the basal cerebral arteries. Therefore, TCD monitoring provides the opportunity to assess the rate of microemboli to the brain in patients with symptomatic high-grade carotid artery stenosis and to verify whether these phenomena have ceased after CEA.

Methods
TCD monitoring was performed in 41 patients to detect high-intensity transient signals indicating microemboli in the middle cerebral artery before and after CEA. In the event that, within 1 week after CEA, TCD monitoring revealed ongoing cerebral microemboli on the side of surgery, the examination was repeated 3 months later.

Results
High-intensity transient signals were detected preoperatively on the side of the affected carotid artery in 22 patients (54%; mean, 10.2 per hour; range, 1 to 88). Linear regression analysis demonstrated a trend toward an inverse relationship between the number of high-intensity transient signals per hour and the time interval since the last episode of neurological symptoms (
P
<.1). CEA resulted in a significant reduction in the number of high-intensity transient signals per hour 7 days after surgery (mean, 6.0 versus 0.4 per hour; median, 0 versus 0; n=37;
P
<.005) and 3 months later (mean, 6.3 versus 0 per hour; median, 1.3 versus 0; n=41;
P
<.0001).

Conclusions
Clearly, TCD monitoring can be helpful in assessing the effect of CEA in removing the suspected source of cerebral microemboli. Ongoing microemboli to the brain should prompt reassessment of the operated carotid artery or a search for other potential sources of cerebral embolism. Carotid artery plaques seem to produce cerebral microemboli for a limited period, which implies that the prophylactic effect of CEA might decrease if the operation is delayed.
Collagenase-Induced Intrastriatal Hemorrhage in Rats Results in Long-term Locomotor Deficits
Authors: Chesney J. A. , Kondoh T. , Conrad J. A. , Low W. C.
Published: June 2011

Background and Purpose
Previous studies have shown that injection of the metalloproteinase collagenase directly into the caudate nucleus of rats causes an intracerebral hemorrhage. The purpose of the present study is to determine functional deficits associated with a collagenase-induced hemorrhagic lesion of the striatum.

Methods
Twelve adult rats received a 2-μL infusion of bacterial collagenase (0.5 U in saline) into the right striatum. The rotational response to apomorphine (1 mg/kg SC) administration was then examined at 1, 4, 7, 21, 35, and 70 days after the surgery. In addition to the rotational asymmetry studies, the initiation of stepping movements in each forelimb was determined 8 weeks after the collagenase injections. In the assessment of rotational asymmetry and stepping ability, an additional six control animals received unilateral injections of saline alone. After behavioral testing, brains were processed for neuropathological evaluation.

Results
A net ipsilateral rotation was noted at all posthemorrhage time periods. The average rotational asymmetries on these days were 14.57±2.9, 20.33±2.7, 19.99±4.4, 18.95±4.9, 17.03±4.9, and 14.4±4.7, respectively (data expressed as mean clockwise rotations per 5 minutes ±SEM). The average number of steps initiated by the forelimb ipsilateral and contralateral to the lesion was 28.3±2.1 steps per minute and 13.6±1.5 steps per minute, respectively. This difference between left and right forelimb stepping was stable and reproducible for 3 consecutive days. Histological studies revealed a long-lasting hematoma cavity surrounded by dense reactive gliosis in the striatum.

Conclusions
We conclude that collagenase-induced intrastriatal hemorrhage results in long-term locomotor deficits and is therefore a useful model for developing and assessing therapeutic approaches for the restoration of neurological function after intracerebral hemorrhage.
Multinational Comparisons of Stroke Epidemiology
Authors: Asplund Kjell , Bonita Ruth , Kuulasmaa Kari , Rajakangas Anna-Maija , Feigin Valeri , Schaedlich Helmut , Suzuki Kazuo , Thorvaldsen Per , Tuomilehto Jaakko
Published: June 2011

Background and Purpose
As part of the WHO MONICA Project (World Health Organization
Moni
toring Trends and Determinants in
Ca
rdiovascular Disease), mortality and incidence rates of acute stroke in 14 centers covering 21 populations from 11 countries were compared.

Methods
In this report, coverage and quality of the MONICA stroke registers were evaluated on five key indicators using data submitted to the MONICA Data Center.

Results
A low ratio of MONICA stroke register to routine statistics of stroke mortality and a low proportion of nonfatal out-of-hospital events were the most common biases; they indicate that identifications of fatal cases and/or case finding of nonfatal events occurring outside the hospital were inadequate in many MONICA centers. In 10 populations, the data quality analyses suggested that clarification of possible biases would be needed before these populations can be included in a comparative study. Data from the remaining 11 populations meet the data quality standards for multinational comparisons with respect to case ascertainment.

Conclusions
These results show that multinational comparisons of stroke incidence involve considerable problems in developing and maintaining appropriate standards of data quality. However, after considerable efforts to ensure quality, comparisons of stroke data within the MONICA Project are possible among a large number of the MONICA populations. Our observations also indicate that results from multinational comparisons of stroke mortality based on routine statistics must be interpreted with caution.
Carotid Diameter and Blood Flow Velocities in Cerebral Circulation in Hypertensive Patients
Authors: Ferrara L. Aldo , Mancini Marcello , Iannuzzi Rita , Marotta Teodoro , Gaeta Iole , Pasanisi Fabrizio , Postiglione Alfredo , Guida Lucio
Published: June 2011

Background and Purpose
The recent development of noninvasive techniques for the evaluation of the carotid arteries has focused attention on the study of arterial wall thickness to identify early lesions of vessels in patients at high risk for atherosclerosis, such as those with hypercholesterolemia, diabetes mellitus, and hypertension.

Methods
In a sample of 70 hypertensive patients without clinical evidence of target organ damage, we showed a thickening of the intimal plus medial layers compared with age- and sex-matched normotensive control subjects. In this sample we also studied the diameter of the carotid arteries by ultrasound imaging, and we studied flow velocities in common carotid, internal carotid, and middle cerebral arteries by Doppler technique. Pulsatility and resistance indexes were calculated.

Results
Absolute values of the carotid diameter were similar in the two groups (6.3±0.7 versus 6.0±0.8 mm); however, the ratio of diameter to blood pressure was significantly reduced in hypertensive compared with normotensive subjects (5.3±0.7 versus 6.5±0.8;
P
<.001 for mean blood pressure). Parietal stress was increased in the hypertensive subgroup and significantly correlated with arterial diameter in the normotensive group but not in the hypertensive group. No significant differences between the two groups were observed in blood flow velocities, with the exception of a slight significant increase of mean velocity in the internal carotid artery in hypertensive patients (37.5±9.1 versus 32.7±3.0 cm/s;
P
<.02).

Conclusions
These results indicate that in addition to the degenerative changes of the common carotid wall, the diameter of the carotid artery and the relation to parietal stress show an early impairment in patients with uncomplicated hypertension.
Distinguishing Carotid Artery Pseudo-Occlusion With Color-Flow Doppler
Authors: Berman Scott S. , Devine Jenifer J. , Erdoes Luke S. , Hunter Glenn C.
Published: June 2011

Background and Purpose
This study was undertaken to determine the impact of color-flow Doppler on the accuracy of noninvasive carotid imaging for distinguishing an internal carotid artery pseudo-occlusion (string sign) from a complete occlusion.

Methods
From January 1985 to January 1994, review of noninvasive vascular studies, arteriograms, and operative reports of 26 consecutive patients undergoing 27 carotid endarterectomies for carotid pseudo-occlusion was performed. Further review was conducted of all patients identified with carotid occlusion by noninvasive testing who underwent confirmatory arteriography during the same interval.

Results
Conventional gray-scale duplex scanning (January 1985 to December 1989) correctly identified 3 of 11 (27%) pseudo-occluded internal carotid arteries compared with 15 of 16 (94%) internal carotid artery pseudo-occlusions correctly identified by color-flow Doppler (January 1990 to June 1994) (
P
<.01). Similarly, carotid occlusion was more accurately identified by color-flow Doppler (33 of 33, 100%) compared with gray-scale duplex scanning (19 of 27, 90%) (
P
<.01).

Conclusions
The addition of color-flow Doppler to the duplex evaluation of the extracranial carotid circulation improves the accuracy of distinguishing carotid pseudo-occlusion from the occluded internal carotid artery and may obviate the need for arteriography to identify patients with this critical level of carotid stenosis.
Insular Lesion Evokes Autonomic Effects of Stroke in Normotensive and Hypertensive Rats
Authors: Butcher Kenneth S. , Cechetto David F.
Published: June 2011

Background and Purpose
Increases in sympathetic activity and frequency of myocardial damage occur after middle cerebral artery occlusion (MCAO) in Wistar rats, while MCAO in the spontaneously hypertensive rat (SHR) decreases sympathoadrenal activity. Autonomic changes have been suggested to result from damage to the insular cortex (IC).

Methods
A lesion of the IC was made using the excitotoxin
d
,
l
-homocysteic acid (DLH; 1 mol/L), in urethane-anesthetized Wistar rats and SHRs. Mean arterial pressure (MAP), heart rate, renal sympathetic nerve discharge (SND), ECG, and plasma catecholamines were measured in 14 SHRs and 14 Wistar male rats after a 500-nL injection of DLH or phosphate-buffered saline (PBS) into the IC.

Results
Histological examination showed that DLH resulted in neuronal damage throughout the IC. DLH injection initially elevated MAP (at approximately 10 minutes after injection) in Wistar rats but not in SHRs. At 4 hours after the DLH injection, there was a secondary, longer-term increase in MAP in the Wistar rats. MAP decreased in the SHRs after IC lesion such that at 6 hours, lesioned SHRs had a MAP that was significantly lower than that of sham-lesioned SHRs. SND initially increased (at 10 minutes) after DLH injection in Wistar rats. In the SHRs, SND decreased significantly from the initial values, by 3 hours after DLH injection. Plasma catecholamine levels were not significantly changed as a result of IC lesion in the Wistar rats or the SHRs. Heart rates increased in all animals, with no differences between groups. There were no changes in the ECG or in the frequency of cardiac myocytolysis in either strain (sham or lesioned animals).

Conclusions
IC lesion in the SHR and Wistar rat therefore appears to result in autonomic changes similar to that seen after MCAO. Unlike MCAO, however, the autonomic changes do not appear to be sufficient to produce myocardial damage.
Hypertensive Encephalopathy After Bilateral Carotid Endarterectomy
Authors: Ille O. , Woimant F. , Pruna A. , Corabianu O. , Idatte J. M. , Haguenau M.
Published: June 2011

Background
Hypertension occurs frequently after carotid endarterectomy and may lead to cerebral vascular complications and myocardial infarction. Its pathophysiology has recently been related to surgically induced damage of carotid baroreceptors.

Case Description
A 45-year-old normotensive man with no history of epilepsy was admitted 3 weeks after bilateral carotid endarterectomy for severe repetitive paroxysmal headaches, vomiting, and agitation that were closely associated with attacks of marked hypertension. During one of these attacks, he had a grand mal seizure. Plasma catecholamine levels during hypertensive attacks were highly elevated despite the absence of pheochromocytoma, reflecting abnormalities in baroreceptor sensitivity that lead to unrestrained activation of the central sympathetic nervous system. Heart rate response to Valsalva maneuver showed suppression of the usual tachycardia, indicating baroreceptor reflex insensitivity.

Conclusions
We report the first case of hypertensive encephalopathy associated with baroreflex failure syndrome after bilateral carotid endarterectomy. The role of blood pressure monitoring may be critical in revealing carotid baroreceptor insensitivity in such clinical settings.
Transcranial Magnetic Stimulation–Evoked Inhibition of Voluntary Muscle Activity (Silent Period) Is Impaired in Patients With Ischemic Hemispheric Lesion
Authors: Braune Hans J. , Fritz Christof
Published: June 2011

Background and Purpose
Transcranial magnetic stimulation of the motor cortex is well established as a valuable method for noninvasive examination of the central motor system. In addition to exciting corticospinal cells and evoking a direct motor response, the magnetic stimulus delivered during voluntary activity produces a prolonged postexcitatory inhibition (silent period) of activity. We investigated silent period changes in patients with ischemic stroke of different clinical degrees.

Methods
Standardized transcranial magnetic stimulation during sustained muscle contraction was performed at the vertex. Electromyographic activity was recorded via surface electrodes placed over the abductor digiti minimi muscle on both sides. We examined 50 patients with stroke (divided into three subgroups according to the degree of impairment) and 50 healthy control subjects.

Results
In the control group we found no statistically significant interside difference in the duration of the silent period, whereas a marked interindividual variation was found. In patients with prior minor stroke who showed no residual motor disturbance, we found a significant prolongation of the postexcitatory inhibition recorded from the affected side compared with the healthy side. This interside discrepancy was even more pronounced in patients with minor hemiparesis and patients with moderate hemiparesis.

Conclusions
Our findings suggest that the measurement of the silent period elicited by transcranial magnetic stimulation is a useful and sensitive neurophysiological parameter in the management of stroke. Particularly in the subgroup of patients with no residual clinical signs of central motor impairment, it is capable of detecting subclinical motor function disturbances.
Prevalence of Stroke at High Altitude (3380 m) in Cuzco, a Town of Peru
Authors: Jaillard Assia Serradj , Hommel Marc , Mazetti Pilar
Published: June 2011

Background and Purpose
We carried out a door-to-door survey on stroke prevalence at high altitude in Cuzco City, a town in the Peruvian Andes located 3380 m above sea level.

Methods and Results
Among the 3246 screened individuals over 15 years old, there were 21 cases of first-ever completed stroke, yielding a crude prevalence ratio of 6.47 per 1000 (95% confidence interval [CI], 3.71 to 8.93 per 1000). The age-adjusted to WHO population point prevalence ratio was 5.74 per 1000 (95% CI, 3.14 to 8.35 per 1000), and the age-adjusted to North American US population point prevalence ratio was 8.58 per 1000 (95% CI, 5.44 to 11.75 per 1000). Multivariate logistic regression analysis suggested that age, polycythemia, high consumption of alcohol, and area of residence were associated with stroke prevalence. Our results suggest that the stroke prevalence in the central areas of Cuzco with sedentary people having a relatively high standard of living was higher than that in the peripheral areas with people with a relatively lower standard of living and less sedentary activities (odds ratio, 5.8; 95% CI, 1.4 to 23).

Conclusions
The prevalence of stroke suggests that stroke may be a public health problem in developing countries. This study suggests the importance of environmental factors such as altitude and lifestyle in stroke occurrence. The role of these factors should be confirmed and taken into account in future stroke prevalence studies.
Leukoaraiosis in Stroke Patients
Authors: Jørgensen Henrik Stig , Nakayama Hirofumi , Raaschou Hans Otto , Olsen Tom Skyhøj
Published: June 2011

Background and Purpose
This study was undertaken to determine factors of importance for the development of leukoaraiosis and to evaluate whether leukoaraiosis influences stroke outcome.

Methods
The study was prospective and consecutive and included 1084 unselected patients with acute stroke and transient ischemic attack admitted from the community of Bispebjerg (Copenhagen, Denmark) during a 25-month period from September 1, 1991, to September 30, 1993. All patients were treated in a stroke unit from the time of acute admission to completion of rehabilitation. Daily alcohol consumption and other putative risk factors were registered on admission, and patients were evaluated weekly to death or time of completed rehabilitation by means of neurological (Scandinavian Stroke Scale) and functional (Barthel Index) scores. Leukoaraiosis was diagnosed on computed tomographic scan. Multivariate analyses were applied to test relations independent of other influencing factors.

Results
Leukoaraiosis was present in 15% of the patients. Age was the only factor that significantly increased the risk of leukoaraiosis (odds ratio [OR] per 10-year increase, 2.4; 95% confidence interval [CI], 1.8 to 3.1), whereas the presence of atrial fibrillation was adversely related to leukoaraiosis (OR, 0.26; 95% CI, 0.13 to 0.52). Moderate daily alcohol consumption (1 to 5 drinks) reduced the risk of leukoaraiosis (OR, 0.50; 95% CI, 0.28 to 0.87), whereas heavy daily alcohol consumption (>5 drinks) tended to increase the risk (OR, 1.3; 95% CI, 0.5 to 3.3). Leukoaraiosis was not related to the presence of hypertension, diabetes, ischemic heart disease, atrial fibrillation, intermittent claudication, smoking, or sex. The presence of leukoaraiosis had no influence on neurological outcome (
P
=.20), functional outcome (
P
=.47), length of hospital stay (
P
=.75), or mortality (
P
=.31).

Conclusions
Moderate daily alcohol intake seems associated with a decreased risk of leukoaraiosis in stroke patients. The relation between alcohol intake and leukoaraiosis may even be U-shaped, like the relation between alcohol intake and coronary heart disease, alcohol intake and mortality, and alcohol intake and stroke. The presence of leukoaraiosis does not seem to influence the rehabilitation process or outcome of stroke.
Relationship Between Wheelchair Propulsion andIndependent Walking in Hemiplegic Stroke
Authors: Blower P. W. , Carter L. C. , Sulch D. A.
Published: June 2011

Background and Purpose
We studied the relationship between wheelchair propulsion and final walking ability in hemiplegic stroke patients who were unable to walk independently 3 or more weeks after stroke.

Methods
Sixty hemiplegic stroke patients unable to walk independently 3 weeks or more after stroke were entered in a study comparing independent walking and wheelchair propulsion. Eight patients were lost to follow-up. Of the remaining 52 patients, 29 were entered 3 weeks and 23 were entered 4 to 10 weeks after stroke. Assessments were performed on admission and 4 and 14 weeks later.

Results
Fifteen of the 17 patients able to propel a wheelchair through a simple course at 3 weeks after stroke learned to walk independently (χ
2
=9.94,
P
=.01), but none of the 12 who failed learned to walk (χ
2
=12,
P
=.001). At the final assessment, the positive association between wheelchair propulsion and walking had been lost: 21 of 21 walkers and 18 of 31 nonwalkers could propel a wheelchair (χ
2
=0.23,
P
=NS). The negative association remained: 13 of 31 nonwalkers failed the wheelchair test, but 0 of 21 walkers failed (χ
2
=13.0,
P
=.001). Visual field deficits were significantly more common in patients unable to walk or propel a wheelchair than in walkers (χ
2
=6.66,
P
=.01). Laterality had no effect on outcome.

Conclusions
Ability to propel a wheelchair 3 weeks after stroke in hemiplegic patients unable to walk is the most accurate guide to walking potential that has been reported to date.
Ultrasonographic Correlates of Carotid Atherosclerosis in Transient Ischemic Attack and Stroke
Authors: Iannuzzi Arcangelo , Wilcosky Timothy , Mercuri Michele , Rubba Paolo , Bryan Fred A. , Bond M. Gene
Published: June 2011

Background and Purpose
Atherosclerotic plaques in extracranial carotid arteries, particularly in the bifurcation of the common carotid and internal carotid arteries, may cause transient cerebral ischemia and stroke by lumen stenosis or plaque-related thromboembolism. B-mode ultrasound imaging has the capability of providing information on plaque thickness, characteristics, and location in carotid arteries.

Methods
A retrospective analysis of 242 stroke and 336 transient ischemic attack (TIA) patients, recruited for the B-Scan Ultrasound Imaging Assessment Program, was performed to determine the ultrasonographic correlates of carotid atherosclerosis and acute cerebral ischemia. A matched case-control study design was used to compare brain hemispheres with ischemic lesions (“cases”) to unaffected contralateral hemispheres (“controls”) with regard to the presence and characteristics of carotid artery plaques.

Results
The first set of analyses examined the association between the presence of carotid plaques ipsilateral to the brain lesion and the occurrence of stroke or TIA and showed an association with recent episodes of TIA and stroke (odds ratio [OR], 1.6;
P
=.03) but not with past episodes. In a subset (n=232) of patients with plaques in both carotid arteries and recent cerebral ischemic events, stroke was associated with ipsilateral carotid artery occlusion (
P
=.02). Lumen measurements at the site of the minimum residual lumen (MRL) diameter showed a significant association between a narrower lumen diameter in the carotid artery ipsilateral to case hemisphere and stroke (difference, 1.0 mm;
P
=.0003). TIA patients showed an association between both hypoechoic carotid plaques (OR, 3.0;
P
=.005) and the presence of longitudinal lesion motion (OR, 3.0;
P
=.02) with ipsilateral brain involvement. Plaque thickness at the MRL was positively correlated with both ipsilateral TIA (ipsilateral side, 4.4±0.15 mm; contralateral side, 3.9±0.16 mm;
P
=.007) and stroke (ipsilateral side, 4.2±0.23 mm; contralateral side, 3.3±0.21 mm;
P
=.0006).

Conclusions
These data demonstrate significant relationships between carotid artery ultrasound plaque characteristics and ischemic cerebrovascular events. These findings encourage further prospective studies in asymptomatic subjects focused on echographic carotid plaque characteristics as predictors of subsequent TIA or stroke.
Environment Influences Functional Outcome of Cerebral Infarction in Rats
Authors: Ohlsson Anna-Lena , Johansson Barbro B.
Published: June 2011

Background and Purpose
The purpose of this study was to determine whether preoperative and postoperative enrichment of the environment can enhance the functional outcome after cerebral infarction in rats.

Methods
The right middle cerebral artery was ligated in adult spontaneously hypertensive male rats, and the functional outcome was studied for 12 weeks after the operation. Three groups were compared: A, rats kept in individual cages before and after the operation (n=9); B, rats kept in individual cages before the operation but transferred to an enriched environment after the operation (n=10); and C, rats kept in an enriched environment all the time (n=12). The enriched environment consisted of a large cage with opportunities for various activities, but rats were not forced to do any particular tasks.

Results
Rats kept in an enriched environment (groups B and C) performed significantly better than rats in group A in a leg-placement test, beam walking, walking on a rotating pole, and climbing. The infarct size and thalamic atrophy did not differ among the groups.

Conclusions
The laboratory environment is important for the functional outcome in brain ischemia. We hypothesize that an enriched environment may stimulate mechanisms that enhance brain plasticity after focal brain ischemia.
Deferoxamine Reduces Early Metabolic Failure Associated With Severe Cerebral Ischemic Acidosis in Dogs
Authors: Hurn Patricia D. , Koehler Raymond C. , Blizzard Kathleen K. , Traystman Richard J.
Published: June 2011

Background and Purpose
Postischemic metabolic injury may be mediated by acidosis and tissue bicarbonate depletion, with consequent iron mobilization and oxygen radical formation during reperfusion. We have previously shown that reducing intracellular pH to below 5.7 and bicarbonate ion to below 1 to 2 mmol/L during hyperglycemic ischemia produces a profound secondary deterioration of brain ATP and cerebral blood flow during reperfusion. This study tested the hypothesis that pretreatment with free deferoxamine ameliorates metabolic decay and delayed hypoperfusion after global hyperglycemic ischemia. In addition, deferoxamine conjugated to a high-molecular-weight starch was administered to determine the importance of an intravascular site of action. Iron-loaded deferoxamine was used to determine whether the iron chelation properties of deferoxamine are important to postischemic viability as distinguished from the agent’s significant radical scavenging potential.

Methods
Cerebral ATP, phosphocreatine, and pH were measured by
31
P magnetic resonance spectroscopy in anesthetized dogs. Tissue bicarbonate concentration was calculated from the Henderson-Hasselbalch equation. Incomplete cerebral ischemia was produced by intracranial pressure elevation for 30 minutes with plasma glucose at 540±15 mg/dL. Free deferoxamine, saline vehicle, hydroxyethyl starch–conjugated deferoxamine, hydroxyethyl starch vehicle, and deferoxamine loaded with equimolar ferric chloride were administered intravenously in five groups of dogs. The dose of deferoxamine was 50 mg/kg before ischemia, 50 mg/kg at the onset of reperfusion, and 50 mg/kg over the 180-minute reperfusion period.

Results
Ischemic hemispheric blood flow (mean, 6 to 8 mL/min per 100 g), intracellular pH (5.7 to 6.0), and bicarbonate levels (1 to 2 mmol/L) were similar in all groups. During reperfusion, cerebral pH and bicarbonate recovered only in the free-deferoxamine group. Both ATP and phosphocreatine initially increased in all groups, but recovery was sustained only in the free-deferoxamine group. Secondary losses of energy phosphates and cerebral oxygen consumption were observed in all other groups, accompanied by progressive reduction of perfusion.

Conclusions
These data support the hypothesis that iron-catalyzed oxygen radical production plays an important role in acidosis-mediated mechanisms of ischemic brain injury. The results with free and iron-loaded deferoxamine suggest that iron scavenging is an important, but not necessarily the principal, component of this mechanism. The poor recovery seen with conjugated deferoxamine indicates that the beneficial action of deferoxamine is not localized within the intravascular compartment.
Prospective CT Confirms Differences Between Vascular and Alzheimer’s Dementia
Authors: Meyer John Stirling , Muramatsu Kazuhiro , Mortel Karl F. , Obara Katsuyuki , Shirai Toshitaka
Published: June 2011

Background and Purpose
Cognitive test performances were correlated prospectively with changes in cerebral CT measurements of atrophy, infarct volume, ventricular enlargement, local tissue density, and local perfusion to contrast annual rates of changes among patients with ischemic vascular dementia (IVD) or dementia of the Alzheimer type (DAT).

Methods
The cerebral atrophic index (ATI; ratio of cerebrospinal fluid or infarcted brain to intracranial volume), infarct volume ratio, ventricular volume ratio (VVR; ventricular volume/intracranial volume), cortical and subcortical gray and white matter local perfusion (local cerebral blood flow [LCBF]), and local Hounsfield unit (HU) density were measured concurrently and compared longitudinally with Cognitive Capacity Screening Examinations (CCSE) scores among 24 treated IVD (age, 68.2±9.7 years; follow-up, 42±27 months) and 24 DAT patients (age, 74.2±6.2 years; follow-up, 30±19 months).

Results
IVD annual changes were as follows: CCSE, +1.2±5.9; ATI, +2.1%/y; VVR, +3.2%/y; and LCBF in the subcortical basal ganglia, −0.74 mL · 100 g
−1
· min
−1
· y
−1
(−1.8%/y). DAT annual changes were as follows: CCSE, −1.8 /y; ATI, +8.1%/y; VVR, +9.6%/y; cortical LCBF, −2.0 mL · 100 g
−1
· min
−1
· y
−1
(−5.2%/y); LCBF in the basal ganglia, −3.0 mL · 100 g
−1
· min
−1
· y
−1
(−6.7%/y); white matter LCBF, −0.75 mL · 100 g
−1
· min
−1
· y
−1
(−4.1%/y); and all cortical tissue densities, −0.83 HU/y (−2.1%/y). In IVD, multiple regression analyses correlated cognitive changes directly with (1) recurrent silent infarctions and (2) bidirectional changes of perfusions within frontal white matter, thalamus, and internal capsules. In DAT, cognitive declines correlated with cerebral atrophy and cortical hypoperfusion related to frontotemporal and parietal cortical polioaraiosis (decreased gray matter tissue densities).

Conclusions
In IVD, recurrent strokes were not observed clinically during risk factor control, and antiplatelet therapy and cognitive impairments improved or stabilized. In DAT, cognitive performance relentlessly declined. Ischemic pathogenesis for vascular dementia is supported by the following: (1) cognitive declines correlate directly with recurrent “silent” strokes, and (2) bidirectional cognitive changes correlate directly with frontal white matter, thalamic, and internal capsular perfusional changes.
The Shifting Stroke Belt
Authors: Casper Michele L. , Wing Steve , Anda Robert F. , Knowles Marilyn , Pollard Robert A.
Published: June 2011

Background and Purpose
The factors that contribute to the Stroke Belt—a concentration of high stroke mortality rates in the southeastern United States—remain unidentified. Previous hypotheses that focused on physical properties of the area have not been confirmed. This study describes changes in the locations of areas with the highest rates of stroke mortality and the implications for new hypotheses regarding the Stroke Belt.

Methods
We calculated annual, age-adjusted stroke mortality rates for black women, black men, white women, and white men for the years 1962 to 1988 using a three-piece log-linear regression model. Maps were produced with the state economic area (SEA) as the unit of analysis. The baseline Stroke Belt was defined as the area with the largest concentration of high-quintile SEAs in 1962.

Results
The concentration of high-rate SEAs tended to shift away from the Piedmont region of the Southeast and toward the Mississippi River valley. For example, whereas among black women in 1962, 72% of SEAs in the baseline Stroke Belt were in the highest quintile, by 1988 this percentage had dropped to 48%. Similar patterns were observed for the other race/sex groups.

Conclusions
Temporal changes in the location of areas with the highest stroke mortality rates suggest that new hypotheses for understanding the geographic pattern of stroke mortality should consider temporal trends in a variety of medical, socioeconomic, and behavioral factors.
Impact of Alcohol Consumption and Cigarette Smoking on Stroke Among the Elderly in Taiwan
Authors: Lee Ti-Kai , Huang Zei-Shung , Ng Sien-Kiat , Chan Kin-Wei A. , Wang Yuh-Shyun , Liu Hong-Wen , Lee Jen-Jyh
Published: June 2011

Background and Purpose
We investigated the influence of alcohol consumption and cigarette smoking on all types of stroke and cerebral infarction, in particular among a representative sample of elderly residents in Taiwan.

Methods
This study was a component of a nationwide survey of health and living status of residents aged 65 years or older in Taiwan in which subjects received detailed physical, neurological, and laboratory examinations. Inquiries were made about medical history, and information on the amount and duration of drinking and smoking was obtained. Diagnoses of stroke were made according to the results of brain computed tomography at the onset of disease or were based on criteria established by the World Health Organization.

Results
Of the 2600 subjects, there were 155 elderly persons with stroke (prevalence, 6%). Excessive drinking of more than 367.6 g/wk of alcohol was associated with a high prevalence of cerebral infarction. Consumption of ≤367.5 g/wk of alcohol did not have an influence on stroke prevalence. The relationship between duration of alcohol drinking and stroke was equivocal. More than 30 pack-years of cigarette smoking was a significant risk factor for all types of stroke and cerebral infarction in particular. Using multiple logistic regression to control for possible confounders, it was found that smoking was an independent risk factors for all stroke and was of borderline significance for cerebral infarction. Although excessive drinking was a significant risk factor for cerebral infarction in univariate analysis, this effect was lost after adjustment for other confounders.

Conclusions
Cigarette smoking was a more important risk factor for stroke and cerebral infarction than excessive drinking of alcohol.