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Biomedical subjects

T K Tatemichi

Publications and source records attributed to T K Tatemichi.

At least 19 recordsLinked to original sources
PubMed1992

Thalamic stroke. Presentation and prognosis of infarcts and hemorrhages.

Thalamic strokes in 62 patients selected from the Stroke Data Bank were studied to determine differences among 18 infarctions (INF), 23 localized hemorrhages (ICH), and 21 hematomas with ventricular extension (IVH). Stupor or coma at onset occurred more frequently in the IVH (62%) than in the INF (6%) or ICH (13%) groups and was reflected in significantly lower median Glasgow Coma Scores in the IVH group (7) than in the INF (15) and ICH (14) groups. Although ocular movements were more frequently abnormal in the IVH group compared with the ICH and INF groups, no significant differences were found in the frequency of motor or sensory deficits. Among the 62 strokes, 32 had restricted lesions of the posterolateral (n = 9), anterior (n = 3), paramedian (n = 7), and dorsal (n = 13) portions of the thalamus. Differences in consciousness and in motor, sensory, and oculomotor deficits were found among the topographic subgroups. Stroke-related deaths occurred in 52% of IVH cases, 13% of ICH cases, and no cases of INF. Median lesion volume as detected with computed tomography was greater in hemorrhages (INF, 2 cm3; ICH, 10 cm3; IVH, 16 cm3), with mortality related to increasing hematoma size. Coma, Glasgow Coma Score lower than 9, weakness score greater than 15 of a possible 30, abnormal ocular movements, and fixed pupils were also associated with stroke-related mortality. We conclude that the initial neurologic syndrome does not discriminate infarcts from intrathalamic hemorrhages. Ventricular extension, however, causes significantly more severe deficits and higher mortality.

Cerebral Hemorrhage↗
PubMed1992

Paramedian thalamopeduncular infarction: clinical syndromes and magnetic resonance imaging.

We prospectively examined 11 patients with magnetic resonance imaging-documented infarction in the paramedian thalamopeduncular region, which is supplied by the superior mesencephalic and posterior thalamosubthalamic arteries. Variations in the size and rostral-caudal extent of infarction correlated with the following three clinical patterns: (1) With unilateral paramedian mesencephalic infarction, an ipsilateral third nerve paresis was accompanied by mild contralateral hemiparesis or hemiataxia. Contralateral ptosis and impaired upgaze were observed in two patients; one of them showed additional damage to the posterior commissure. (2) With bilateral infarction in the thalamopeduncular junction, involving the mesencephalic reticular formation, supranuclear vertical gaze defects were accompanied by impaired consciousness or memory, and mild aphasia in some patients. Persistent amnesia was observed only when the dominant anterior nucleus or mamillothalamic tract was damaged. (3) With larger thalamopeduncular infarcts, partial or complete third nerve paresis was combined with supranuclear gaze disturbance and delayed contralateral tremor. An unusual gaze disorder, a variant of the vertical "one-and-a-half syndrome," occurred with a small strategically placed lesion at the thalamopeduncular junction, best explained by selective damage to supranuclear pathways or partial nuclear involvement. The primary cause of these infarctions was embolism to the basilar apex or local atheroma at the origin of the posterior cerebral artery.

Adult↗
PubMed1992

Early clinical differentiation of cerebral infarction from severe atherosclerotic stenosis and cardioembolism.

BACKGROUND AND PURPOSE: Hyperacute cerebral infarction trials require early differentiation of infarction subtype. Our aim was to determine clinical factors predictive of infarction subtype from data collected in the early hours of admission. METHODS: Using the 1,273 patients enrolled in the Stroke Data Bank, stroke risk factors and demographic, clinical, and radiological features were compared between the 246 cardioembolic and 113 large-vessel atherosclerotic cerebral infarcts. RESULTS: Stroke Data Bank definitions ensured more transient ischemic attacks in atherosclerotic infarcts and more cardiac disease in cardioembolic infarcts, but the diagnosis was distinguished further using a logistic regression model. Fractional arm weakness (shoulder different from hand) (odds ratio 3.1, 95% confidence interval [CI] 1.6-5.8), hypertension (odds ratio 2.8, CI 1.4-5.3), diabetes (odds ratio 2.5, CI 1.2-5.1) and male gender (odds ratio = 2.2, CI 1.2-4.1) occurred more frequently in patients with atherosclerotic than cardioembolic infarcts. Reduced consciousness (odds ratio = 3.2, CI 1.4-7.3) was more frequent in cardioembolism. For a male patient with hypertension, diabetes, and fractional arm weakness, the estimated odds of an atherosclerotic infarction were 47-fold that of a cardioembolic infarction. Patients with atherosclerotic infarcts were more likely to have a fractional arm weakness regardless of infarct size, whereas, for those with cardioembolic infarctions, fractional weakness was more frequent in infarcts less than 20 cc in volume. CONCLUSIONS: Clinical features that are observed at stroke onset can help distinguish cerebral infarction subtypes and may allow for early stratification in therapeutic trials.

Aged↗
PubMed1992

Caudate hemorrhage with moyamoya-like vasculopathy from atherosclerotic disease.

BACKGROUND AND PURPOSE: Caudate hemorrhage usually results from hypertension, rupture of arteriovenous malformation or aneurysm, or rarely, moyamoya disease. Moyamoya-like changes related to severe atherosclerotic occlusive disease, usually causing ischemic stroke, have been reported. CASE DESCRIPTION: A 51-year-old normotensive patient was admitted with headache due to a left caudate hematoma with ventricular extension. There was a history of smoking, leg claudication, elevated cholesterol, and coronary artery disease. Angiography demonstrated complete extracranial carotid occlusion on the left and atherosclerotic stenosis at the bifurcation on the right, with supraophthalmic occlusion distally. At the base of the brain, bilateral moyamoya-like vessels, presumed to be secondary to atherosclerotic occlusion, were evident, but neither aneurysm nor arteriovenous malformation was present. Cerebral blood flow and transcranial Doppler studies indicated severely impaired cerebral perfusion that improved after bilateral extracranial-to-intracranial bypass surgery. CONCLUSIONS: Atherosclerotic occlusive carotid disease with moyamoya-like changes may be a rare cause of caudate hemorrhage. A decrease in moyamoya vessels with bypass surgery may reduce the risk of recurrent hemorrhage.

Carotid Arteries↗
PubMed1992

Confusion and memory loss from capsular genu infarction: a thalamocortical disconnection syndrome?

We examined six patients with an abrupt change in behavior after infarction involving the inferior genu of the internal capsule. The acute syndrome featured fluctuating alertness, inattention, memory loss, apathy, abulia, and psychomotor retardation, suggesting frontal lobe dysfunction. Contralateral hemiparesis and dysarthria were generally mild, except when the infarct extended into the posterior limb. Neuropsychological testing in five patients with left-sided infarcts revealed severe verbal memory loss. Additional cognitive deficits consistent with dementia occurred in four patients. A right-sided infarct caused transient impairment in visuospatial memory. Functional brain imaging in three patients showed a focal reduction in hemispheric perfusion most prominent in the ipsilateral inferior and medial frontal cortex. We infer that the capsular genu infarct interrupted the inferior and anterior thalamic peduncles, resulting in functional deactivation of the ipsilateral frontal cortex. These observations suggest that one mechanism for cognitive deterioration from a lacunar infarct is thalamocortical disconnection of white-matter tracts, in some instances leading to "strategic-infarct dementia."

Aged↗
PubMed1992

Left hemiparalexia.

Three patients with left splenial lesions made paralexic errors restricted to the left end of words. Errors appeared more frequently when a correct response was highly dependent on the initial letter of the stimulus. One patient had full visual fields with hemialexia affecting the left visual field. The other two patients had complete right hemianopia. We attribute left-sided reading errors in the hemianopic patients to a retinotopically restricted disconnection pattern that selectively disrupts transfer of information originating from the peripheral left visual field. Functional resistance of the more numerous transcallosal projections representing visual field adjacent to the vertical meridian may account for such a pattern. The emergence of positional reading errors from retinotopically restricted left hemifield disconnection suggests that callosal information transfer during normal reading may primarily involve elemental sensory rather than lexical/semantic information.

Adult↗
PubMed1992

Dementia after stroke: baseline frequency, risks, and clinical features in a hospitalized cohort.

We determined the frequency of dementia in a cohort of 251 patients aged greater than or equal to 60 years hospitalized with acute ischemic stroke, based on examinations performed 3 months after stroke onset. Using modified DSM-III-R criteria, we found dementia in 66 patients (26.3%). Diagnostic agreement among raters was excellent (kappa = 0.96). In a control sample of 249 stroke-free subjects recruited from the community and matched by age, we found dementia in eight subjects (3.2%). Using a logistic regression model to estimate the risk of dementia associated with stroke in the combined samples, the odds ratio (OR) for stroke patients compared with control subjects was 9.4 (p less than 0.001). Advancing age and fewer years of education were significant, independent correlates of dementia, with a trend evident for race (non-white versus white). Confining the analysis to subjects residing in the Washington Heights-Inwood community of northern Manhattan, the OR was 10.3 (p less than 0.001) with significant age and race effects. We conclude that ischemic stroke significantly increases the risk of dementia, with independent contributions by age, education, and race.

Aged↗
PubMed1992

Neurologic improvement in pure motor hemiparesis: implications for clinical trials.

Knowledge of the natural history of certain stroke subtypes is essential for the proper analysis and interpretation of clinical trials of stroke therapy. We evaluated the degree of weakness on admission and again 7 to 10 days later in 62 patients with pure motor hemiparesis (PMH) and 280 patients with motor deficits from other stroke syndromes (OSS). During the 7-to-10-day study interval, we found that the OSS group worsened slightly in motor function, whereas the PMH group improved (p = 0.01). Among those who improved in both groups, those in the PMH group improved to a greater extent than did those in the OSS group (p = 0.02). This occurred despite a greater frequency of worsening during the first 12 hours after stroke onset in the PMH group. By the fourth day following PMH onset, a majority of patients had improved, and this improvement was sustained until day 10. The two groups did not differ significantly in age, race, sex, history of cardiac disease, hematocrit, anticoagulation treatment, blood glucose, or medical complications in hospital. Lacunar infarcts occurred in 84% of PMH and 23% of OSS. Patients with PMH show significant spontaneous improvement in weakness within 7 to 10 days of admission, compared with patients with OSS. Stratification by admission stroke syndrome in clinical trials may be necessary before judging the efficacy, or lack thereof, of a therapeutic agent.

Aged↗
PubMed1991

Safety of hypercapnic challenge: cardiovascular and neurologic considerations.

The hemodynamic, cerebrovascular, and neurologic effects of hypercapnia with 4% and 6% CO2 were retrospectively reviewed in 217 patients referred for regional CBF (rCBF) procedures. Inhalation of CO2 significantly increased rCBF, blood pressure, and pulse from baseline. The findings suggest a higher incidence of side effects with 6% CO2 concentration and an equivalent vasoreactivity to 4%. We recommend the use of 4% CO2 for hypercapnic stimulation, and present safety guidelines for its use.

Administration, Inhalation↗
PubMed1991

The anterior choroidal artery does not supply the corona radiata and lateral ventricular wall.

BACKGROUND AND PURPOSE: We sought first to characterize the clinical syndromes of patients found to have angiographic, computed tomographic, or magnetic resonance imaging scan indexes of anterior choroidal artery territory infarction and then to determine the frequency of involvement of the periventricular corona radiata in such patients. METHODS: Sixteen patients were selected based on angiographically, or surgically, documented occlusion of the anterior choroidal artery or based on infarcts whose minimal lesions included the anterior choroidal territory as defined by Kolisko and Beevor. We mapped the lesions using the templates of the Matsui and Hirano atlas and entered them into a computer using a program allowing overlapping diagrams of the cases. RESULTS: The anatomic distributions were fairly uniform, all involving the lower portion of the posterior limb of the internal capsule, the medial pallidum (75% of cases), cerebral peduncle in 44%, thalamus in 37%, and the medial temporal lobe in 38%. None extended outside these areas to include the upper corona radiata. The clinical picture corresponded to the well-established neurological syndrome featuring motor deficits with varying degrees of visual field and sensory impairments. Only two showed hypesthetic ataxic hemiparesis. CONCLUSIONS: Our findings indicate that the syndrome of anterior choroidal artery infarction is fairly uniform; ataxic hemiparesis occurs infrequently; and lesions in the lateral ventricular wall and the corona radiata are not part of the territory supplied by the anterior choroidal artery.

Adult↗
PubMed1991

Clinical-computed tomographic correlations of lacunar infarction in the Stroke Data Bank.

Lacunar stroke was diagnosed in 337 (26%) of the 1,273 patients with cerebral infarction among the 1,805 total in the Stroke Data Bank. We analyzed the 316 patients with classic lacunar syndromes. Among these, 181 (57%) had pure motor hemiparesis, 63 (20%) sensorimotor syndrome, 33 (10%) ataxic hemiparesis, 21 (7%) pure sensory syndrome, and 18 (6%) dysarthria-clumsy hand syndrome. No striking differences were found among the risk factors for the lacunar subtypes, but differences were found between lacunar stroke as a group and other types of infarcts. Compared to 113 patients with large-vessel atherosclerotic infarction, those with lacunar stroke had fewer previous transient ischemic attacks and strokes. Compared to 246 with cardioembolic infarction, patients with lacunar stroke more frequently had hypertension and diabetes and less frequently had cardiac disease. We found a lesion in 35% of the lacunar stroke patients' computed tomograms, with most lesions located in the internal capsule and corona radiata. The mean infarct volume was greater in patients with pure motor hemiparesis or sensorimotor syndrome than in those with the other lacunar stroke subtypes. In patients with pure motor hemiparesis and infarcts in the posterior limb of the internal capsule, there was a correlation between lesion volume and hemiparesis severity except for the few whose infarct involved the lowest portion of the internal capsule; in these patients severe deficits occurred regardless of lesion volume. Taken together, the computed tomographic correlations with the syndromes of hemiparesis showed only slight support for the classical view of a homunculus in the internal capsule.

Aged↗
PubMed1991

Clinical discriminators of lobar and deep hemorrhages: the Stroke Data Bank.

Of the 1,805 patients with acute stroke enrolled in the Stroke Data Bank, 237 had parenchymatous hemorrhage. After excluding 34 secondary intracerebral and 31 infratentorial hemorrhage patients, a logistic regression analysis of the 172 patients with primary supratentorial intracerebral hemorrhage (ICH) elucidated clinical factors that distinguished the 65 patients with lobar hemorrhage (LH) from the 107 patients with deep hemorrhage (DH) located in the basal ganglia and thalamus. In LH, severe headache was more common than in DH, while hypertension and motor deficit were significantly less common. Patients with either LH or DH had a similar prognosis and mean Glasgow Coma Scale (GCS) scores, despite the hematoma volume measured on the initial CT being significantly greater for LH than DH. The presence of intraventricular extension (IVH) was more frequent in DH. The frequency of IVH increased with hematoma volume in LH, but remained constant for DH. Two CT variables (IVH and hematoma volume) that differed in these two hemorrhage groups were important predictors of coma (GCS less than or equal to 8) in a logistic regression model. Differences in the frequency of IVH may help explain why the degree of impairment in consciousness was similar in the two groups. Among patients with supratentorial ICH, location of the hematoma is related to both volume and IVH, which are important determinants of the level of consciousness.

Aged↗
PubMed1990

Fatal or severely disabling cerebral infarction during hospitalization for stroke or transient ischemic attack.

Six (1%) of 578 patients admitted for cerebral infarction or transient ischemic attack (TIA) suffered a fatal or severely disabling in-hospital cerebral infarction following a period of stabilization or improvement lasting more than 1 day. These infarctions were characterized by the sudden onset of stupor or coma and subsequent development of transtentorial herniation due to carotid or middle cerebral artery territory infarction, or widespread brain-stem infarction due to basilar occlusion. Only one patient survived. Four patients had large-vessel disease documented by Doppler, angiography, or at autopsy. Each of these six infarcts occurred during the morning hours, 4-9 days after the initial event, 3-8 days after initiation of intravenous heparin, and within 4-8 h after intravenous heparin had been discontinued. No coagulation abnormalities were documented. We believe that these cases indicate that among patients admitted for cerebral infarction or TIA, fatal or severely disabling in-hospital cerebral infarction after a period of stabilization or improvement may occur in patients having an initially mild to moderate clinical deficit, that those suffering large artery disease may be at greater risk, and that there may be a relationship between heparin withdrawal and cerebral infarction in some patients.

Cerebral Infarction↗
PubMed1990

Embolic stroke after smoking "crack" cocaine.

A 39-year-old woman had an embolic upper division middle cerebral artery branch occlusion 3 hours after smoking the free base of cocaine ("crack"). Radionuclide ventriculography demonstrated cardiomyopathy, and echocardiography documented a left atrial thrombus. This case demonstrates that embolism is one mechanism of ischemic stroke after cocaine use, and that cardiomyopathy, possibly cocaine induced, may be the source of embolus. A cardiac source of embolus should be sought in patients with cocaine-associated cerebral infarction.

Adult↗
PubMed1990

Transcranial Doppler ultrasonographic changes after treatment for arteriovenous malformations.

We performed transcranial Doppler ultrasonography on 15 patients with arteriovenous malformations before and after embolization or surgical resection to compare quantitatively the hemodynamic effects of these two treatments. Changes in mean blood velocity and pulsatility index were analyzed in 19 treated feeding arteries. Blood velocity decreased by a mean of 38.1% or 46.5 cm/sec (p less than 0.0001, two-tailed paired t test); decreases were greater for surgically resected arteries (46.2% or 55.9 cm/sec, p less than 0.003) than for embolized arteries (30.8% or 38.0 cm/sec, p less than 0.0003). Pulsatility index increased by a mean of 54.7% or 0.25 (p = 0.0001); increases were greater for surgically resected arteries (65.8% or 0.29, p = 0.0045) than for embolized arteries (44.8% or 0.20, p less than 0.001). The differences in the changes in blood velocity and pulsatility index between treatment groups were not significant. These data demonstrate that embolization results in hemodynamic changes that are qualitatively similar to those occurring after surgical resection of arteriovenous malformations. Transcranial Doppler ultrasonography is a reliable and convenient noninvasive method for monitoring hemodynamic effects of treatments for arteriovenous malformations.

Adolescent↗
PubMed1990

Perfusion insufficiency in limb-shaking transient ischemic attacks.

We describe a 63-year-old man with severe bilateral internal carotid artery disease who presented with repeated, brief attacks of left limb shaking precipitated by his standing up. Cerebral blood flow measured by xenon-133 inhalation showed reduced resting flows and a focal perfusion deficit in the right dorsofrontal and upper rolandic regions. Blood flow velocity and pulsatility index of the right middle cerebral artery measured by transcranial Doppler ultrasonography were also reduced. With hypercapnic challenge, both hemispheric tissue perfusion and blood flow velocity showed impaired reactivity. With induced hypotension, the focal perfusion deficit in the right dorsofrontal region was accentuated. Following right internal carotid endartectomy, resting cerebral blood flow and blood flow velocity improved, as did hypercapnic vasoreactivity. These reversible deficits in cerebral blood flow and vasoregulation, which were maximal in the dorsofrontal region, are consistent with low perfusion in the border zone territory or the distal fields and demonstrate that hemodynamic failure is the likely mechanism for limb-shaking transient ischemic attacks from severe carotid artery disease.

Biomechanical Phenomena↗
PubMed1990

Dementia in stroke survivors in the Stroke Data Bank cohort. Prevalence, incidence, risk factors, and computed tomographic findings.

We determined the prevalence of dementia in 927 patients with acute ischemic stroke aged greater than or equal to 60 years in the Stroke Data Bank cohort based on the examining neurologist's best judgment. Diagnostic agreement among examiners was 68% (kappa = 0.34). Of 726 testable patients, 116 (16%) were demented. Prevalence of dementia was related to age but not to sex, race, handedness, educational level, or employment status before the stroke. Previous stroke and previous myocardial infarction were related to prevalence of dementia although hypertension, diabetes mellitus, atrial fibrillation, and previous use of antithrombotic drugs were not. Prevalence of dementia was most frequent in patients with infarcts due to large-artery atherosclerosis and in those with infarcts of unknown cause. Computed tomographic findings related to prevalence of dementia included infarct number, infarct site, and cortical atrophy. Among 610 patients who were not demented at stroke onset, we used methods of survival analysis to determine the incidence of dementia occurring during the 2-year follow-up. Incidence of dementia was related to age but not sex. Based on logistic regression analysis, the probability of new-onset dementia at 1 year was 5.4% for a patient aged 60 years and 10.4% for a patient aged 90 years. With a multivariate proportional hazards model, the most important predictors of incidence of dementia were a previous stroke and the presence of cortical atrophy at stroke onset.

Aged↗