Toshiro Yonehara

Aphasia during the acute phase in ischemic stroke.

Objectives: We investigated the incidence, clinical characteristics, outcome and factors associated with aphasia and early improvement in acute ischemic stroke. Methods: We consecutively studied 855 patients with acute ischemic stroke who were admitted to our hospital within 48 h after onset and who were not comatose on admission. Assessment of aphasia was performed on admission (day 0) and day 10. We examined the incidence, severity, and subtypes of aphasia, and compared the clinical background of patients with and without aphasia on admission, and also those with and without early improvement by day 10. In addition, we investigated the independent factors associated with the presence of aphasia on admission and with early improvement. Results: Of the 855 patients, 130 (15.2%) had aphasia on admission. The National Institutes of Health Stroke Scale (NIHSS) on admission (OR 1.21; 95% CI 1.17–1.26) was a significant and independent factor associated with the presence of aphasia on admission. Early improvement was seen in 56 of 121 aphasic patients (46.3%) who were still alive on day 10. A history of hypercholesterolemia (OR 3.27; 95% CI 1.14–9.39) was a significant and independent factor associated with early improvement in aphasia during the acute phase and NIHSS on admission (OR 0.95; 95% CI 0.90–0.99) was marginally significant. Conclusion: It is difficult to predict the outcome of aphasia within the first few days after the onset of ischemic stroke.

Neurologic features of chronic Minamata disease (organic mercury poisoning) and incidence of complications with aging

To elucidate the neurologic features of chronic Minamata disease, and the incidence of complications with aging, we studied 80 patients with documented Minamata disease (organic mercury poisoning) from 1986 to 1994 (mean age: 63 years). Of the cardinal neurologic findings, sensory impairment was seen with highest frequency in 98.8% of patients limited to the extremities in 86.3%. Impairment of lower extremity coordination was observed in 60%, constriction of the visual field in 51.9%, and retrocochlear hearing loss in 41%. To assess age-related complications, patients were separated into three groups by age: Group I (10 to 39 years); Group II (40 to 69 years); Group III (> or = 70 years). The incidences of hypertension and cerebrovascular diseases, organic ophthalmologic disorders (including cataracts), presbyacusis, and cervical spondylosis deformans increased significantly with age. Compared with a preceding survey (1981 to 1985, 171 patients, mean age: 63.5 years), the incidences of complicated hypertension and cataracts had decreased, whereas those of cerebrovascular disease and retinitis pigmentosa remained unchanged. The incidences of abnormal brain computed tomography (CT), presbyacusis, cervical spondylosis deformans, and positive tests for urine sugar also increased. The incidences of these complications other than retinitis pigmentosa were similar to those in the general population. These results accurately reflect the recent epidemiological disease tendencies in Japan toward a decreased incidence of hypertension and an increased incidence of diabetes.

Hyperacute Diffusion-Weighted Imaging Abnormalities in Transient Ischemic Attack Patients Signify Irreversible Ischemic Infarction

Background: To characterize the frequency and clinical features of diffusion-weighted imaging (DWI) abnormalities in the hyperacute phase of transient ischemic attacks (TIAs). Methods: We performed DWI in 21 consecutive patients with TIA (mean age 64 years; 17 men and 4 women) during both the hyperacute phase (within 6 h after onset) and subacute phase (within 2–9 days after onset). Results: DWI abnormalities were present in the hyperacute phase in 11 patients (positive group) and absent in the other 10 patients (negative group). These groups could not be differentiated based on the clinical characteristics. In the subacute phase, all 11 patients from the positive group had abnormalities on MRI including T2-weighted and fluid attenuation inversion recovery images as well as DWI, with lesions being located in regions similar to those observed in the hyperacute phase. Of the 10 patients in the negative group, new DWI abnormalities were noted in 2 during the subacute phase. Conclusions: Approximately half of TIA patients in whom MRI was performed in the hyperacute phase had DWI abnormalities, all of which persisted in the subacute phase. The findings suggest that essentially all hyperacute DWI abnormalities in TIA patients may indicate irreversibility and signify the presence of brain infarction.

Detection of reverse flow by duplex ultrasonography in orthostatic hypotension.

The aim of this study is to elucidate the effect of orthostatic hypotension on changes in cerebral blood flow. Methods Blood flow velocities of both the common carotid artery and vertebral artery were measured using duplex ultrasonography in 12 patients: 6 with familial amyloidotic polyneuropathy, 3 with Shy-Drager syndrome, 2 with pandysautonomia, and 1 with senile orthostatic hypotension. Simultaneously, peripheral blood flow was also evaluated by laser-Doppler flowmetry. Results The patients showing dizziness or syncope when tilted to a 70° upright position exhibited characteristic reverse flow at the end-diastolic phase on the Doppler flow image of both the common carotid and vertebral arteries, which was effectively treated by infusion of 2.5 μg/min norepinephrine for 10 minutes. This end-diastolic reverse flow was not seen in any patients who did not have dizziness or syncope. After subjects were tilted from a supine to a 70° upright position, decrease in the peripheral blood flow of the patients with orthostatic hypotension remained unchanged for at least 5 minutes, whereas that of control subjects was recovered within 2 minutes. However, no significant difference between the patients with and without clinical symptoms was observed. Conclusions These results suggest that detection of this specific echographic pattern may be quantitatively useful in examination of clinical symptoms accompanying orthostatic hypotension and that duplex ultrasonography may be a helpful tool to evaluate the effect of drugs used for controlling these clinical signs.

Rotational vertigo associated with parietal cortical infarction

A 65-year-old woman experienced sudden positional vertigo with rightward, horizontal nystagmus that resolved within days. MRI revealed a left parietal lobe infarction involving the supramarginal gyrus. The patient experienced a transient recurrence of vertigo after 7 days but MRI failed to reveal the presence of any new lesions; furthermore, the patients EEG was normal. We suggest that this patients vertigo was due to her parietal cortical infarction.

Bilateral medial medullary infarction with oculomotor disorders

Background and Purpose: We describe the first case of bilateral medial medullary infarction demonstrated by magnetic resonance imaging. We discuss the relation between this lesion and the oculomotor signs that were observed clinically. Case Description: A 71-year-old man initially presented with pure motor hemiparesis, which progressed to complete quadriplegia. He also developed nearly complete vertical and horizontal ophthalmoplegia. Magnetic resonance imaging revealed upper medial medullary infarctions bilaterally that extended to the pontomedullary junction. Conclusions: We propose that the vertical oculomotor disorders resulted from involvement of the oculomotor system in the caudal brain stem, especially the caudal paramedian pontine reticular formations on both sides.

Presence of Deep White Matter Lesions on Diffusion-Weighted Imaging Is a Negative Predictor of Early Dramatic Improvement after Intravenous Tissue Plasminogen Activator Thrombolysis

Background: The impact of deep white matter lesions observed at the corona radiata on diffusion-weighted MRI (DWI-W lesions) on the clinical recovery of patients after tissue plasminogen activator (tPA) therapy is unclear. Our goal was to elucidate whether DWI findings before tPA could predict clinical recovery. Methods: A total of 83 consecutive patients with hyperacute anterior circulation ischemic stroke were enrolled. All patients underwent MRI within 3 h and received intravenous tPA. The relationships among the Alberta Stroke Program Early CT Score (ASPECTS) on DWI (DWI-ASPECTS), DWI-W lesions, early dramatic improvement (≧10-point reduction in the total National Institutes of Health Stroke Scale, NIHSS, score or a total NIHSS score of 0–2 after 24 h), early improvement (≧4-point reduction in the total NIHSS score after 24 h) and worsening (≧4-point increase in the total NIHSS score after 24 h) were assessed. Results: The median of the baseline DWI-ASPECTS value was 9 (range: 5–10), and DWI-W lesions were found in 36 patients (43%). Patients with early dramatic improvement had a shorter time from onset to tPA (116.1 ± 34.9 vs. 133.2 ± 33.1 min; p = 0.0281) and higher DWI-ASPECTS (medians: 9 vs. 9; p = 0.0568). DWI-W lesions were seen less frequently in patients with than without early dramatic improvement (26 vs. 54%; p = 0.0213). Multivariate logistic regression analysis demonstrated that absence of DWI-W lesions (OR: 1.80; 95% CI: 1.08–3.13; p = 0.0279), higher ASPECTS (OR: 1.56; 95% CI: 1.06–2.46; p = 0.0346) and shorter time from onset to tPA (OR: 0.98; 95% CI: 0.97–0.99; p = 0.0429) were independent predictors of early dramatic improvement. Conclusions: DWI-ASPECTS and DWI-W lesions appear to be useful tools for predicting early dramatic improvement.

Role of nitric oxide in the peripheral vessels of patients with familial amyloidotic polyneuropathy (FAP) type I

In order to establish the generation of endothelial derived relaxating factor (EDRF) in patients with familial amyloidotic polyneuropathy (FAP) type I, the muscle temperature of the lower limb was measured with a deep portion thermometer. The temperature of the gastrocunemius muscle in FAP patients was significantly decreased compared with control subjects. In order to investigate the generation of EDRF in FAP patients, we administered NG-monomethyl-L-arginine (L-NMMA), specific inhibitor of nitric oxide, from the brachial artery and measured the changes in blood flow. Although 61.7 +/- 18.2% of the blood flow was transiently decreased after administration of L-NMMA in control subjects, FAP patients showed poor responses. In contrast, in the same way as in control subjects, significant vasodilatation was seen in FAP patients after administration of L-arginine. The urinary secreted NO2-/NO3- levels per day, which reflect the synthesis of nitric oxide in the systemic circulation, was a great deal lower in FAP patients than in control subjects. These results suggest that, although peripheral vessels can be dilated when a large amount of the substrate for NO synthase, L-arginine, is supplied, production of nitric oxide may be suppressed, and, as the result of this phenomenon, blood flow is decreased in the peripheral tissues of FAP patients in a static state.

Anticoagulation therapy for vertebral artery stump syndrome.

There are very few reports describing the presence of a stump embolism after vertebral artery occlusion. We describe three patients who presented with posterior circulation ischemic strokes after vertebral artery occlusion. These patients were successfully treated with anticoagulation therapy without surgical or endovascular treatment.

Vertebral artery stump syndrome in acute ischemic stroke.

Although the carotid artery stump as an embolic source for ischemic stroke has been well described, there have been few systematic reports of a similar syndrome in the posterior circulation (PC) after vertebral artery (VA) origin occlusion. The aim of this study was to identify the incidence and characteristics of acute ischemic stroke with VA stump syndrome. Of 3463 consecutive patients who were admitted within 7 days after onset, 865 patients with acute ischemic stroke in the PC were enrolled. The diagnostic criteria of VA stump syndrome included: (1) acute ischemic stroke in the posterior circulation; (2) the VA origin occlusion identified on MRA, duplex ultrasound, CT angiography, and/or conventional angiography; (3) presence of distal antegrade flow in the ipsilateral VA; and (4) absence of other causes of ischemic stroke. Of the 865 patients with PC stroke, 12 (1.4%) were diagnosed as having VA stump syndrome. The ischemic lesions included the cerebellum in all patients. Nine patients had multiple ischemic lesions in the brain stem, thalamus, or posterior lobe other than cerebellum. On duplex ultrasound, a to-and-fro flow pattern was observed in the culprit VA in 10 patients. Three patients had recurrences of ischemic stroke in the PC during the acute phase. VA stump syndrome was not a rare mechanism of PC stroke, and there was a high rate of stroke recurrence during the acute phase. Vascular assessment by a multimodality approach can be used to promptly detect VA stump syndrome.