Th. Büttner

Elevated plasma levels of homocysteine in Parkinson's disease.

Significantly elevated plasma levels of homocysteine, but not cysteine and cysteinylglycine, were found in treated parkinsonian patients compared to controls. Elevated levels of homocysteine may be either caused by an unknown endogenous metabolic disturbance or by antiparkinsonian treatment, because no association to severity or duration of disease was found. Based on the results of this study one may speculate that homocysteine may be an independent risk factor for vascular disease in Parkinson’s disease.

DISTORTED COLOR DISCRIMINATION IN DE NOVO' PARKINSONIAN PATIENTS

Article abstract—We performed the Farnsworth-Munsell 100–hue test in 16 “de novo” patients with Parkinsons disease and 16 age-matched controls to determine their color discrimination ability. “he mean total error score in patients was significantly elevated as compared with controls (64.6 in patients versus 16.0 in controls). We conclude that the impairment of color discrimination may be an early sign in Parkinsons disease.

Ultrasonic evaluation of pathological brain perfusion in acute stroke using second harmonic imaging

OBJECTIVE To evaluate the use of transient response second harmonic imaging (HI) by means of ultrasound to assess abnormalities of cerebral echo contrast agent enhancement in patients with acute stroke. METHODS The study comprised 25 patients with acute onset of hemispheric stroke (<24 h) with sufficient insonation conditions and 14 control subjects without cerebrovascular disease. All stroke patients had HI, extracranial and transcranial colour coded duplex examinations of the arteries supplying the brain, and clinical examinations (European stroke scale) performed in the acute phase, on day 2, and within 1 week. Acute CT was repeated within 1 week and facultatively accompanied by angiography. Examinations using HI were performed in an axial diencephalic plane of section using the transtemporal acoustic bone window. After bolus application of galactose based microbubbles, 61 ultrasound images with a cardiac cycling triggering frequency of once every 2 seconds were recorded and evaluated off line. Focal perfusion deficit was identified if no contrast enhancement was visualised in a circumscribed region of interest and insufficient temporal bone window was excluded. In cases of reappearance of contrast enhancement reperfusion was assessed. RESULTS Adequate cerebral contrast enhancement could be seen in 21 subjects. In seven, a large hemispheric deficit of contrast enhancement affecting the entire middle cerebral artery (MCA) territory was detectable; the lentiform nucleus was affected in three subjects. Assessment of cerebral contrast abnormalities was possible in two patients with superficial MCA infarctions but in none of the patients with lacunar ischaemias. None of the control persons had focal deficits of cerebral echo contrast enhancement. In all patients with complete MCA infarction and striatocapsular infarction, presumed ischaemic areas in HI examinations correlated with final CT findings. Overall sensitivity and specifity of HI examinations for predicting size and localisation of the infarction were 75 and 100%, respectively. During follow up, reappearance of contrast enhancement was determined in three patients, in two patients circulatory arrest due to malignant brain oedema with missing contrast enhancement in the entire cerebral hemisphere could be seen. Extent of contrast enhancement deficits significantly correlated with the clinical status on admission and after 1 week (p<0.01). CONCLUSIONS Second harmonic imaging is the first ultrasonic technique that enables visualisation of pathological cerebral echo contrast enhancement. Because this method identifies deficits of focal contrast enhancement in patients with acute stroke and allows estimation of the final infarct size and clinical prognosis, it may help to select and monitor patients for invasive therapies.

L-dopa improves colour vision in Parkinson's disease

SummaryIn recent studies disorders of colour vision in Parkinsonian patients have been demonstrated. Up to now, the influence of dopaminergic treatment on those phenomena remains unclear. We therefore performed a colour vision test (Farnsworth-Munsell 100 Hue Test) in 19 patients with Parkinsons disease before and aater the oral application of the morning dose of L-dopa. The colour discrimination was significantly improved after the ingestion of L-Dopa. There was no different effect of L-Dopa on the blue-yellow or red-green axis of colour vision. The morphological structures responsible for these colour vision disturbances are unknown, but it can be concluded that the dopamine deficiency in Parkinsons disease is not restricted to the basal ganglia but may involve the visual system as well.

Basal ganglia alterations and brain atrophy in Huntington's disease depicted by transcranial real time sonography.

OBJECTIVES AND METHODS Transcranial real time sonography (TCS) was applied to 49 patients with Huntington’s disease and 39 control subjects to visualise alterations in the echotexture of the basal ganglia. For comparison T1 weighted, T2 weighted, and fast spin echo MRI was performed in 12 patients with Huntington’s disease with and in nine patients without alterations of the basal ganglia echotexture as detected by TCS and T1 weighted, T2 weighted, and fast spin echo MRI. Furthermore, the widths of the frontal horns, third ventricle, and the lateral ventricles were depicted in TCS examinations and correlations examined with corresponding CT slices. RESULTS Eighteen out of 45 (40%) of the patients with Huntington’s disease with adequate insonation conditions showed hyperechogenic lesions of at least one basal ganglia region. In 12 patients TCS depicted hyperechogenic lesions of the substantia nigra; in six patients the head of the caudate nucleus was affected. The lentiform nucleus (n=3) and the thalamus (n=0) were less often affected or spared. Hyperechogenic lesions were significantly more frequent in patients with Huntington’s disease than in 39 control subjects, who had alterations of the echotexture in 12.8% (4/39) of the examinations. The number of CAG repeats and the clinical status correlated with the identification of hyperechogenic lesions of the substantia nigra (p<0.01). Hyperechogenic lesions of the caudate nucleus were associated with an increased signal intensity in T2 weighted MR images (p<0.05). All TCS parameters indicating brain atrophy correlated with CT findings (p<0.0001). CONCLUSIONS TCS detects primarily abnormalities of the caudate nucleus and substantia nigra in Huntington’s disease. These changes in the echotexture may represent degenerative changes in the basal ganglia matrix and are partially associated with CAG repeat expansion and the severity of clinical findings.

Recanalization of acute symptomatic occlusions of the internal carotid artery.

Background Little is known about the natural course of internal carotid artery (ICA) occlusion and its possible recanalization. The present study was designed to evaluate recanalization rates of extracranial ICA occlusions in acute stroke patients by means of color-coded duplex sonography (CCDS). Methods 305 patients with acute ischemia in the territory of the middle cerebral artery were included in this study. All patients had a neurological examination on admission and on discharge and were rated by means of the European Stroke Scale (ESS). Extracranial color-coded duplexsonography, transcranial Doppler sonography and cranial computed tomography were immediately performed after admission and within 7 days. Results 254 patients showed no sign of hemodynamic relevant stenosis greater than 70 % of the ICA. 21 patients had symptomatic high grade ICA stenosis. 20 patients had an acute occlusion and 10 patients an old ICA occlusion as judged by duplex sonographic criteria. Six patients (5 male, 1 female; age range 57 to 77 years) with an acute atherothrombotic or cardioembolic occlusion showed a recanalization of the ICA in the follow-up ultrasonography. Two patients with cardiogenic embolic occlusion of the ICA had the most favorable outcome and these patients showed no residual stenosis. 4 patients who had ultrasound findings consistent with atherosclerosis on follow-up examination (2 high-grade stenosis, 2 with carotid plaques) did not show a notable improvement of their ESS-score. Patients with carotid plaques developed complete MCA infarctions; the other 4 patients had partial anterior circulation infarction on follow-up CT. Conclusions The present study showed that recanalization of the occluded ICA in acute stroke patients is more frequent than generally presumed. CCDS should be routinely performed in the follow-up of stroke patients as spontaneous recanalization may influence clinical outcome.

Chromatic and achromatic visual evoked potentials in Parkinson's disease

Chromatic and achromatic visual evoked potentials (VEP) were evaluated in 39 patients with idiopathic Parkinsons disease (PD) (age 64.0 +/- 8.6 years) and 43 healthy controls (age 62.8 +/- 8.7 years). The following pattern-reversal checkerboard stimuli were performed: (1) achromatic with luminance contrast 86% (achr.hk.) (2) achromatic with luminance contrast 20% (achr.lk.); (3) chromatic isoluminant blue-yellow (by.); (4) chromatic isoluminant red-green (rg.). The mean latencies N70, P100, and N135 of chromatic and achromatic VEP were significantly delayed in patients with PD as compared to controls. The highest rate (41.0%) of pathological findings could be demonstrated by achromatic stimulation (luminance contrast 86%). Isolated abnormalities of chromatic VEP (in combination with normal achromatic VEP) were found in 5 (12.8%) patients. The delay of VEP-latencies was significantly correlated with the severity of motor symptoms in PD patients. We conclude that VEP are valuable tools to demonstrate a dysfunction of the visual system in PD. Although chromatic VEP are less sensitive than achromatic VEP, the combination of both will increase the diagnostic yield. Therefore, there seems to exist a variety of individual characters of visual impairment in PD.

Disturbance of colour perception in Parkinson's disease

SummaryA computer-aided method for the determination of colour fusion time (CFT) was developed. CFT indicates the acuity of the perception of monochromatic contours. CFT was determined in 36 patients with Parkinsons disease (PD) and compared with a group of 36 age- and sexmatched controls. Patients with PD generally had a shortened fusion time, especially for dark-green, light-blue and dark-red stimuli. The results give evidence to the hypothesis of a colour peception disorder in PD. The physiological and pathoanatomical basis of this phenomenon is unknown, but a functional deficit of cortical neurons may be a probable cause.

Effects of apomorphine on visual functions in Parkinson's disease.

Summary. The effect of apomorphine on visual functions in Parkinsons disease (PD) was evaluated by use of a static contrast sensitivity test (VCTS charts), a colour discrimination test (Farnsworth-Munsell 100 Hue test) and the examination of achromatic and chromatic contour perception. 31 patients (14 male, 17 female; mean age 60.9 ± 9.2 years) with idiopathic PD were tested before and after an indivdual dosage of subcutaneously applied apomorphine showing a significant effect on motor function during the whole experiment. The achromatic spatial contrast sensitivity improved significantly after apomorphine injection with respect to all spatial frequencies. The improvement of colour discrimination after apomorphine application was minimal and not statistically significant. The small advantage of apomorphine with respect to colour discrimination may be explained by negative cognitive side-effects of apomorphine interfering with the test performance. The achromatic contour perception before and after apomorphine injection was unaltered. The contour fusion latency for the green stimulus was shortened, the latency for the rest of the examined coloured stimuli was delayed (=normalized) after apomorphine application. We conclude that apomorphine may be used as a test-drug for the examination of the dopaminergic response of the visual system in patients with PD. The improvement of basal visual functions by dopaminergic stimulation with apomorphine underlines the role of dopamine deficiency for visual dysfunction in PD.

Early CCT signs of supratentorial brain infarction: Clinico-radiological correlations

Early signs of brain infarction can be detected by modern CCT technology even within the first 6 h after stroke. Little is known about the prognostic significance of early infarction signs in CCT. We prospectively evaluated clinical and CCT findings of 95 consecutive patients with an acute ischemia in the territory of the middle cerebral artery. All patients were admitted to our stroke unit within 6 h after stroke. In 55 patients CCT was performed within 3 h, and in 40 cases between 3 and 6 h. In all patients the clinical findings were assessed by the Scandinavian Stroke Scale (SSS). The disability due to stroke was evaluated after 4 weeks by use of the modified Rankin Scale. We could demonstrate the following early signs of cerebral infarction: focal hypodensity (23.2%), obscuration of basal ganglia (12.6%), focal brain swelling (22.1%), hyperdense middle cerebral artery sign (HMCA; 11.5%). In 3 patients early edema led to ventricular compression, in 1 patient to midline shift. The occurrence of early infarction signs did not depend on the etiology of ischemia but was significantly associated with a severe neurological deficit at admission and an unfavourable disability status 4 weeks after stroke. Focal brain swelling and HMCA were often followed by extensive infarction lesions on the follow‐up CCT. In conclusion, early signs of hemispheric brain infarction visible on CCT scans performed within 6 h after stroke are correlated with severe stroke and an unfavourable functional outcome. However, a substantial part of our patients had a benign course of the disease in spite of early CCT pathology. Decisions on therapy in individual patients therefore should not depend on early CCT findings exclusively.