Predictive models of syncope causes in an outpatient clinic.

UNLABELLED: The investigation of unexplained syncope remains a challenging clinical problem. In the present study we sought to evaluate the diagnostic value of a standardized work-up focusing on non invasive tests in patients with unexplained syncope referred to a syncope clinic, and whether certain combinations of clinical parameters are characteristic of rhythmic and reflex causes of syncope. METHODS AND RESULTS: 317 consecutive patients underwent a standardized work-up including a 12-lead ECG, physical examination, detailed history with screening for syncope-related symptoms using a structured questionnaire followed by carotid sinus massage (CSM), and head-up tilt test. Invasive testings including an electrophysiological study and implantation of a loop recorder were only performed in those with structural heart disease or traumatic syncope. Our work-up identified an etiology in 81% of the patients. Importantly, three quarters of the causes were established non invasively combining head-up tilt test, CSM and hyperventilation testing. Invasive tests yielded an additional 7% of diagnoses. Logistic analysis identified age and number of significant prodromes as the only predictive factors of rhythmic syncope. The same two factors, in addition to the duration of the ECG P-wave, were also predictive of vasovagal and psychogenic syncope. These factors, optimally combined in predictive models, showed a high negative and a modest positive predictive value. CONCLUSION: A standardized work-up focusing on non invasive tests allows to establish more than three quarters of syncope causes. Predictive models based on simple clinical parameters may help to distinguish between rhythmic and other causes of syncope.

Cerebral vascular autoregulation assessed by perfusion-CT in severe head trauma patients.

PURPOSE: To use perfusion-CT technique in order to characterize cerebral vascular autoregulation in a population of severe head trauma patients with features of cerebral edema either on the admission or on the follow-up conventional noncontrast cerebral CT. MATERIAL AND METHODS: A total of 80 perfusion-CT examinations were obtained in 42 severe head trauma patients with features of cerebral edema on conventional noncontrast cerebral CT, either on admission or during follow-up. Perfusion-CT results, i.e. the regional cerebral blood volume (rCBV) and flow (rCBF), were correlated with the mean arterial pressure (MAP) measured during each perfusion-CT examination. Ratios were defined to integrate the concept of cerebral vascular autoregulation, and cluster analysis performed, which allowed identification of different subgroups of patients. MAP values and perfusion-CT results in these groups were compared using Kruskal-Wallis and Wilcoxon (Mann-Whitney) tests. Moreover, the functional outcome of the 42 patients was evaluated 3 months after trauma on the basis of the Glasgow Outcome Scale (GOS) score and similarly compared between groups. RESULTS: Three main groups of patients were identified: 1) 22 perfusion-CT examinations were collected in 13 patients, characterized by high rCBV and rCBF values and by significant dependence of perfusion-CT rCBV and rCBF results on MAP values (p<0.001), 2) 23 perfusion-CT examinations collected in 19 patients showing perfusion-CT results similar to control trauma subjects, and 3) 33 perfusion-CT collected in 16 patients, with low rCBV and rCBF values and near-independence of perfusion-CT results with respect to MAP values. The first group was interpreted as showing impaired cerebral vascular autoregulation, which was preserved in the third group. The second group was associated with the best functional outcome; it was linked to the first group, because eight patients went from one group to the other from admission to follow-up. CONCLUSION: Perfusion-CT in severe head trauma patients was able to provide direct and quantitative assessment of cerebral vascular autoregulation with a single measurement. It could hence be used as a guide for brain edema therapy, as well as to monitor the treatment efficiency.

Stroke patterns, etiology, and prognosis in patients with diabetes mellitus.

BACKGROUND: Although diabetes mellitus (DM) is a risk factor for stroke, it is unclear whether stroke features are different in diabetic vs nondiabetic individuals. OBJECTIVE: To assess the role of DM in stroke patients. METHODS: Risk factors, etiology, lesion topography, clinical features, and outcome were assessed in 611 diabetic individuals (history of DM or fasting plasma glucose level of > or =7.0 mmol/L) among 4,064 consecutive patients of the Lausanne Stroke Registry. RESULTS: Patients with DM were 5.3 years older than non-DM patients. After multivariate analysis, DM was associated with lower relative prevalence of intracerebral hemorrhage (ICH; odds ratio [95% CI]: 0.63 (0.45 to 0.9); p = 0.022), higher relative prevalence of subcortical infarction (SCI; 1.34 [1.11 to 1.62]; p = 0.009), and higher relative frequency of small-vessel (SVD; 1.78 [1.31 to 3.82]; p = 0.012) and large-artery (LAD; 2.02 [1.31 to 2.02]; p = 0.002) disease. In the cohort of diabetic stroke patients, there was no interaction of DM with either hypertension or age for the outcomes of ICH, SCI, SVD, and LAD. Moderate to severe deficit on admission (31.1 vs 31.6%; p = 0.4) and poor functional outcome at 1 month (14.1 vs 15.3%; p = 0.24) did not differ in patients with DM compared with non-DM patients. In multivariate analysis, neither DM (0.86 [0.63 to 1.11]; p = 0.15) nor hypertension (1.09 [0.91 to 1.39]; p = 0.32) was associated with poor functional outcome. CONCLUSIONS: Diabetic stroke patients are associated with specific patterns of stroke type, etiology, and topography but not with poor functional outcome. There was no interaction between DM and hypertension or age.

Glomerular filtration rate: measure creatinine and height rather than cystatin C!

AIM: Inulin clearance (Cin) is the gold standard for assessing glomerular filtration rate (GFR). Other methods are based on the plasma creatinine concentration (Pcreat), creatinine clearance (Ccreat), the Haycock-Schwartz formula and the plasma concentration of cystatin C (PcysC), a 13 kDa basic protein produced at a constant rate by all nucleated cells. The present prospective study was thus designed to evaluate the reliability of PcysC as a marker of GFR in comparison with that of Pcreat, Ccreat and the Haycock-Schwartz formula, using Cin as the gold standard. METHODS: Ninety-nine children (51 m/48 f), with a median age of 8.3 y (1.0-17.9) were studied. Using a cut-off for Cin of 100 ml/min per 1.73 m2, 54 children (54.5%) had impaired GFR. Those with normal GFR were comparable for age, height, weight and body mass index. RESULTS: Logistic regression, ROC analysis and linear regression all showed that Ccreat was the best parameter to discriminate between impaired and normal GFR, followed by the Haycock-Schwartz formula, PcysC, and finally Pcreat, each one being significantly more predictive than the next. CONCLUSION: GFR is better assessed by the Haycock-Schwartz formula than by PcysC or Pcreat alone. It is therefore concluded that when urine collection is not possible, simply measuring the child's Pcreat and height is the best, easiest and cheapest way to assess GFR.

Prodromal and early epileptic seizures in acute stroke: does higher serum cholesterol protect?

In a case-control study, patients (n = 43/3,628) presenting seizures <1 week before (n = 6), < or =3 hours after (n = 26), and 3 to 24 hours after (n = 11) a first-ever stroke were studied. On multivariate analysis, they were characterized by lower levels of serum cholesterol (5.86 +/- 0.51 vs 6.34 +/- 0.58; p < 0.0001). Mortality and functional outcome at discharge were not influenced. Early poststroke seizures occur mainly during the critical 3-hour window for thrombolysis. Hypercholesterolemia appears to protect against seizures and cerebral ischemia.

Oxidative stress in gastric mucosa of asymptomatic humans infected with Helicobacter pylori: effect of bacterial eradication.

BACKGROUND: Inducible nitric oxide synthase (iNOS) and interleukin 8 (IL-8) are positive in approximately 50% of Helicobacter pylori-related diseases but it is not clear whether oxidative stress is also present in H. pylori asymptomatic humans. Our aim was to study the expression of iNOS, superoxide dismutase, catalase and IL-8 production in H. pylori-infected asymptomatic humans, and to investigate the effect of eradication of H. pylori. MATERIALS AND METHODS: Biopsies of corpus and antrum of asymptomatic H. pylori positive and negative humans served for determination of the gastritis score and H. pylori status; iNOS was measured by reverse transcriptase polymerase chain reaction and immunohistochemistry and superoxide dismutase and catalase by immunohistochemistry. IL-8 in biopsies was assessed by enzyme-linked immunosorbent assay. RESULTS: Immunostaining of iNOS, catalase and superoxide dismutase was significantly associated with H. pylori infection and was localized to inflammatory cells. IL-8 concentrations were greater in the H. pylori positive than H. pylori negative group and decreased after bacterial eradication. A decrease in staining for iNOS and catalase was observed after H. pylori eradication. CONCLUSIONS: INOS and antioxidant enzymes are present in gastric biopsies of asymptomatic H. pylori positive humans. Eradication caused a significant decrease in staining for iNOS and catalase. These results indicate that oxidative stress occurs in asymptomatic patients and can be modulated by H. pylori eradication.

Stroke or transient ischemic attacks with basilar artery stenosis or occlusion: clinical patterns and outcome.

BACKGROUND: Basilar artery occlusion (BAO) is associated with a high mortality rate, although cases with spontaneous favorable outcomes have recently been reported, and basilar artery stenosis (BAS) has received little consideration until now. OBJECTIVE: To study the prognostic clinical factors by testing numerous combinations of admission status characteristics of patients with brain ischemia caused by BAO or BAS. METHODS: We conducted a retrospective review from the Lausanne Stroke Registry (group 1) of patients with stroke or transient ischemic attack caused by BAS less than 50% or BAO as diagnosed by magnetic resonance angiography who were not treated by thrombolysis. Neurologic findings on admission were correlated with outcomes. We compared clinical patterns associated with poor outcomes in group 1 with those in patients with stroke who died from BAO or BAS (confirmed at autopsy) (group 2). RESULTS: Eighty-eight patients were studied. The outcomes of patients with stroke in group 1 (35/43) was poor (severe disability or death) in 54% of cases. A statistical analysis revealed that 4 factors-dysarthria, pupillary disorders, lower cranial nerve involvement, and consciousness disorders on admission-were strongly (P<.001) associated with poor outcomes. The multivariate analysis showed that the outcome was poor in 100% of cases in which consciousness disorders or the combination of the remaining 3 factors were present, whereas in the absence of these factors, a poor outcome was reported in only 11%. In 87% of the 45 patients with stroke in group 2, the same clinical patterns were present on admission. CONCLUSIONS: The prognosis of BAS greater than 50% or BAO is diverse and certain clinical characteristics seem to predict a lower risk of poor outcome. Their presence may help to decide the most suitable therapy.

Risk of falls for hospitalized patients: a predictive model based on routinely available data.

The incidence rate of falls is often used as an indicator of nursing care outcome. Comparing outcome between different settings should, however, make allowance for case mix. To measure the incidence of falls, describe their circumstances and develop a prediction model based on routinely collected data to allow comparison between hospital settings with different case mix. A dynamic population of patients hospitalized over a year in which a case was defined as any accidental fall systematically reported on an ad hoc form. A Swiss university hospital of 800 beds; 634 falls were reported for 26,643 hospitalizations over 236,307 hospitalization days. First fall rates were analyzed using a Poisson regression model with routinely computerized discharge data as independent variables. The incidence rate of first falls was 2.2 per 1000 patient-days. For subsequent falls the rates of incidence increased with the number of falls. Five independent variables played a significant role: age, gender, morbidity predisposition, surgical procedure and length of stay. Two of the interactions between these variables were significant and remained in the model (length of stay with age, morbidity with age). The model offers good medical plausibility and satisfactory predictive performance. The proposed model can be used by national health agencies to compute expected first fall rates accounting for case mix. Hospitals can use these rates for evaluation. Recommendations for measuring, monitoring and assessing fall rates are also given.

Ischemic stroke and active migraine.

OBJECTIVE: To determine the characteristics of acute ischemic stroke (IS) in patients with active migraine in a prospective stroke registry. METHODS: The authors studied the characteristics of patients admitted to a population-based primary-care center with IS and active migraine. The diagnosis of previous migraine was made based on replies to International Headache Society-based questions. Patients with migraine were divided into two age groups, one below 45 years of age and one 45 years or older, and compared by univariate and multivariate analysis with age-matched control subjects with IS, but without migraine. RESULTS: Of the 3,502 patients with acute IS, 130 (3.7%) had active migraine; 66 of these were younger than 45 years and 64 were 45 years or older (15.8% and 2.1% of the total for the corresponding age group). The proportion of women was significantly higher in both groups of patients with migraine (74% and 63% in the younger and older groups) than in control subjects. In young migraineurs, the posterior circulation involvement and the presence of patent foramen ovale were characteristic. In the younger migraine group, nine patients developed IS during a typical attack of migraine with aura, and 15 during migraine attack without aura in the absence of any other determined cause. In the older group, surprisingly, absence of vascular risk factors (previous hypertension, ischemic heart disease, and cigarette smoking) was characteristic. CONCLUSIONS: Migraine is frequent in young patients with IS and infrequent in older patients with IS. Patients with IS and migraine are mainly women with stroke features that are age dependent.

Irritancy of the skin disinfectant n-propanol.

Hand disinfection with short-chain aliphatic alcohols, so-called "rub-ins" is the method of choice for cross-infection prevention in health care environments, but their irritant potential is not well known. Skin tolerance is a major compliance factor, and a high proportion of health care workers suffer from low-grade irritant contact dermatitis. Therefore, assessment of the irritancy of the skin disinfectant n-propanol 60%, and comparative 100% and 0% solutions, was performed in the setting of experimental low-grade ICD. ICD was induced by overnight patch exposure to H2O, and to 0.3% sodium dodecyl sulfate (SDS), in 12 probands, followed by repeated open exposure to the test substances. Outcome variables were transepidermal water loss (TEWL), and skin surface capacitance. On skin sites pre-irritated by SDS, all n-propanol concentrations (100%, 60%, 0%) increased TEWL. However, a clear divergence appeared between pure n-propanol, and the lower concentrations. In contrast to pure n-propanol, n-propanol 60% and 0% had no significant effect on TEWL on H2O-pre-irritated skin sites. Capacitance of pre-irritated skin sites was increased by exposure to H2O-containing n-propanol solutions (60% and 0%). These results show a clear difference between the irritant potential of n-propanol 100% on one side, and n-propanol 60% and 0% on the other side. The level of pre-existent skin irritation is a pertinent factor in susceptibility to irritation, as the irritant potential of n-propanol 60%, the concentration used in daily practice, and n-propanol 0% (water) became significant only on detergent-irritated skin. Thus, preventive skin care may be a constructive approach in increasing tolerance of modern hand disinfection practices.

Comparison of 2 methods for calculating adjusted survival curves from proportional hazards models.

CONTEXT: Adjusted survival curves are often presented in medical research articles. The most commonly used method for calculating such curves is the mean of covariates method, in which average values of covariates are entered into a proportional hazards regression equation. Use of this method is widespread despite published concerns regarding the validity of resulting curves. OBJECTIVE: To compare the mean of covariates method to the less widely used corrected group prognosis method in an analysis evaluating survival in patients with and without diabetes. In the latter method, a survival curve is calculated for each level of covariates, after which an average survival curve is calculated as a weighted average of the survival curves for each level of covariates. DESIGN, SETTING, AND PATIENTS: Analysis of cohort study data from 11 468 Alberta residents undergoing cardiac catheterization between January 1, 1995, and December 31, 1996. MAIN OUTCOME MEASURES: Crude and risk-adjusted survival for up to 3 years after cardiac catheterization in patients with vs without diabetes, analyzed by the mean of covariates method vs the corrected group prognosis method. RESULTS: According to the mean of covariates method, adjusted survival at 1044 days was 94.1% and 94.9% for patients with and without diabetes, respectively, with misleading adjusted survival curves that fell above the unadjusted curves. With the corrected group prognosis method, the corresponding survival values were 91.3% and 92.4%, with curves that fell more appropriately between the unadjusted curves. CONCLUSIONS: Misleading adjusted survival curves resulted from using the mean of covariates method of analysis for our data. We recommend using the corrected group prognosis method for calculating risk-adjusted curves.

The efficacy of a protective cream in a real-world apprentice hairdresser environment.

The object of this study was to compare the protective action of a new barrier cream (Excipial Protect, Spirig Pharma AG, Egerkingen, Switzerland) to its vehicle in the context of hand irritation of apprentice hairdressers caused by repeated shampooing and exposure to hair-care products. This was a double-blind cross-over comparing Excipial Protect (containing aluminium chlorohydrate 5% as active ingredient) against its vehicle alone. The efficacy of the creams was evaluated taking into account: (1) clinical scores by researchers, (2) biometric measurements, (3) subjective opinions of the subjects. An analysis of variance was performed considering order of application, degree of atopy, and reported number of shampoos. We observed very little difference in efficacy between the protective cream and its vehicle. The presence, however, of aluminium chlorhydrate in the protective cream was shown to have a positive effect against work-related irritation. The cosmetic qualities of the creams seemed, to the participants, to be as important as their real protective and hydrating properties, an important factor in compliance issues.

Stroke with internal carotid artery stenosis.

BACKGROUND: Stroke patterns in patients with different degrees of carotid stenosis have not been systematically studied. OBJECTIVE: To determine first-ever stroke subtypes in nonselected patients with extracranial internal carotid artery (ICA) stenosis, based on a primary care hospital stroke registry. METHODS: One hundred seventy-three patients who experienced their first-ever stroke and who had 50% or greater (North American Symptomatic Carotid Endarterectomy Trial method) ipsilateral extracranial ICA stenosis, corresponding to 6.5% of 2649 patients with anterior circulation stroke included in the Lausanne Stroke Registry, were studied. All these patients underwent Doppler ultrasonography, carotid angiography (conventional or magnetic resonance angiography), neuroimaging (computed tomography or magnetic resonance imaging), and other investigations from the standard protocol of the Lausanne Stroke Registry. RESULTS: We found the following types of infarct in the middle cerebral artery territory: anterior pial in 54 (31%) of the patients; subcortical, 34 (20%); posterior pial, 32 (19%); large hemispheral, 20 (12%); and border zone, 17 (10%). There were multiple pial in 14 (8%) and multiple deep infarcts in 2 (1%) of the patients. Moderate (50%-69%) ICA stenosis was significantly associated with large hemispheral infarcts and a normal contralateral ICA (P =.04 and P =.02, respectively). Seventy percent to 89% of ICA stenosis was associated with prior transient ischemic attacks (P =.02). After adjusting for cardioembolism, border zone infarcts showed a strong trend to appear mostly in patients with 90% to 99% ICA stenosis (P =.06). CONCLUSIONS: The association of a large hemispheral infarct with moderate ICA stenosis suggests a large embolism and/or an inadequate collateral supply. While an embolism may also contribute, the association of border zone infarcts with 90% to 99% ICA stenosis emphasizes the significance of hemodynamic disturbance in the pathogenesis of these types of infarct.

Is there a place for duplex screening of brachial artery in haemodialysis patients with vascular access?

BACKGROUND: Vascular access (VA) stenosis with subsequent thrombosis remains one of the major causes of morbidity and hospitalization in haemodialysis patients. The present cross-sectional study was planned in order to analyze the usefulness of brachial artery duplex ultrasound for detection and prediction of vascular access stenoses. METHODS: Color duplex ultrasound (Apogée Cx200, sectorial probe 7.5 MHz) was used to obtain the anatomical pattern of the VA and flow velocity waveforms of the brachial artery in 77 non-selected VA (47 Ciminio-Brescia fistulae and 30 PTFE grafts). In each VA, the resistance index (RI), the mean blood flow rate (Q) and the blood flow ratio index (QI) (QI = VA flow rate/contralateral flow rate) were calculated at the level of the brachial artery. The sensitivity and specificity of these brachial Doppler parameters were calculated for the detection of VA stenosis. In normal VA, positive (PPV) and negative predictive (NPV) values were calculated for the development of clinical stenotic complications 3 months post ultrasound examination. RESULTS: Thirteen of the 77 VA (17%) were identified as stenosed by duplex ultrasound and confirmed by fistulography and/or during surgical exploration. The best screening tests for VA stenosis detection were a QI threshold < 4.0 with a sensitivity and specificity of 69 and 69% and an RI > 0.55 with a sensitivity and specificity of 62 and 66%, respectively. In the VA considered as normal by ultrasound, the prediction of subsequent stenosis within three months post-ultrasound examination gave a PPV of only 18% and 19% for RI and QI, respectively. NPV for RI and QI were 90% and 88%. CONCLUSIONS: While Doppler ultrasound is a useful non-invasive test for the detection of prevalent VA stenosis, our results do not confirm that abnormal brachial Doppler flow parameters can predict short term development of VA stenosis.

[Neurological comorbidity in parkinsonism]. / Comorbidités neurologiques du parkinsonisme.

We studied the neurological comorbidity of parkinsonism in 368 consecutive patients from the Lausanne Movement Disorders Registry. Only 6 patients had no neurological comorbidity. We found that 23p.100 of our patients had ischemic strokes, especially large vessel strokes, i.e three times more than in an age-matched control study performed in a recent survey in our country, which is a new finding in contradiction with previous reports mentioning that Parkinson's disease may be a protective factor against stroke. This finding opens new directions for further studies concerning some shared mechanisms in both diseases associated with age. Predominantly tremulous parkinsonism (46p.100) and progressive supranuclear palsy patients (PSP) (40p.100) had the highest prevalence of cerebrovascular disease of all subgroups of parkinsonism, especially lacunar infarcts, which is in accord with a higher frequency of hypertension in these subgroups according to a recent study of ours. Transient ischemic attacks or hemorrhages were not more frequent than in the general population. We did not find a higher frequency of head trauma except for Parkinson's disease, but a trend for a higher frequency of headache and migraine. Brain tumors were more frequent in Parkinson's disease and hydrocephalus and radiculopathies in parkinsonism in general when compared to age-matched populations from the literature. Polyneuropathies were more frequently observed in familial parkinsonism only, but myopathies and cranial neuropathies were not more frequent in our patients. Epilepsy was significantly less frequent in parkinsonism, especially in Parkinson's disease, infectious diseases of the nervous system were rarely encountered, and restless legs syndrome was surprisingly not more frequent than in a normal population. Dementia was associated in 20p.100, but multiple sclerosis is noticeably absent.

Heart and carotid artery disease in stroke patients with intermittent claudication.

Much has been published on the natural history of intermittent claudication (IC), but little is known about the clinical features of stroke patients with IC. The purpose of this study was to examine clinical features and risk factors in stroke patients with or without IC, including heart disease and carotid artery disease. A hospital-based study was conducted of 3901 stroke patients, who were prospectively coded and entered into a computerized databank. Of these patients, 219 had symptoms of IC. Patients were subdivided by age into 10-year categories. There were at least 12 times more non-IC than IC patients in each category. An age-matched random sample was obtained containing 12 non-IC cases for each IC case, resulting in 219 cases of IC and 2628 non-IC cases. The prevalence of IC in the total stroke population was 5.6%. IC prevalence increased sharply with age until about 70 years. Cardiac ischaemia and internal carotid artery (ICA) disease were significantly more frequent in stroke with IC than without IC. IC patients also exhibited a higher prevalence of atherosclerotic disease as well as other risk factors such as smoking, hypercholesterolaemia, elevated haematocrit, and family history of stroke. Ischaemic heart disease and ICA disease are especially common in stroke with IC. IC, large artery disease and stroke share similar risk factors. IC symptoms in stroke patients may indicate extensive generalized atherosclerosis.

[Reference values of intima-medial thickness of carotid and femoral arteries in subjects aged 20 to 60 years and without cardiovascular risk factors]. / Valeurs de référence des épaisseurs intima-média des artères carotidiennes et fémorales chez des sujets âgés de 20 à 60 ans et sans facteur de risque cardiovasculaire.

Many studies have shown a close correlation between intima-medial thickness of the carotid artery measured by high resolution ultrasonography and the presence of coronary artery disease or atherogenic risk factors. However, reference values for the value of intima-medial thickness (IMT) in healthy subjects have not yet been established. The aim of this study was, therefore, to determine the reference values of carotid (C-IMT) and femoral intima-medial thickness (F-IMT) with respect to age and gender in healthy subjects (53 women and 45 men) aged 20 to 60, with no family or personal history of cardiovascular disease or atherogenic risk factors, underwent high resolution colour echo-Doppler examination. The mean C-IMT was 556 +/- 57 microns in women and 573 +/- 70 microns in men (NS), and the femoral equivalent was 543 +/- 63 microns in women and 562 +/- 74 microns in men (NS). Between the ages of 20 and 60, the C-IMT increased by 1.8 microns per year (p < 0.03) in women and 3.4 microns (p < 0.001) in men, the variations being respectively 1.2 microns (NS) and 3.1 microns (p < 0.002) in the femoral artery. Multiple regression analysis including gender and individual values of age, body mass index and lipid profile confirmed that only age was significantly correlated to the increase in thickness. The authors conclude that the reference values of IMT do not differ with gender or site of analysis, but there is a slight influence with respect to age.

Effects of proximal and distal muscles' groups contraction and mental stress on the amplitude and frequency of physiological finger tremor. An accelerometric study.

Physiological finger tremor was assessed by two-dimensional solid accelerometry in 40 healthy normal subjects at rest (R) with the hand hanging over the armrest of a chair, in posture (P) with the arm rested on the armrest but the hand extended from the wrist, and finally adding proximal muscles contraction in extension (E) with the arm extended in front of the patient, each time with and without mental stress. The mean amplitude for physiological tremor, about 30 microns, was almost doubled by hand extension and increased by 4 to 5-fold by arm extension with further increase by mental stress in each position, which gives a good estimation of the contribution of proximal and distal muscles into the amplitude of physiological tremor. There was no significant effect of age between 20 and 60 years on tremor amplitude, but mean tremor frequency decreased significantly between 40 to 60 years. Mental stress increased amplitude but decreased tremor frequency of both across all position, possibly by increasing the synchronization of motor unit firing and by modifying the gain of the motoneurones and the stretch reflex as shown by electrophysiological studies.

Coexisting causes of ischemic stroke.

BACKGROUND: Coexistence of multiple potential causes of cerebral infarct (MPCI) has been poorly studied. OBJECTIVE: To determine the risk factors, clinical findings, and topographical patterns of patients with at least 2 potential causes of cerebral infarct. DESIGN: Data analysis from a prospective acute stroke registry (the Lausanne Stroke Registry, Lausanne, Switzerland) in a community-based primary care center. RESULTS: Among 3525 patients with first-ever ischemic stroke consecutively admitted to a primary care stroke center, 250 patients (7%) had at least 2 MPCIs, with the following subgroups: large artery disease and a cardiac source of embolism (LAD + CSE) (43%), small artery disease and CSE (SAD + CSE) (34%), LAD + SAD (18%), and LAD + SAD + CSE (5%). Hypertension, cardiac ischemia, and a history of atrial fibrillation predominated in the LAD + SAD + CSE subgroup (P<.001), while cigarette smoking was more prevalent in the LAD + SAD subgroup (P<.05). A decreased level of consciousness and speech disorders were more common in the LAD + CSE subgroup (P<.001). Lacunar syndromes predominated in the LAD + SAD subgroup. Pure motor stroke was the most frequent lacunar syndrome in all subgroups, but sensory motor stroke predominated in the LAD + CSE subgroup (P<.05). The outcome at 1 month was worse in the LAD + CSE and SAD + CSE subgroups (P<.001). Other stroke characteristics and clinical features did not differ significantly between the 4 subgroups of patients with MPCI. CONCLUSIONS: Our findings suggest that MPCIs are uncommon. The most frequent association is LAD + CSE. Topographical patterns of stroke and clinical characteristics in patients with MPCI only rarely allow emphasis of a preeminent cause. Arch Neurol. 2000;57:1139-1144