***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: BACKGROUND AND PURPOSE Traditional spectral and nonspectral methods have shown that heart rate ( HR ) variability is reduced after stroke . Some patients with poor outcome , however , show r and omlike , complex patterns of HR behavior that traditional analysis techniques are unable to quantify . Therefore , we design ed the present study to evaluate the complexity and correlation properties of HR dynamics after stroke by using new analysis methods based on nonlinear dynamics and fractals ( " chaos theory " ) . METHODS In addition to the traditional spectral components of HR variability , we measured instantaneous beat-to-beat variability and long-term continuous variability analyzed from Poincaré plots , fractal correlation properties , and approximate entropy of R-R interval dynamics from 24-hour ambulatory ECG recordings in 30 healthy control subjects , 31 hemispheric stroke patients , and 15 brain stem stroke patients ( 8 medullary , 7 pontine ) in the acute phase of stroke and 6 months after stroke . RESULTS In the acute phase , the traditional spectral components of HR variability and the long-term continuous variability from Poincaré plots were impaired ( P<0.01 ) in patients with hemispheric and medullary brain stem stroke , but not in patients with pontine brain stem stroke , in comparison with control subjects . At 6 months after stroke , measures of HR variability in hemispheric stroke patients were still lower ( P<0.05 ) than those of the control subjects . Various complexity and fractal measures of HR variability were similar in patients and control subjects . The conventional frequency domain measures of HR variability as well as the Poincaré measures showed strong correlations ( Pearson correlation coefficient , r=0.68 to r=0.90 ) with each other but only weak correlations ( r=0.09 to r=0.56 ) with the complexity and fractal measures of HR variability . CONCLUSIONS Hemispheric and medullary brain stem infa rct ions seem to damage the cardiovascular autonomic regulatory system and appear as abnormalities in the magnitude of HR variability . These abnormalities can be more easily detected with the use of analysis methods of HR variability , which are based on moment statistics , than by methods based on nonlinear dynamics . Abnormal HR variability may be involved in prognostically unfavorable cardiac complications and other known manifestations of autonomic failure associated with stroke Background and Purpose — The baroreceptor reflex arc is important in the short-term regulation of the cardiovascular system , and small studies have reported impaired cardiac baroreceptor sensitivity ( BRS ) after acute stroke . However , the prognostic significance of impaired BRS is uncertain . Methods — One hundred twenty-four patients underwent simultaneous ECG and noninvasive beat-to-beat blood pressure ( BP ) monitoring within 72 hours of neuroradiologically confirmed acute ischemic stroke . Cardiac BRS was assessed from the combined & agr;-index by means of power spectral analysis techniques . Baseline data for acute stroke patients were compared with those of a control group matched for age , sex , and casual BP . Patients were followed up for a median of 1508 days ( range , 9 to 2656 days ) , and outcome was compared between patients with and without impaired BRS . Results — Median BRS values were significantly lower in stroke patients than in controls ( 5 [ interquartile range , 3.5 to 7.4 ] versus 6.2 [ interquartile range , 4.5 to 8.3 ] ms/mm Hg;P = 0.04 ) . Sixty-one ( 33 male ) patients ( mean age , 70.2 [ SD 10.5 ] years ) had impaired BRS ( ≤5.0 ms/mm Hg ) compared with 63 ( 35 male ) patients ( mean age , 70.6 [ SD 11.7 ] years ) without impaired BRS ( > 5.0 ms/mm Hg ) . Stroke patients with impaired BRS values had a significantly poorer prognosis ( 28 % versus 8 % mortality rate during the follow-up period ) although there were no differences in age , stroke severity , stroke type , or casual or 24-hour BP parameters between the 2 groups . Conclusions — Impaired cardiac BRS is associated with increased long-term mortality after acute ischemic stroke , irrespective of age , sex , stroke type , and BP . This may reflect cardiac arrhythmias , but the mechanisms underlying this association are unknown , although therapies that improve cardiac BRS after stroke warrant further investigation Background The increasing burden of cardiovascular diseases ( CVD ) in the ageing population of industrialized nations requires an intensive search for means of reducing this epidemic . In order to improve prevention , detection , therapy and prognosis of cardiovascular diseases on the population level in Eastern Germany , it is necessary to examine reasons for the East-West gradient of CVD morbidity and mortality , potential causal mechanisms and prognostic factors in the elderly . Psychosocial and nutritional factors have previously been discussed as possible causes for the unexplained part of the East-West gradient . A reduced heart rate variability appears to be associated with cardiovascular disease as well as with psychosocial and other cardiovascular risk factors and decreases with age . Nevertheless , there is a lack of population -based data to examine the role of heart rate variability and its interaction with psychosocial and nutritional factors regarding the effect on cardiovascular disease in the ageing population . There also is a paucity of epidemiological data describing the health situation in Eastern Germany . Therefore , we conduct a population -based study to examine the distribution of CVD , heart rate variability and CVD risk factors and their associations in an elderly East German population . This paper describes the design and objectives of the CARLA Study . Methods / design For this study , a r and om sample of 45–80 year-old inhabitants of the city of Halle ( Saale ) in Eastern Germany was drawn from the population registry . By the end of the baseline examination ( 2002–2005 ) , 1750 study participants will have been examined . A multi-step recruitment strategy aims at achieving a 70 % response rate . Detailed information is collected on own and family medical history , socioeconomic , psychosocial , behavioural and biomedical factors . Medical examinations include  anthropometric measures , blood pressure of arm and ankle , a 10-second and a 20-minute electrocardiogram , a general physical examination , an echocardiogram , and laboratory analyses of venous blood sample s.  On 200 participants , a 24-hour electrocardiogram  is recorded . A detailed system of quality control ensures high data quality . A follow-up examination is planned . Discussion This study will help to eluci date pathways to CVD involving autonomic dysfunction and lifestyle factors which might be responsible for the CVD epidemic in some population Objective : To characterize the nature of sensory impairments after stroke , identify associated factors , and assess the relationships between sensory impairment , disability , and recovery . Methods : Prospect i ve cross-sectional survey of 102 people with hemiparesis following their first stroke .  Tactile and proprioceptive sensation  in the affected arm and leg were measured using the Rivermead Assessment of Somatosensory Perception 2 - 4 weeks post-stroke . Demographics , stroke pathology , weakness , neglect , disability , and recovery were documented . Results : Tactile impairment was more common than proprioceptive ( P < .000 ) , impairment of discrimination was more common than detection ( P < .000 ) , and tactile sensation was more severely impaired in the leg than the arm ( P < .000 ) . No difference in proprioception between the arm and leg ( P = .703 ) or between proximal and distal joints ( P = .589 , P = .705 ) was found . The degree of weakness and the degree of stroke severity were significantly associated with sensory impairment ; demographics , stroke side and type , and neglect were not associated . All the sensory modalities were significantly related to independence , mobility , and recovery ( r = 0.287 [ P < .011 ] to r = 0.533 [ P < .000 ] ) . Conclusion : Sensory impairments of all modalities are common after stroke , although tactile impairment is more frequent than proprioceptive loss , especially in the leg . They are associated with the degree of weakness and the degree of stroke severity but not demographics , stroke pathology , or neglect , and they are related to mobility , independence in activities of daily living , and recovery BACKGROUND Experimental evidence suggests that autonomic markers such as heart-rate variability and baroreflex sensitivity ( BRS ) may contribute to postinfa rct ion risk stratification . There are clinical data to support this concept for heart-rate variability . The main objective of the ATRAMI study was to provide prospect i ve data on the additional and independent prognostic value for cardiac mortality of heart-rate variability and BRS in patients after myocardial infa rct ion in whom left-ventricular ejection fraction ( LVEF ) and ventricular arrhythmias were known . METHODS This multicentre international prospect i ve study enrolled 1284 patients with a recent ( < 28 days ) myocardial infa rct ion .  24 h Holter recording was done to quantify heart-rate variability ( measured as st and ard deviation of normal to normal RR intervals [ SDNN ] ) and ventricular arrhythmias . BRS was calculated from measurement of the rate-pressure response to intravenous phenylephrine . FINDINGS During 21 ( SD 8) months of follow-up , the primary endpoint , cardiac mortality , included 44 cardiac deaths and five non-fatal cardiac arrests . Low values of either heart-rate variability ( SDNN < 70 ms ) or BRS ( < 3.0 ms per mm Hg ) carried a significant multivariate risk of cardiac mortality ( 3.2 [ 95 % CI 1.42 - 7.36 ] and 2.8 [ 1.24 - 6.16 ] , respectively ) . The association of low SDNN and BRS further increased risk ; the 2-year mortality was 17 % when both were below the cut-offs and 2 % ( p<0.0001 ) when both were well preserved ( SDNN > 105 ms , BRS > 6.1 ms per mm Hg ) . The association of low SDNN or BRS with LVEF below 35 % carried a relative risk of 6.7 ( 3.1 - 14.6 ) or 8.7 ( 4.3 - 17.6 ) , respectively , compared with patients with LVEF above 35 % and less compromised SDNN ( > or = 70 ms ) and BRS ( > or = 3 ms per mm Hg ) . INTERPRETATION ATRAMI provides clinical evidence that after myocardial infa rct ion the analysis of vagal reflexes has significant prognostic value independently of LVEF and of ventricular arrhythmias and that it significantly adds to the prognostic value of heart-rate variability INTRODUCTION Decreased heart rate variability ( HRV ) and abnormal nonlinear HRV shortly after myocardial infa rct ion ( MI ) are risk factors for mortality . Traditional HRV predicts mortality in patients with a range of times post-MI , but the association of nonlinear HRV and outcome in this population is unknown . METHODS AND RESULTS HRV was determined from 740 tapes recorded before antiarrhythmic therapy in Cardiac Arrhythmia Suppression Trial patients with ventricular premature contractions ( VPCs ) suppressed on the first r and omized treatment . Patients were 70 + /- 121 days post-MI . Follow up was 362 + /- 241 days ( 70 deaths ) . The association between traditional time and frequency-domain HRV and mortality and nonlinear HRV and mortality were compared for the entire population ( ALL ) , those without coronary artery bypass graft post-MI ( no CABG ) , and those without CABG or diabetes ( no CABG , no DIAB ) using univariate and multivariate Cox regression analysis . Strength of association was compared by P values and Wald Chi-square values . Nonlinear HRV included short-term fractal scaling exponent , power law slope , and SD12 ( Poincare dimension ) . For ALL and for no CABG , increased daytime SD12 had the strongest association with mortality ( P=0.002 ALL and P < 0.001 no CABG ) . For no CABG , no DIAB increased 24-hour SD12 hours had the strongest association ( P < 0.001 ) with mortality . Upon multivariate analysis , increased SD12 , decreased ln ULF ( ultra low frequency ) , and history of prior MI and history of congestive heart failure each remained in the model . CONCLUSION Nonlinear HRV is associated with mortality post-MI . However , as with traditional HRV , this is diluted by CABG surgery post-MI and by diabetes . Results suggest that decreased long-term HRV and increased r and omness of heart rate are each independent risk factors for mortality post-MI BACKGROUND AND PURPOSE Abnormal heart rate variability is related to prognostically unfavorable ventricular arrhythmias and sudden arrhythmic death in coronary artery disease . Short-term electrocardiographic ( ECG ) recordings have shown similar abnormalities of heart rate variability in patients with acute stroke . However , there is no information regarding the clinical significance of these abnormalities and of heart rate variability in long-term ECG recordings in stroke . METHODS In this prospect i ve study , we analyzed the time domain and frequency domain measures of heart rate variability from  24-hour ECG recordings in 31 consecutive patients with hemispheric brain infa rct ion in the acute phase and at 1 and 6 months after the infa rct ion and in 31 age- and sex-matched healthy control subjects . RESULTS All the measured components of heart rate variability , ie , st and ard deviation of RR 
    Output:
    
The included papers provided some information regarding predicting incident stroke , which largely seems to be best predicted by time- and frequency-domain HRV parameters .
Furthermore , post-stroke complications and functionality are similarly predicted by time- and frequency-domain parameters , as well as non-linear parameters in some instances .
Conclusions : Current research provides good evidence that HRV parameters may have utility as a biomarker for stroke and for post-stroke complications and /or functionality .