Monitoring of myocardial injury by serial measurements of QRS area and T area: The MaastrICCht cohort.

BACKGROUND: Manually derived electrocardiographic (ECG) parameters were not associated with mortality in mechanically ventilated COVID-19 patients in earlier studies, while increased high-sensitivity cardiac troponin-T (hs-cTnT) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) were. To provide evidence for vectorcardiography (VCG) measures as potential cardiac monitoring tool, we investigated VCG trajectories during critical illness. METHODS: All mechanically ventilated COVID-19 patients were included in the Maastricht Intensive Care Covid Cohort between March 2020 and October 2021. Serum hs-cTnT and NT-proBNP concentrations were measured daily. Conversion of daily 12-lead ECGs to VCGs by a MATLAB-based script provided QRS area, T area, maximal QRS amplitude, and QRS duration. Linear mixed-effect models investigated trajectories in serum and VCG markers over time between non-survivors and survivors, adjusted for confounders. RESULTS: In 322 patients, 5461 hs-cTnT, 5435 NT-proBNP concentrations and 3280 ECGs and VCGs were analyzed. Non-survivors had higher hs-cTnT concentrations at intubation and both hs-cTnT and NT-proBNP significantly increased compared with survivors. In non-survivors, the following VCG parameters decreased more when compared to survivors: QRS area (-0.27 (95% CI) (-0.37 to -0.16, p < .01) µVs per day), T area (-0.39 (-0.62 to -0.16, p < .01) µVs per day), and maximal QRS amplitude (-0.01 (-0.01 to -0.01, p < .01) mV per day). QRS duration did not differ. CONCLUSION: VCG-derived QRS area and T area decreased in non-survivors compared with survivors, suggesting that an increase in myocardial damage and tissue loss play a role in the course of critical illness and may drive mortality. These VCG markers may be used to monitor critically ill patients.

A novel positive end-expiratory pressure titration using electrical impedance tomography in spontaneously breathing acute respiratory distress syndrome patients on mechanical ventilation: an observational study from the MaastrICCht cohort.

There is no universally accepted method for positive end expiratory pressure (PEEP) titration approach for patients on spontaneous mechanical ventilation (SMV). Electrical impedance tomography (EIT) guided PEEP-titration has shown promising results in controlled mechanical ventilation (CMV), current implemented algorithm for PEEP titration (based on regional compliance measurements) is not applicable in SMV. Regional peak flow (RPF, defined as the highest inspiratory flow rate based on EIT at a certain PEEP level) is a new method for quantifying regional lung mechanics designed for SMV. The objective is to study whether RPF by EIT is a feasible method for PEEP titration during SMV. Single EIT measurements were performed in COVID-19 ARDS patients on SMV. Clinical (i.e., tidal volume, airway occlusion pressure, end-tidal CO2) and mechanical (cyclic alveolar recruitment, recruitment, cumulative overdistension (OD), cumulative collapse (CL), pendelluft, and PEEP) outcomes were determined by EIT at several pre-defined PEEP thresholds (1-10% CL and the intersection of the OD and CL curves) and outcomes at all thresholds were compared to the outcomes at baseline PEEP. In total, 25 patients were included. No significant and clinically relevant differences were found between thresholds for tidal volume, end-tidal CO2, and P0.1 compared to baseline PEEP; cyclic alveolar recruitment rates changed by -3.9% to -37.9% across thresholds; recruitment rates ranged from - 49.4% to + 79.2%; cumulative overdistension changed from - 75.9% to + 373.4% across thresholds; cumulative collapse changed from 0% to -94.3%; PEEP levels from 10 up to 14 cmH2O were observed across thresholds compared to baseline PEEP of 10 cmH2O. A threshold of approximately 5% cumulative collapse yields the optimum compromise between all clinical and mechanical outcomes. EIT-guided PEEP titration by the RPF approach is feasible and is linked to improved overall lung mechanics) during SMV using a threshold of approximately 5% CL. However, the long-term clinical safety and effect of this approach remain to be determined.

Prediction model for hypertension in first decade after pre-eclampsia in initially normotensive women.

OBJECTIVE: To develop a prediction model for the development of hypertension in the decade following pre-eclampsia in women who were normotensive shortly after pregnancy. METHODS: This was a longitudinal cohort study of formerly pre-eclamptic women attending a university hospital in The Netherlands between 1996 and 2019. We developed a prediction model for incident hypertension using multivariable logistic regression analysis. The model was validated internally using bootstrapping techniques. RESULTS: Of 259 women, 185 (71%) were normotensive at the first cardiovascular assessment, at a median of 10 (interquartile range (IQR), 6-24) months after a pre-eclamptic pregnancy, of whom 49 (26%) had developed hypertension by the second visit, at a median of 11 (IQR, 6-14) years postpartum. The prediction model, based on birth-weight centile, mean arterial pressure, total cholesterol, left ventricular mass index and left ventricular ejection fraction, had good-to-excellent discriminative ability, with an area under the receiver-operating-characteristics curve (AUC) of 0.82 (95% CI, 0.75-0.89) and an optimism-corrected AUC of 0.80. The sensitivity and specificity of our model to predict hypertension were 98% and 34%, respectively, and positive and negative predictive values were 35% and 98%, respectively. CONCLUSIONS: Based on five variables, we developed a good-to-excellent predictive tool to identify incident hypertension following pre-eclampsia in women who were normotensive shortly after pregnancy. After external validation, this model could have considerable clinical utility in tackling the cardiovascular legacy of pre-eclampsia. © 2023 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Alcohol and red wine consumption, but not fruit, vegetables, fish or dairy products, are associated with less endothelial dysfunction and less low-grade inflammation: the Hoorn Study.

PURPOSE: Endothelial dysfunction and low-grade inflammation are key phenomena in the pathobiology of cardiovascular disease (CVD). Their dietary modification might explain the observed reduction in CVD that has been associated with a healthy diet rich in fruit, vegetables and fish, low in dairy products and with moderate alcohol and red wine consumption. We investigated the associations between the above food groups and endothelial dysfunction and low-grade inflammation in a population-based cohort of Dutch elderly individuals. METHODS: Diet was measured by food frequency questionnaire (n = 801; women = 399; age 68.5 ± 7.2 years). Endothelial dysfunction was determined (1) by combining von Willebrand factor, and soluble intercellular adhesion molecule 1 (sICAM-1), vascular cell adhesion molecule 1, endothelial selectin and thrombomodulin, using Z-scores, into a biomarker score and (2) by flow-mediated vasodilation (FMD), and low-grade inflammation by combining C-reactive protein, serum amyloid A, interleukin 6, interleukin 8, tumour necrosis factor α and sICAM-1 into a biomarker score, with smaller FMD and higher scores representing more dysfunction and inflammation, respectively. We used linear regression analyses to adjust associations for sex, age, energy, glucose metabolism, body mass index, smoking, prior CVD, educational level, physical activity and each of the other food groups. RESULTS: Moderate [ß (95% CI) -0.13 (-0.33; 0.07)] and high [-0.22 (-0.45; -0.003)] alcohol consumption, and red wine [-0.16 (-0.30; -0.01)] consumption, but none of the other food groups, were associated with a lower endothelial dysfunction biomarker score and a greater FMD. The associations for FMD were, however, not statistically significant. Only red wine consumption was associated with a lower low-grade inflammation biomarker score [-0.18 (-0.33; -0.04)]. CONCLUSIONS: Alcohol and red wine consumption may favourably influence processes involved in atherothrombosis.

Adherence to a Mediterranean dietary pattern in early life is associated with lower arterial stiffness in adulthood: the Amsterdam Growth and Health Longitudinal Study.

OBJECTIVES: To investigate whether adherence to a Mediterranean dietary pattern during adolescence and early adulthood affects arterial stiffness in adulthood, and the extent to which any such association may be attributed to a beneficial impact of this diet on cardiovascular disease risk factors such as blood pressure, central fatness and dyslipidaemia. SETTING: The Amsterdam Growth and Health Longitudinal Study. DESIGN AND SUBJECTS: We compared longitudinal levels of adherence to a Mediterranean dietary pattern (aMED score with range 0-9) during adolescence and adulthood (two to eight repeated measures obtained between the ages of 13 and 36) between individuals with different levels of arterial stiffness in adulthood. The study population included 373 (196 women) apparently healthy adults in whom properties of the carotid, brachial and femoral arteries were assessed using ultrasonography at 36 years of age. RESULTS: After adjustments for potential confounders, individuals with stiffer carotid arteries (defined on the basis of the most adverse tertile of, for instance, the distensibility coefficient) had lower aMED scores (-0.32, 95% CI -0.60; -0.06) and were less likely to have adhered to this dietary pattern (aMED score ≥5, odds ratio 0.69, 95% CI 0.50; -0.94) during the preceding 24 years compared with those with less stiff arteries. Differences in aMED scores were already present in adolescence and were only in part explained by the favourable associations between the Mediterranean dietary pattern and other cardiovascular disease risk factors (up to 26%), particularly mean blood pressure (up to 19%). CONCLUSIONS: Promoting the Mediterranean diet in adolescence and early adulthood may constitute an important means of preventing arterial stiffness in adulthood.

Unhealthy dietary patterns associated with inflammation and endothelial dysfunction in type 1 diabetes: the EURODIAB study.

BACKGROUND AND AIMS: A healthy diet has been inversely associated with endothelial dysfunction (ED) and low-grade inflammation (LGI). We investigated the association between nutrient consumption and biomarkers of ED and LGI in type 1 diabetes. METHODS AND RESULTS: We investigated 491 individuals. Nutrient consumption and lifestyle risk factors were measured in 1989 and 1997. Biomarkers of ED (von Willebrand factor, soluble vascular cell adhesion molecule-1 and soluble endothelial selectin) and LGI (C-reactive protein, interleukin 6 and tumour necrosis factor α) were measured in 1997 and averaged into Z-scores. The nutrient residual method was used to adjust individual nutrient intake for energy intake. Data were analysed with generalised estimation equations. We report increments/decrements in nutrient consumption, averaged over time, per +1 standard deviation (SD) of 1997 ED or LGI Z-scores, after adjustment for sex, age, duration of diabetes, investigation centre, body mass index, energy intake, smoking behaviour, alcohol consumption, and each of the other nutrients. One SD elevation in ED Z-score was associated with a diet lower in fibre [ß(95%CI);-0.09(-0.18;-0.004)], polyunsaturated fat [-0.18(-0.31;-0.05)] and vegetable protein [-0.10(-0.20;-0.001)]. For the LGI Z-score results showed associations with fibre [-0.09(-0.17;-0.01)], polyunsaturated fat [-0.14(-0.24;-0.03)] and cholesterol [0.10(0.01; 0.18)]. CONCLUSION: In type 1 diabetes, consumption of less fibre, polyunsaturated fat and vegetable protein, and more cholesterol over the study period was associated with more ED and LGI. Following dietary guidelines in type 1 diabetes may reduce cardiovascular disease risk by favourably affecting ED and LGI.

Effects of anodal transcranial direct current stimulation over the leg motor area on lumbar spinal network excitability in healthy subjects.

In recent years, two techniques have become available for the non-invasive stimulation of human motor cortex: transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS). The effects of TMS and tDCS when applied over motor cortex should be considered with regard not only to cortical circuits but also to spinal motor circuits. The different modes of action and specificity of TMS and tDCS suggest that their effects on spinal network excitability may be different from that in the cortex. Until now, the effects of tDCS on lumbar spinal network excitability have never been studied. In this series of experiments, on healthy subjects, we studied the effects of anodal tDCS over the lower limb motor cortex on (i) reciprocal Ia inhibition projecting from the tibialis anterior muscle (TA) to the soleus (SOL), (ii) presynaptic inhibition of SOL Ia terminals, (iii) homonymous SOL recurrent inhibition, and (iv) SOL H-reflex recruitment curves. The results show that anodal tDCS decreases reciprocal Ia inhibition, increases recurrent inhibition and induces no modification of presynaptic inhibition of SOL Ia terminals and of SOL-H reflex recruitment curves. Our results indicate therefore that the effects of tDCS are the opposite of those previously described for TMS on spinal network excitability. They also indicate that anodal tDCS induces effects on spinal network excitability similar to those observed during co-contraction suggesting that anodal tDCS activates descending corticospinal projections mainly involved in co-contractions.

Impact of precision grip tasks on cervical spinal network excitability in humans.

Motor skill acquisition in the lower limb may induce modifications of spinal network excitability. We hypothesized that short-term motor adaptation in precision grip tasks would also induce modifications of cervical spinal network excitability. In a first series of experiments, we studied the impact of two different precision grip force control tasks (a visuomotor force-tracking task and a control force task without visual feedback) on cervical spinal network excitability in healthy subjects. We separately tested the efficacy of two key components of the spinal circuitry: (i) presynaptic inhibition on flexor carpi radialis (FCR) Ia terminals, and (ii) disynaptic inhibition directed from extensor carpi radialis (ECR) to FCR. We found that disynaptic inhibition decreased temporarily after both force control tasks, independently of the presence of visual feedback. In contrast, the amount of presynaptic inhibition on FCR Ia terminals decreased only after the visuomotor force tracking task. This temporary decrease was correlated with improved tracking accuracy during the task (i.e. short-term motor adaptation). A second series of experiments confirmed these results and showed that the visuomotor force-tracking task resulted also in an increase of the Hmax/Mmax ratio and the slope of the ascending part of the H-reflex recruitment curve. In order to address the role of presynaptic inhibition in the motor adaptation process, we conducted a third series of experiments during which presynaptic inhibition was recorded before and after two consecutive sessions of visuomotor force tracking. The results showed that (i) improved tracking accuracy occurred during both sessions, and (ii) presynaptic inhibition decreased only after the first session of visuomotor force tracking. Taken together, these results suggest thus that the nature of the motor task performed has a specific impact on the excitability of these cervical spinal circuits. These findings also suggest that early motor adaptation is associated with a modulation of presynaptic Ia inhibition in the upper limb.

Incidence of thrombotic complications and overall survival in hospitalized patients with COVID-19 in the second and first wave.

INTRODUCTION: In the first wave, thrombotic complications were common in COVID-19 patients. It is unknown whether state-of-the-art treatment has resulted in less thrombotic complications in the second wave. METHODS: We assessed the incidence of thrombotic complications and overall mortality in COVID-19 patients admitted to eight Dutch hospitals between September 1st and November 30th 2020. Follow-up ended at discharge, transfer to another hospital, when they died, or on November 30th 2020, whichever came first. Cumulative incidences were estimated, adjusted for competing risk of death. These were compared to those observed in 579 patients admitted in the first wave, between February 24th and April 26th 2020, by means of Cox regression techniques adjusted for age, sex and weight. RESULTS: In total 947 patients with COVID-19 were included in this analysis, of whom 358 patients were admitted to the ICU; 144 patients died (15%). The adjusted cumulative incidence of all thrombotic complications after 10, 20 and 30 days was 12% (95% confidence interval (CI) 9.8-15%), 16% (13-19%) and 21% (17-25%), respectively. Patient characteristics between the first and second wave were comparable. The adjusted hazard ratio (HR) for overall mortality in the second wave versus the first wave was 0.53 (95%CI 0.41-0.70). The adjusted HR for any thrombotic complication in the second versus the first wave was 0.89 (95%CI 0.65-1.2). CONCLUSIONS: Mortality was reduced by 47% in the second wave, but the thrombotic complication rate remained high, and comparable to the first wave. Careful attention to provision of adequate thromboprophylaxis is invariably warranted.

Impact of transcranial direct current stimulation on spinal network excitability in humans.

Transcranial direct current stimulation (tDCS) when applied over the motor cortex, modulates excitability dependent on the current polarity. The impact of this cortical modulation on spinal cord network excitability has rarely been studied. In this series of experiments, performed in healthy subjects, we show that anodal tDCS increases disynaptic inhibition directed from extensor carpi radialis (ECR) to flexor carpi radialis (FCR) with no modification of presynaptic inhibition of FCR Ia terminals and FCR H-reflex recruitment curves. We also show that cathodal tDCS does not modify spinal network excitability. Our results suggest that the increase of disynaptic inhibition observed during anodal tDCS relies on an increase of disynaptic interneuron excitability and that tDCS over the motor cortex in human subjects induces effects on spinal network excitability. Our results highlight the fact that the effects of tDCS should be considered in regard to spinal motor circuits and not only to cortical circuits.

Effects of loading the unaffected limb for one session of locomotor training on laboratory measures of gait in stroke.

BACKGROUND: Walking following stroke involves compensatory strategies by the unaffected leg to cope with the deficits in the hemiparetic leg. Recently, training paradigms based on the principles of task-oriented repetitive exercise have provided a valuable insight regarding the influence of restraining compensatory movements to improve motor performances. We investigated changes in the walking movements of each lower extremity after weighting the unaffected leg. METHODS: Ten individuals early after a stroke (range: 3-7 months) who were able to walk 10 m with no aids, participated to this study. Subjects were instructed to walk on a treadmill with an external mass attached around the non affected ankle during a single session. The short-term effects on gait performance were quantified by a 3D-gait analysis system before, immediately after and 20 min after the walking technique. FINDINGS: A one factor repeated measures model revealed that stroke participants significantly improved in walking speed (P<0.001), step length (P<0.01) and cadence (P<0.01). Weight-bearing on the paretic leg increased (P<0.01) along with kinematic modifications including greater hip and knee excursion. When the mass was removed, these adaptations were maintained 20 min later. INTERPRETATION: Preliminary findings suggest that even brief gait training using a treadmill with a restrictive weight placed on the distal extremity of the non-hemiplegic lower limb can improve laboratory measures of gait ability in a sample of stroke subjects. Future studies must evaluate the effect of this technique in longer-term locomotor retraining.

Polymorbidity in diabetes in older people: consequences for care and vocational training.

OBJECTIVE: To investigate the prevalence of complicating and concurrent morbidities in older diabetic patients and to evaluate to what extent their occurrence affects the burden of disease and use of medical healthcare. STUDY DESIGN: Cross-sectional analysis of retrospectively obtained data on comorbidities and use of medical healthcare. Healthcare registration systems were used to retrieve data on 300 patients with diabetes aged >or=60 years who, according to the severity of their disease and intensity of care required, were treated in a regional general practitioner (GP), diabetes nurse specialist (DNS) or medical specialist (MS) practice. RESULTS: Complicating and concurrent morbidities were often found irrespective of the type of practice involved. After adjustments for differences in sex, age and glycosylated haemoglobin (HbA1c), the extent of complicating comorbidities showed sequential increases in patients managed by GP, DNS and MS (mean number of 3.6, 4.7 and 6.7, respectively; p(trend)<0.001). However, the mean number of concurrent comorbidities was similar across all three settings (2.1, 1.8 and 2.0, respectively). Both complicating and concurrent comorbidities were similarly associated with the extent of drug use (beta = 0.49 (95% CI 0.40 to 0.58) and beta = 0.57 (95% CI 0.52 to 0.72), respectively) and the number of consultations with specialists other than the main care giver (beta = 1.19 (95% CI 1.15 to 1.24) and beta = 1.21 (95% CI 1.14 to 1.28), respectively). However, the mean number of different specialists involved in a patient's care per additional concurrent comorbidity was twice as high as per any additional complicating comorbidity (beta = 0.60 (95% CI 0.48 to 0.71) vs beta = 0.31 (95% CI 0.24 to 0.39)). CONCLUSIONS: The use of healthcare facilities by older patients with diabetes is substantial, irrespective of the complexity of the disease and the kind of practice involved. The common manifestation of complicating and concurrent comorbidities and their varying complexity in individual patients requires a patient-oriented rather than a disease-oriented approach and vocational training programmes for care givers that are tailored to the complexity of multiple chronic diseases.

[Management of increase in spasticity in patients with intrathecal baclofen pumps]. / Conduite à tenir devant une recrudescence de spasticité chez un patient porteur d'une pompe à baclofène.

INTRODUCTION: The incidence of complications after baclofen pump implantation is relatively high. Diagnosis of these complications can be difficult. A diagnostic tree would be a useful tool in cases of suspected malfunctioning of the intrathecal bacolfen infusion system and would standardise the diagnostic procedure. METHOD: From results in the literature and the experience of our department, we designed a diagnostic tree to aid in finding the cause of a recrudescence of spasticity in patients with implanted baclofen pumps. RESULTS: The potential causes of recrudescence of spasticity are described and a diagnostic pathway is proposed. DISCUSSION: The aim of a standardised hierarchical method of diagnosis of the cause of increased spasticity in patients with intrathecal baclofen pumps is to gain time in the diagnosis and treatment. Such diagnosis should improve patient care by permitting rapid restoration of an adequate level of baclofen infusion as well as decreasing the length of hospital stay and, as a consequence, the cost relating to malfunctioning pumps.

[Pharmacological treatment of neurogenic detrusor hyperactivity: intrathecal drugs]. / Traitement pharmacologique de l'hyperactivité détrusorienne neurologique: drogues intrathécales.

Intrathecal clonidine has been tested in spinal cord injury patients not supporting or resistant to anticholinergic drugs. Although the acute effect of clonidine on urodynamic parameters was satisfactory, cardiovascular adverse effects limited the long-term efficacy of this treatment. Intrathecal baclofen has a limited effect on overactive bladder in patients with spinal spasticity, but can modify the quality of erections and induce an incapacity to trigger ejaculation by vibratory penile stimulation.

Control of an ACC-1-producing Klebsiella pneumoniae outbreak in a physical medicine and rehabilitation unit.

This article describes an outbreak of ACC-1-producing Klebsiella pneumoniae involving 40 patients. These were mainly men under 40 years old with a spinal cord injury, in a physical medicine and rehabilitation unit. The main risk factors were prolonged hospital stay, multiple-bed rooms, tracheostomy care and assisted defaecation. The outbreak was only controlled after the introduction of rigorous patient placement (i.e. single rooms or cohorting in the same room), while allowing the patients to have free access to the various technical services (e.g. physiotherapy and occupational therapy) and living spaces necessary for re-education.

Evidence for cognitive processes involved in the control of steady state of walking in healthy subjects and after cerebral damage.

OBJECTIVE: The involvement of cognitive processes in the control of walking at steady state was studied in 10 healthy subjects and 18 subjects after unilateral vascular brain damage. A dual task paradigm was used to compare the performance level of a probe reaction time (RT) in sitting (simple task) and during standing or walking on a treadmill (dual task conditions). In this latter condition, RTs were classified and analyzed in relation to the different phases of the gait cycle. RESULTS: The results show a marked increase in RT while walking compared to sitting and standing only in stroke subjects. Specific changes in RTs related to the gait cycle phases were observed in both healthy subjects and those after brain damage. It is concluded that walking at steady state is attentionally demanding. The phase-dependent modulations of the RTs suggest that cognitive processes may play a role in the control of the step cycle. The increase of attentional demand during walking in subjects who had suffered a stroke varies, depending on severity of impairments of walking but also on a reduced general attentional capacity. The dual task paradigm provides a sensitive tool in the assessment of walking ability in stroke subjects.

Mechanisms underlying transcranial direct current stimulation in rehabilitation.

For a few years, the non-invasive modulation of motor cortex has become the centre of much attention because of its possible clinical impact. Among the different mechanism allowing to modify motor-cortex excitability, transcranial direct current stimulation (tDCS), with its efficacy and ease of use, plays a major role. The aim of this review is to improve the understanding of the underlying mechanisms of the tDCS effect in the field of rehabilitation. The mechanisms underlying tDCS effects when applied over the motor cortex differ depending on the polarity used. Moreover, the mechanisms underlying these effects differ during stimulation (per-stimulation) and after the end of it (after-effects). This review highlights the known mechanisms involved in tDCS effects on brain excitability and illustrates that most remain not well understood and debated. Further studies are necessary to elucidate the mode of action of tDCS and determine the best paradigm of stimulation depending on the goals.

Relationship between hip flexion and ankle dorsiflexion during swing phase in chronic stroke patients.

BACKGROUND: During the clinical examination of stroke patients, it is common to observe that involuntary hip flexion occurs during voluntary ankle dorsiflexion (synkinesia). This suggests that there is a relationship between these two joints. We hypothesized that there may be a relationship between hip and ankle flexion during swing phase of the gait cycle. The objective of this study was to determine if there is a biomechanical relationship between peak hip flexion and peak ankle dorsiflexion during the swing phase of the gait cycle following stroke. METHOD: The paretic lower limbs of 60 patients with stroke were evaluated using clinical tests and 3D-gait analysis. The clinical assessment included muscle strength, spasticity and passive range of ankle motion. The gait analysis focused on sagittal frontal and transverse kinematic gait parameters during swing. FINDINGS: A stepwise-linear-regression indicated that peak hip flexion and gait speed were the only 2 parameters which accounted for peak ankle dorsiflexion. There was also a significant negative correlation between peak hip flexion and peak ankle dorsiflexion during swing, and a significant positive correlation between hip flexor and ankle dorsiflexor muscle strength. INTERPRETATION: These results suggest that the biomechanical behaviour of hip and ankle joints during the swing phase of the gait cycle is linked in patients with stroke. They also suggest that two strategies exist: if sufficient ankle dorsiflexion is present, less hip flexion is required (distal-strategy) whereas if dorsiflexion is reduced, it is compensated for by an increase in peak hip flexion (proximal-strategy).

Longitudinal study of motor recovery after stroke: recruitment and focusing of brain activation.

BACKGROUND AND PURPOSE: The goal of this study was to characterize cortical reorganization after stroke and its relation with the site of the stroke-induced lesion and degree of motor recovery using functional MRI (fMRI). METHODS: Fourteen stroke patients with an affected upper limb were studied longitudinally. Three fMRI sessions were performed over a period of 1 to 6 months after stroke. Upper limb recovery, Wallerian degeneration of the pyramidal tract, and responses to transcranial magnetic stimulation were assessed. RESULTS: Two main patterns of cortical reorganization were found. Pattern 1 was focusing, in which, after initial recruitment of additional ipsilateral and contralateral areas, activation gradually developed toward a pattern of activation restricted to the contralateral sensorimotor cortex in 9 patients. Five patients were found to have pattern 2, persistent recruitment, in which there was an initial and sustained recruitment of ipsilateral activity. Occurrence of recruitment or focusing seemed to depend mainly on whether the primary motor cortex (M1) was lesioned; persistent recruitment was observed in 3 of 4 patients with M1 injury, and focusing was seen in 8 of 10 patients with spared M1. These patterns had no relation to the degree of recovery; in particular, focusing did not imply recovery. However, there was a clear relation between the degree of recovery and the degree of Wallerian degeneration. CONCLUSIONS: These results suggest that ipsilateral recruitment after stroke corresponds to a compensatory corticocortical process related to the lesion of the contralateral M1 and that the process of compensatory recruitment will persist if M1 is lesioned; otherwise, it will be transient.

Functional anatomy of neuropsychological deficits after severe traumatic brain injury.

BACKGROUND: Neurobehavioral disorders after severe traumatic brain injury (TBI) are poorly correlated with focal lesions detected by structural neuroimaging techniques such as CT scan or MRI. OBJECTIVE: To explore the relationships between regional cerebral glucose metabolism at rest, as measured by PET, and neurobehavioral status after severe TBI at the subacute stage. METHODS: Thirteen patients without focal structural lesion on MRI were studied. Neuropsychological assessment included tests of memory, attention and speed of information processing, and executive functions, and a global neurobehavioral assessment. Regional cerebral glucose metabolism at rest was measured with (18F)-fluorodeoxyglucose and PET. RESULTS: A close link was found between cognitive and behavioral disorders and decreased cortical metabolism in prefrontal and cingulate cortex. Tests of memory and executive functions significantly correlated with regional metabolism in the mesial and lateral prefrontal cortex and the cingulate gyrus. Behavioral disorders correlated significantly with mesial prefrontal and cingulate metabolisms. CONCLUSION: These results suggest a predominant role of prefrontal and cingulate dysfunction in cognitive and behavioral disorders of patients with severe traumatic brain injury, even in the absence of focal structural lesion of the brain. Further cognitive functional activation research using PET or functional MRI might help clarify the relative contributions of both areas to dysfunction.