Evaluating quiet standing posture of post-stroke patients by classifying cerebral infarction and cerebral hemorrhage patients

Characterization of Postural Control in Post-Stroke Patients by Musculoskeletal Simulation

An association is observed between the standing sway posture and falls in patients with stroke; hence, it is important to study their standing balance. Although there are studies on the standing balance in stroke patients, differences in control have not been adequately investigated. This study aims to propose a method to characterize the postural sway in standing stroke patients using a mathematical model. A musculoskeletal model and neural controller model were used to simulate ten stroke patients (five patients with cerebral hemorrhages and five patients with cerebral infarctions) and eight young healthy participants, and their data were monitored during quiet standing. The model parameters were adjusted by focusing on the maximum-minimum difference in sway, which was considered important in a previous study, and sway speed, which is frequently used in the analysis. The adjusted model parameters were subjected to dimension reduction using non-negative matrix factorization. Consequently, the sway characteristics of stroke patients were expressed as the magnitude of gain parameters related to the extension of the entire body. The results of this study demonstrated the possibility of representing the characteristics of postural sway as model parameters in stroke patients using a mathematical model. This characterization could lead to the design of individualized rehabilitation systems in the future.

Related Factors of Cerebral Hemorrhage after Cerebral Infarction and the Effect of Atorvastatin Combined with Intensive Nursing Care

Background

Cerebral infarction is a common neurological disease with high incidence, which is the main factor causing death and disability in adults in China. Cerebral hemorrhage transformation is a common clinical complication. High NIHSS score at admission, atrial fibrillation, and small artery occlusion cerebral infarction can increase the risk of cerebral infarction complicated with hemorrhage transformation.

Aim

To explore the related factors of cerebral hemorrhage transformation after cerebral infarction and the value of atorvastatin calcium tablets combined with early intensive care measures.

Methods

In this study, a case-control study was conducted. Sixty patients with hemorrhagic transformation after cerebral infarction admitted to the Department of Neurology of our hospital from January 2017 to June 2021 were selected as the observation group, and 90 patients with cerebral infarction without hemorrhagic transformation during the same period were selected as the control group. The risk factors of hemorrhagic transformation after cerebral infarction were analyzed.

Results

The results of logistic regression model showed that the increased National Institutes of Health Stroke Scale (NIHSS) score at admission, hypertension, atrial fibrillation, TOAST classification of small artery occlusion, and large infarction lesions were the risk factors for hemorrhagic transformation in patients with cerebral infarction (P < 0.05). After 2 weeks and 4 weeks of treatment, the NIHSS scores of the intervention group were lower than those of the conventional group (P < 0.05). NIHSS scores of the two groups after treatment were significantly lower than those before treatment (P < 0.05). After three months of treatment, the patients in the intervention group with GOS score of 5 points accounted for 16.67%, and the patients with GOS score of 4 points accounted for 56.67%. The patients in the conventional group with GOS score of 5 points accounted for 6.67%, and the patients with GOS score of 4 points accounted for 33.33%. The prognosis of the intervention group was better than that of the conventional group on the whole (P < 0.05).

Conclusion

Patients with hypertension, large infarction lesions, high NIHSS score at admission, atrial fibrillation, and small artery occlusion cerebral infarction can increase the risk of bleeding transformation in patients with cerebral infarction. For patients with bleeding transformation, atorvastatin calcium tablets combined with early intensive nursing intervention has a certain value for improving the prognosis of patients.

Evaluation of Postural Sway in Post-stroke Patients by Dynamic Time Warping Clustering

Post-stroke complications are the second most frequent cause of death and the third leading cause of disability worldwide. The motor function of post-stroke patients is often assessed by measuring the postural sway in the patients during quiet standing, based on sway measures, such as sway area and velocity, which are obtained from temporal variations of the center of pressure. However, such approaches to establish a relationship between the sway measures and patients' demographic factors have hardly been successful (e.g., days after onset). This study instead evaluates the postural sway features of post-stroke patients using the clustering method of machine learning. First, we collected the stroke patients' multi-variable motion-capture standing-posture data and processed them into t s long data slots. Then, we clustered the t-s data slots into K cluster groups using the dynamic-time-warping partition-around-medoid (DTW-PAM) method. The DTW measures the similarity between two temporal sequences that may vary in speed, whereas PAM identifies the centroids for the DTW clustering method. Finally, we used a post-hoc test and found that the sway amplitudes of markers in the shoulder, hip, knee, and center-of-mass are more important than their sway frequencies. We separately plotted the marker amplitudes and frequencies in the medial-lateral direction during a 5-s data slot and found that the post-stroke patients' postural sway frequency lay within the bandwidth of 0.5–1.5 Hz. Additionally, with an increase in the onset days, the cluster index of cerebral hemorrhage patients gradually transits in a four-cluster solution. However, the cerebral infarction patients did not exhibit such pronounced transitions over time. Moreover, we found that the postural-sway amplitude increased in clusters 1, 3, and 4. However, the amplitude of cluster 2 did not follow this pattern, owing to age effects related to the postural sway changes with age. A rehabilitation doctor can utilize these findings as guidelines to direct the post-stroke patient training.