Background
Cerebral hemorrhage occurs in 18.5% of stroke patients and thalamic hemorrhage accounts for 26% of all cerebral hemorrhages [
1]. The thalamus is a vital structure that has extensive neural connections with other structures, allowing it to send signals throughout the brain including to the cerebral cortex. As such, the thalamus is involved in sensory and motor signal relays and in the regulation of consciousness. Given its interconnectedness with other regions, thalamic hemorrhages can cause cognitive dysfunctions such as aphasia, unilateral neglect, and memory impairments, as well as motor paralysis and sensory disturbances. These deficits can greatly affect a patient’s ability to perform activities of daily living (ADLs) [
2]. The prognosis of patients with thalamic hemorrhage varies depending on the patient’s age, neurological severity, hematoma location and size, complications, and treatment type.
In rehabilitation wards, patients undergo intensive treatment in the early stages after stroke to help decrease ADL impairments and hasten recovery. Upon returning home, the reacquisition of walking ability is a major focus for patients with stroke with disabilities. However, few reports discuss the factors related to walking in patients with thalamic hemorrhage [
3]. Understanding these factors is important for predicting patient outcome and for efficiently and effectively advancing their rehabilitation program.
The information available upon discharge of the patient from the acute-care hospital may be useful for predicting whether a patient will be able to walk independently upon discharge from the rehabilitation hospital. Here, we analyzed the factors related to independent walking in patients with thalamic hemorrhage who were admitted to a rehabilitation hospital.
Discussion
The present study examined the relationships among evaluations performed upon admission to the rehabilitation hospital (i.e., after discharge from the acute-care hospital) and independent walking. Additionally, based on medical information frequently used in acute-care hospitals (CT images, NIHSS scores, MMSE scores), we performed a decision-tree analysis to investigate whether it is possible to predict independent walking upon admission to the rehabilitation hospital. Although a study indicated that patients’ functional outcomes could be predicted based on their NIHSS and MMSE scores at the time of admission to an acute-care hospital [
10], few studies have investigated walking outcomes using the evaluation methods performed at acute-care hospital discharge [
3].
We found that the dependent- and independent-walking groups were significantly different in terms of age, duration from symptom onset to rehabilitation hospital admission, presence/absence of ventricular bleeding, hematoma volume, NIHSS score, MMSE score, and presence/absence of unilateral neglect. Fukiishi et al. [
3] noted that among the factors related to walking ability in patients with thalamic hemorrhage, the patient’s age, CT classification, hematoma volume, and state of consciousness at the time of admission to an acute-care hospital are particularly important. Indeed, evidence shows that the greater the hematoma volume, the poorer the functional outcome [
11]. Unilateral neglect is also known to inhibit independent walking, and patients with unilateral neglect have lower ADL scores than do patients without neglect [
2]. Consistent with these previous studies, the present study also revealed that age, hematoma volume, and neurological severity, as measured with the NIHSS, were related to independent walking in patients with thalamic hemorrhage. Reports from rehabilitation hospitals show that there is a strong relationship between an improved functional outcome at rehabilitation hospital discharge and the early initiation of rehabilitation services [
12,
13]. Since no information on the rehabilitation interventions performed at the acute-care hospital was available in this study, this factor should be studied in the future.
Our decision-tree analysis revealed that the NIHSS and MMSE scores, hematoma volume, and presence/absence of ventricular bleeding were factors related to independent walking. By using the NIHSS and MMSE, which are standard, comprehensive evaluations performed at acute-care hospitals for patients with stroke, independent walking could be predicted in about 80% of the patients without using special evaluation scales like the Functional Independence Measure. Here, the MMSE was selected in the decision-tree analysis as a factor that was related to independent walking. This may be because patients with low MMSE scores need some assistance walking in the clinical setting, as they are unable to adapt to the environment and ultimately fall down. Such patients were given an FAC of 3 or less because they either required verbal supervision or stand-by help from one person. Therefore, patients with low MMSE scores often could not walk independently.
Our study suggests that independent walking can be estimated by adding the image-based diagnosis after stratification by NIHSS, MMSE, and age. Although the accuracy of predictions based only on neuroimaging data is not sufficiently high [
14], the present study confirmed that neuroimaging data (hematoma volume and ventricular bleeding) are useful after stratification with neurologic symptoms using decision-tree analyses.
One limitation of the present study is that we utilized CT images. In order to improve the accuracy, future studies should consider the effects of microbleeds and asymptomatic cerebral infarctions using magnetic resonance images. Another limitation is that we did not consider the location of the lesion in the thalamus. This may be problematic, as different regions of the thalamus are involved in different functions. Specifically, the ventrolateral thalamus is involved in motor function, while the ventroposterolateral thalamus is involved in somatosensory function. Although we evaluated patients’ neurological deficits using the NIHSS, as well as the hematoma type, additional studies that consider the lesion location should be performed in the future to confirm our findings.
Conclusion
Neuroimaging data, including the hematoma volume and presence of ventricular bleeding, along with age, neurological symptoms, and cognitive functions were useful for predicting the walking ability of patients with thalamic hemorrhage.
Acknowledgements
We would like to thank all of the patients who participated in this study.