RESUMO
Ischemic stroke of the middle cerebral artery (MCA), a major brain vessel that supplies the primary motor and premotor cortex, is one of the most common causes for severe upper limb impairment. Currently available motor rehabilitation training largely lacks satisfying efficacy with over 70% of stroke survivors showing residual upper limb dysfunction. Motor imagery-based functional magnetic resonance imaging neurofeedback (fMRI-NF) has been suggested as a potential therapeutic technique to improve motor impairment in stroke survivors. In this preregistered proof-of-concept study (https://osf.io/y69jc/), we translated graded fMRI-NF training, a new paradigm that we have previously studied in healthy participants, to first-time MCA stroke survivors with residual mild to severe impairment of upper limb motor function. Neurofeedback was provided from the supplementary motor area (SMA) targeting two different neurofeedback target levels (low and high). We hypothesized that MCA stroke survivors will show (1) sustained SMA-region of interest (ROI) activation and (2) a difference in SMA-ROI activation between low and high neurofeedback conditions during graded fMRI-NF training. At the group level, we found only anecdotal evidence for these preregistered hypotheses. At the individual level, we found anecdotal to moderate evidence for the absence of the hypothesized graded effect for most subjects. These null findings are relevant for future attempts to employ fMRI-NF training in stroke survivors. The study introduces a Bayesian sequential sampling plan, which incorporates prior knowledge, yielding higher sensitivity. The sampling plan was preregistered together with a priori hypotheses and all planned analysis before data collection to address potential publication/researcher biases. Unforeseen difficulties in the translation of our paradigm to a clinical setting required some deviations from the preregistered protocol. We explicitly detail these changes, discuss the accompanied additional challenges that can arise in clinical neurofeedback studies, and formulate recommendations for how these can be addressed. Taken together, this work provides new insights about the feasibility of motor imagery-based graded fMRI-NF training in MCA stroke survivors and serves as a first example for comprehensive study preregistration of an (fMRI) neurofeedback experiment.
RESUMO
AIM: This study aimed to determine the 28-day, 1-year, and 5-year survival probabilities in first-ever stroke patients in a relatively understudied setting: a suburban hospital that serves a predominantly rural population in the east coast of Peninsular Malaysia. METHODS AND RESULTS: A retrospective record review was conducted among 432 first-ever stroke patients admitted to the Hospital Universiti Sains Malaysia, Kelantan, Malaysia. Data from between January 1, 2005 and December 31, 2011, were extracted from the medical records. The Kaplan-Meier product limit estimator was applied to determine the 28-day, 1-year, and 5-year survival probabilities. Log-rank test was used to test the equality of survival time between different groups. A total of 101 patients died during the study period. The 28-day, 1-year, and 5-year survival probabilities were 78.0% (95% confidence interval [CI]: 73.5-81.9), 74.2% (95% CI: 69.4-78.4), and 70.9% (95% CI: 65.1-75.9), respectively. There were significant differences in the survival time based on the types of stroke, Glasgow Coma Scale, hyperlipidaemia, atrial fibrillation, fasting blood glucose, and diastolic blood pressure. CONCLUSION: This study, though retrospective, highlights several clinical parameters that influenced the survival probabilities among first-ever stroke patients managed in a suburban setting in Malaysia, and compared them to those reported in more urban regions. Our data emphasise the need for wider establishment of specialized stroke units and teams, as well as for prospective multi-centre studies on first-ever stroke patients to better inform the development of stroke care provision in Malaysia.
