Prevalence and clinical impact of white matter hyperintensities, cerebral microbleeds, and medial temporal lobe atrophy on short- and long-term outcomes after stroke rehabilitation

Abstract

Background: The influence of cerebral structural abnormality on stroke rehabilitation outcome is unclear. This study examined the prevalence and clinical impact of white matter hyperintensities (WMH), cerebral microbleeds (CMB) and medial temporal lobe atrophy (MTLA) on short and long term outcome after stroke rehabilitation. Methods: We analysed the data for 377 consecutive patients with confirmed stroke admitted to the stroke rehabilitation unit at Tung Wah Hospital between 1 March 2008 and 23 May 2014. 3T MRI brain images were retrospectively examined for the severity and location of WMH (Fazekas Score 0-3, >1 abnormal), CMB (Microbleed Anatomical Rating Scale 0-3, >0 abnormal) and MTLA (Scheltens Score 0-4, >1 abnormal). Stroke rehabilitation outcomes were assessed by comparing functional status between admission and discharge. For 208 patients who were admitted between March 2008 and May 2012, we also retrieved data on clinical outcomes (death or any vascular events, post-stroke dementia) at 2 years. Results: Mean (± s.d.) age was 70 ± 12 years. 94% were ischaemic strokes, and the overall stroke severity was mild to moderate according to the baseline functional scores. 12.6% of the patients had abnormal periventricular WMH, 48% had abnormal subcortical WMH, 52% had CMB, and up to 33% had abnormal MTLA. Stroke subtypes and functional status on admission, but not MRI abnormalities, independently predicted functional improvement during stroke rehabilitation. At 2 years follow-up, 11% had died or any vascular events. Functional status (Barthel index) on admission, but not MRI abnormalities, independently predicted this 2-year outcome. Furthermore, age, WMH and MTLA independently predicted the development of post-stroke dementia at 2 years. Conclusion: Amongst Chinese stroke patients with mild to moderate stroke severity, MRI evidence of small vessel disease and medial temporal lobe atrophy are highly prevalent. These MRI abnormalities do not appear to predict short-term functional improvement during stroke rehabilitation, or 2-year mortality or vascular events. However, WMH and MTLA may predict development of post-stroke dementia at 2 years. Future larger prospective studies are warranted to confirm these findings.