April 2014: Dong et al (2013) Cognitive screening improves the predictive value of stroke severity scores for functional outcome 3-6 months after mild stroke and transient ischemic attack: an observational study. BMJ Open, 3(9):e003105. doi: 10.1136/bmjopen-2013-003105.
OBJECTIVES: To investigate the prognostic value of the neurocognitive status measured by screening instruments, the Montreal Cognitive Assessment (MoCA) and Mini-Mental State Examination (MMSE), individually and in combination with the stroke severity scale, the National Institute of Health Stroke Scale (NIHSS), obtained at the subacute stroke phase or the baseline (≤2 weeks), for functional outcome 3-6 months later.
DESIGN: Prospective observational study. SETTING: Tertiary stroke neurology service.
PARTICIPANTS: 400 patients with a recent ischaemic stroke or transient ischaemic attack (TIA) received NIHSS, MoCA and MMSE at baseline and were followed up 3-6 months later.
PRIMARY OUTCOME MEASURES: At 3-6 months following the index event, functional outcome was measured by the modified Rankin Scale (mRS) scores.
RESULTS: Most patients (79.8%) had a mild ischaemic stroke and less disability (median NIHSS=2, median mRS=2 and median premorbid mRS=0), while a minority of patients had TIA (20.3%). Baseline NIHSS, MMSE and MoCA scores individually predicted mRS scores at 3-6 months, with NIHSS being the strongest predictor (NIHSS: R(2) change=0.043, p<0.001). Moreover, baseline MMSE scores had a small but statistically significant incremental predictive value to the baseline NIHSS for mRS scores at 3-6 months, while baseline MoCA scores did not (MMSE: R(2) changes=0.006, p=0.03; MoCA: R(2) changes=0.004, p=0.083). However, in patients with more severe stroke at baseline (defined as NIHSS>2), baseline MoCA and MMSE had a significant and moderately large incremental predictive value to the baseline NIHSS for mRS scores at 3-6 months (MMSE: R(2) changes=0.021, p=0.010; MoCA: R(2) changes=0.017, p=0.021).
CONCLUSIONS: Cognitive screening at the subacute stroke phase can predict functional outcome independently and improve the predictive value of stroke severity scores for functional outcome 3-6 months later, particularly in patients with more severe stroke.
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