Stroke associated with acute and persistent cognitive decline

1. In this study, stroke survivors showed a faster decline in global cognition and executive function in the years following stroke compared to expected pre-stroke slopes of decline.

2. Stroke was shown to be associated with an acute decline in global cognition, new learning, and verbal memory, however the declines in new learning and verbal memory were not at a faster rate of decline when compared to expected pre-stroke slopes of decline.

Evidence Rating Level: 2 (Good)

Study Rundown: There are currently millions of stroke survivors, many of whom bear life long cognitive and physical impairments following stroke. While the acute cognitive decline usually seen after such incidents is well documented, it is currently unclear whether survivors experience a faster rate of cognitive decline in the years following a stroke, compared to the expected pre-stroke rate of decline. The authors of this study sought to determine how this post-stroke rate of decline compared to the expected pre-stroke rate of decline.

This study found that stroke was associated with an acute decline in global cognition, new learning, and verbal memory. Further, global cognition and executive function, but not new learning and verbal memory, were shown to decline more rapidly over the following 6 years when compared to the expected pre-stroke rate of decline. This study was strengthened by its prospective design and ability to compare post-stroke cognitive decline to pre-stroke rates. However, it is weakened by not accounting for stroke location and size as well as various treatments received. Based on these study results, efforts to promote screening for cognitive impairment in post-stroke individuals both acutely and subacutely may prove useful in patient management. Further research is required to evaluate how best improve cognitive function in post-stroke individuals.

Click to read the study, published today in JAMA

Click to read the accompanying editorial, published today in JAMA

Relevant Reading: Association of cognitive functioning, incident stroke, and mortality in older adults

In-Depth [prospective cohort]: This study evaluated 23 572 participants from the prospective Reasons for Geographic and Racial Differences in Stroke (REGARDS) trial over a median follow up period of 6.1 years, during which 515 experienced a stroke. Patients with a baseline cognitive impairment were excluded. In stroke survivors, an acute decline in global cognition after stroke was noted, with an adjusted decline in Six-Item Screener score of 0.10 points (95%CI 0.04-0.17, p = 0.001), as well as an increased rate of decline in global cognition following stroke (prestroke slope 0.021, post-stroke slope -0.035). Stroke was associated with acute declines in new learning and verbal memory (World List Learning 1.80 points, 95%CI 0.73-2.86, p = 0.001; World List Delayed Recall 0.60 points, 95%CI 0.13-1.07, p = 0.01) but the rate of decline in new learning and verbal memory following stroke were not accelerated (p = 0.91 for World List Learning and p = 0.70 for World List Delayed Recall). Executive function declined acutely in one analysis model but not another, but continued to decline rapidly in the years following the stroke (change in slope after incident stroke 0.63 points per year, 95%CI 0.12-1.15, p = 0.02).

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