[Frequency and risk factors associated with post-stroke dementia-an observational study on stroke patients without premorbid cognitive impairment]

BACKGROUND

Longitudinal studies on cognitive outcomes after stroke revealed heterogeneous results and the underlying pathology and risk factors for so-called post-stroke dementia are unclear.

OBJECTIVE

To assess long-term cognitive performance changes in patients after the first ischemic stroke and to evaluate possible risk factors for post-stroke dementia.

MATERIAL AND METHODS

In this study 66 clinically mildly affected patients aged 54-87 years without a history of dementia underwent extensive neuropsychological assessment after first ever ischemic stroke and again 6 months after the event (follow-up assessment). Demographic, clinical and paraclinical parameters were assessed as potential predictors for long-term cognitive outcome.

RESULTS

At the group level significant performance improvements were found for most of the neurocognitive domains at the follow-up assessment. The greatest cognitive improvement was found in visuospatial processing. Immediately after stroke 54.5% of patients were considered cognitively impaired (z-scores < -2 in at least 2 neurocognitive domains). At follow-up only 16.7% were considered cognitively impaired according to this criterion and among these only 2 patients (3%) had developed a new, clinically relevant cognitive impairment (i.e. post-stroke dementia). Patients with inferior cognitive performance improvements at follow-up had on average larger brain lesions caused by the stroke as well as a prediabetic metabolic status.

DISCUSSION

The probability of developing a post-stroke dementia syndrome is lower than previously assumed in patients with first ever stroke, with only mild clinical disability and without premorbid cognitive impairment. Long-term cognitive impairment could primarily be determined by the size of the lesioned brain area as well as the premorbid (pre)diabetic status.

Refinement of detecting atrial fibrillation in stroke patients: results from the TRACK-AF Study

BACKGROUND AND PURPOSE

Detection of occult atrial fibrillation (AF) is crucial for optimal secondary prevention in stroke patients. The AF detection rate was determined by implantable cardiac monitor (ICM) and compared to the prediction rate of the probability of incident AF by software based analysis of a continuously monitored electrocardiogram at follow-up (stroke risk analysis, SRA); an optimized AF detection algorithm is proposed by combining both tools.

METHODS

In a monocentric prospective study 105 out of 389 patients with cryptogenic stroke despite extensive diagnostic workup were investigated with two additional cardiac monitoring tools: (a) 20 months' monitoring by ICM and (b) SRA during hospitalization at the stroke unit.

RESULTS

The detection rate of occult AF was 18% by ICM (n = 19) (range 6-575 days) and 62% (n = 65) had an increased risk for AF predicted by SRA. When comparing the predictive accuracy of SRA to ICM, the sensitivity was 95%, specificity 35%, positive predictive value 27% and negative predictive value 96%. In 18 patients with AF detected by ICM, SRA also showed a medium risk for AF. Only one patient with a very low risk predicted by SRA developed AF revealed by ICM after 417 days.

CONCLUSIONS

A combination of SRA and ICM is a promising strategy to detect occult AF. SRA is reliable in predicting incident AF with a high negative predictive value. Thus, SRA may serve as a cost-effective pre-selection tool identifying patients at risk for AF who may benefit from further cardiac monitoring by ICM.

Serum C-reactive protein is linked to cerebral microstructural integrity and cognitive function

OBJECTIVE

C-reactive protein is a marker of inflammation and vascular disease. It also seems to be associated with an increased risk of dementia. To better understand potential underlying mechanisms, we assessed microstructural brain integrity and cognitive performance relative to serum levels of high-sensitivity C-reactive protein (hs-CRP).

METHODS

We cross-sectionally examined 447 community-dwelling and stroke-free individuals from the Systematic Evaluation and Alteration of Risk Factors for Cognitive Health (SEARCH) Health Study (mean age 63 years, 248 female). High-field MRI was performed in 321 of these subjects. Imaging measures included fluid-attenuated inversion recovery sequences for assessment of white matter hyperintensities, automated quantification of brain parenchyma volumes, and diffusion tensor imaging for calculation of global and regional white matter integrity, quantified by fractional anisotropy (FA). Psychometric analyses covered verbal memory, word fluency, and executive functions.

RESULTS

Higher levels of hs-CRP were associated with worse performance in executive function after adjustment for age, gender, education, and cardiovascular risk factors in multiple regression analysis (beta = -0.095, p = 0.02). Moreover, higher hs-CRP was related to reduced global fractional anisotropy (beta = -0.237, p < 0.001), as well as regional FA scores of the frontal lobes (beta = -0.246, p < 0.001), the corona radiata (beta = -0.222, p < 0.001), and the corpus callosum (beta = -0.141, p = 0.016), in particular the genu (beta = -0.174, p = 0.004). We did not observe a significant association of hs-CRP with measures of white matter hyperintensities or brain atrophy.

CONCLUSION

These data suggest that low-grade inflammation as assessed by high-sensitivity C-reactive protein is associated with cerebral microstructural disintegration that predominantly affects frontal pathways and corresponding executive function.