Autonomic dysfunction after mild acute ischemic stroke and six months after: a prospective observational cohort study.

INTRODUCTION: Autonomic dysfunction is prevalent in ischemic stroke patients and associated with a worse clinical outcome. We aimed to evaluate autonomic dysfunction over time and the tolerability of the head-up tilt table test in an acute stroke setting to optimize patient care. PATIENTS AND METHOD: In a prospective observational cohort study, patients were consecutively recruited from an acute stroke unit. The patients underwent heart rate and blood pressure analysis during the Valsalva maneuver, deep breathing, active standing, and head-up tilt table test if active standing was tolerated. In addition, heart rate variability and catecholamines were measured. All tests were performed within seven days after index ischemic stroke and repeated at six months follow-up. RESULTS: The cohort was comprised of 91 acute stroke patients, mean (SD) age 66 (11) years, median (IQR) initial National Institute of Health Stroke Scale 2 (1-4) and modified Ranking Scale 2 (1-3). The head-up tilt table test revealed 7 patients (10%) with orthostatic hypotension. The examination was terminated before it was completed in 15%, but none developed neurological symptoms. In the acute state the prevalence of autonomic dysfunction varied between 10-100% depending on the test. No changes were found in presence and severity of autonomic dysfunction over time. CONCLUSION: In this cohort study of patients with mild stroke, autonomic dysfunction was highly prevalent and persisted six months after index stroke. Head-up tilt table test may be used in patients who tolerate active standing. Autonomic dysfunction should be recognized and handled in the early phase after stroke.

Cortical hemodynamic response during cognitive Stroop test in acute stroke patients assessed by fNIRS.

BACKGROUND: Following acute ischemic stroke (AIS) many patients experience cognitive impairment which interferes neurorehabilitation. Understanding and monitoring pathophysiologic processes behind cognitive symptoms requires accessible methods during testing and training. Functional near-infrared spectroscopy (fNIRS) can assess activational hemodynamic responses in the prefrontal cortex (PFC) and feasibly be used as a biomarker to support stroke rehabilitation. OBJECTIVE: Exploring the feasibility of fNIRS as a biomarker during the Stroop Color and Word Test (SCWT) assessing executive function in AIS patients. METHODS: Observational study of 21 patients with mild to moderate AIS and 22 healthy age- and sex-matched controls (HC) examined with fNIRS of PFC during the SCWT. Hemodynamic responses were analyzed with general linear modeling. RESULTS: The SCWT was performed worse by AIS patients than HC. Neither patients nor HC showed PFC activation, but an inverse activational pattern primarily in superolateral and superomedial PFC significantly lower in AIS. Hemodynamic responses were incoherent to test difficulty and performance. No other group differences or lateralization were found. CONCLUSIONS: AIS patients had impaired executive function assessed by the SCWT, while both groups showed an inverse hemodynamic response significantly larger in HC. Investigations assessing the physiology behind inverse hemodynamic responses are warranted before deeming clinical implementation reasonable.