Cardiovascular autonomic dysfunction after stroke.

Strokes are the paradigmatic example of the sudden impairment of the cerebral regulation of cardiac autonomic regulation. Although several aspects of dysautonomic cardiovascular regulation post stroke remain unanswered, there has been a wealth of research in this area in the last decade. In this article, we present a state-of-the-art review on the anatomical and functional organization of cardiovascular autonomic regulation, and the pathophysiology, incidence, time course, diagnosis, clinical aspects, prognosis, and management of post-stroke cardiovascular autonomic dysfunction.

Electrodiagnostic assessment of the autonomic nervous system: A consensus statement endorsed by the American Autonomic Society, American Academy of Neurology, and the International Federation of Clinical Neurophysiology.

Evaluation of disorders of the autonomic nervous system is both an art and a science, calling upon the physician's most astute clinical skills as well as knowledge of autonomic neurology and physiology. Over the last three decades, the development of noninvasive clinical tests that assess the function of autonomic nerves, the validation and standardization of these tests, and the growth of a large body of literature characterizing test results in patients with autonomic disorders have equipped clinical practice further with a valuable set of objective tools to assist diagnosis and prognosis. This review, based on current evidence, outlines an international expert consensus set of recommendations to guide clinical electrodiagnostic autonomic testing.

Abnormal motor unit firing rates in chronic inflammatory demyelinating polyneuropathy.

Objective: Patients with CIDP have impairments, including muscle weakness, that could be consequences of demyelination, conduction block, and eventually axonal loss and denervation, leading to muscle atrophy. Consequently, motor unit (MU) activation of the muscle may be impaired contributing to weakness; but this has not been explored in CIDP.

Methods: MU firing rates were recorded at four levels of voluntary isometric dorsiflexion contractions (25%, 50%, 75% and 100% of maximal voluntary contraction [MVC]) in 8 (6 male, 2 female) patients with CIDP and 7 (4 male, 3 female) controls.

An Evaluation of Heart Rate Variability in Female Youth Soccer Players Following Soccer Heading: A Pilot Study.

Most head impacts in soccer occur from purposeful heading; however, the link between heading and neurological impairment is unknown. Previous work suggests concussion may result in an uncoupling between the autonomic nervous system and cardiovascular system. Accordingly, heart rate variability (HRV) may be a sensitive measure to provide meaningful information regarding repetitive heading in soccer.

Evidence of Impaired Cerebellar Connectivity at Rest and During Autonomic Maneuvers in Patients with Autonomic Failure.

The objective of the current study was to investigate whether patients with neurogenic orthostatic hypotension (NOH) secondary to autonomic failure have impaired functional connectivity between the cerebellum and central autonomic structures during autonomic challenges. Fifteen healthy controls (61 ± 14 years) and 15 NOH patients (67 ± 6 years; p = 0.12) completed the following tasks during a functional brain MRI: (1) 5 min of rest, (2) 5 min of lower-body negative pressure (LBNP) performed at - 35 mmHg, and (3) Three, 15-s Valsalva maneuvers (VM) at 40 mmHg.

Neurogenic orthostatic hypotension impairs information processing speed and attention.

Neurogenic orthostatic hypotension (NOH) is characterized by a drop in systolic blood pressure (SBP) ≥20 mmHg or diastolic blood pressure (DBP) ≥10 mmHg within three minutes of upright posture. NOH is common in the elderly population. This group of individuals is at an increased risk for deficits in multiple cognitive domains such as information processing speed (IPS) and attention.

Reduced brainstem functional connectivity in patients with peripheral autonomic failure.

Autonomic homeostasis is dependent upon several brainstem nuclei, as well as several cortical and subcortical structures. Together, these sites make up, in part, the central autonomic network. Neurogenic orthostatic hypotension (NOH) is a cardinal feature of autonomic failure that occurs due to a failure to increase sympathetic efferent activity in response to postural changes.

The Orthostatic Discriminant and Severity Scale (ODSS): an assessment of orthostatic intolerance.

Purpose: To assess the ability of the Orthostatic Discriminant and Severity Scale (ODSS) to distinguish symptoms of orthostatic intolerance from non-orthostatic symptoms.

Methods: Clinical evaluations and questionnaire responses were collected in 73 healthy controls and 132 patients referred to the Autonomic Disorders Clinic from September 1, 2016, through April 30, 2018, for queries regarding autonomic dysfunction. A receiver operating characteristic (ROC) curve analysis was used to interpret sensitivity and specificity and to determine cutoff scores for symptom assessment.

Cerebellar impairment during an orthostatic challenge in patients with neurogenic orthostatic hypotension.

Objective: Compare activation patterns within the cortical autonomic network in patients with neurogenic orthostatic hypotension (NOH) versus healthy age-matched controls during an orthostatic challenge.

Methods: Fifteen health controls and 15 NOH patients performed 3 Valsalva maneuvers, and 5-min of lower-body negative pressure (LBNP) during a functional brain MRI.

Results: Compared to controls, NOH patients had significantly less activation within the cerebellum during both LBNP and VM.

An updated normative data set from the autonomic reflex screen representative of Southwestern Ontario.

In evaluating autonomic dysfunction, the autonomic reflex screen (ARS) is an established set of standardized tests to evaluate the presence and severity of autonomic dysfunction. Our laboratory previously reported normative data on 121 healthy individuals; however, the sample size in older individuals was reduced compared with other age groups. Therefore, the objective of the current study was to provide updated normative values representative of young, middle-aged, and older individuals from Southwestern Ontario.

Impaired cortical autonomic responses during sympathetic activation in neurogenic orthostatic hypotension characterized by postganglionic autonomic dysfunction.

Neurogenic orthostatic hypotension (NOH) is a cardinal feature of autonomic dysfunction. The cortical autonomic network (CAN) is a network of brain regions associated with autonomic function. Therefore, our objective was to investigate whether impairment of CAN structures is involved in the pathophysiology of NOH.

Reductions in muscle quality and quantity in chronic inflammatory demyelinating polyneuropathy patients assessed by magnetic resonance imaging.

Introduction: Weakness in patients with chronic inflammatory demyelinating polyneuropathy (CIDP) may be caused by decreases in muscle quantity and quality, but this has not been explored.

Methods: Twelve patients with CIDP (mean age 61 years) and 10 age-matched (mean age 59 years) control subjects were assessed for ankle dorsiflexion strength, and two different MRI scans (T1 and T2) of leg musculature.

Results: Isometric strength was 36% lower in CIDP patients compared with controls.

Role of melatonin in blood pressure regulation: An adjunct anti-hypertensive agent.

Cardiovascular diseases account for approximately one-third of all deaths each year. Of this, hypertension accounts for approximately 9.4 million deaths.

Initial validation of symptom scores derived from the orthostatic discriminant and severity scale.

Objective: To develop a scale to quantify and discriminate orthostatic from non-orthostatic symptoms. In the current study, we present validation and reliability of orthostatic and non-orthostatic symptom scores taken from the orthostatic discriminate and severity scale (ODSS).

Methods: Validity and reliability were assessed in participants with and without orthostatic intolerance.

Utility of Time and Frequency Domain Parameters of Heart Rate Variability in the Context of Autonomic Disorders Characterized by Orthostatic Dysfunction.

Purpose: The clinical significance of heart rate variability in the context of autonomic dysfunction continues to be a matter of debate. A consensus is lacking on the best heart rate variability measures for clinical purposes. Therefore, the purpose of this study was to investigate the utility of heart rate variability parameters in healthy versus autonomic dysfunction.

Comparison of Heart Rate Variability Parameters to the Autonomic Reflex Screen in Postural Orthostatic Tachycardia Syndrome and Neurogenic Orthostatic Hypotension.

Purpose: The clinical significance of heart rate variability (HRV) in the context of autonomic dysfunction continues to be a matter of debate. Therefore, the purpose of the current study was to investigate the clinical relevance of HRV in the context of autonomic dysfunction.

Methods: Heart rate variability data from 225 volunteers consisting of controls (n = 166) and patients with mild (n = 25) and severe (n = 34) autonomic dysfunction were retrospectively analyzed.

Pathophysiology and Risk of Atrial Fibrillation Detected after Ischemic Stroke (PARADISE): A Translational, Integrated, and Transdisciplinary Approach.

Background: It has been hypothesized that ischemic stroke can cause atrial fibrillation. By elucidating the mechanisms of neurogenically mediated paroxysmal atrial fibrillation, novel therapeutic strategies could be developed to prevent atrial fibrillation occurrence and perpetuation after stroke. This could result in fewer recurrent strokes and deaths, a reduction or delay in dementia onset, and in the lessening of the functional, structural, and metabolic consequences of atrial fibrillation on the heart.

Management of Supine Hypertension Complicating Neurogenic Orthostatic Hypotension.

Neurogenic orthostatic hypotension (NOH) can be present in a number of disorders, including synucleinopathies, autoimmune disorders, and various genetic disorders. All are characterized by defective norepinephrine release from sympathetic terminals upon standing, resulting in impaired vasoconstriction. NOH is defined as a drop in systolic blood pressure ≥20 mmHg or diastolic blood pressure ≥10 mmHg, or both, within 3 minutes of standing or head up-tilt at a minimum of 60°.

Multi-Domain Assessment of Autonomic Function in Spinal Cord Injury Using a Modified Autonomic Reflex Screen.

The aim of this study was to characterize autonomic lesions in participants with spinal cord injury (SCI; n = 10) using an autonomic reflex screen, incorporating sudomotor, cardiovagal, and sympathetic adrenergic tests, as well as hemodynamic responses to head-up tilt (HUT). Hemodynamic responses were compared to healthy controls (n = 20) and previously published normative cutoffs in order better identify autonomic impairments. Sympathetic skin responses (SSRs), heart rate response to deep breathing (HR), and heart rate and beat-to-beat blood pressure responses to Valsalva maneuver (VM) and HUT were measured.

Electrodiagnostic Characterization of Hereditary Neuropathy With Liability to Pressure Palsies.

Objectives: The study objective was electrodiagnostic characterization of a large cohort of patients with genetically confirmed hereditary neuropathy with liability to pressure palsies (HNPP).

Methods: A retrospective review was conducted on all patients with HNPP seen at the neuromuscular clinic (London, Canada) from 1977 to 2015. Clinical data obtained included patient characteristics, examination findings, and nerve conduction study results.