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PubMed2002

Obesity is not a confounding factor for performing autonomic function tests in individuals with diabetes mellitus.

AIM: Cardiovascular autonomic neuropathy is a serious complication of diabetes mellitus. Previous studies have revealed conflicting results with regard to the role of obesity and its effect on the performance of tests (e.g. RR-variation during deep breathing) for the determination of the presence of cardiovascular autonomic dysfunction. The objective of this study was to determine if obesity affects the performance and the reproducibility of autonomic function tests. METHODS: This cross-sectional study included 159 diabetic individuals. Autonomic function tests included: RR-variation during deep breathing and the Valsalva ratio. These tests were assessed using the ANS2000 ECG Monitor and Respiration Pacer. RR-variation was measured by vector analysis (i.e. mean circular resultant, MCR). Reproducibility of the autonomic function tests was assessed by determining the coefficient of variation (CV) on repeat testing. RESULTS: Using cut-off points to describe normal weight (body mass index (b.m.i.) < or = 25 kg/m(2)), overweight (b.m.i. 25.01-30 kg/m(2)), obese (b.m.i. 30.01-40 kg/m(2)), and morbidly obese (b.m.i. > or = 40.1 kg/m(2)), no difference was found for the MCR, Valsalva ratio, CV of the MCR, or CV of the Valsalva ratio among the various weight levels for individuals with type 1 or type 2 diabetes. CONCLUSIONS: The results of this study indicate that obesity is not a confounding factor in the performance of autonomic function tests. Likewise, the reproducibility of autonomic function testing is not affected by obesity. Assessment of autonomic function is important for obese and non-obese individuals given that reduced RR-variation is associated with exercise intolerance, intraoperative cardiovascular lability and increased risk of mortality.

Adult↗

PubMed2005

Idiopathic REM sleep behavior disorder: toward a better nosologic definition.

REM sleep behavior disorder (RBD) is a parasomnia characterized by a lack of motor inhibition during REM sleep leading to potentially harmful dream-enacting behaviors. RBD affects mainly older men and its prevalence in the general population is estimated to be around 0.5%. RBD may be idiopathic or associated with other neurologic disorders. A strong association between RBD and alpha-synucleinopathies has been recently observed, with the parasomnia often heralding the clinical onset of the neurodegenerative disease. The idiopathic form accounts for up to 60% of the cases reported in the three largest series of patients with RBD. Small clinical follow-up studies revealed that a proportion of these patients will eventually develop a parkinsonian syndrome or a dementia of Lewy bodies type in the years following the RBD diagnosis, while some patients will never show other neurologic signs within several decades from the RBD onset. Recent studies have looked at neurophysiologic and neuropsychological functions in idiopathic RBD and have found evidences of CNS dysfunction during both wakefulness and sleep. An impairment of the cortical activity, specific neuropsychological deficits, and signs of autonomic dysfunction have been observed in a variable proportion of these patients, challenging the concept of idiopathic RBD. Identifying subjects with a high risk of developing a neurodegenerative process may be crucial in order to develop early intervention strategies.

Brain↗

PubMed1985

Plasma pancreatic polypeptide response to insulin-induced hypoglycemia as a marker for defective glucose counterregulation in insulin-dependent diabetes mellitus.

Defective glucose counterregulation occurs in some insulin-dependent diabetic subjects (IDDMs) as a result of a combined deficiency of glucagon (IRG) and epinephrine (EPI) secretion in response to insulin-induced hypoglycemia. To determine whether the deficient glucagon response, the deficient epinephrine response, or both are manifestations of autonomic dysfunction, we used the pancreatic polypeptide (PP) secretory response to insulin-induced hypoglycemia as a marker for autonomic neuropathy. Seven nondiabetic controls and 21 IDDMs were given insulin at 40 mU/kg/h after overnight euglycemia. Eight of the IDDMs had defective counterregulation (-CR), and 13 had adequate counterregulation (+CR) by our previously published criteria. Those with -CR had a blunted EPI (delta EPI = 102 +/- 16 pg/ml; mean +/- SEM) and PP (delta PP = 12 +/- 13 pg/ml) response as compared with controls (delta EPI = 310 +/- 49; delta PP = 498 +/- 43) and IDDMs with +CR (delta EPI = 291 +/- 32; delta PP = 521 +/- 86). In controls, IRG rose by 31 +/- 6 pg/ml; in IDDMs, IRG failed to rise significantly above baseline regardless of counterregulatory status. Although the PP and EPI responses correlated well (r = 0.626, P less than 0.001), the IRG response failed to correlate with either the EPI or the PP response. We conclude that the deficient epinephrine, but not glucagon, secretory response to hypoglycemia in diabetic subjects is a result of autonomic neuropathy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed2001

Atrial natriuretic factor and mitral valve prolapse syndrome.

Mitral valve prolapse (MVP), is the most frequent valvulopathy, although it is difficult to evaluate its incidence since this pathology is often asymptomatic. However, in some patients a rich variety of symptoms such as chest pain, dyspnea, palpitations, syncope, dizziness, panic attacks and autonomic dysfunctions have been found. The pathogenesis of these symptoms, incompletely understood, appears to be multifactorial, related to altered autonomic function, adrenergic responsiveness and to combinations of these factors. In patients with MVP a variety of neuroendocrine anomalies has been found: high epinephrine and norepinephrine plasma levels, altered rennin-angiotensin-aldosteron (RAA) response to volume depletion and orthostatic stimulation, and high plasma levels of atrial natriuretic factor (ANF) especially in hypovolaemic individuals. The role of ANF could be important in the genesis of MVP syndrome, it could contribute to determine: the imbalance between the sympathetic and parasympathetic system, the altered RAA response to orthostatic stimulus, the volemic and venous flow reductions (with a direct action, other than diuretic and natriuretic action). Factors that can determine ANF secretion abnormality in MVP could be: 1) Mitral regurgitation; 2) increased heart rate and the high incidence, in MVP syndrome, of arrhythmias; 3) central nervous system neuroendocrine imbalance; 4) increased catecholamines secretion.

Atrial Natriuretic Factor↗

PubMedDate not supplied

Evaluation in autonomic diabetic neuropathy using a dual-channel self-balancing impedance reactometer. Preliminary study.

The electrodermal reflex to an external acoustic stimulus was determined by means of an original device "'The Neurovegetative Reactometer", as variation of the skin electric resistance delta R/R (recorded on millimetric paper) and latency in the appearance of the response (seconds), in 39 diabetic patients (20 males, 19 females, aged 55 +/- 10 years, and the duration of diabetes of 6 +/- 4 years) with or without clinical neuropathy and, comparatively, in 24 apparently healthy controls. The results showed a statistically significant difference both between the amplitude of the skin electric resistance variation evaluated on millimetric paper (6.77 +/- 4.06 mm versus 22.79 +/- 5.39 mm in the controls, p less than 0.001) and latency (4.29 +/- 1.55 versus 2.49 +/- 0.57 seconds, p less than 0.001). These two parameters reflect quantitatively the skin sympathetic activity in lower limbs. The results obtained recommend neurovegetative reactometry as a practical, non-invasive, rapid and readily applicable method, which is highly technical and sensitive for evaluating autonomic dysfunction in diabetic neuropathy.

Autonomic Nervous System Diseases↗

PubMed1995

Sympathetic skin response: correlation with autonomic and somatic involvement in multiple sclerosis.

The sympathetic skin response (SSR) was studied in 63 multiple sclerosis (MS) patients, 54 with clinical definite and 9 with clinical probable form. The test was recorded from palms and soles and induced by electric stimulus. SSR was abnormal, absent or mildly delayed, in 26 patients (41%). The average score in the Kurtzke Expanded Disability Status Scale was higher in patients with abnormal SSR, showing a positive correlation with the latencies (p < 0.05). When compared to other evoked responses (somatosensory, brainstem auditory and visual evoked potentials), only visual evoked potentials showed a positive correlation (p < 0.05). Among the signs of autonomic dysfunction, bladder impairment was the most frequently associated with altered SSR (p < 0.05). These results could be probably due to the higher incidence of these abnormalities during the course of the disease. It is concluded that SSR is a simple test for a dynamic evaluation of MS, well correlated with the degree of disability, able to detect subclinical lesions in the sympathetic tracts, but with slight localizing value. It has also a low sensitivity for autonomic impairment related only with the bladder dysfunction. These facts exclude the SSR as a primary diagnostic tool in MS.

Adolescent↗

PubMed2004

Heart rate variability and diastolic heart failure.

Diastolic heart failure accounts for up to 40% of patients with congestive heart failure (CHF), and is associated with a better prognosis as compared to patients with systolic dysfunction. Nevertheless, patients with diastolic dysfunction have a significantly higher mortality as compared to the normal population. Reduced heart rate variability (HRV), a marker of autonomic dysfunction, is associated with increased mortality in patients with systolic heart failure. We therefore sought to determine to what extent HRV is altered in a population of patients with diastolic heart failure. Twenty-four hour ambulatory (Holter) recordings were performed in 19 consecutive patients with diastolic heart failure, in 9 patients with systolic heart failure, as well as in 9 healthy volunteers (normal controls). Time and frequency domain HRV variables were obtained for all three groups of patients. Both Time and Frequency domain variables were found to be reduced in both heart failure groups compared to normal controls. When compared with each other, patients with diastolic function had relatively higher values of HRV variables, compared to those with systolic dysfunction (SDNN, Total power, ULF power, all P <or= 0.05). Patients with diastolic dysfunction have reduced HRV, suggesting a disturbed sympathetic-parasympathetic balance. Nevertheless, values for HRV are not as profoundly reduced as in patients with systolic dysfunction. The relative preservation of sympathetic-parasympathetic balance may explain the better prognosis in this patient population.

Analysis of Variance↗

PubMed1984

Orthostatic hypotension. I. Functional and neurogenic causes.

The maintenance of adequate upright BP requires both a baroreceptor-mediated feedback loop and an effective circulating blood volume. Although functional disruptions of these mechanisms are reversible and common, several permanent and often progressive neurologic disorders exist that interfere with necessary reflexes and orthostatic BP control. Multiple system atrophy affects diffuse neurologic systems; autonomic dysfunction causes a failure of peripheral vasoconstriction from defective sympathetic stimulation. Idiopathic orthostatic hypotension is a selective disorder of autonomic nerves; postganglionic neurons cannot release norepinephrine properly and are supersensitive to exogenous pressors. Conversely, excessive sympathetic discharge occurs in sympathicotonic orthostatic hypotension, the pathogenesis and incidence of which are unclear. Any peripheral neuropathy may interfere with sympathetic vasoconstrictor activity and is most commonly seen in diabetes mellitus.

Blood Volume↗

PubMed1994

Autonomic involvement in Guillain-Barré syndrome: a review.

Autonomic neuropathy is an important and common complication of Guillain-Barré syndrome (GBS). Manifestations be present in cardiovascular, sudomotor, gastrointestinal and other systems involving both sympathetic and parasympathetic fibers. Some apparently selective acute autonomic neuropathies may be subvarieties of GBS. Experimental work in animal models, pathological studies of GBS patients, and autonomic function studies have provided some help in the understanding of this complication. In managing GBS patients with autonomic dysfunction there are important practical considerations that can improve their care. In this article we review the literature on autonomic neuropathy in GBS and propose a management scheme to accommodate it in the overall treatment of the neuropathy.

Animals↗

PubMed2002

Myocardial and Pericardial Disease in HIV.

Cardiovascular complications are frequently encountered in the HIV-infected population. Cardiac care providers should implement appropriate preventive, screening, and therapeutic strategies to maximize survival and quality of life in this increasingly treatable, chronic disease. All HIV-infected individuals should undergo periodic cardiac evaluation, including echocardiography, in order to identify subclinical cardiac dysfunction. Left ventricular (LV) dysfunction can result from, or be exacerbated by, a variety of treatable infectious, endocrine, nutritional, and immunologic disorders. Aggressive diagnosis and treatment of these conditions may lead to improvement or even normalization of myocardial function. Endomyocardial biopsy should be considered to direct etiology-specific therapy. Standard measures for the prevention and treatment of congestive heart failure are recommended for HIV-infected patients. Afterload reduction with angiotensin-converting enzyme inhibitors may be indicated for patients with elevated afterload and preclinical LV dysfunction diagnosed by echocardiogram. However, judicious drug selection and titration are necessary in this cohort of patients with frequent autonomic dysfunction, at risk for a number of potentially lethal drug interactions. Carnitine, selenium, and multivitamin supplementation should be considered, especially in those with wasting or diarrhea syndromes. Monthly intravenous immunoglobulin (IVIG) infusions have been demonstrated to preserve LV parameters in HIV-infected children; ventricular recovery has been documented in some children with recalcitrant HIV-related cardiomyopathy following IVIG infusion. We support the use of immunomodulatory therapy in the pediatric population, and look forward to further study into the efficacy and broader application of this approach. Highly active antiretroviral therapy (HAART) may be associated with dyslipidemia and the metabolic syndrome. This should be treated with dietary and possibly with pharmacologic interventions. Drug interactions need to be considered when instituting pharmacologic therapies. Pericardial effusions are often seen in patients with advanced HIV infection. Asymptomatic effusions are most often nonspecific in nature, related to the proinflammatory milieu found in advanced AIDS. Nonspecific effusions are a marker of advanced disease and do not require exhaustive etiologic evaluation. In contrast, large or symptomatic effusions are often associated with infection or malignancy, and warrant thorough investigation and etiology-specific treatment.

Journal Article↗

PubMed1994

Spectral components of short-term RR interval variability in healthy subjects and effects of risk factors.

Cardiac neural control can be estimated by frequency domain characterization of RR interval variations. This technique may become a clinical tool, as autonomic dysfunction is involved in the pathophysiology of sudden cardiac death. The study was designed to investigate 24-h cardiac autonomic control in 104 healthy subjects aged 40-77 years and to evaluate the impact of gender, age, smoking and physical training level. The sympathovagal balance was evaluated by spectral analysis of RR interval oscillations. The square-root of power of the high- (HF; 0.15-0.40) and low-frequency (LF; 0.04-0.15 Hz) bands were considered indexes of the vagal function and of the sympathovagal interaction, respectively. In addition, the precise centre frequency of the LF and HF oscillations was determined. The vagal mediated respiratory-dependent HF oscillation exhibited a clear circadian variation, and obtained the highest power values during sleep. The centre frequency was significantly lower during sleep (0.26 Hz vs 0.28 Hz), probably due to a slower respiratory frequency at night. Values for vagal tone were higher in physically trained subjects throughout the 24-h, and decreased by 13% for every 10-year increase in age; it was also reduced in smokers. The amplitude of the LF oscillation exhibited no clear diurnal variation. The mean LF/HF ratio was 3.1. LF power was much higher in males, was reduced by 15% per 10 year increase in age, and was lower in sedentary and smoking subjects, throughout the 24-h. The mean centre frequency of this component was reduced with advancing age (0.08 to 0.06 Hz from age 40 to 80 years). LF and HF power correlated positively, (r = 0.68), and 46% and 16% of the interindividual variation in LF and HF power, respectively, was explained by the four factors (gender, age, smoking, physical activity). Thus gender, age smoking and physical training level have a significant impact on the power and centre frequency of the HF and LF components. These effects must be addressed in investigations on autonomic balance.

Adult↗

PubMed2005

High prevalence and severity of cardiac autonomic neuropathy in Vietnamese diabetic patients.

AIMS: Malnutrition is frequent in Vietnamese people and may influence cardiac autonomic neuropathy (CAN). The aim of the present study was to investigate cardiac autonomic function in healthy subjects living in Vietnam and the prevalence of CAN in Vietnamese diabetic patients. METHODS: One hundred and five diabetic patients (BMI = 19.8 +/- 0.3 kg/m(2)), 50 Type 1 and 55 Type 2, living in Hué (Vietnam) were selected and compared with 60 non-diabetic healthy Vietnamese controls (BMI = 20.8 +/- 0.2 kg/m(2)) and also European controls. CAN function was evaluated by five standardized tests: three tests for heart rate variations (HRV) which depend mainly on parasympathetic activity, and two tests for blood pressure (BP) response which depend mainly on sympathetic activity. RESULTS: With age taken into account, 41 of the 60 Vietnamese controls had at least mild CAN, as defined by one abnormal test for HRV when compared with the European control series, and 11 of them had two or three abnormal tests. Among the Vietnamese control men, those with abnormal HRV had lower BMI than those without (P = 0.036). Seven Vietnamese controls had postural hypotension and 16 had an abnormal BP response to the handgrip test. Compared with the Vietnamese controls, 71 diabetic patients (67.6%), 40 Type 1 and 31 Type 2, had at least mild CAN, 37 of them had two or three abnormal HRV tests, and 56 diabetic patients (53.3%) had an abnormal BP response to the sympathetic tests. Abnormal HRV were associated with significantly lower BMI, waist and hip circumferences, longer diabetes duration and higher fasting blood glucose. In the logistic regression analyses, abnormal HRV were associated significantly with duration of diabetes and BMI in patients with Type 2 diabetes. CONCLUSIONS: Cardiac autonomic dysfunction is frequent in normal Vietnamese subjects. CAN appears to be a more frequent complication of diabetes in Vietnam than in Western countries and diabetic parasympathetic dysfunction is frequently associated with sympathetic disorders. This confirms the deleterious effect a poor nutritional state has on cardiac autonomic function.

Adult↗

PubMed2000

[Neurological masks of depression (effectiveness of tianeptine)].

40 patients with panic attacks, chronic algesic syndromes (chronic headaches of tension, cardialgias) entered the study. They also had depression of mild or moderate degree. 65% of the patients denied actively disorders of the mood; 80% were sure that they had a severe disease that was difficult to diagnose; most of them doubted the efficiency of therapy with psychotropic preparations. An analysis of the polymorphism of clinical symptomatology of the masked depression revealed in more than half of the patients some combinations of clinical syndromes, such as autonomic dysfunction, algesic manifestations, motivation and insomniac disorders. A structure of panic attacks was characterized by the prevalence of the autonomic symptoms as compared with the anxious ones. All the patients were treated with tianeptine (37.5 mg/day) during six weeks. The therapy was effective in 67.5% of the patients. The study revealed an equal efficiency of the drug in comorbid depressive, anxious and autonomic disorders as well as a good tolerance.

Adult↗

PubMed1995

[Sympathetic denervation of an extremity as a presentation form of apical lung cancer].

We report a 56 years old male patient presenting with a sympathetic denervation of the right upper limb due to an apical lung cancer. Vasomotor paralysis of the limb was objectively documented with a contact termography. The clinical presentation of this patient was unusual, considering that the alteration occurred without sensory or motor changes of the limb or autonomic disturbances of the face. The absence of clinical and neurophysiological involvement of large and small caliber fibres of the brachial plexus and the lack of autonomic dysfunction of the face was explained by a predominant tumoral infiltration of T2 and T4 ventral roots, which supply autonomic innervation to the upper limbs.

Adenocarcinoma↗

PubMed1992

Heart rate and plasma norepinephrine responsivity to orthostatic challenge in anxiety disorders. Comparison of patients with panic disorder and social phobia and normal control subjects.

Heart rate and plasma norepinephrine responsivity to a physiologic challenge, ie, orthostasis, were measured in 20 patients with panic disorder (PD) and 20 age- and sex-matched normal control subjects. While the two groups exhibited similar supine heart rates, patients with PD had a significantly greater heart rate response to orthostatic challenge. Plasma norepinephrine responses did not differ between patients with PD and normal control subjects. In a matched subgroup of 14 patients with PD, 14 normal control subjects, and 14 patients with social phobia, the patients with social phobia exhibited supine and upright plasma norepinephrine levels that were significantly higher than those of the other two diagnostic groups. Taken together, and in the context of findings from other studies, these preliminary observations suggest that the anxiety disorders may demonstrate differing patterns of autonomic dysfunction.

Adult↗

PubMed1995

Sympathetic skin response in Guillain-Barré syndrome.

Dysautonomia is a common feature of Guillain-Barré (GB) syndrome and is sometimes the cause of significant morbidity and death. Changes in sympathetic skin response (SSR) may be one of the accompaniments of dysautonomia. An attempt was made to correlate SSR changes with clinical and electrophysiologic features in a group of 24 patients with GB syndrome fulfilling NINDS (National Institute of Neurological Disorders and Stroke) criteria. A total of nine patients had absent SSR. Thirteen patients had clinical dysautonomia, of whom five had absent SSR. Five patients had features of predominant axonal damage and preserved SSR. A trend towards correlation of SSR abnormalities with common peroneal nerve conduction parameters (velocity and compound muscle action potential amplitude) was noted. We conclude that SSR abnormalities are common in GB syndrome and may be complementary to bed-side tests for autonomic dysfunction.

Action Potentials↗

PubMed1995

[Disorders of autonomic regulation in Parkinson syndrome].

Ever since the first description of Parkinson's disease, it has not only been associated with the classical triad of akinesia, rigor and tremor but also with autonomic regulation disorders. However, the studies published on this subject show differing and partly contradictory results. A large number of studies demonstrate a distinct autonomic disorder. On the other hand there are authors who question an affliction of the autonomic nervous system and others who attribute the autonomic disorder to Parkinson specific medication. To make matters worse, the various pathogeneses of Parkinson's syndrome within the patients collectives have not been sufficiently differentiated and nomenclature of the multisystem degeneration was handled in different ways. Taking our examinations of the various autonomic functions and the underlying literature into critical consideration, we come to the conclusion that regulation disorders of the cardiovascular system, gastrointestinal and urinary tract, as well as sweat and thermoregulation are often seen in the idiopathic Parkinson's disease. In our opinion the idiopathic Parkinson's syndrome must be attributed to the multisystem degenerations. Autonomic dysfunction occurs in different intensities in the disease.

Antiparkinson Agents↗

PubMed1989

[Multiple system atrophy: an analytic study of 20 cases].

An analytic study was made on 20 cases of multiple system atrophy. The patients included OPCA 12, SND 3, and SDS 5. This study showed that in 90% of the cases, the symptom began in middle life. Both sexes affected similarly and the mean course was about 5 years. Approximately three years after the appearance of the primary symptom, the features of other central nervous system lesions were presented. Comparative study of clinical features of the three types repealed the following: Cerebellar symptom: OPCA greater than SDS greater than SND. Symptoms and signs of extrapyramidal system: SND greater than SDS greater than OPCA, autonomic dysfunction: SDS greater than OPCA greater than SND.

Adult↗