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PubMed1993

Prevalence and clinical correlates of cardiovascular autonomic and peripheral diabetic neuropathy in patients attending diabetes centers. The Diacan Multicenter Study Group.

The objective of the study was to evaluate the prevalence of and the factors associated with cardiovascular autonomic diabetic neuropathy (CADN) and peripheral neuropathy in patients attending clinical and outpatient diabetes centers. The design was a multicenter cross section study with random selection of patients with Type 1 or Type 2 diabetes from seventeen German, three Swiss, and two Austrian inpatient and outpatient diabetes centers. A total of 1,642 patients were recruited, 1,171 of whom (Type 1: n = 647, age: 11-69 years; Type 2: n = 524, age: 16-72 years) were studied. Measurements and results. The following six autonomic function tests based on heart rate variation were used for the diagnosis of CADN: coefficient of variation and power spectrum in the low- and mid-frequency bands at rest, mean circular resultant during deep breathing, Valsalva ratio, and max/min 30:15 ratio to standing. The age-dependent lower limit of the normal range in these tests had previously been defined at the 2.3 centile in 120 healthy subjects. Definite CADN defined by the strict criterion of abnormal results in > or = 3 of these 6 tests was detected in 16.8% of the Type 1 and 22.1% of the Type 2 diabetic patients (p < 0.05). The corresponding rates of borderline CADN defined as the presence of 2 abnormalities were 8.5% and 12.2%, respectively (p < 0.05). Peripheral neuropathy defined as the presence of > or = 2 abnormalities among 3 criteria (neuropathic symptoms, absent tendon reflexes, and abnormal malleolar vibration perception threshold) was observed in 17.1% of Type 1 and 34.8% of Type 2 diabetic patients (p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Vagal reflexes referred from the upper aerodigestive tract: an infrequently recognized cause of common cardiorespiratory responses.

OBJECTIVE: To review the physiologic basis for normal and abnormal vagal reflexes arising from the pharynx, larynx, and esophagus, as well as the relevance of vagal reflexes to the pathogenesis of such clinically common cardiorespiratory responses as bradycardia, tachycardia, dysrhythmia, coronary angiospasm, bronchospasm, laryngospasm, prolonged apnea, and singultus (hiccups). DATA SOURCES: Pertinent articles and reviews were identified through a MEDLINE search (April 1966 to October 1991). Older studies and others not identified in the MEDLINE search were found through a manual search of the bibliographies of the retrieved articles. STUDY SELECTION: Experimental studies in both humans and animals, as well as case series and single case reports, were selected for evaluation and citation. In instances where a similar phenomenon was described in multiple independent reports, only studies that provided a novel finding or interpretation were cited. More authoritative book chapters and peer-reviewed summaries were also cited in support of commonly accepted principles. DATA EXTRACTION AND SYNTHESIS: Most of the clinical data are derived from case reports and small case series and are therefore anecdotal; equal weight was given to all such studies. Reports of conflicting observations or interpretations were clearly identified and were cited without exception. CONCLUSIONS: Stimulation of the upper aerodigestive tract can lead to clinically significant cardiorespiratory responses. Although the prevalence of and risk factors for such responses have not been established, we suggest that a pharyngeal, a laryngeal, or an esophageal source for abnormal cardiorespiratory responses be sought whenever a detailed clinical evaluation fails to reveal a cause, particularly when there are concurrent symptoms or signs of upper aerodigestive tract disease, such as dysphagia or gastroesophageal reflux.

Cardiovascular System↗
PubMed1989

Impaired reflex response to volume expansion in NaCl-sensitive spontaneously hypertensive rats.

Abnormal baroreceptor reflex function that antedates or is a consequence of NaCl loading could contribute to the NaCl-induced exacerbation of hypertension in NaCl-sensitive spontaneously hypertensive rats (SHR-S). The current study tested the hypothesis that an impairment in cardiopulmonary baroreceptor reflex function exists in SHR-S before NaCl loading. The reflex response to volume expansion was compared in SHR-S, NaCl-resistant SHR (SHR-R), and normotensive Wistar-Kyoto (WKY) and Sprague-Dawley rats maintained on a normal NaCl diet. Conscious, free-moving SHR-S, SHR-R, WKY, and Sprague-Dawley rats were volume expanded with whole blood to 15% of blood volume within 6 minutes, and mean arterial pressure, heart rate, and lumbar sympathetic nerve activity were recorded. Heart rate and lumbar sympathetic nerve activity decreased significantly in SHR-R, WKY, and Sprague-Dawley rats after volume expansion. In contrast, in SHR-S neither heart rate after volume expansion nor lumbar sympathetic nerve activity was significantly different from levels before volume expansion. The blunted reflex response of heart rate and lumbar sympathetic nerve activity to volume expansion suggests impaired cardiopulmonary volume receptor function in SHR-S. This likely contributes to NaCl-induced hypertension in SHR-S on a high NaCl diet.

Animals↗
PubMed1998

Tympanoscopy to increase the accuracy of diagnosis in conductive hearing loss.

The diagnosis of conductive hearing loss is usually based on audiological methods and radiology. The aim of our study was to show that there is a useful additive method to clarify the findings of diseases with conductive hearing loss. Patients (151 ears) with conductive hearing loss were examined using several methods: otomicroscopy, air- and bone-conduction threshold,pure tone average, speech threshold, speech discrimination, tympanometry and stapedial reflex and tympanoscopy. The management of the patients changed in 17 per cent of cases due to tympanoscopy. In a group with normal tympanic membrane the movement of the stapes during endoscopy was compared to stapedial reflex. Stiff stapes were found more often than an abnormal stapedial reflex. Middle ear endoscopy can increase the accuracy of diagnosis of conductive hearing loss thus enhancing decision making in the case of the patient.

Adolescent↗
PubMed1993

[Prenatal and early postnatal motor development and its importance in recognizing developmental disorders].

The normal central nervous system is characterized by both activity and reactivity. Under normal circumstances the former leads the latter. In abnormal conditions reactivity may predominate, usually in the form of reflexes and abnormal postural reactions. Ultrasound registration shows that the first spontaneous motor movements can be seen in the seventh to eighth gestational week. Movement patterns develop fast, and in mid-pregnancy all patterns are observed that can be found in the term newborn baby. During the second half of pregnancy movement patterns are refined: the first differentiation leading to variable and fluent movements. The intrauterine movements are qualitatively more or less similar to those seen in normal preterm babies, the main difference being that the latter as to counteract gravity forces to a greater extent. Qualitative changes of the movement patterns signal deteriorating intrauterine conditions. Stereotyped quality of movement can be a sign of abnormal development. During infancy normal development is characterized by great variability in performance, developmental sequences and relationships. Stereotype performance and strong relationship between the various motor functions, reactions and reflexes should arouse the suspicion that there may be a disturbance in development.

Child, Preschool↗
PubMed1990

Normal proprioceptive trigeminal afferents in patients with Sjögren's syndrome and sensory neuronopathy.

A pure sensory neuropathy due to neuronal damage in the gasserian and spinal ganglia has been described in patients with Sjögren's syndrome. Conventional electromyographic (EMG) studies can demonstrate the selective involvement of the sensory pathways but they do not provide definite evidence for the site of the lesion. Noting that the trigeminal sensory neurons carrying cutaneous and muscular afferents are differentially located in the gasserian and mesencephalic nuclei, respectively, we carried out an electrophysiological study of the trigeminofacial and trigeminotrigeminal reflexes in 5 patients with Sjögren's syndrome and pure sensory neuropathy, in 10 patients with sensory-motor neuropathies of other causes, and in 10 healthy subjects. Our results show that patients with Sjögren's syndrome and pure sensory neuropathy who exhibited abnormal blink reflexes and an abnormal, cutaneous-induced masseter silent period had normal jaw jerks, whereas patients with sensory-motor neuropathies who exhibited abnormal cutaneous responses had abnormal jaw jerks. These findings suggest that the lesion in pure sensory neuropathy involves damage to the neurons of the gasserian ganglia and not to the trigeminal axons, since an axonal lesion would be expected to involve the large axons from muscle spindle receptors.

Adult↗
PubMed1988

The relationship between sleep and sudden infant death.

Infants epidemiologically at high risk for SIDS demonstrate a variety of abnormalities in sleep-state organization, maturation, and sleep-state modulation of cardio-respiratory control mechanisms. These involve both the REM and quiet-sleep states and are seen in twins who have had no evidence of clinical cardio-respiratory compromise during infancy as well as in near-miss infants who have suffered serious cardio-respiratory failure. Although these infants have higher levels of REM sleep around 40 weeks, of special concern is the decrease in the maturation of the quiet system, which becomes evident after 44 weeks, and the reported quiet-sleep abnormalities in reflex control of respiration and arousal. The source of these abnormalities is environmental rather than genetic and most likely occurs prenatally. During the critical period for SIDS, infant sleep begins to coalesce from a series of naps to more prolonged night time sleep periods that last up to 8 hours. We believe that the ability to maintain physiologic homeostasis during prolonged sleep is a challenge facing infants who are epidemiologically at risk for sudden infant death. The challenge facing sleep research is the more complete understanding of the relationship between prolonged inhibition, homeostasis, arousal, and development.

Diseases in Twins↗
PubMed1987

Isolated foveal hypoplasia.

Fifteen patients presented with foveal hypoplasia as an isolated ocular finding. The characteristic findings associated with this entity are a visual acuity of 6/21 or worse, nystagmus, and a typical ophthalmoscopic appearance of the macular area, including absent or abnormal maculofoveal reflexes, unclear definition of the maculofoveal area, and capillaries running abnormally close to the presumed macular area, some of them even crossing the horizontal meridian. Fluorescein angiography revealed a variable and incomplete filtering effect of the choroidal fluorescence in the macular area, suggesting abnormalities in the amount and distribution of macular pigments. The fundal findings of isolated foveal hypoplasia, although typical, are very subtle and often difficult to detect, especially because of the accompanying nystagmus. For this reason we suspect that foveal hypoplasia may be more common than is generally believed.

Adolescent↗
PubMed1979

Respiratory influence on heart rate in diabetes mellitus.

To find a simple and accurate test of autonomic nervous dysfunction in diabetes mellitus, 41 insulin-dependent diabetics and 25 controls were investigated. The diabetics, none of whom had symptoms of autonomic dysfunction, were tested for retinopathy and sensory neuropathy. Each subject also performed maximal deep-breathing procedures while undergoing electrocardiographic recording: in normal subjects the intervals are shortened during inspiration and prolonged during expiration, and a difference in the heart rate between inspiration and expiration of 10% or less seems to indicate autonomic dysfunction. This difference was calculated as an E:I ratio of the mean of the longest R-R interval during maximal expiration to the mean of the shortest during maximal inspiration. Ten of the 18 patients found to have sensory neuropathy had abnormal E:I ratios, and among those with absent ankle reflexes the proportion was even higher (9 out of 11). The E:I ratio also seemed to be as accurate as traditional tests for autonomic dysfunction and easier to perform. Diabetics with autonomic dysfunction have an increased risk of acute cardiorespiratory death during and after surgery, and maximal deep breathing and calculation of the E:I ratio may be a useful test to perform on diabetics at risk.

Adult↗
PubMed1995

Episodic hypertension due to autonomic dysreflexia in acute and chronic spinal cord-injured rats.

Spinal cord injury results in abnormal sympathetic control of the cardiovascular system, consisting of exaggerated reflexes with resulting hypertension and bradycardia that has been termed autonomic dysreflexia. We studied changes in arterial pressure and heart rate caused by colon or urinary bladder distension in unanesthetized acute (7 day) and chronic (30 day) spinal cord-injured rats to evaluate the time course of these responses in an animal model of spinal cord injury. In conscious control rats colon and bladder distension caused brief (2-10 s) pressor responses of 10 mmHg associated with tachycardia and escape reactions. Colon distension in spinal cord-injured rats increased arterial pressure by 41 +/- 2, 22 +/- 3; and 49 +/- 5 mmHg at 24 h and 7 and 30 days after cord transection, respectively. These responses lasted 30 s-5 min and were accompanied by bradycardia. Distension of the urinary bladder caused similar responses in spinal rats after 24 h and 30 days of cord transection. We propose that the initial responses may be related to loss of descending inhibition of spinal reflexes but that plastic changes in the spinal cord is one of the mechanisms for the autonomic dysreflexia occurring 1 mo after injury.

Acute Disease↗
PubMedDate not supplied

[Spasmodic torticollis and vertebral hemangioma].

INTRODUCTION: Spasmodic torticollis in young patients should give rise to a clinical suspicion that this is secondary to another primary disorder. Therefore a series of diagnostic tests should be carried out before it is labelled as idiopathic. CLINICAL CASE: The patient was a thirty year old man who had had difficulty in writing with his right hand since childhood. At the age of 20 years he was diagnosed as having writer's cramp and idiopathic spasmodic torticollis. On general physical examination no abnormalities were found. On neurological examination he had: absence of reflexes of both arms, limited but painless rotation of the neck towards the left and hypertrophy of the left trapezius muscle. Laboratory, neurophysiological and neuroimaging investigations seeking a secondary cause for the torticollis were all normal. There were no Keyser-Fleischer rings. Chest X-ray showed, dorsal scoliosis with convexity to the left. CAT and MR of the spine showed a hemangioma in the body of T1. On arteriography of the supra-aortic and vertebral trunks a hemangioma was found at T1 which received contrast material via a branch of the right thyro-bi-cervico-scapular trunk. Various treatments were tried (diazepam, Botox, Dysport, tetrabenazine, baclofen, etc.) with no improvement. A definite diagnosis of secondary torticollis could not be made since the hemangioma was supplied by a very narrow vascular pedicle, so embolization was contraindicated. CONCLUSION: Cervical spinal cord alterations may cause focal dystonia due to increased excitability of the spinal motor neurone, due to dysfunction of the disinhibitory descending reciprocal paths.

Adult↗
PubMedDate not supplied

Electrophysiological study on jaw-opening reflex recorded from digastric muscle in Parkinson's disease and primary cranial dystonias.

We investigated digastric reflex excitability in normals and in patients with extrapyramidal disorders such as primary cranial dystonias and Parkinson's disease. Relationships between exteroceptive suppression of masseter muscle and digastric reflex were also investigated in some cases. Digastric reflex hyperexcitability was observed in dystonic patients when compared to normals and parkinsonian patients. Furthermore, some patients with cranial dystonia presented absence of exteroceptive suppression reflex in masseter muscle with enlarged digastric response. These results indicate hyperexcitability of the digastric reflex and abnormal agonist-antagonist muscle co-contraction in chewing reflexes of patients with cranial dystonias. This shows that digastric reflex is an important electrophysiological investigation to explore the physiopathological mechanisms of primary cranial dystonias.

Aged↗