Autonomic neuropathy: the diagnosis

Abstract

The diagnosis of autonomic neuropathy is often difficult to establish, since clinical symptoms generally appear late in the course of the disease, and may be non-specific. A number of recently developed quantifiable and reproducible autonomic nerve function tests are reviewed, with emphasis on the physiological basis of the tests and on practical applicability. Finally, diagnostic criteria, based on autonomic nerve function tests, are suggested.

Signs of Cardiac Autonomic Dysfunction during Sleep in Patients with Alzheimer’s Disease

“…They require considerable collabora tion from the patients and the results can be modified by his or her emotional status. Moreover, many tests are influenced by both the parasympathetic and the sympa thetic system at the same time [14], Finally, some tests may be dangerous for some pa tients, such as the handgrip test for patients with cerebrovascular or cardiac disorders and Valsalva maneuver for patients with diabetic retinopathy. Probably because of these limitations, not much is known at present about ANS function in many neuro logical disorders.…”

“…In recent years autonomic dysfunction has received increasing attention, since it has been recognized as a possible lethal complication in several common disorders, such as diabetes mellitus [7,8,14,31], chronic alcoholism [6] and Parkinson's dis ease [12,23], Autonomic dysfunction may not be suspected at first because the symp toms appear late in the course of a chronic disease and may be subtle, and, therefore, are not recognized, or are disregarded by the patients, who are preoccupied with the longlasting major symptoms of the disease. Since there are at present no direct electrophysiological methods for the assessment of the autonomic nervous system (ANS) func tion available for use in clinical practice, several tests have been proposed for the evaluation of different autonomic functions by investigating reflexes controlled by ANS.…”

Autonomic nervous system dysfunction in Parkinson’s disease

“…• Heart rate increased when standing in normal control individuals, with the maximal heart rate occurring after approximately 15 beats [84], and decreasing by the 30th beat. The ratio between the R-R interval on electrocardiogram at beat 15 and the R-R interval at beat 30 is called the 30 to 15 ratio [84]. Meco et al [87] found significantly reduced ratios in PD patients before and after therapy compared with control individual.…”

“…There were no significant differences in ANS indices between the patients who were treated with levodopa and those who were not. • Heart rate increased when standing in normal control individuals, with the maximal heart rate occurring after approximately 15 beats [84], and decreasing by the 30th beat. The ratio between the R-R interval on electrocardiogram at beat 15 and the R-R interval at beat 30 is called the 30 to 15 ratio [84].…”

“…De novo PD patients generally have impairment of the parasympathetic nervous system, and is evidenced by abnormal cardiovascular reflexes [83]. Tests of parasympathetic nerve function include beat-to-beat variation in heart rate, the 30 to 15 ratio, and the Valsalva ratio [84]. • Variation in heart rate with deep breathing is indicative of parasympathetic influence on cardiovascular dysfunction.…”